Sociodemographic and behavioural factors associated with body mass index among men and women in Nairobi slums: AWI-Gen Project

Figures & data

Figure 1. A theoretical conceptual framework of risk factors for obesity.

Table 1. Distribution of socio-demographic, behavioural and biological characteristics by sex.

Characteristics	Men	Women
Sociodemographic
Sex	886 (45.6%)	1056 (54.4%)
Mean age (SD*)	48.8 (5.6)	48.3 (5.3)
Marital status
Currently married/Cohabitating	91.2%	46.1%
Never married/Cohabitated	1.5%	6.6%
Divorced/Separated/Widowed	7.3%	47.3%
Mean number of pregnancies (SD)		4.9 (2.5)
Highest level of education
No formal education	3.8%	10.7%
Primary	50.5%	62.8%
Secondary	43.2%	26.1%
Tertiary	2.5%	0.4%
Employment
Employed	97.4%	91.5%
Unemployed	2.6%	8.5%
Household wealth quintile
First quintile	10.6%	13.4%
Second quintile	19.0%	25.0%
Third quintile	23.6%	22.8%
Fourth quintile	19.4%	21.2%
Fifth quintile	27.4%	17.6%
Household density (SD)	2.3 (2.2)	3.2 (2.3)
Behavioural
Tobacco use
Never smoke	46.0%	91.4%
Current smoker	22.8%	2.2%
Former smoker	27.2%	4.9%
Snuff use	3.5%	1.1%
Chewing tobacco use	0.5%	0.4%
Alcohol consumption
Never consumed	29.0%	71.8%
Current non-problematic	19.6%	3.0%
Current problematic	14.2%	2.8%
Former consumer	37.1%	22.4%
Mean MVPA** (minutes per week) (SD)	1966.6 (1780.7)	1566.7 (1669.8)
Mean Sedentary Time (minutes per day) (SD)	872.7 (453.0)	868.9 (452.5)
Mean Sleep (average hours per night) (SD)	7.8 (1.5)	8.0 (1.5)
Diet
Vegetable servings/day, Mean (SD)	3.9 (2.5)	4.3 (2.6)
Fruit servings/day, Mean (SD)	1.5(0.8)	1.5 (0.9)
Bread in slices/day, Mean (SD)	3.0 (2.3)	2.5 (2.0)
Eating-Out or from Vendor/week, Mean times (SD)	2.2 (2.4)	1.5 (1.9)
Number of sugary Drink/week, Mean (SD)	0.8 (2.6)	0.5 (1.1)
Biological
Ethnicity
Kikuyu	26.1%	44.2%
Kamba	21.9%	18.0%
Luhya	22.9%	14.8%
Luo	19.8%	13.4%
Other	9.4%	9.7%
Self-reported diabetes
No	98.0%	96.0%
Yes	2.0%	4.1%
Tested HIV positive
No	94.0%	83.8%
Yes	7.0%	16.2%
Reported tuberculosis infection
No	88.8%	89.3%
Yes	11.2%	10.7%
Menopausal status
Premenopause		43.8%
Perimenopause		17.1%
Postmenopause		39.1%
Outcome variable
Mean height (m) (SD)	1.7 (0.1)	1.6 (0.1)
Mean weight (kg) (SD)	65.7 (12.0)	69.5 (15.5)
Mean BMI*** (kg/m^2)-mean (SD)	22.8 (3.9)	27.6 (6.1)
Median BMI (kg/m^2) (IQR****)	22.2 (21.9, 22.5)	26.9 (26.4, 27.3)
BMI categories
Underweight	11.7%	3.9%
Healthy weight	63.5%	33.1%
Overweight	19.6%	30.9%
Obese	5.1%	32.1%

Notes: *SD- standard deviation, **MVPA-Moderate to Vigorous Physical Activity, ***BMI- Body Mass Index, ****IQR- Interquartile range

Figure 2. Prevalence of overweight and obesity by ethnicity among men and women aged 40–60 years in the Nairobi slums (2015–2016).

Table 2. Factors associated BMI among men and women in Nairobi slums (Univariate analysis).

