A systematic review of longitudinal risk factors for loneliness in older adults

Figures & data

Table 1. Characteristics of included articles.

Reference Overall quality of study	Aim(s)	Study Year of baseline and follow-up(s) Loneliness measure	Geographical setting Sample Subsample for analyses Subsample participant characteristics: age and gender at baseline (unless otherwise stated)	Data collection method Sampling method Response rate Attrition (loss to each wave) Analytic sample size
Aartsen & Jylhä, 2011 Medium	To investigate the impact of baseline levels of a wide range of social and personal resources, and losses in these resources, on the onset of loneliness in older age. Also, to investigate to what extent gender differences can be explained in terms of a differential exposure to risk factors across men and women.	Tampere Longitudinal Study on Aging (TamELSA) 1979; 1989; 1999; 2006 Single item: Do you feel lonely? (often; sometimes; never; don’t know)	Tampere, Finland Sample: 60–89 years Subsample: Not lonely at baseline Age: M = 66.2 (SD = 5.6) Female gender: 53.3%	Face-to-face interviews in 1979, 1989, 1999; telephone interviews in 2006 Random selection from population register, stratified by gender and 5-year birth cohorts Response rate: 82% Attrition rates from wave 1: 3.5%; 57.5%; 93.5% N = 469
Ayalon et al., 2016 Medium	Focused on the association of memory functioning and loneliness in an attempt to identify its temporal order.	The Health and Retirement Study (HRS) 2004; 2008; 2012 Scale: 3-item revised version of the UCLA Loneliness Scale	United States Sample: 50+ years. According to Fisher and Ryan (2018), including spouses of any age and excluding institutionalised individuals Age: M = 65.6 (SE 9.02) Female gender: 59.8%	Self-administrated questionnaire, and face-to-face or telephone interviews Sampling method not stated. According to Fisher and Ryan (2018), multi-stage, national area-clustered probability sample frame of households, with oversampling of Black and Hispanic populations and Florida residents Response rate: approx. 70% Attrition: Not stated N = 1225 (data for loneliness and memory functioning in 2004 and at least one additional measurement point, i.e. 2008, 2012)
Brittain et al., 2017 Medium	To explore the extent to which people aged 85 years are lonely and how loneliness changes between age 85 and 88, as well as the associated risk factors.	The Newcastle 85+ Study 2006, follow-up after 18 and 36 months Single item: Wording not stated (always; often; sometimes; never)	Newcastle, England Sample: 85 years at baseline. Registered with a participating general practice in Newcastle or North Tyneside National Health Service Primary Care Trust Age: 85 years Female gender: 61.3%	Multidimensional health assessment Total population included Response rate: Not stated; calculation based on flow-chart 58.0% Attrition: Not stated. Calculations based on available figures: 21.3%, 21.5% N = 750; 590; 463 (data available for study variables)
Böger & Huxhold, 2018 Medium	To investigate how the interrelationship between loneliness and social integration and that between loneliness and physical health changes as people move from middle adulthood into old age. Also, to investigate the extent to which a person’s level of negative affect may serve as age-differentiated mediator on the pathway that leads from loneliness to impaired physical health.	German Ageing Survey 1996; 2002; 2008; 2011 Scale: 6-item de Jong-Gierveld Scale	Germany Sample: 40–84 years living in the community Age: M = 59.1 (SD = 11.9) Female gender: 49.1%	In-home interviews and self-administrated questionnaires National probability sampling, stratified by gender, place of residence and age group Response rate: Not stated. According to Klaus et al. (2017), 50.3% Attrition: Not stated. According to Klaus et al. (2017), 31.5%; 20.5%; 21.5% N = 11,010 (one valid measure for each of the constructs of interest)
Cacioppo et al., 2010 Medium	To determine the relationship between loneliness and depressive symptoms in a sample of individuals born between 1935 and 1952.	Chicago Health, Aging, and Social Relations Study (CHASRS) (2002/2003; 2003/2004); 2004/2005; 2005/2006; 2006/2007 [Wave 3 onwards is included in this review, as Wave 4 is the first wave with 60+ age group] Scale: 20-item UCLA Loneliness Scale-Revised	Cook County, Illinois, United States Sample: English-speaking; born 1935–1952; non-Hispanic White, African American or non-Black Latino American persons; sufficiently ambulatory to come to the University and participate in the study According to Cacioppo et al., 2017, age at wave 3: M = 59.4 (SD = 4.3) Female gender at wave 3: 54.7%	Psychological and demographic surveys, health and medication interviews, anthropometric measurements, and a cardiovascular protocol Multistage probability design: a) identifying a subset of households estimated to have high probability of containing at least one adult aged 50–65 years. A stratified, equal-probability of selection sample drawn from this subset. Strata: (1) households from census tracts in which at least 80 percent of the residents were African American, (2) households for which the associated surname was identified by the U.S. Census Department as ‘Hispanic’, and (3) all remaining households. b) Selecting one age-eligible individual per household, and screening to include only those who belonged to one of the three racial/ethnic groups of interest and were sufficiently ambulatory to come to the University and participate in the study. Quota sampling strategy used at both the household and individual levels to achieve an approximately equal distribution of participants across the six gender by racial/ethnic group combinations Response rate: approached 45% overall Attrition: On average 7.2% annually (year 1–5) N = 192 (Wave 3); 178; 163; 140; 127; 117; 116; 113
Cacioppo et al., 2017 Medium to low	Our goal in this study was to contrast four competing hypotheses: Hypothesis 1: Loneliness prospectively predicts self-centeredness but self-centeredness does not prospectively predict loneliness. Hypothesis 2: Loneliness does not prospectively predict self-centeredness but self-centeredness prospectively predicts loneliness. Hypothesis 3: Loneliness and self-centeredness may prospectively predict one another. Null Hypothesis: There is no lagged association between loneliness and self-centeredness.	Chicago Health, Aging, and Social Relations Study (CHASRS) (2002/2003; 2003/2004); 2004/2005; 2005/2006; 2006/2007; 2008/2009; 2009/2010; 2010/2011; 2011/2012; 2012/2013 [Wave 3 onwards is included in this review, as Wave 4 is the first wave with 60+ age group] Scale: 20-item Revised UCLA Loneliness Scale	Cook County, Illinois, United States Sample: English-speaking; born 1935–1952; sufficiently ambulatory to come to the University of Chicago for an annual, daylong visit; non-Hispanic White, Blacks/African American or Hispanic. Age at wave 3: M = 59.4 (SD = 4.3) Female gender at wave 3: 54.7%	Survey questionnaire, demographic and psychological surveys, health and medication interviews, anthropometric measurements, physiological assessments, and blood draws. Multistage probability sampling design; oversampling of minorities to ensure approximately equal sample sizes across ethnicities Response rate: Not stated. According to Cacioppo et al. (2010), 45% Attrition: Not stated. According to Cacioppo et al. (2010), on average 7.2% annually (year 1–5) N = 192 (Wave 3); 178; 163; 140; 127; 117; 116; 113
Cohen-Mansfield et al., 2009 Medium	To examine whether loneliness increases with age; characteristics of the lonely older population; and predictors of becoming lonely in old age.	The Cross-Sectional and Longitudinal Aging Study (CALAS) 1989/1992; 1993/1994 Single item: from the 20-item Center for Epidemiologic Studies Depression Scale (CES-D): frequency at which participants had felt lonely during the last month (no; sometimes; most of the time; almost every day)	Israel Sample: Jews 75+ years Subsample: Self-respondent. Non-institutionalised at baseline For total baseline sample (N = 1147) Age: M = 83.1 (SD = 5.32) Female gender: 44.9%	In-home questionnaire-based interviews. Proxy interviews. Random selection from Israeli National Population Register stratified by age groups, gender and place of birth (Europe/America, Middle East/North Africa, Israel) Response rate: 75.8% Attrition: Not stated, calculations based on available figures: 47.2% N = 588 (with data on loneliness for both waves)
