Somatic symptom profiles in the general population: a latent class analysis in a Danish population-based health survey

Figures & data

Table 1 Characteristics of the population

	Na	%a
Age, mean (SD)	50.8 (14.2)	–
Sex
Women	20,025	55.4
Men	16,138	44.6
Symptomsb
Back pain	4072	11.5
Pain in leg/hip/knee	4087	11.5
Neck/shoulder pain	4032	11.4
Stomach pain	1716	4.8
Indigestion	1586	4.4
Nausea	501	1.4
Cold/coughing	2028	5.8
Respiratory distress	1144	3.2
Rapid heartbeat	512	1.4
Chest pain	365	1.0
Tiredness	3832	10.7
Sleeplessness	2089	5.9
Headache	2209	6.2
Dizziness	784	2.2
Urinary incontinence	728	2.0
Urinary retention	229	0.6
Skin rash/itching	1207	3.4
Impaired hearing	1090	3.1
Impaired vision	787	2.2
Chronic diseases
Musculoskeletalc	10,826	30.8
Cardio-metabolicd	6913	19.6
Mentale	3352	9.4
Pulmonaryf	3209	9.1
Self-perceived health
Poor	4549	12.7

Notes: The Regional Health Survey 2006/2007, the Capital Region of Denmark. N=35,122–35,810.

a All presented numbers except age are the frequency (N) and proportion (%) of participants with the given characteristic. For age, the presented numbers are mean (SD).

b Presence of symptom defined as being considerably bothered by the sensation during 14 days preceding the survey; self-reported.

c Arthrosis/arthritis, osteoporosis, and herniated disk; self-reported.

d Angina, diabetes, and hypertension; self-reported;

e Mental disorder, eg, depression and anxiety; self-reported.

f Asthma and chronic bronchitis; self-reported.

Abbreviation: SD, standard deviation.

Table 2 Conditional probabilities of the 19 symptoms given the 10 classes in the LCA model, including class size and expected number of symptoms

Profile label	No symptoms	Few, mixed symptoms	Headache	MS	GI	Fatigue	Pulmonary	MS + GS	MS + GI + GS	All symptoms
Class size	0.740	0.049	0.052	0.068	0.020	0.018	0.015	0.023	0.012	0.004
Expected number of symptoms	0.2	1.7	1.9	2.6	3.0	3.0	3.6	5.8	6.7	11.5
Back pain	0.03	0.09	0.14	0.72	0.13	0.11	0.18	0.81	0.69	0.74
Pain in leg/hip/knee	0.03	0.28	0.05	0.64	0.09	0.08	0.22	0.82	0.68	0.85
Neck/shoulder pain	0.02	0.12	0.34	0.53	0.09	0.20	0.11	0.87	0.77	0.80
Stomach pain	0.01	0.02	0.06	0.03	0.88	0.13	0.10	0.08	0.99	0.75
Indigestion	0.00	0.06	0.03	0.04	0.79	0.08	0.13	0.15	0.80	0.62
Nausea	0.00	0.01	0.04	0.00	0.15	0.07	0.06	0.06	0.23	0.47
Cold/coughing	0.03	0.08	0.18	0.06	0.08	0.08	0.35	0.19	0.13	0.44
Respiratory distress	0.01	0.04	0.02	0.03	0.03	0.01	0.81	0.22	0.16	0.75
Rapid heartbeat	0.00	0.01	0.01	0.00	0.01	0.10	0.25	0.13	0.10	0.59
Chest pain	0.00	0.01	0.01	0.01	0.00	0.04	0.20	0.09	0.09	0.43
Tiredness	0.02	0.18	0.29	0.19	0.27	0.85	0.46	0.67	0.64	0.86
Sleeplessness	0.01	0.13	0.05	0.10	0.13	0.66	0.16	0.46	0.36	0.70
Headache	0.01	0.01	0.48	0.09	0.09	0.23	0.09	0.36	0.32	0.64
Dizziness	0.00	0.06	0.07	0.02	0.03	0.10	0.11	0.22	0.18	0.67
Urinary incontinence	0.00	0.11	0.01	0.03	0.02	0.03	0.08	0.15	0.14	0.47
Urinary retention	0.00	0.04	0.00	0.00	0.01	0.02	0.04	0.04	0.05	0.24
Skin rash/itching	0.01	0.14	0.05	0.04	0.07	0.09	0.13	0.13	0.16	0.41
Impaired hearing	0.01	0.19	0.02	0.04	0.04	0.06	0.09	0.14	0.08	0.44
Impaired vision	0.00	0.10	0.04	0.03	0.04	0.05	0.05	0.16	0.11	0.63

Notes: The table shows the profile label, class size, expected number of symptoms, and conditional probability of the symptoms given the classes. Numbers in bold indicates a symptom probability of >0.30. The profiles are sorted according to number of expected symptoms. The model includes direct effects between rapid heartbeat and chest pain and between urinary incontinence and urinary retention. GS includes headache, tiredness, and sleeplessness. N=36,163.