Characteristics	Men Coefficient (95% CI)	Women Coefficient (95% CI)
Sociodemographic
Age	0.001 (−0.001, 0.003)	0.003 (0.001, 0.006)
Marital status
Never married or co-habited (REF*)
Married/Cohabitating	0.116 (0.026, 0.207)	0.076 (0.022, 0.131)
Divorced/Widowed	0.032 (−0.066, 0.130)	0.019 (−0.035, 0.073)
Highest level of education
No formal education (REF)
Primary	−0.002 (−0.060, 0.056)	0.015 (−0.029, 0.059)
Secondary	0.018 (−0.040, 0.077)	0.020 (−0.028, 0.068)
Tertiary	−0.004 (−0.093, 0.086)	0.047 (−0.171, 0.265)
Employment
Unemployed (REF)
Employed	0.014 (−0.055, 0.083)	0.023 (−0.024, 0.071)
Wealth quintile
First Quintile (REF)
Second Quintile	0.085 (0.045, 0.126)	0.067 (0.024, 0.110)
Third Quintile	0.103 (0.064, 0.142)	0.115 (0.072, 0.159)
Fourth Quintile	0.131 (0.091, 0.172)	0.171 (0.127, 0.215)
Fifth Quintile	0.152 (0.114, 0.190)	0.202 (0.156, 0.248)
Household density (persons/bedrooms)	−0.001 (−0.008, 0.006)	−0.007 (−0.015, 0.001)
Behavioural
Tobacco use
Never smoked (REF)
Current smoker	−0.119 (−0.146, 0.092)	−0.208 (−0.298, −0.119)
Former smoker	−0.004 (−0.030, 0.021)	−0.013 (−0.073, 0.048)
Snuff use	−0.036 (−0.094, 0.023)	−0.025 (−0.149, 0.098)
Chewing tobacco use	−0.086 (-.244, .071)	−0.027 (−0.240, 0.187)
Alcohol use
Never consumed (REF)
Current non-problematic	−0.066 (−0.097, 0.034)	0.033 (−0.045, 0.110)
Current problematic	−0.099 (−0.133, −0.064)	−0.081 (−0.161, −0.002)
Former consumer	−0.003 (−0.030, 0.023)	−0.004 (−0.036, 0.028)
Physical activity
MVPA** (minutes per week)	−0.001(−0.001, 0.001)***	0.001 (−0.001, 0.001)***
Sleep (average hours per night)	−0.014 (−0.021, 0.007)	−0.022 (−0.031, 0.013)
Sedentary Time (minutes per day)	0.003 (0.001, 0.001)***	0.001 (0.001, 0.001)***
Diet
Vegetable intake (servings/week)	0.006 (0.002, 0.011)	0.002 (−0.003, 0.007)
Fruit intake (servings/week)	−0.006 (−0.019, 0.007)	0.010 (−0.005, 0.025)
Bread (slices/week)	0.008 (0.003, 0.013)	0.001(−0.006, 0.007)
Eating-out or from vendor (times/week)	−0.002 (−0.007, 0.002)	−0.002 (−0.009, 0.005)
Sugary drink (number/week)	0.005 (0.001, 0.009)	0.012 (0.0001, 0.024)
Biological
Ethnicity
Kikuyu (REF)
Kamba	−0.016 (−0.047, 0.016)	−0.037 (−0.074, −0.001)
Luo	−0.005 (−0.036, 0.026)	−0.093 (−0.132, −0.053)
Luhya	0.011 (−0.021, 0.044)	−0.076 (−0.116, −0.035)
Others	0.015 (−0.027, 0.057)	−0.070 (−0.116, −0.024)
Self-reported diabetes
No (REF)
Yes	0.113 (0.034, 0.193)	0.071 (0.004, 0.139)
Tested HIV positive
No (REF)
Yes	−0.066 (−0.108, 0.024)	−0.123 (−0.158, −0.088)
Reported tuberculosis infection
No (REF)
Yes	−0.091 (−0.125, 0.056)	−0.107 (−0.149, −0.065)
Number of pregnancies		−0.001 (−0.007, 0.004)
Menopausal status
Pre-menopause (REF)
Peri-menopause		0.006 (−0.032, 0.044)
Menopause		0.007 (−0.022, 0.036)

Notes: *REF- reference group against which other variable categories were compared, **MVPA- Moderate to Vigorous Physical Activity, *** values corrected to 3 decimal places from very low values

Table 3. Factors associated with BMI among men aged 40–60 years in Nairobi slums (2014–2015).