Dahlberg et al., 2015 Medium	To examine the extent to which older women and men (70+) report feelings of loneliness with a focus on changes in reported loneliness as people age, and which factors predict loneliness.	Swedish Panel Study of Living Conditions of the Oldest Old (SWEOLD) 2004; 2011 Single item: Are you ever bothered by feelings of loneliness? (nearly always; often; seldom; almost never)	Sweden Sample: 70+ years Age: M = 76.7 (SD = 5.23) Female gender: 61.8%	Telephone interviews in 2004. Primarily face-to-face interviews in 2014 (21.0% telephone interviews). Also proxy interviews (4.8% in 2004; 11.1% in 2011). 1 in 1000 of population. According to Lennartsson et al. (2014), random sample Response rate: 87.3% Attrition: Not stated. Calculations based on available figures: 42.9% N = 587 (with data on loneliness for both waves)
Dahlberg et al., 2018 Medium	The aim of this study was to examine whether there is an association between loneliness in old age and social engagement 20 years earlier.	Swedish Level of Living Survey (LNU) and Swedish Panel Study of Living Conditions of the Oldest Old (SWEOLD) 1981/1991 (pooled); 2002/2011 (pooled) Single item: Are you ever bothered by feelings of loneliness? (nearly always; often; seldom; almost never)	Sweden Sample: Not stated. Calculations based on available figures: 56+ years Age: M = 62.2 Female gender: 59.0%	Structured interviews, primarily face-to-face, also via telephone. 1 in 1000 of population. According to Lennartsson et al. (2014), random sample Response rate: 76.1% in 1981 and 72.7% in 1991 Attrition: Not stated N = 823 (with data on loneliness for both waves)
Deckx et al., 2015 Medium	To study the frequency and evolution of social and emotional loneliness in older cancer patients in comparison with younger cancer patients and older people without cancer, and to evaluate if changes in common cancer-related and ageing-related problems such as fatigue, cognitive functioning and functional status contributed to the occurrence of loneliness.	The KLIMOP study (Dutch acronym for project on older cancer patients in Belgium and Netherlands) Until August 2012, 1-year follow-up Scale: 11-item de Jong-Gierveld Loneliness Scale	Belgium and Netherlands Sample: 50+ year old patients with new diagnosis of breast or coleorectal cancer, and older people without cancer Age: Not stated Female gender: Not stated, calculations based on available figures: 75.4%	Personal interviews or self-administered questionnaires Cancer patients recruited through 7 hospitals in Belgium and Netherlands. Older people without cancer recruited through general practices and home nurses in the same regions. Exclusion of non-Dutch speakers, dementia diagnosis, and estimated life expectancy of < 6 months Response rate: Not stated Attrition: Not stated. Calculations based on available figures: 38.5% N = 422
Donovan et al., 2017 Medium	To examine the reciprocal relations of loneliness and cognitive function in older adults, adjusting for social network, depression and other demographic and health-related factors	Health and Retirement Study (HRS) 1998; 2000; 2002; 2004; 2006; 2008; 2010 Single item from Center for Epidemiologic Studies Depression Scale (CES-D), 8-item version, whether symptom ‘felt lonely’ was present or absent ‘much of the time during the past week’ (present, not present).	United States Sample: 50+ years living in households. According to Fisher and Ryan (2018), including spouses of any age Subsample: Non-Hispanic White and Black participants, age 65+ in 2000 Age M = 73.2 (SD = 6.47) Female gender: 60%	Cognitive and clinical assessments Probability sample. According to Fisher and Ryan (2018), multi-stage, national area-clustered probability sample frame of households, with oversampling of Black and Hispanic populations and Florida residents Response rate: Not stated Attrition: Not stated N = 8382
Dykstra et al., 2005 High	To examine loneliness and its correlates – health, residential care, partner status, and network size – over a seven-year period among adults born between 1908 and 1937.	Living Arrangements and Social Networks of Older Adults (NESTOR-LSN); Longitudinal Aging Study Amsterdam (LASA) 1992; 1992/1993; 1995/1996; 1998/1999 Scale: 11-item de Jong-Gierveld Loneliness Scale	Geographical setting not stated. According to Huisman et al. (2011), three regions in Netherlands Sample: Born 1908–1937 For participants with data on all four waves (N = 1701): Age: M = 66.9 (SD = 8.1) Female gender: 54.6%	Face-to-face interviews Stratified random sample with overrepresentation of the oldest individuals, in particular the oldest men. According to Huisman et al. (2011) and Knipsher, de Jong Gierveld, van Tilburg, and Dykstra (1995), sample recruited from 11 municipal registries in three regions N = 2925 (data for at least two waves) Response rate: 62% Calculations based on figures in Huisman et al. (2011): 18.3%, 18.1%, 18.4%
Gum et al., 2017 Medium	To gather evidence about the potential impacts that hopelessness and loneliness have on each other over time, using longitudinal data from the US HRS and controlling for several covariates of both constructs, including depressive symptoms and medical conditions.	Health and Retirement Study (HRS) 2006; 2010; 2014 Scale: 3-item Revised UCLA Loneliness Scale	United States Sample: 50+ years and their spouses of any age. According to Fisher and Ryan (2018), excluding institutionalised individuals M = 66.0 (SE 0.21) Female gender: 54.7%	Self-administered questionnaire Sampling method not stated. Over-representation of Blacks, Hispanics, and residents of the State of Florida. According to Fisher and Ryan (2018), multi-stage, national area-clustered probability sample frame of households Response rate: Not stated Attrition: Not stated. N = 7831
Hawkley & Kocherginsky, 2018 Medium	To examine protective and risk factors for changes in loneliness.	National Social Life, Health an Aging project (NSHAP) 2005/2006; 2010/2011 Scale: 3-item UCLA Loneliness Scale	United States Sample: Community residing adults born between 1920 and 1947 Age: M = 67.1 (SD = 7.2) Female gender: 52.2%	Interview, leave behind questionnaire Complex, multistage area probability sample with poststratification; oversampling of Blacks, non-Black Hispanics, and the oldest old. According to O’Muircheartaigh, English, Pedlow, and Kwok (2014), based on national household screening carried out by HRS 2004 and 2010 cohorts. Response rate: Not stated. According to O’Muircheartaigh et al. (2014): 75.5% Attrition: Not stated, calculation based on available figures: 24.8% N = 2261
Hoogendijk, Suanet, Dent, Deeg, & Aartsen, 2016 Medium	To examine the association between physical frailty and social functioning among older adults, both cross-sectionally and prospectively over 3 years. Social functioning included network size, instrumental and emotional support received, and loneliness, which cover both structural and functional aspects of social networks.	Longitudinal Aging Study Amsterdam (LASA) 2005/2006; 2008/2009 Scale: 11-item de Jong-Gierveld Loneliness Scale	Netherlands Sample: 55–85 years Subsample: People aged 65 years or older M = 74.0 (SD = 6.6) Female gender: 54.2%	In-home face-to-face main interview, separate medical interview including medical tests Sampling method not stated. According to Huisman et al. (2011) and Knipsher et al. (1995), stratified random sample recruited from 11 municipal registries in three regions, with overrepresentation of the oldest individuals, in particular older men. Response rate: Not stated. Calculations based on available figures: 80.6% Attrition: Not stated. Calculation based on available figures: 23.2% N = 856
Houtjes et al., 2014 Medium to low	To investigate whether the course of late-life depression impacts network size and perceived loneliness, taking into account gender and age of the respondents involved.	Longitudinal Aging Study Amsterdam (LASA) 1992/1993; 1995/1996; 1998/1999; 2001/2002; 2005/2006 Scale: 11-item de Jong-Gierveld Loneliness Scale	Netherlands Sample: >55 years Subsample: Scoring ≥ 16 on Center for Epidemiological Studies Depression Scale (CES-D) Age: M = 71.8 (SD = 8.8) Female gender: 65%	Interviews Sampling method not stated. Stratified for sex, age and level of urbanicity, with oversampling of oldest old and men. According to Huisman et al. (2011) and Knipsher et al. (1995), sample recruited from 11 municipal registries in three regions. Response rate: Not stated. According to Huisman et al. (2011), 85% for total sample. Attrition: Not stated. Calculations based on available figures: 38.2% N = 277 (CES-D data on at least two follow-ups)
