Lifestyle risk factors, non-communicable diseases and labour force participation in South Africa

Figures & data

Table 1. Definitions and descriptive statistics.

Variables	Definition	Total		Male		Female
		Mean	SD	Mean	SD	Mean	SD
Labour force	Employed or unemployed but not retired or discouraged work seekers	0.704	0.457	0.784	0.412	0.636	0.481
NCDs
Stroke	Diagnosis of stroke	0.008	0.087	0.005	0.073	0.010	0.010
Diabetes	Diagnosis of diabetes	0.035	0.186	0.031	0.173	0.040	0.196
Heart disease	Diagnosis of heart disease	0.020	0.140	0.013	0.112	0.026	0.159
Hypertension	Diagnosis of high blood pressure	0.126	0.332	0.081	0.274	0.165	0.371
Married	Married or living with partner	0.344	0.475	0.336	0.472	0.351	0.477
Age	between 20 and 64 years old	37.058	12.141	36.685	12.014	37.389	12.242
Education
No education	No educational attainment	0.056	0.231	0.049	0.217	0.063	0.242
Primary	Primary completed	0.171	0.376	0.178	0.382	0.165	0.371
Secondary	not completed secondary school	0.414	0.493	0.413	0.492	0.415	0.493
Matric	secondary school completed	0.194	0.396	0.202	0.402	0.187	0.390
Tertiary	University diploma or degree completed	0.165	0.371	0.158	0.365	0.170	0.376
Race
African	African population	0.806	0.395	0.812	0.391	0.802	0.399
Coloureds	Coloureds population	0.097	0.296	0.094	0.292	0.099	0.299
White	White population	0.097	0.295	0.094	0.292	0.099	0.299
Area
Rural formal	Living in rural area	0.066	0.248	0.071	0.256	0.062	0.241
Traditional authority	Living in farm or traditional area	0.273	0.446	0.243	0.429	0.300	0.458
Urban formal	Living in urban formal area	0.559	0.497	0.581	0.493	0.539	0.499
Urban informal	Living in urban informal	0.102	0.303	0.105	0.307	0.099	0.299
Household size	Number of individuals in the household	4.635	3.301	4.050	3.222	5.152	3.284
Risk factors
Obese	BMI is more than or equal to 30	0.394	0.489	0.332	0.471	0.45	0.497
Exercise	(regular physical activity)	0.121	0.326	0.177	0.382	0.074	0.261
Smoking	smoke regularly	0.052	0.221	0.092	0.289	0.029	0.167
Drinking	consume alcohol regularly	0.036	0.186	0.063	0.243	0.013	0.114

Note: Population weighted mean adjusted for national representation using post stratified weights.

Table 2. Probit model of labour force participation and NCDs.

	Labour force	Stroke	Heart diseases	Diabetes	Hypertension
	(I)	(II)	(III)	(IV)	(V)
Stroke	−0.173***
Heart disease	−0.036	0.014***
Diabetes	−0.003	0.003	0.013***
Hypertension	−0.006	0.011***	0.025***	0.065***
Age	0.326***	0.000***	0.001***	0.002***	0.008***
Age squared	−0.418***
Female	ref
Men	0.133***
Not married	ref
Married	0.002
No education	ref
Primary	0.063***
Secondary	0.118***
Matric	0.165***
Tertiary	0.311***
Traditional area	ref
Rural	0.113***
Urban-formal	0.097***
Urban-informal	0.122***
White	ref
Coloured	0.026
African	0.019
Household size	−0.008***
Wave 1	ref
Wave2	−0.129***	−0.003	−0.014***	0.002	−0.040***
Wave3	−0.073***	−0.002	−0.012***	0.005	0.010**
Wave4	−0.055***	−0.002	−0.014***	0.005	−0.023***
Obese		0.000	0.003	0.016***	0.075***
Exercise		−0.006**	0.006*	−0.001	−0.008
Smoking		−0.001	0.003	0.011	0.014*
Drinking		−0.014***	−0.030***	−0.009	−0.016
Constant	−1.096***	−0.055***	−0.112***	−0.237***	−0.568***
Wald χ^2	2900.43	272.75	421.26	950.18	5070.38
Pseudo R^2	0.145	0.121	0.1226	0.2301	0.1906
P-value	0.000	0.000	0.000	0.000	0.000
N	46 477	40 069	40 137	40 286	40 519

Notes: (***), (**) and (*) indicate 1%, 5% and 10% significant, respectively.

Table 3. Marginal effects from probit models of labour force and NCD by gender.

