Characteristics of the main (SAGE South Africa Wave 2, 2015) and subsample study cohort
| Main SAGE cohort n=2887 | Subsample* n=875 | P value | |||
| Median | IQR | Median | IQR | ||
| Female, n (%) | 1939 | 67 | 671 | 77 | <0.001 |
| Age (years) | 57 | 46, 69 | 55 | 44, 67 | 0.468 |
| Aged over 50 years, n (%) | 1979 | 69 | 567 | 65 | 0.171 |
| Ethnicity, n (%) | |||||
| Black | 1988 | 69 | 410 | 74 | <0.001 |
| Coloured, mixed race | 465 | 16 | 96 | 17 | |
| Indian | 306 | 11 | 41 | 7 | |
| White | 128 | 4 | 11 | 2 | |
| Rural, n (%) | 792 | 28 | 163 | 29 | 0.418 |
| Education (years) | 10 | 7, 13 | 9 | 6, 12 | 0.028 |
| Never been to school, n (%) | 495 | 18 | 109 | 20 | 0.180 |
| Never had paid employment, n (%) | 1101 | 55 | 238 | 56 | 0.403 |
| BMI (kg/m2) | 28.8 | 23.9, 33.7 | 29.1 | 24.0, 34.2 | 0.540 |
| Waist-to-height ratio | 0.59 | 0.52, 0.67 | 0.58 | 0.50, 0.66 | 0.070 |
| Never used alcohol, n (%) | 1576 | 80 | 353 | 83 | 0.052 |
| Never used tobacco, n (%) | 1635 | 83 | 367 | 86 | 0.023 |
| Systolic BP (mm Hg) | 131 | 118, 144 | 128 | 116, 141 | 0.073 |
| Diastolic BP (mm Hg) | 81 | 73, 89 | 79 | 71, 87 | 0.029 |
| Hypertension, n (%) | 1233 | 45 | 232 | 43 | 0.239 |
| Diabetes, n (%) | 248 | 13 | 46 | 11 | 0.355 |
*Subsample: all respondents with spot UIC, valid 24-hour urine, sex and age recorded. Some variables may contain missing data as indicated by percentages. Data shown as median and IQR (25th, 75th percentiles) unless otherwise indicated. Hypertensive by measured BP≥140 and/or 90 mm Hg or previous diagnosis. Education, tobacco/alcohol use, ethnicity, employment and diabetes prevalence by self-report. Continuous variables compared using independent samples Mann-Whitney U test, categorical variables compared using Pearson’s χ2test and Fisher’s exact test.
BMI, body mass index; BP, blood pressure; SAGE, Study on global AGEing and adult health.