Margelisch et al., 2017 Medium	To identify groups of long-term married persons with respect to marital satisfaction and to compare them longitudinally concerning their well-being outcomes, marital stressors, personality and socio-demographic variables.	Study not stated. Sample provided by Federal Office of Statistics 2012; 2014 Scale: 6-item de Jong Gierveld Loneliness Scale	Switzerland Sample: People aged 40–90 years Subsample: Continuously married individuals aged 60–89 and married for 40+ years. Age: M = 74.3 (SD = 7.4) Female gender: Not stated. Calculations based on available figures: 49.7%	Survey Random sample stratified by age, gender and marital status. Response rate: Not stated Attrition: 33% N = 252
Moreh et al., 2010 Medium	To evaluate the association of fatigue with health, functional status, and mortality from ages 70–88 years.	Jerusalem Longitudinal Cohort Study 1990/1991; 1997/1998; 2005/2006 Loneliness measure: Not stated (often or occasionally; never)	Jerusalem, Israel Sample: Jerusalem residents born 1920–1921 Subsample: Not lonely at baseline. Age: 70 years Female gender: Not stated. Calculations based on available figures: 45.7%	Medical and social interviews; medical assessment, system review, and examination Randomly recruited participants from electoral registry, i.e. complete register of Jerusalem residents born 1920–1921. Response rate: Not stated. Calculations based on available figures: 79.7% Attrition: Not stated/unclear. N = Not stated. Calculations based on available figures: N = 178 for 70- to 78-year olds; N = 341 for 78- to 85-year olds
Newall et al., 2009 Medium	To examine older individuals’ causal beliefs about affiliation as immediate and long-term predictors of loneliness.	Aging in Manitoba (Canada) Study 1996; 2001 Scale: de Jong-Gierveld 11-item loneliness scale.	Manitoba, Canada Sample: Manitobans aged 65 years or older Subsample: Community-dwelling Age: M = 78.9 (SD = 4.68) Female gender: Not stated (M = 1.59, SD = .49, with men = 1, women = 2)	Face-to-face interviews Random selection of community-dwelling 65+ in Manitoba, stratified by place of residence (community vs. personal care home) and region. Response rate: Not stated Attrition: Not stated. Calculations based on available figures: 35.8% N = 688
Nicolaisen & Thorsen, 2012 Medium	To examine the extent to which socio-demographic factors, health status and mastery influence loneliness in older adults without impairments and older adults with impairments.	Norwegian Life Course, Ageing and Generation Study (NorLAG) 2002/2003; 2007/2008 Single item: Do you feel lonely? (often; sometimes; seldom; never)	30 municipalities and townships, Norway Sample: People aged 40–79 years living outside institutions Subsample: 67–79 years Age: M = 71.9 (SD = 3.4) for people without impairments, M = 73.2 (SD = 3.7) for people with impairments Female gender: 46% for people without impairments, 72% for people with impairments	Public registries, telephone interviews and postal questionnaires. Sampling method not stated. According to Lappegård and Veenstra (2010), random sample stratified by age, gender, geographical region and centrality of residential municipality Response rate: 67% for telephone interview, of which 75% returned postal questionnaire, i.e. 50.2%. According to Lappegård and Veenstra (2010), 60.0% and 72.5%, respectively. Attrition: 28.4% N = 699
Nicolaisen & Thorsen, 2014 Medium to low	The primary aim of this study is to explore how early and later life events during the life course influence the experience of loneliness for men and women in different age groups.	Norwegian study of the life course, ageing and generations (NorLAG) 2002/2003; 2007/2008 Single item: Do you feel lonely? (often; sometimes; seldom; never)	30 municipalities and townships, drawn from four regions, Norway Sample: People aged 40–80 years not living in institutions For this review, analyses selected for people aged 60–80 years Age: Not stated Female gender: 51%. For older group: Not stated; Calculations based on available figures: 50.6%	Public records, telephone interviews and postal questionnaires. Sample stratified by age and gender. According to Lappegård and Veenstra (2010), random sample, stratified by age, gender, geographical region and centrality of residential municipality Response rate: 67% for telephone interview, of which 75% returned postal questionnaire, i.e. 50.2%. According to Lappegård and Veenstra (2010), 60.0% and 72.5%, respectively. Attrition: 28.4% N = 1352
Pikhartova et al., 2016 Medium to low	To determine if those, who think that old age is time of loneliness and expect that, as they get older, they will become more lonely, report higher rates of loneliness than those who do not support these views.	English Longitudinal Study of Ageing (ELSA) 2004; 2006; 2008; 2010; 2012 Scale: 3-item UCLA Loneliness Scale	England Sample: 50+ years. Living in private address. Subsample: Not lonely at baseline Age: M = 64.1 Female gender: Not stated. Calculations based on available figures: 52.2%	Data collection method not stated. According to Steptoe, Breeze, Banks, and Nazroo (2013), computer-assisted personal interviews and self-completion questionnaires. Drawn from Health Survey for England. According to Steptoe et al. (2013), drawn from 1998, 1999 and 2000 waves of the Health Survey for England (HSE), where at least one person in HSE household must have agreed to follow-up Response rate: Not stated. According to Steptoe et al. (2013), 82% Attrition: Not stated N = 4465
Pronk et al., 2011 Medium	To determine the possible longitudinal relationships between hearing status and depression, and hearing status and loneliness in the older population.	Longitudinal Aging Study Amsterdam (LASA) 2001/2002; 2005/2006 Scale: 11-item de Jong-Gierveld Loneliness Scale	Netherlands Sample: 55–85 years Subsamples: Hearing status based on self-report (SR) and speech-in-noise (SNT) Age: M = 76.4 (SD = 8.0) in SR sample, 73.4 (SD = 6.5) in SNT sample Female gender: 57% in SR sample, 56% in SNT sample	Interviews, test Random sample, stratified for age and gender. According to Huisman et al. (2011) and Knipsher et al. (1995), sample recruited from 11 municipal registries in three regions, with overrepresentation of the oldest individuals, in particular older men. Response rate: Not stated. Attrition: Not stated. Calculations based on available figures: 27.6% N = 996 for SR-sample; N = 830 for SNT-sample
Pronk et al., 2014 Medium	To investigate whether there is an association between the rate of hearing decline and the rate of decrease in psychosocial health (i.e. loneliness and depression) in a population-based sample of older adults; and to investigate whether baseline hearing status, sociodemographic characteristics, and health-related characteristics (age, gender, level of education, level of income, partner status, hearing aid use, comorbid conditions, vision problems, and cognition) moderate this association.	Longitudinal Aging Study Amsterdam (LASA) 2001/2002; 2005/06; 2008/09 Scale: 11-item de Jong-Gierveld Loneliness Scale	Netherlands Sample: 55–85 years Age: median = 72.4 for T1T2 sample; 67.8 for T2T3 sample Female gender: Not stated (value given for multilevel model including repeated measurement of some individuals, so not valid)	In-home measurements Random sample, stratified for age and gender. According to Huisman et al. (2011) and Knipsher et al. (1995), sample recruited from 11 municipal registries in three regions, with overrepresentation of the oldest individuals, in particular older men. Response rate: Not stated. Attrition: Not stated. Calculation based on available figures: 48.2% N = 1178
Rius-Ottenheim et al., 2012 Medium	To investigate the relationship between dispositional optimism and the presence of feelings of loneliness in older men.	Zutphen Elderly Study 1990; 1993; 1995; 2000 Scale: 11-item de Jong Gierveld Loneliness Scale	Zutphen, Netherlands Sample: Older male inhabitants of Zutphen Age: M = 74.9 (SD = 4.7) Female gender: 0%	Face-to-face interviews Sampling method not stated Response rate: 78.0% Attrition: Not stated N = 416