	Males					Females
	Labour force	Stroke	Heart diseases	Diabetes	Hypertension	Labour force	Stroke	Heart diseases	Diabetes	Hypertension
	(I)	(II)	(III)	(IV)	(V)	(VI)	(VII)	(VIII)	(IX)	(X)
Stroke	−0.256***					−0.130***
Heart disease	−0.113**	0.012***				−0.004	0.014***
Diabetes	0.040	−0.010	−0.007			−0.031	0.005*	0.024***
Hypertension	−0.001	0.007***	0.018***	0.059***	0.005***	0.003	0.012***	0.026***	0.069***
Age	0.253***	0.000	0.001***	0.002***	0.008***	0.378***	0.001***	0.001***	0.002***	0.008***
Age squared	−0.539***					−0.351***
Not married	ref					ref
Married	0.095***					−0.054***
No education	ref					ref
Primary	0.063***					0.057***
Secondary	0.088***					0.137***
Matric	0.113***					0.200***
Tertiary	0.205***					0.380***
Traditional	ref					ref
Rural	0.149***					0.074***
Urban-formal	0.088***					0.094***
urban-informal	0.095***					0.139***
White	ref					ref
Coloured	−0.083**					0.076**
African	−0.090***					0.062**
Household size	−0.012***					−0.006***
Wave 1	ref					ref
Wave2	−0.120***	−0.007**	−0.008*	−0.001	−0.013	−0.134***	0.000	−0.017***	0.003	−0.039***
Wave3	−0.065***	−0.005*	−0.003	0.001	0.024**	−0.079***	0.002	−0.016***	0.006	0.009
Wave4	−0.045***	−0.007***	−0.013***	0.002	0.010	−0.062***	0.002	−0.014***	0.005	−0.029***
Obese		0.001	0.003	0.015**	0.053***		0.000	0.000	0.018***	0.080***
Exercise		−0.004**	0.012***	−0.008	−0.019*		−0.002	0.000	0.004	0.000
Smoking		−0.001	0.002	0.003	0.025**		−0.001	0.008	0.012	0.037
Drinking		−0.033**	−0.078	−0.008	0.024			−0.030**	−0.025	0.072
Constant	−0.746***	−0.035***	−0.065***	−0.219***	−0.418***	−1.183***	−0.066***	−0.128***	−0.235***	−0.610***
Wald χ^2	1382.64	151.46	107.71	385.61	415.15	1676.12	192.64	330.42	661.29	1272.45
Pseudo R^2	0.1524	0.1852	0.1722	0.2584	0.2001	0.1285	0.1078	0.1153	0.2219	0.1651
P-value	0.000	0.000	0.000	0.000	0.000	0.000	0.000	0.000	0.000	0.000
Sample size	18 825	12 526	12 542	12 579	12 652	27 652	27 352	27 592	27 704	27 864

Notes: (***), (**) and (*) indicate 1%, 5% and 10% significant, respectively.

Table 4. Correlation coefficients from multivariate probit model.

	Total (I)	Males (II)	Females (III)
ρlabour force, stroke	0.247** (0.102)	0.771*** (0.147)	0.212 (0.208)
Ρlabour force, heart	0.291*** (0.087)	0.365** (0.145)	0.306** (0.140)
ρlabour force, diabetes	0.220** (0.091)	−0.027 (0.142)	0.264*** (0.074)
ρlabour force, hypertension	0.219*** (0.079)	0.161 (0.102)	0.335*** (0.084)
ρstroke, heart	0.254*** (0.045)	0.306** (0.133)	0.402*** (0.060)
ρstroke, diabetes	0.099** (0.049)	−0.027 (0.127)	0.263*** (0.062)
ρstroke, hypertension	0.138*** (0.036)	0.167 (0.108)	0.323*** (0.043)
ρheart, diabetes	0.152*** (0.042)	0.126* (0.076)	0.308*** (0.045)
ρheart, hypertension	0.191*** (0.031)	0.344*** (0.080)	0.318*** (0.030)
ρdiabetes, hypertension	0.370*** (0.024)	0.558*** (0.050)	0.507*** (0.029)

Notes: standard errors in brackets. (***), (**) and (*) indicate 1%, 5% and 10% significant, respectively.

Table 5. Multivariate probit model of labour force participation.