Abbreviations: GI, gastrointestinal; GS, general symptoms; MS, musculoskeletal.

Table 3 OR for being in the symptom profiles compared to the “no symptoms” profile according to age, sex, and chronic disease

Profile	No symptoms	Few, mixed symptoms	Headache	MS	GI	Fatigue	Pulmonary	MS + GS	MS + GI + GS	All symptoms
Age
OR, per year	1	1.14	0.92	1.03	0.98	0.97	1.05	1.04	1.02	1.03
(95% CI)	(Ref.)	(1.11–1.16)	(0.91–0.93)	(1.03–1.04)	(0.97–0.99)	(0.96–0.98)	(1.04–1.06)	(1.03–1.04)	(1.01–1.03)	(1.02–1.05)
Sex
Women vs men, OR	1	0.9	7.3	1.8	2.6	2.0	0.7	2.1	3.5	1.3
(95% CI)	(Ref.)	(1.9–2.9)	(5.1–10.3)	(1.6–2.0)	(2.1–3.2)	(1.5–2.6)	(0.6–0.9)	(1.7–2.5)	(2.6–4.8)	(0.9–1.9)
Chronic disease
Musculoskeletal, OR	1	8.8	0.9	48.9	1.5	1.2	3.2	17.5	9.5	11.5
(95% CI)	(Ref.)	(6.9–11.3)	(0.7–1.2)	(34.0–70.3)	(1.2–1.9)	(0.9–1.6)	(2.6–4.1)	(13.5–22.8)	(7.2–12.4)	(7.1–18.5)
Cardio-metabolic, OR	1	6.5	0.4	2.5	1.2	1.7	6.4	5.1	3.5	8.1
(95% CI)	(Ref.)	(5.3–7.9)	(0.2–0.6)	(2.2–2.8)	(1.0–1.6)	(1.2–2.3)	(5.0–8.1)	(4.2–6.1)	(2.7–4.4)	(5.3–12.3)
Mental, OR	1	5.8	5.2	3.5	6.8	24.3	7.7	19.9	14.1	33.8
(95% CI)	(Ref.)	(4.5–7.5)	(4.2–6.5)	(2.9–4.2)	(5.4–8.5)	(18.9–31.2)	(5.8–10.1)	(16.3–24.4)	(10.9–18.2)	(22.0–51.9)
Pulmonary, OR	1	2.7	1.9	2.2	1.7	0.7	39.7	5.2	4.6	14.7
(95% CI)	(Ref.)	(2.1–3.5)	(1.5–2.5)	(1.8–2.6)	(1.2–2.3)	(0.3–1.7)	(28.9–54.6)	(4.2–6.5)	(3.4–6.1)	(9.8–22.2)

Notes: The model includes direct effects between rapid heartbeat and chest pain and between urinary incontinence and urinary retention. N=35,188–36,163. GS includes headache, tiredness, and sleeplessness.

Abbreviations: GI, gastrointestinal; GS, general symptoms; MS, musculoskeletal; OR, odds ratio; Ref., reference profile.

Table 4 The probability of poor self-perceived health within each of the 10 symptom profiles

Symptom profiles	Poor self-perceived health
	%	(95% CI)
No symptoms	1.2	(0.9–1.5)
Few, mixed symptoms	35.3	(29.5–41.2)
Headache	14.1	(11.1–17.1)
MS	47.1	(44.1–50.1)
GI	17.7	(13.6–21.8)
Fatigue	52.9	(46.3–59.4)
Pulmonary	68.9	(63.5–74.2)
MS + GS	87.4	(83.1–91.8)
MS + GI + GS	73.3	(67.1–79.5)
All symptoms	91.6	(84.7–98.4)

Notes: The numbers are adjusted for sex, age, and chronic disease. N=33,696. GS includes headache, tiredness, and sleeplessness.

Abbreviations: GI, gastrointestinal; GS, general symptoms; MS, musculoskeletal.

Figure 1 Ten graphs each representing a symptom profile.

Notes: The graph indicates the probability of being considerably bothered by the symptoms given at the X-axis when belonging to the specific symptom profile. The names of the graphs represent the profile labels. The symptoms at the X-axis are sorted according to type/site of the symptom (categories in brackets below the graph). The model includes direct effects between rapid heartbeat and chest pain and between urinary incontinence and urinary retention. GS includes headache, tiredness, and sleeplessness.
Abbreviations: CP, cardiopulmonary; GI, gastrointestinal; GS, general symptoms; MS, musculoskeletal; OS, other symptoms.