Rouxel et al., 2017 Medium	To examine the cross-sectional and longitudinal associations between oral health-related quality of life (OHRQoL) and loneliness amongst older adults living in England. Also, to examine the contribution of socio-demographic and socio-economic factors, health, smoking, and psychosocial factors in explaining the aforementioned association, and assess if the combination of edentulousness with poor OHRQoL increased the risk of loneliness.	English Longitudinal Study of Ageing (ELSA) 2006/2007; 2010/2011 Scale: 3-item UCLA Loneliness Scale	England Sample: 50+ years. Living in private household. Age: Not stated. Female gender: Not stated. Calculations based on available figures: 52.4%	Face-to-face Computer Assisted Personal Interview (CAPI) and self-completion questionnaires Drawn from Health Survey of England (HSE). According to Steptoe et al. (2013), drawn from 1998, 1999 and 2000 waves of the Health Survey of England (HSE), where at least one person in HSE household must have agreed to follow-up Response rate: Not stated. According to Steptoe et al. (2013), 73% Attrition: Not stated N = 4640
Sutin et al., 2015 Medium	To examine whether discrimination based on eight personal characteristics shares similar or different associations with health outcomes; to test the effect of discrimination on three domains of health – physical, emotional, and cognitive – to examine whether different forms of discrimination have differential associations with these aspects of health; and to test the longitudinal association between discrimination and change in physical, emotional, and cognitive health across four years to examine whether discrimination is associated with changes in health over time.	Health and Retirement Study (HRS) 2006; 2010 Scale: 3-item UCLA Loneliness Scale	United States Sample: 50+ years. According to Fisher and Ryan (2018), including spouses of any age and excluding institutionalised individuals Age: M = 67.5 (SD = 10.6) Female gender: 58.8%	Psychosocial questionnaire completed at home Sampling method not stated. According to Fisher and Ryan (2018), multi-stage, national area-clustered probability sample frame of households, with oversampling of Black and Hispanic populations and Florida residents N = 5507 Response rate: Not stated Attrition: Not stated
Taekema et al., 2010 Medium	To assess if handgrip strength predicts changes in functional, psychological and social health among oldest old.	Leiden 85-plus Study Enrolment 1997–1999; annual follow-ups. Scale: 11-item de Jong Gierveld Loneliness Scale	Leiden, Netherlands Sample: All inhabitants who reached 85 years, including nursing home residents. Age: 85 (M, SD = not stated) Female gender: 65.0%	Recordings at home visits, performance tests, blood sample, electrocardiogram, medical history via general practitioner or nursing home physician Total sample N = 555 Response rate: 87% Attrition: Not stated. Calculations based on available figures: 7.3%
Taube et al., 2013 Medium to low	To investigate the prevalence and predictors of loneliness in older people (aged 78+) over a six year period.	Swedish National Study on Aging and Care (SNAC-B) 2001/2003; 2004/2006; 2007/2009 Single item: Do you ever feel lonely? (never; seldom; sometimes; often)	One municipality in the region of Blekinge, Sweden Sample: People aged 60–96 years Subsample: Aged 78 years or older Age: M = 84.2 (SD = 4.68) Female gender: 59.4%	Structural interviews, medical examinations, supplementary questionnaires Sampling method not stated. Response rate: 61% for total sample Attrition: Not stated. Calculations based on available figures: 33.5%, 38.0% N = 511; 317
Tijhuis et al., 1999 Medium	To analyse to what extent feelings of loneliness are related to age, cohort effects or time trends, and to investigate the relationship between loneliness and changes in situational factors like institutionalization, health and partner status.	Zutphen Elderly Study 1985; 1990; 1995 Scale: 11-item de Jong Gierveld Loneliness Scale	Zutphen, Netherlands Sample: Men born between 1900 and 1920 living in Zutphen Age: M = 72.6 (SD = 5.4) Female gender: 0%	Questionnaire Random selection Response rate: 74% Attrition: Not stated. Calculations based on available figures: 40.4%, 38.7% N = 343
van Baarsen, 2002 Medium	To focus on the role of self-esteem and social support in adjustment to loneliness experienced by bereaved elderly persons, and to examine the contributions of a general and a specific coping theory toward explaining loneliness. A distinction has been made between emotional loneliness and social loneliness/perceived support.	Widowhood Adaptation Longitudinal Study (WALS) Year of baseline and follow-up(s): Not stated, 5 follow-ups with 6- to 7-month interval Scale: 11-item de Jong Gierveld Loneliness Scale	11 municipalities, Netherlands Sample: People aged 55–89 years Subsample: Those who had lost their partner in previous 7 months Age: M = 73 (SD = 8.4) Female gender: Not stated. Calculation based on available figures: 61.3%	Interviews Sampled from the Living Arrangements and Social Networks of Older Adults (NESTOR). According to Huisman et al. (2011) and Knipsher et al. (1995), stratified random sample recruited from 11 municipal registries in three regions in Netherlands, with overrepresentation of the oldest individuals, in particular older men. Response rate: 62% Attrition: Not stated. Calculation based on available figures: 21.1% across the study period N = 111
Warner & Adams, 2016 High	To (1) test the stress deterioration hypothesis by examining whether changes in older adults’ social resources mediate the association between functional limitations and changes in loneliness; (2) to test the stress buffering hypothesis by assessing whether changes in social resources moderate the association between functional limitations and changes in loneliness, where positive social relations may buffer physical disability and negative social relations may exacerbate physical disability; and (3) to evaluate the extent to which the associations identified between functional limitations, changes in social relations, and changes in loneliness differ for married men and women.	National Social Life, Health, and Aging Project (NSHAP) 2005/2006; 2010/2011 Scale: 3-item UCLA Loneliness Scale	United States Sample: Community-dwelling people aged 57–85 years Subsample: Married/partnered at both waves Age: M = 65.9 (SE 0.28) Female gender: 44%	Interviews, leave behind questionnaire Sampling method not stated. According to O’Muircheartaigh et al. (2014), multi-stage area probability sample design, with oversampling of areas with high density of Blacks and Latinos, based on national household screening carried out by HRS 2004 and 2010 cohorts. Response rate: 84% for leave behind questionnaire. For interviews not stated. According to O’Muircheartaigh et al. (2014), 75.5% for total sample. Attrition: 24.8% N = 914
Wong & Waite, 2017 Medium	To test the theory that elder mistreatment leads to declines in health, and that social support buffers its ill effects.	National Social Life, Health, and Aging Project (NSHAP) 2005/2006; 2010/2011 Scale: NSHAP Felt Loneliness Measures, constructed using 3-item UCLA Loneliness Scale	United States Sample: Aged 57–85 According to O’Muircheartaigh et al. (2014), household-resident. Age at follow-up: M = 73 Female gender at follow-up: 52.1%	Interviewer-administered in-home questionnaire, in-home biomeasure collection procedure, a self-administered post-interview/leave-behind questionnaire Multiple-stage probability sampling to randomly select individuals, complex sampling design balancing age and gender but oversampling Blacks and Hispanics. According to O’Muircheartaigh et al. (2014), based on national household screening carried out by HRS 2004 and 2010 cohorts. Response rate: 75.5% Attrition: Not stated. Calculations based on available figures: 24.8% N = 2261
Yang, 2018 Medium	To reveal the patterns of longitudinal loneliness; to test the longitudinal stability of loneliness; and to discover whether the risk factors identified in cross-sectional studies remain statistically significant longitudinally.	English Longitudinal Study of Ageing (ELSA) 2004/2005; 2006/2007; 2008/2009; 2010/2011; 2012/2013 Note: Data seems to be pooled. Scale: 3-item UCLA Loneliness Scale	England Sample: 50+ years. According to Steptoe et al. (2013), living in private households. M = 66.4 (SD = 10.26) Female gender: 55.5%	Data collection method not stated. According to Steptoe et al. (2013), computer-assisted personal interviews and self-completion questionnaires. Sampling method not stated. According to Steptoe et al. (2013), drawn from 1998, 1999 and 2000 waves of the Health Survey of England (HSE), where at least one person in HSE household must have agreed to follow-up Response rate: Not stated. According to Steptoe et al. (2013), 82% Attrition: 20%–40% Sample size: Not stated.