	Direct effects	Indirect effects from NCDs				Total effect
		Stroke	heart disease	Diabetes	Hypertension
	(I)	(II)	(III)	(IV)	(V)	(VI)
Stroke						−0.319***
Heart disease					−0.240***
Diabetes						−0.117**
Hypertension						−0.116***
Female	ref					ref
Male	0.139***					0.139***
Not married	ref					ref
Married	−0.006					−0.006
Wave 1	ref	ref	ref	ref	ref	ref
Wave 2	−0.141***	0.005**	0.017***	0.003	0.033***	−0.088***
Wave 3	−0.066***	0.002	0.012***	−0.009	−0.012*	−0.073**
Wave 4	−0.066***	0.000	0.016***	0.003	0.023**	−0.024**
Age	0.334***	−0.001***	−0.001***	−0.003***	−0.008***	0.321***
Age squared	−0.416***					−0.416***
Not educated	ref					ref
Primary	0.096***					0.096***
Secondary	0.158***					0.158***
Matric	0.226***					0.226***
Tertiary	0.400***					0.400***
Traditional area	ref					ref
Urban-informal	0.158***					0.158***
Urban-formal	0.115***					0.115***
Rural	0.118***					0.118***
White	ref					ref
African	0.017					0.017
Coloured	−0.012					−0.012
Household size	−0.007***					−0.007***
Obese		−0.003*	−0.007***	−0.021***	−0.076***	−0.107***
Exercise	0.006**	−0.008**	0.005	0.020*	0.024*
Smoking		−0.001	−0.001	−0.011	−0.029**	−0.041
Drinking		0.018***	0.029***	0.010	0.007	0.063**
Constant	−1.135***	0.070***	0.127***	0.261***	0.554***	−0.123***

Notes: (***), (**) and (*) indicate 1%, 5% and 10%significant, respectively.

Table 6. Multivariate probit results by gender.

Males							Females
	Direct effects	Indirect effects				Total marginal effect	Direct effects	Indirect effects				Total marginal effect
		Stroke	heart disease	Diabetes	Hypertension			Stroke	heart disease	Diabetes	Hypertension
	(I)	(II)	(III)	(IV)	(V)	(VI)	(VII)	(VIII)	(IX)	(X)	(XI)	(XII)
Stroke						−0.780***						−0.218
Heart disease						−0.374***						−0.181
Diabetes						0.086						−0.138**
Hypertension						−0.069						−0.170***
Age	0.272***	0.000	−0.001***	−0.001***	−0.005***	0.265***	0.382***	−0.001***	−0.001***	−0.003***	−0.009***	0.368***
Age squared	−0.538***					−0.538***	−0.351***					−0.351***
Not married	ref					ref	ref					ref
Married	0.100***					0.100***	−0.049***					−0.049***
Not educated	ref					ref	ref					ref
Primary	0.117***					0.117***	0.063***					0.063***
Secondary	0.115***					0.115***	0.137***					0.137***
Matric	0.156***					0.156***	0.205***					0.205***
Tertiary	0.255***					0.255***	0.375***					0.375***
Traditional area	ref					ref	ref					ref
Urban-informal	0.113***					0.113***	0.136***					0.136***
Urban-formal	0.085***					0.085***	0.093***					0.093***
Rural	0.152***					0.152***	0.064***					0.064***
White	ref					ref	ref					ref
African	−0.066**					−0.066**	0.037					0.037
Coloured	−0.096**					−0.096**	0.018					0.018
Household size	−0.012***					−0.012***	−0.005***					−0.005***
Wave 1	ref	ref	ref	ref	ref	ref	ref	ref	ref	ref	ref	ref
Wave 2	−0.132***	0.006***	0.009**	0.002	0.012	−0.103**	−0.149	0.001	0.020***	0.003	0.037***	−0.088**
Wave 3	−0.049***	0.005**	0.003	−0.006	−0.022**	−0.069**	−0.079	−0.002	0.015***	−0.007	−0.011	−0.084*
Wave 4	−0.054***	0.008***	0.010**	0.013	−0.002	−0.025**	−0.075	−0.006*	0.018***	0.005	0.036***	0.022**
Obese		−0.003*	−0.007***	−0.017***	−0.051***	−0.078***		−0.002	−0.004	−0.022***	−0.072***	−0.100**
Exercise		0.008**	−0.013***	0.013*	0.015***	0.023**		0.003	0.000	−0.003	−0.001	−0.001
Smoking		0.001	−0.004	−0.013	−0.039	−0.037		−0.002	−0.001	−0.005	−0.045*	−0.053
Drinking		0.007**	−0.019***	0.000	−0.017	0.029**		0.118***	0.026*	0.048*	−0.002	0.190*
Constant	−0.917***	0.035***	0.090***	0.232***	0.409***	−0.151***	−1.121***	0.089***	0.143***	0.273***	0.612***	−0.004***

Notes: (***), (**) and (*) indicate 1%, 5% and 10% significant, respectively

Table A1. Coefficient of multivariate probit regression.