Table S1 Model fit statistics for latent class models with 1–15 classes based on data on 19 self-reported symptoms

Number of classes	LL	BICLL	CAICLL	Classification error
1	−121,722	243,664	243,685
2	−107,331	215,093	215,134	0.044
3	−106,073	212,786	212,847	0.068
4	−104,923	210,697	210,778	0.087
5	−104,298	209,655	209,756	0.095
6	−104,080	209,430	209,551	0.099
7	−103,926	209,331	209,472	0.111
8	−103,790	209,270	209,431	0.119
9	−103,657	209,214	209,395	0.123
10	−103,541	209,191	209,392	0.127
11	−103,466	209,252	209,473	0.132
12	−103,409	209,347	209,588	0.144
13	−103,354	209,448	209,709	0.139
14	−103,309	209,567	209,848	0.149
15	−103,260	209,680	209,981	0.140

Note: The model includes direct effects between rapid heartbeat and chest pain and between urinary incontinence and urinary retention.

Abbreviations: BIC, Bayesian Information Criterion; CAIC, Consistent Akaike’s Information Criterion; LL, log likelihood statistics.

Table S2 Classification table for the latent model with 10 classes based on 19 self-reported symptoms

Profiles	No symptoms	MS	Headache	Few, mixed symptoms	MS + GS	GI	Fatigue	Pulmonary	MS + GI + GS	All symptoms	Total
No symptoms	24,617.4	413.9	685.8	818.8	5.7	64.0	80.0	60.2	1.2	0.3	26,747.2
MS	413.9	1417.0	163.4	175.4	177.0	17.6	34.8	25.4	15.5	0.9	2440.8
Headache	685.8	163.4	718.4	104.4	31.3	33.2	89.7	31.2	6.7	0.4	1864.3
Few, mixed symptoms	818.8	175.4	104.4	503.8	27.2	26.8	65.3	46.8	2.7	1.2	1772.4
MS + GS	5.7	177.0	31.3	27.2	483.8	3.0	26.6	28.4	36.3	22.7	841.9
GI	64.0	17.6	33.2	26.8	3.0	493.7	24.9	11.2	46.4	0.6	721.2
Fatigue	80.0	34.8	89.7	65.3	26.6	24.9	288.0	18.5	8.8	1.3	637.9
Pulmonary	60.2	25.4	31.2	46.8	28.4	11.2	18.5	307.8	7.2	3.6	540.5
MS + GI + GS	1.2	15.5	6.7	2.7	36.3	46.4	8.8	7.2	292.4	20.8	437.9
All symptoms	0.3	0.9	0.4	1.2	22.7	0.6	1.3	3.6	20.8	107.2	158.9
Total	26,747.2	2440.8	1864.3	1772.4	841.9	721.2	637.9	540.5	437.9	158.9	36,163.0

Notes: The table shows the cross-tabulation of the true profile membership against the predicted profile membership based on proportional assignment. The shaded diagonal represents those who have been assigned correctly. The model includes direct effects between rapid heartbeat and chest pain and between urinary incontinence and urinary retention. GS includes headache, tiredness, and sleeplessness.

Abbreviations: GI, gastrointestinal; GS, general symptoms; MS, musculoskeletal.

Table S3 Conditional probabilities of the symptoms given the 9 classes in the LCA model based on 13 more commonly measured symptoms including class size and expected number of symptoms

Profile	No symptoms	Headache	Fatigue	MS	GI	CP	MS +GS	MS + GI + GS	All symptoms
Class size	0.773	0.026	0.052	0.078	0.020	0.009	0.026	0.011	0.006
Expected number of symptoms	0.2	2.0	2.0	2.1	2.8	3.8	4.5	6.1	8.4
Back pain	0.02	0.20	0.11	0.61	0.13	0.24	0.84	0.74	0.75
Pain in leg/hip/knee	0.03	0.04	0.14	0.60	0.10	0.30	0.81	0.73	0.78
Neck/shoulder pain	0.03	0.47	0.16	0.44	0.10	0.22	0.91	0.80	0.84
Stomach pain	0.01	0.06	0.09	0.03	0.87	0.13	0.05	0.98	0.60
Indigestion	0.01	0.03	0.07	0.04	0.84	0.15	0.13	0.79	0.47
Nausea	0.00	0.05	0.05	0.00	0.16	0.09	0.04	0.23	0.34
Respiratory distress	0.01	0.02	0.10	0.05	0.05	0.67	0.13	0.17	0.63
Rapid heartbeat	0.00	0.01	0.04	0.00	0.01	0.57	0.04	0.00	0.84
Chest pain	0.00	0.00	0.01	0.01	0.01	0.49	0.02	0.03	0.59
Tiredness	0.02	0.25	0.64	0.14	0.28	0.47	0.63	0.69	0.77
Sleeplessness	0.01	0.04	0.36	0.09	0.14	0.17	0.39	0.38	0.67
Headache	0.02	0.74	0.18	0.04	0.10	0.09	0.35	0.34	0.61
Dizziness	0.00	0.09	0.09	0.02	0.04	0.17	0.15	0.19	0.51