Table 2. Results of risk factors for loneliness.

Risk factor	Bivariate longitudinal association		Multivariable longitudinal association
Demographic factors (n = 3)
1. Age	+	Dahlberg et al., 2015; Newall et al., 2009; Nicolaisen & Thorsen, 2014; Pikhartova et al., 2016	+	Donovan et al., 2017; Dykstra et al., 2005; age squared: Sutin et al., 2015; at T2: Taube et al., 2013
	n.s.	Aartsen & Jylhä, 2011; Cohen-Mansfield et al., 2009	n.s.	Aartsen & Jylhä, 2011; Cacioppo et al., 2017; Dahlberg et al., 2015; Deckx et al., 2015; Hawkley & Kocherginsky, 2018; in married people: Margelisch et al., 2017; Newall et al., 2009; Nicolaisen & Thorsen, 2012, 2014; Sutin et al., 2015; at T1: Taube et al., 2013; in men: Tijhuis et al., 1999; Warner & Adams, 2016
2. Gender (female)	+	Aartsen & Jylhä, 2011; Cohen-Mansfield et al., 2009; Dahlberg et al., 2015; Nicolaisen & Thorsen, 2014; Pikhartova et al., 2016	+	Cohen-Mansfield et al., 2009; Donovan et al., 2017
			−	Dykstra et al., 2005; in married people, for emotional loneliness at T2: van Baarsen, 2002
	n.s.	Newall et al., 2009	n.s.	Aartsen & Jylhä, 2011; Brittain et al., 2017; Cacioppo et al., 2017; Dahlberg et al., 2015; Deckx et al., 2015; Hawkley & Kocherginsky, 2018; in married people: Margelisch et al., 2017; Newall et al., 2009; Nicolaisen & Thorsen, 2012, 2014; Taube et al., 2013; in widows/widowers, for emotional loneliness, T1, T3, for social loneliness all waves: van Baarsen, 2002; Warner & Adams, 2016; Yang, 2018
Gender (direction of coding not specified)			+	Sutin et al., 2015
3. Ethnicity			n.s.	Hawkley & Kocherginsky, 2018; Sutin et al., 2015
(ref. White)
Hispanic			−	Warner & Adams, 2016
			n.s.	Cacioppo et al., 2017
Black			−	Cacioppo et al., 2017
			n.s.	Donovan et al., 2017; Warner & Adams, 2016
Other			n.s.	Warner & Adams, 2016
Socio-economic factors (n = 7)
1. Household income	−	Pikhartova et al., 2016	n.s.	Cacioppo et al., 2017; Warner & Adams, 2016
(ref. High)
Medium to high			+	Donovan et al., 2017
Medium			n.s.	Donovan et al., 2017
Medium to low			n.s.	Donovan et al., 2017
Low			+	Donovan et al., 2017
2. Income-to-needs ratio			n.s.	Hawkley & Kocherginsky, 2018
Financial situation
3. Not having enough money	+	Cohen-Mansfield et al., 2009	+	Cohen-Mansfield et al., 2009
			n.s.	in married people: Margelisch et al., 2017
4. Household assets/wealth			−	Donovan et al., 2017
			n.s.	Hawkley & Kocherginsky, 2018
5. Education	−	Nicolaisen & Thorsen, 2014; Pikhartova et al., 2016	−	Donovan et al., 2017; Sutin et al., 2015
	n.s.	Cohen-Mansfield et al., 2009; Dahlberg et al., 2015; Newall et al., 2009	n.s.	Cacioppo et al., 2017; Dahlberg et al., 2015; Deckx et al., 2015; Hawkley & Kocherginsky, 2018; Newall et al., 2009; Nicolaisen & Thorsen, 2012, 2014; Warner & Adams, 2016
6. Social status	−	Pikhartova et al., 2016
7. Employment status
Employed	−	Pikhartova et al., 2016
			n.s.	Hawkley & Kocherginsky, 2018
Social factors (n = 58)
1. Marital/partner status
Married/partnered	−	Cohen-Mansfield et al., 2009; Nicolaisen & Thorsen, 2014; Pikhartova et al., 2016	−	Deckx et al., 2015; Dykstra et al., 2005; in people without impairments: Nicolaisen & Thorsen, 2012; Pikhartova et al., 2016; in men: Tijhuis et al., 1999
	n.s.	Aartsen & Jylhä, 2011; Dahlberg et al., 2018	n.s.	Cohen-Mansfield et al., 2009; Dahlberg et al., 2018; Hawkley & Kocherginsky, 2018; in individuals with impairments: Nicolaisen & Thorsen, 2012; Nicolaisen & Thorsen, 2014; Taube et al., 2013
Widowed	+	Dahlberg et al., 2015	+	Dahlberg et al., 2015
2. No. of times previously married			n.s.	Warner & Adams, 2016
3. Length of widowhood
(ref. Not widowed)
1–2 years			n.s.	Brittain et al., 2017
3–4 years			n.s.	Brittain et al., 2017
>5 years			−	Brittain et al., 2017
4. Age when widowed			−	in widows/widowers, for social loneliness at T3: van Baarsen, 2002
			n.s.	in widows/widowers for emotional loneliness all follow-ups, for social loneliness at T1, T2: van Baarsen, 2002
Marital/partner status change			n.s.	Yang, 2018
Becoming widowed	+	Dahlberg et al., 2015	+	Dahlberg et al., 2015; Nicolaisen & Thorsen, 2014
Partner loss, unspecified	+	Aartsen & Jylhä, 2011	+	Aartsen & Jylhä, 2011; Dykstra et al., 2005; in men: Tijhuis et al., 1999
New partner			n.s.	Dykstra et al., 2005
Living arrangement
5. Living alone	+	Newall et al., 2009	+	Brittain et al., 2017; Newall et al., 2009; at T1: Taube et al., 2013
			n.s.	Hawkley & Kocherginsky, 2018; at T2: Taube et al., 2013
6. Household size	−	Pikhartova et al., 2016
7. In residential care			+	Brittain et al., 2017; in men: Tijhuis et al., 1999
			n.s.	Dykstra et al., 2005
Living arrangement change
Entered residential care			+	in men: Tijhuis et al., 1999
			n.s.	Dykstra et al., 2005
Social contacts
8. Social contacts	−	Dahlberg et al., 2015
	n.s.	Dahlberg et al., 2018	n.s.	Dahlberg et al., 2018; Dahlberg et al., 2015
9. Social network			−	Böger & Huxhold, 2018; Donovan et al., 2017; Dykstra et al., 2005
			n.s.	Cacioppo et al., 2010; Hawkley & Kocherginsky, 2018
10. Proportion of kin in network			n.s.	Hawkley & Kocherginsky, 2018
11. Number of close relationships	−	Pikhartova et al., 2016
12. Number of friends			n.s.	Hawkley & Kocherginsky, 2018
13. Having sufficient number of friends			n.s.	Taube et al., 2013
14. Having close friends	n.s.	Aartsen & Jylhä, 2011
15. Number of close family members			n.s.	Hawkley & Kocherginsky, 2018
16. Socialising frequently			n.s.	Hawkley & Kocherginsky, 2018
Social contact change
Social contact reduction	n.s.	Dahlberg et al., 2015	n.s.	Dahlberg et al., 2015
Social network reduction			+	Dykstra et al., 2005
Loss of close friends	+	Aartsen & Jylhä, 2011	n.s.	Aartsen & Jylhä, 2011
Close friends (number)			n.s.	Yang, 2018
Close family members (number)			n.s.	Yang, 2018
17. Close children* (number)			n.s.	Yang, 2018
Relationship quality
18. Positive marital quality/marital satisfaction	−	in married people: Margelisch et al., 2017	−	in married people, for social loneliness: Margelisch et al., 2017; Warner & Adams, 2016
			n.s.	in married people, for emotional loneliness: Margelisch et al., 2017
19. Closeness of non-spousal relationships			n.s.	Hawkley & Kocherginsky, 2018
20. Negative marital quality/marital strain			n.s.	in married people: Margelisch et al., 2017; Warner & Adams, 2016
21. Family strain			n.s.	Hawkley & Kocherginsky, 2018
22. Verbal abuse by family			+	Wong & Waite, 2017
23. Financial abuse by family			n.s.	Wong & Waite, 2017
24. Family and friendship strain			n.s.	Warner & Adams, 2016
25. Friendship strain			+	Hawkley & Kocherginsky, 2018
26. Verbal abuse by non-family			n.s.	Wong & Waite, 2017
27. Financial abuse by non-family			n.s.	Wong & Waite, 2017
Relationship quality change
Reduced closeness to partner			+	Yang, 2018
Positive marital quality			−	Warner & Adams, 2016
Negative marital quality			n.s.	Warner & Adams, 2016
Family and friendship strain			n.s.	Warner & Adams, 2016
Social support
28. Social support			−	Cacioppo et al., 2010
29. Marital support			n.s.	Wong & Waite, 2017
30. Marital support prior to widowhood			−	in widows/widowers, for social loneliness at T3: van Baarsen, 2002
			n.s.	in widows/widowers, for emotional loneliness at all follow-ups, for social loneliness at T1, T2: van Baarsen, 2002
31. Family support			−	Hawkley & Kocherginsky, 2018; Wong & Waite, 2017
32. Friendship support			n.s.	Hawkley & Kocherginsky, 2018; Wong & Waite, 2017
33. Family and friendship support			n.s.	Warner & Adams, 2016
34. Network support			n.s.	in widows/widowers: van Baarsen, 2002
35. Having a best female friend			n.s.	in widows/widowers: van Baarsen, 2002
36. Having a best male friend			+	in widows/widowers, for social loneliness at T3: van Baarsen, 2002
			n.s.	in widows/widowers, for emotional loneliness at all follow-ups, for social loneliness at T2: van Baarsen, 2002
37. Emotional support	−	Dahlberg et al., 2018	−	Dahlberg et al., 2018
	n.s.	Cohen-Mansfield et al., 2009
Social support change
Family and friendship support			n.s.	Warner & Adams, 2016
Value of social support and contact
38. Perceived need of support			+	for widows/widowers, for emotional loneliness: van Baarsen, 2002
			n.s.	for widows/widowers, for social loneliness: van Baarsen, 2002
39. Importance of family contact			−	for widows/widowers, for emotional loneliness at T2: van Baarsen, 2002