	Model 1		Model 2		Model 3
Characteristics	Coeff	(95% CI)	Coeff	95% CI	Coeff	95% CI
Sociodemographic
Wealth quintile
First Quintile (REF)
Second Quintile	0.074	0.034, 0.115	0.056	0.017, 0.096	0.063	0.020, 0.107
Third Quintile	0.090	0.050, 0.130	0.068	0.030, 0.107	0.063	0.021, 0.104
Fourth Quintile	0.109	0.068, 0.150	0.089	0.049, 0.129	0.083	0.039, 0.126
Fifth Quintile	0.138	0.098, 0.177	0.100	0.061, 0.139	0.092	0.050, 0.133
Behavioural
Tobacco consumption
Never smoked (REF)
Current smoker			−0.084	−0.113,-0.055	−0.087	−0.120, −0.054
Former smoker			0.003	−0.025, 0.030	0.021	−0.010, 0.052
Snuff use			−0.038	−0.096, 0.020	−0.036	−0.098, 0.026
Chewing tobacco use			−0.104	−0.258, 0.050	−0.05	−0.200, 0.100
Diet
Vegetable servings/week			0.001	−0.000, 0.001
Bread slices/week			0.001	0.000, 0.002	0.001	0.001, 0.003
Sugary drinks/week			0.003	−0.001, 0.007
Biological
Self-reported Diabetes					0.099	0.023, 0.175
Tested HIV positive					−0.066	−0.113, −0.019
Reported tuberculosis					−0.082	−0.118, −0.045
R^2	0.075		0.16		0.196
∆R^2			0.074		0.036
F (p-value)	<0.001		<0.001		<0.001
BIC	−702.152		−719.666		−561.063

Notes: Only statistically significant factors in the final model are shown in the table. Other factors included are shown in the models: Model 1: Sociodemographic factors (Age, marital status, wealth index); Model 2: Model 1+ behavioural factors (Smoking, Alcohol, Diet); Model 3: Model 2+ Biological factors (Ethnicity, Diabetes, HIV, Tuberculosis)

Coeff = Coefficients

Table 4. Factors associated with BMI among women aged 40–60 years in Nairobi slums (2014–2015).

	Model 1		Model 2		Model 3
Characteristics	Coeff	95% CI	Coeff	95% CI	Coeff	95% CI
Sociodemographic
Household SES
First Quintile (REF)
Second Quintile	0.061	0.020, 0.103	0.049	0.007, 0.091	0.053	0.008, 0.097
Third Quintile	0.109	0.065, 0.151	0.101	0.058, 0.144	0.089	0.043, 0.135
Fourth Quintile	0.164	0.120, 0.208	0.146	0.103, 0.190	0.131	0.084, 0.177
Fifth Quintile	0.188	0.142, 0.234	0.172	0.126, 0.219	0.144	0.095, 0.193
Behavioural
Tobacco use
Never smoked (REF)
Current smoker			−0.158	−0.246, −0.071	−0.175	−0.264, −0.087
Former smoker			0.013	−0.047, 0.074	0.017	−0.046, 0.079
Snuff use			0.005	−0.114, 0.124	−0.018	−0.140, 0.103
Chewing tobacco use			−0.016	−0.220, 0.188	0.029	−0.250, 0.308
Alcohol consumption
Never consumed (REF)
Current non-problematic			0.075	0.003, 0.148	0.078	0.004, 0.151
Current problematic			−0.017	−0.096, 0.062	−0.028	−0.110, 0.054
Former consumer			0.01	−0.022, 0.041	0.009	−0.024, 0.041
Average sleep time per night			−0.015	−0.023, −0.006	−0.012	−0.021, −0.003
Sedentary time (minutes/day			0.001	0.001, 0.001	0.001	0.001, 0.001
Biological
Ethnicity
Kikuyu (REF)
Kamba					−0.043	−0.079, −0.007
Luo					−0.070	−0.110, −0.030
Luhya					−0.072	−0.113, −0.031
Others					−0.085	−0.131, −0.038
HIV infection					−0.101	−0.138, −0.064
Tuberculosis infection					−0.077	−0.120–0.034
R2	0.104		0.124		0.189
∆R2			0.02		0.065
F (p-value)	<0.001		<0.001		<0.001
BIC	−283.211		−266.763		−240.352

Only statistically significant factors in the final model are shown in the table. Other factors included are shown in the models.Model 1: Sociodemographic factors (Age, marital status, wealth index): Model 2: Model 1+ behavioural factors (Smoking, Alcohol, Diet) Model 3: Model 2+ Biological factors (Ethnicity, Diabetes, HIV, Tuberculosis).