Notes: The table shows the class size, expected number of symptoms, and symptom probability given the classes. Numbers in bold indicate a symptom probability of >0.30. The profiles are sorted according to the number of expected symptoms. The model includes a direct effect between dizziness and nausea. GS includes headache, tiredness, and sleeplessness. N=36,163.

Abbreviations: CP, cardiopulmonary; GI, gastrointestinal; GS, general symptoms; LCA, latent class analysis; MS, musculoskeletal.

Table S4 OR for being in the symptom profiles compared to the healthy profile, based on the LCA on 13 symptoms

Profile	No symptoms	Headache	Fatigue	MS	GI	CP	MS + GS	MS + GI + GS	All symptoms
Age
Average (year)	1	0.93	0.98	1.05	0.98	1.06	1.02	1.02	1.01
(95% CI)	(Ref.)	(0.91–0.94)	(0.98–0.99)	(1.04–1.05)	(0.97–0.99)	(1.04–1.07)	(1.01–1.03)	(1.01–1.03)	(1.00–1.02)
Sex
Women vs men, OR	1	8.6	2.0	1.5	2.6	0.6	2.5	2.8	2.1
(95% CI)	(Ref.)	(5.0–14.7)	(1.7–2.4)	(1.3–1.7)	(2.1–3.2)	(0.4–0.8)	(2.0–3.1)	(2.1–3.7)	(1.5–2.9)
Chronic disease
Musculoskeletal, OR	1	1.3	1.5	114.5	1.5	3.7	14.8	11.3	11.7
(95% CI)	(Ref.)	(1.0–1.6)	(1.2–1.7)	(48.0–273.3)	(1.2–1.9)	(2.8–5.1)	(11.7–18.7)	(8.4–15.2)	(7.8–17.3)
Cardio-metabolic, OR	1	0.3	2.0	3.0	1.4	10.7	3.2	3.2	6.3
(95% CI)	(Ref.)	(0.1–0.6)	(1.7–2.4)	(2.6–3.4)	(1.1–1.7)	(7.5–15.2)	(2.6–3.9)	(2.5–4.1)	(4.5–8.6)
Mental, OR	1	3.0	16.1	2.7	6.1	7.3	15.5	14.9	29.3
(95% CI)	(Ref.)	(2.1–4.3)	(13.6–19.0)	(2.1–3.3)	(4.9–7.6)	(5.1–10.5)	(12.8–18.8)	(11.5–19.2)	(20.8–41.2)
Pulmonary, OR	1	1.2	3.2	2.6	1.8	11.6	3.8	5.1	8.0
(95% CI)	(Ref.)	(0.8–1.9)	(2.6–3.9)	(2.2–3.0)	(1.3–2.4)	(8.6–15.7)	(3.0–4.8)	(3.9–6.7)	(5.7–11.3)

Notes: The model includes a direct effect between dizziness and nausea. N=35,188–36,163. GS includes headache, tiredness, and sleeplessness.

Abbreviations: CP, cardiopulmonary; GI, gastrointestinal; GS, general symptoms; LCA, latent class analysis; MS, musculoskeletal; OR, odds ratio; Ref., reference profile.

Table S5 The probability of poor self-perceived health within each of the 9 symptom profiles based on the LCA on 13 symptoms

Symptom profiles	Poor self-perceived health
	%	(95% CI)
No symptoms	2.0	(1.7–2.2)
Headache	16.9	(12.7–21.1)
Fatigue	45.0	(41.4–48.7)
MS	40.7	(37.9–43.4)
GI	20.5	(16.2–24.8)
CP	65.9	(57.5–74.2)
MS + GS	87.9	(83.7–92.2)
MS + GI + GS	76.0	(70.0–82.1)
All symptoms	84.5	(78.3–90.7)

Notes: The model is adjusted for sex, age, and chronic disease. The model includes a direct effect between dizziness and nausea. N=33,696. GS includes headache, tiredness, and sleeplessness.

Abbreviations: CP, cardiopulmonary; GI, gastrointestinal; GS, general symptoms; LCA, latent class analysis; MS, musculoskeletal.