			n.s.	for widows/widowers, for emotional loneliness at T3, for social loneliness at T2, T3: van Baarsen, 2002
40. Importance of non-family contact			+	for widows/widowers, for emotional loneliness at T2: van Baarsen, 2002
			n.s.	for widows/widowers, for emotional loneliness at T3, for social loneliness at T2, T3: van Baarsen, 2002
Social activity
41. Social activity	−	Newall et al., 2009	−	Böger & Huxhold, 2018; Dahlberg et al., 2018; Newall et al., 2009
	n.s.	Aartsen & Jylhä, 2011; Dahlberg et al., 2018
42. Membership in organisations and active in neighbourhood	−	Pikhartova et al., 2016
43. Attendance at group meetings			n.s.	Hawkley & Kocherginsky, 2018
44. Attendance at religious services	n.s.	Dahlberg et al., 2018	n.s.	Hawkley & Kocherginsky, 2018
45. Spending last Passover with close friends/relatives	n.s.	Cohen-Mansfield et al., 2009
Social activity change
Reduced social activity	+	Aartsen & Jylhä, 2011	+	Aartsen & Jylhä, 2011
Life events
46. Traumatic	n.s.	Cohen-Mansfield et al., 2009
47. Significant			n.s.	Cacioppo et al., 2010
Childhood
48. Conflict between parents	+	Nicolaisen & Thorsen, 2014
49. Being bullied	+	Nicolaisen & Thorsen, 2014
50. Economic problems in the home	+	Nicolaisen & Thorsen, 2014
Discrimination
51. Age			+	Sutin et al., 2015
52. Weight			+	Sutin et al., 2015
53. Physical disability			+	Sutin et al., 2015
54. Physical appearance			+	Sutin et al., 2015
55. Race			n.s.	Sutin et al., 2015
56. Ancestry			n.s.	Sutin et al., 2015
57. Sex			n.s.	Sutin et al., 2015
58. Sexual orientation			n.s.	Sutin et al., 2015
Health-related factors (n = 23)
Self-perceived health
1. Self-perceived health	−	Cohen-Mansfield et al., 2009; Nicolaisen & Thorsen, 2014; Pikhartova et al., 2016	−	Dykstra et al., 2005; in men: Tijhuis et al., 1999; in widows/widowers at T2, T3: van Baarsen, 2002
	n.s.	Aartsen & Jylhä, 2011	n.s.	Brittain et al., 2017; Cohen-Mansfield et al., 2009; Nicolaisen & Thorsen, 2012; in widows/widowers at T1: van Baarsen, 2002
2. Self-perceived physical health			n.s.	Hawkley & Kocherginsky, 2018
3. Self-perceived health compared to other people the same age	−	Newall et al., 2009
Self-perceived health change
Improved self-perceived health			−	Dykstra et al., 2005
			n.s.	Nicolaisen & Thorsen, 2014; Yang, 2018
Reduction	n.s.	Aartsen & Jylhä, 2011
(ref. Healthy at all times)
Improvement			n.s.	in men: Tijhuis et al., 1999
Reduction			+	in men: Tijhuis et al., 1999
Less healthy at all times			+	in men: Tijhuis et al., 1999
4. Partner’s health			n.s.	in married people: Margelisch et al., 2017
Health conditions
5. Health conditions	+	Newall et al., 2009
			n.s.	Böger & Huxhold, 2018; Donovan et al., 2017
6. Health status			−	Newall et al., 2009
7. Limiting long-standing illness			n.s.	Brittain et al., 2017
8. Co-morbidity	+	Cohen-Mansfield et al., 2009
			n.s.	Cohen-Mansfield et al., 2009
9. Leg pain			+	at T1: Taube et al., 2013
			n.s.	at T2: Taube et al., 2013
10. Cancer stage			n.s.	Deckx et al., 2015
Health conditions change
Limiting long-standing illness			n.s.	Yang, 2018
11. Health-related quality of life			n.s.	Taube et al., 2013
Health-related quality of life change
12. Reduction in at least one area of quality of life due to oral health problems*			+	Rouxel et al., 2017
Cognitive functioning
13. Cognitive functioning			n.s.	Donovan et al., 2017; Taube et al., 2013; in men: Tijhuis et al., 1999
14. Memory functioning	−	Ayalon et al., 2016	−	Ayalon et al., 2016
Change in cognitive functioning
(ref. Not impaired)
Was impaired			n.s.	Deckx et al., 2015
Became impaired			+	Deckx et al., 2015
Persistently impaired			+	Deckx et al., 2015
15. Frailty
(ref. Not frail)
Pre-frail			n.s.	Hoogendijk et al., 2016
Frail			+	Hoogendijk et al., 2016
Functional limitation
16. Activities of daily living (ADL) limitations			+	Hawkley & Kocherginsky, 2018; Warner & Adams, 2016
17. Instrumental activities of daily living (IADL) limitations	+	Newall et al., 2009
	n.s.	Cohen-Mansfield et al., 2009	n.s.	Newall et al., 2009
18. ADL and IADL limitations			+	Dykstra et al., 2005
	n.s.	Aartsen & Jylhä, 2011	n.s.	Deckx et al., 2015; Taube et al., 2013; in men: Tijhuis et al., 1999
(ref. No limitations)
Low ADL and IADL limitations			+	Brittain et al., 2017
Medium ADL and IADL limitations			n.s.	Brittain et al., 2017
High ADL and IADL limitations			n.s.	Brittain et al., 2017
19. Mobility problems	+	Dahlberg et al., 2015
			n.s.	Dahlberg et al., 2015
Functional limitation change
Increase in ADL and IADL limitations	+	Aartsen & Jylhä, 2011	+	Dykstra et al., 2005
			n.s.	Aartsen & Jylhä, 2011
Mobility problems	n.s.	Dahlberg et al., 2015	n.s.	Dahlberg et al., 2015
20. Handgrip strength			n.s.	Taekema et al., 2010
21. Fatigue	+	Moreh et al., 2010	+	in people aged 85 at follow-up: Moreh et al., 2010
			n.s.	in people aged 78 at follow-up: Moreh et al., 2010; Taube et al., 2013
Fatigue change
(ref. Not fatigued)
Was fatigued			n.s.	Deckx et al., 2015
Became fatigued			n.s.	Deckx et al., 2015
Persistently fatigued			+	Deckx et al., 2015
Hearing status
22. Self-reported			n.s.	Pronk et al., 2011
23. Speech reception			−	for emotional loneliness: Pronk et al., 2011
			n.s.	for social loneliness: Pronk et al., 2011
Hearing status change
Self-reported			n.s.	Taube et al., 2013
Speech reception	n.s.	Pronk et al., 2014	n.s.	Pronk et al., 2014
Psychological factors (n = 29)
1. Self-perceived mental health			−	Warner & Adams, 2016
2. Depression	+	Cacioppo et al., 2017; Cacioppo et al., 2010; Pikhartova et al., 2016	+	Brittain et al., 2017; Donovan et al., 2017
			n.s.	Cacioppo et al., 2017; Cacioppo et al., 2010
Depression change
Remission			−	in people with depression: Houtjes et al., 2014
Fluctuating			n.s.	in people with depression: Houtjes et al., 2014
Chronic			+	in people with depression: Houtjes et al., 2014
3. Depressed mood	+	at T1-4, T6-7: Cacioppo et al., 2017; Dahlberg et al., 2015	+	Dahlberg et al., 2015
	n.s.	Aartsen & Jylhä, 2011; at T5: Cacioppo et al., 2017	n.s.	Cacioppo et al., 2017; Taube et al., 2013
Depressed mood change
Increased depressed mood	+	Aartsen & Jylhä, 2011; Cacioppo et al., 2017; Dahlberg et al., 2015	+	Aartsen & Jylhä, 2011; Dahlberg et al., 2015
4. Anxiety			+	Wong & Waite, 2017
Affect
5. Negative affect			+	Böger & Huxhold, 2018
6. Overall negative mood	n.s.	Cacioppo et al., 2017	n.s.	Cacioppo et al., 2017
7. Hopelessness	+	Gum et al., 2017	+	Gum et al., 2017
8. Feelings of uselessness	n.s.	Aartsen & Jylhä, 2011
9. Nervousness	n.s.	Aartsen & Jylhä, 2011
10. Irritability	n.s.	Aartsen & Jylhä, 2011
Affect change
Increased feelings of uselessness	+	Aartsen & Jylhä, 2011	+	Aartsen & Jylhä, 2011
Increased nervousness	+	Aartsen & Jylhä, 2011	+	Aartsen & Jylhä, 2011
Increased irritability	n.s.	Aartsen & Jylhä, 2011
11. Perceived stress			n.s.	Cacioppo et al., 2010
12. Subjective age (older)	+	Pikhartova et al., 2016
13. Life satisfaction			−	at T1: Taube et al., 2013
			n.s.	at T2: Taube et al., 2013
14. Self-esteem			n.s.	in widows/widowers: van Baarsen, 2002
Personality
15. Openness			−	at T2: Taube et al., 2013
			n.s.	at T1: Taube et al., 2013
16. Extraversion			n.s.	in married people: Margelisch et al., 2017; Taube et al., 2013
17. Neuroticism			+	in married people, for emotional loneliness: Margelisch et al., 2017
			n.s.	Cacioppo et al., 2010; in married people, for social loneliness: Margelisch et al., 2017; Taube et al., 2013
18. Agreeableness			n.s.	Taube et al., 2013
19. Conscientiousness			n.s.	Taube et al., 2013
20. Self-centeredness	+	at T1-3, T6: Cacioppo et al., 2017	+	Cacioppo et al., 2017
	n.s.	at T4-5, T7: Cacioppo et al., 2017
21. Resilience			n.s.	in married people: Margelisch et al., 2017
22. Mastery			−	Nicolaisen & Thorsen, 2012
23. Optimism	−	Rius-Ottenheim et al., 2012	−	Rius-Ottenheim et al., 2012
Causal beliefs for affiliation
24. Effort	−	Newall et al., 2009	−	Newall et al., 2009
25. Context	n.s.	Newall et al., 2009	n.s.	Newall et al., 2009
26. Luck	+	Newall et al., 2009	+	Newall et al., 2009
Perceptions of loneliness
27. Compared to ten years ago
(ref. About the same)
Less lonely			−	Brittain et al., 2017
More lonely			+	Brittain et al., 2017
28. Stereotypes	+	Pikhartova et al., 2016	+	Pikhartova et al., 2016
29. Expectations	+	Pikhartova et al., 2016	+	Pikhartova et al., 2016