	Total		Males		Females
	Coefficient	Robust Std. Err.	Coefficient	Robust Std. Err.	Coefficient	Robust Std. Err.
Labour force
stroke	−1.02***	0.266	−2.807***	0.448	−0.662	0.606
diabetes	−0.373**	0.16	0.309	0.28	−0.420**	0.172
Heart diseases	−0.766**	0.201	−1.347***	0.459	−0.549	0.347
Hypertension	−0.371***	0.136	−0.249	0.201	−0.516***	0.155
Age	0.202***	0.008	0.222***	0.012	0.190***	0.009
Age2	−0.002***	0.000	−0.003***	0.000	−0.002***	0.000
Males	0.373***	0.025
Married	−0.015	0.028	0.359***	0.062	−0.148***	0.032
Primary	0.257***	0.044	0.421***	0.091	0.191***	0.049
Secondary	0.421***	0.044	0.415***	0.089	0.415***	0.05
Matric	0.604***	0.05	0.562***	0.097	0.623***	0.058
Tertiary	1.070***	0.058	0.918***	0.113	1.139***	0.065
Urban formal	0.309***	0.025	0.305***	0.047	0.283***	0.03
Rural	0.316***	0.041	0.546***	0.086	0.196**	0.047
Urban informal	0.425***	0.041	0.407***	0.077	0.413**	0.048
Coloured	−0.038	0.084	−0.344**	0.149	0.054	0.104
African	0.054	0.071	−0.238**	0.121	0.113	0.089
Household size	−0.023	0.003	−0.042***	0.006	−0.012***	0.004
Wave 1	−0.450***	0.032	−0.474***	0.058	−0.452***	0.039
Wave 2	−0.212***	0.031	−0.178***	0.06	−0.239***	0.037
Wave 3	−0.210***	0.036	−0.195***	0.065	−0.229***	0.043
Constant	−3.628***	0.163	−3.301***	0.273	−3.402***	0.185
Stroke
Wave 1	−0.216**	0.109	−0.538***	0.189	−0.045	0.098
Wave 2	−0.110	0.108	−0.466**	0.21	0.067	0.092
Wave 3	−0.005	0.135	−0.673***	0.236	0.206***	0.121
Exercise	−0.272**	0.131	−0.678**	0.341	−0.100	0.155
Obese	0.125*	0.071	0.235*	0.137	0.085	0.072
Smoke	0.026	0.150	−0.058	0.207	0.080	0.240
Drinking	−0.796***	0.249	−0.573**	0.284	−4.370***	0.123
Age	0.020***	0.003	0.018***	0.006	0.020***	0.003
Constant	−3.185***	0.201	−2.980***	0.46	−3.276***	0.141
Heart diseases
Wave 1	−0.398***	0.069	−0.375**	0.176	−0.379***	0.070
Wave 2	−0.272***	0.060	−0.130	0.149	−0.285***	0.061
Wave 3	−0.359***	0.086	−0.379**	0.165	−0.334***	0.097
Exercise	0.180**	0.091	0.513***	0.161	−0.001	0.096
Obese	0.158***	0.048	0.292***	0.112	0.073	0.052
Smoke	0.021	0.120	0.143	0.167	0.025	0.17
Drinking	−0.655***	0.190	−0.740***	0.278	−0.489*	0.273
Age	0.024***	0.002	0.031***	0.006	0.023***	0.002
Constant	−2.905***	0.106	−3.584***	0.272	−2.715***	0.11
Diabetes
Wave 1	−0.038	0.068	−0.028	0.114	−0.036	0.08
Wave 2	0.091	0.059	0.094	0.113	0.09	0.066
Wave 3	−0.119	0.083	−0.206	0.187	−0.068	0.09
Exercise	−0.075	0.122	−0.218*	0.127	0.043	0.166
Obese	0.281***	0.049	0.287***	0.096	0.278***	0.055
Smoke	0.147	0.113	0.208	0.152	0.069	0.177
Drinking	−0.135	0.199	−0.007	0.213	−0.611*	0.324
Age	0.039***	0.002	0.044***	0.004	0.036***	0.002
Constant	−3.568***	0.106	−3.816***	0.197	−3.452***	0.121
Hypertension
Wave 1	−0.179***	0.045	−0.103	0.085	−0.174***	0.05
Wave 2	0.066*	0.04	0.183**	0.083	0.052	0.044
Wave 3	−0.125**	0.052	0.015	0.117	−0.171***	0.056
Exercise	−0.112*	0.064	−0.127	0.101	0.004	0.081
Obese	0.420***	0.032	0.432***	0.068	0.341***	0.036
Smoke	0.157**	0.077	0.333***	0.093	0.214*	0.115
Drinking	−0.039	0.141	0.14	0.187	0.009	0.182
Age	0.044***	0.001	0.045***	0.003	0.045***	0.001
Constant	−3.042***	0.062	−3.476***	0.123	−2.911***	0.07
Sample size	35 825		11 097		24 728
Log likelihood	−6.82E + 07		−1.90E + 07		−4.8E + 07
Wald χ^2	5142.6		1742.02		9058.9
LR test, p-value	0.000		0.000		0.000