Note: + significant positive association (high levels of the factor predict high levels of loneliness); − significant negative association (high levels of the factor predict low levels of loneliness); n.s. non-significant association; T0 baseline, T1 first follow-up, T2 second follow-up etc. regardless of time intervals between waves.

*A change variable is only counted as a unique risk factor where it is the only representation of that factor.

Figure 1. Flowchart of article selection.

Aartsen, M., & Jylhä, M. (2011). Onset of loneliness in older adults: Results of a 28 year prospective study. European Journal of Ageing, 8(1), 31–38. doi:https://doi.org/10.1007/s10433-011-0175-7

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Ayalon, L., Shiovitz-Ezra, S., & Roziner, I. (2016). A cross-lagged model of the reciprocal associations of loneliness and memory functioning. Psychology and Aging, 31(3), 255–261. doi:https://doi.org/10.1037/pag0000075

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Fisher, G. G., & Ryan, L. H. (2018). Overview of the Health and Retirement Study and introduction to the special issue. Work, Aging and Retirement, 4(1), 1–9. doi:https://doi.org/10.1093/workar/wax032

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Brittain, K., Kingston, A., Davies, K., Collerton, J., Robinson, L. A., Kirkwood, T. B. L., … Jagger, C. (2017). An investigation into the patterns of loneliness and loss in the oldest old – Newcastle 85+ Study. Ageing and Society, 37(1), 39–62. doi:https://doi.org/10.1017/S0144686X15001142

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Böger, A., & Huxhold, O. (2018). Do the antecedents and consequences of loneliness change From middle adulthood into old age? Developmental Psychology, 54(1), 181–197. doi:https://doi.org/10.1037/dev0000453

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Klaus, D., Engstler, H., Mahne, K., Wolff, J. K., Simonson, J., Wurm, S., & Tesch-Römer, C. (2017). Cohort profile: The German Ageing Survey (DEAS). International Journal of Epidemiology, 46(4), 1105–1105g. +. doi:https://doi.org/10.1093/ije/dyw326

 PubMed Web of Science ®Google Scholar

Cacioppo, J. T., Hawkley, L. C., & Thisted, R. A. (2010). Perceived social isolation makes me sad: 5-year cross-lagged analyses of loneliness and depressive symptomatology in the Chicago Health, Aging, and Social Relations Study. Psychology and Aging, 25(2), 453–463. doi:https://doi.org/10.1037/a0017216

 PubMed Web of Science ®Google Scholar

Cacioppo, J. T., Chen, H. Y., & Cacioppo, S. (2017). Reciprocal Influences Between Loneliness and Self-Centeredness: A Cross-Lagged Panel Analysis in a Population-Based Sample of African American, Hispanic, and Caucasian Adults. Personality & Social Psychology Bulletin, 43(8), 1125–1135. doi:https://doi.org/10.1177/0146167217705120

 PubMed Web of Science ®Google Scholar

Cohen-Mansfield, J., Shmotkin, D., & Goldberg, S. (2009). Loneliness in old age: Longitudinal changes and their determinants in an Israeli sample. International Psychogeriatrics, 21(6), 1160–1170. doi:https://doi.org/10.1017/S1041610209990974

 PubMed Web of Science ®Google Scholar

Dahlberg, L., Andersson, L., McKee, K. J., & Lennartsson, C. (2015). Predictors of loneliness among older women and men in Sweden: A national longitudinal study. Aging & Mental Health, 19(5), 409–417. doi:https://doi.org/10.1080/13607863.2014.944091

 PubMed Web of Science ®Google Scholar

Lennartsson, C., Agahi, N., Hols-Salén, L., Kelfve, S., Kåreholt, I., Lundberg, O., … Thorslund, M. (2014). Data resource profile: The Swedish Panel Study of Living Conditions of the Oldest Old (SWEOLD). International Journal of Epidemiology, 43(3), 731–738. doi:https://doi.org/10.1093/ije/dyu057

 PubMed Web of Science ®Google Scholar

Dahlberg, L., Andersson, L., & Lennartsson, C. (2018). Long-term predictors of loneliness in old age: Results of a 20-year national study. Aging & Mental Health, 22(2), 190–196. doi:https://doi.org/10.1080/13607863.2016.1247425

 PubMed Web of Science ®Google Scholar

Deckx, L., van den Akker, M., van Driel, M., Bulens, P., van Abbema, D., Tjan-Heijnen, V., … Buntinx, F. (2015). Loneliness in patients with cancer: The first year after cancer diagnosis. Psycho-Oncology, 24(11), 1521–1528. doi:https://doi.org/10.1002/pon.3818

 PubMed Web of Science ®Google Scholar

Donovan, N. J., Wu, Q., Rentz, D. M., Sperling, R. A., Marshall, G. A., & Glymour, M. M. (2017). Loneliness, depression and cognitive function in older US adults. International Journal of Geriatric Psychiatry, 32(5), 564–573. doi:https://doi.org/10.1002/gps.4495

 PubMed Web of Science ®Google Scholar

Dykstra, P. A., van Tilburg, T. G., & de Jong Gierveld, J. (2005). Changes in older adult loneliness: Results from a seven-year longitudinal study. Research on Aging, 27(6), 725–747. doi:https://doi.org/10.1177/0164027505279712

 Web of Science ®Google Scholar

Huisman, M., Poppelaars, J., van der Horst, M., Beekman, A. T. F., Brug, J., van Tilburg, T. G., & Deeg, D. J. H. (2011). Cohort profile: The Longitudinal Aging Study Amsterdam. International Journal of Epidemiology, 40(4), 868–876. doi:https://doi.org/10.1093/ije/dyq219

 PubMed Web of Science ®Google Scholar

Knipsher, C. P. M., de Jong Gierveld, J., van Tilburg, T., & Dykstra, P. A. (Eds.). (1995). Living arrangements and social networks of older adults. Amsterdam: VU University Press.

 Google Scholar

Gum, A. M., Shiovitz-Ezra, S., & Ayalon, L. (2017). Longitudinal associations of hopelessness and loneliness in older adults: Results from the US health and retirement study. International Psychogeriatrics, 29(9), 1451–1459. doi:https://doi.org/10.1017/S1041610217000904

 PubMed Web of Science ®Google Scholar

Hawkley, L. C., & Kocherginsky, M. (2018). Transitions in loneliness among older adults: A 5-year follow-up in the National Social Life, Health, and Aging Project. Research on Aging, 40(4), 365–387. doi:https://doi.org/10.1177/0164027517698965

 PubMed Web of Science ®Google Scholar

O’Muircheartaigh, C., English, N., Pedlow, S., & Kwok, P. K. (2014). Sample design, sample augmentation, and estimation for wave 2 of the NSHAP. The Journals of Gerontology Series B: Psychological Sciences and Social Sciences, 69(Suppl 2), S15–S26. doi:https://doi.org/10.1093/geronb/gbu053

 PubMedGoogle Scholar

Hoogendijk, E. O., Suanet, B., Dent, E., Deeg, D. J. H., & Aartsen, M. J. (2016). Adverse effects of frailty on social functioning in older adults: Results from the Longitudinal Aging Study Amsterdam. Maturitas, 83, 45–50. doi:https://doi.org/10.1016/j.maturitas.2015.09.002

 PubMed Web of Science ®Google Scholar

Houtjes, W., van Meijel, B., van de Ven, P. M., Deeg, D., van Tilburg, T., & Beekman, A. (2014). The impact of an unfavorable depression course on network size and loneliness in older people: A longitudinal study in the community. International Journal of Geriatric Psychiatry, 29(10), 1010–1017. doi:https://doi.org/10.1002/gps.4091

 PubMed Web of Science ®Google Scholar

Margelisch, K., Schneewind, K. A., Violette, J., & Perrig-Chiello, P. (2017). Marital stability, satisfaction and well-being in old age: Variability and continuity in long-term continuously married older persons. Aging & Mental Health, 21(4), 389–398. doi:https://doi.org/10.1080/13607863.2015.1102197

 PubMed Web of Science ®Google Scholar

Moreh, E., Jacobs, J. M., & Stessman, J. (2010). Fatigue, function, and mortality in older adults. Journals of Gerontology Series a-Biological Sciences and Medical Sciences, 65(8), 884–892. doi:https://doi.org/10.1093/gerona/glq064

 Google Scholar

Newall, N. E., Chipperfield, J. G., Clifton, R. A., Perry, R. P., Swift, A. U., & Ruthig, J. C. (2009). Causal beliefs, social participation, and loneliness among older adults: A longitudinal study. Journal of Social and Personal Relationships, 26(2-3), 273–290. doi:https://doi.org/10.1177/0265407509106718

 Web of Science ®Google Scholar

Nicolaisen, M., & Thorsen, K. (2012). Impairments, mastery and loneliness. A prospective study of loneliness among older adults. Norsk Epidemiologi, 22(2), 143–150. doi:https://doi.org/10.5324/nje.v22i2.1560

 Google Scholar

Lappegård, T., & Veenstra, M. (Eds.). (2010). Life-course, generation and gender. LOGG 2007. Field report of the Norwegian Generations and Gender Survey. Oslo: Statistics Norway.

 Google Scholar

Nicolaisen, M., & Thorsen, K. (2014). Loneliness among men and women-a five-year follow-up study . Aging & Mental Health, 18(2), 194–206. doi:https://doi.org/10.1080/13607863.2013.821457

 PubMed Web of Science ®Google Scholar

Pikhartova, J., Bowling, A., & Victor, C. (2016). Is loneliness in later life a self-fulfilling prophecy? Aging & Mental Health, 20(5), 543–549. doi:https://doi.org/10.1080/13607863.2015.1023767

 PubMed Web of Science ®Google Scholar

Steptoe, A., Breeze, E., Banks, J., & Nazroo, J. (2013). Cohort profile: The English Longitudinal Study of Ageing. International Journal of Epidemiology, 42(6), 1640–1648. doi:https://doi.org/10.1093/ije/dys168

 PubMed Web of Science ®Google Scholar

Pronk, M., Deeg, D. J. H., Smits, C., van Tilburg, T. G., Kuik, D. J., Festen, J. M., & Kramer, S. E. (2011). Prospective effects of hearing status on loneliness and depression in older persons: Identification of subgroups. International Journal of Audiology, 50(12), 887–896. doi:https://doi.org/10.3109/14992027.2011.599871

 PubMed Web of Science ®Google Scholar

Pronk, M., Deeg, D. J. H., Smits, C., Twisk, J. W., van Tilburg, T. G., Festen, J. M., & Kramer, S. E. (2014). Hearing loss in older persons: Does the rate of decline affect psychosocial health? Journal of Aging and Health, 26(5), 703–723. doi:https://doi.org/10.1177/0898264314529329

 PubMed Web of Science ®Google Scholar

Rius-Ottenheim, N., Kromhout, D., van der Mast, R. C., Zitman, F. G., Geleijnse, J. M., & Giltay, E. J. (2012). Dispositional optimism and loneliness in older men. International Journal of Geriatric Psychiatry, 27(2), 151–159. doi:https://doi.org/10.1002/gps.2701

 PubMed Web of Science ®Google Scholar

Rouxel, P., Heilmann, A., Demakakos, P., Aida, J., Tsakos, G., & Watt, R. G. (2017). Oral health-related quality of life and loneliness among older adults. European Journal of Ageing, 14(2), 101–109. doi:https://doi.org/10.1007/s10433-016-0392-1

 PubMed Web of Science ®Google Scholar

Sutin, A. R., Stephan, Y., Carretta, H., & Terracciano, A. (2015). Perceived discrimination and physical, cognitive, and emotional health in older adulthood. The American Journal of Geriatric Psychiatry : official Journal of the American Association for Geriatric Psychiatry, 23(2), 171–179. doi:https://doi.org/10.1016/j.jagp.2014.03.007

 PubMed Web of Science ®Google Scholar

Taekema, D. G., Gussekloo, J., Maier, A. B., Westendorp, R. G. J., & de Craen, A. J. M. (2010). Handgrip strength as a predictor of functional, psychological and social health. A prospective population-based study among the oldest old. Age and Ageing, 39(3), 331–337. doi:https://doi.org/10.1093/ageing/afq022

 PubMed Web of Science ®Google Scholar

Taube, E., Kristensson, J., Midlöv, P., Holst, G., & Jakobsson, U. (2013). Loneliness among older people. Results from the Swedish National Study on Aging and Care – Blekinge. The Open Geriatric Medicine Journal, 6(1), 1–10. doi:https://doi.org/10.2174/1874827901306010001

 Google Scholar

Tijhuis, M. A. R., de Jong Gierveld, J., Feskens, E. J. M., & Kromhout, D. (1999). Changes in and factors related to loneliness in older men. The Zutphen Elderly Study. Age and Ageing, 28(5), 491–495. doi:https://doi.org/10.1093/ageing/28.5.491

 PubMed Web of Science ®Google Scholar

van Baarsen, B. (2002). Theories on coping with loss: The impact of social support and self-esteem on adjustment to emotional and social loneliness following a partner's death in later life. The Journals of Gerontology. Series B, Psychological Sciences and Social Sciences, 57(1), S33–S42. doi:https://doi.org/10.1093/geronb/57.1.s33

 PubMed Web of Science ®Google Scholar

Warner, D. F., & Adams, S. A. (2016). Physical disability and increased loneliness among married older adults: The role of changing social relations. Society and Mental Health, 6(2), 106–128. doi:https://doi.org/10.1177/2156869315616257

 PubMed Web of Science ®Google Scholar

Wong, J. S., & Waite, L. J. (2017). Elder mistreatment predicts later physical and psychological health: Results from a national longitudinal study. Journal of Elder Abuse & Neglect, 29(1), 15–42. doi:https://doi.org/10.1080/08946566.2016.1235521

 PubMed Web of Science ®Google Scholar

Yang, K. M. (2018). Longitudinal loneliness and its risk factors among older people in England. Canadian Journal on Aging = La Revue Canadienne du Vieillissement, 37(1), 12–21. doi:https://doi.org/10.1017/s0714980817000526

 PubMedGoogle Scholar