Table 4.
Associations of risk factors with hypertension: age-adjusted and distal-factor-adjusted risk ratios
|
Male (n=11 062) |
Female (n=17 829) |
|||||
|---|---|---|---|---|---|---|
| Age adjusted | Distal factor adjusted* | Additional BMI adjustment† | Age adjusted | Distal factor adjusted* | Additional BMI adjustment† | |
| Site | ||||||
| Karonga (rural) | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) |
| Lilongwe (urban) | 1·61 (1·48–1·76) | 1·38 (1·22–1·55) | 1·32 (1·17–1·48) | 1·82 (1·70–1·96) | 1·37 (1·24–1·51) | 1·28 (1·15–1·55) |
| Age group, years | ||||||
| 18–29 | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) |
| 30–39 | 2·01 (1·73–2·35) | 2·03 (1·72–2·39) | 1·80 (1·53–2·12) | 3·27 (2·76–3·86) | 3·30 (2·82–3·94) | 2·92 (2·45–3·47) |
| 40–49 | 2·03 (2·58–3·54) | 3·06 (2·58–3·62) | 2·58 (2·17–3·06) | 7·66 (6·52–8·99) | 8·29 (7·09–9·85) | 6·73 (5·66–8·00) |
| 50–59 | 5·10 (4·38–5·94) | 5·40 (4·60–6·34) | 4·57 (3·88–5·38) | 15·81 (13·6–18·4) | 18·45 (15·7–21·5) | 14·14 (11·95–16·27) |
| 60–69 | 8·03 (6·93–9·29) | 8·62 (7·42–10·01) | 7·12 (6·10–8·31) | 21·76 (18·7–25·3) | 26·79 (22·3–31·0) | 20·77 (17·54–24·59) |
| ≥70 | 9·41 (8·20–10·8) | 12·0 (10·31–14·03) | 10·01 (8·59–11·79) | 27·49 (23·7–31·8) | 35·10 (29·4–41·4) | 29·07 (24·46–34·55) |
| p value for trend | <0·0001 | <0·0001 | <0·0001 | <0·0001 | <0·0001 | <0·0001 |
| Wealth quintiles | ||||||
| Poorest | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) |
| Second | 1·09 (0·94–1·29) | 1·07 (0·91–1·25) | 1·06 (0·90–1·24) | 0·92 (0·90–1·13) | 1·03 (0·92–1·15) | 0·99 (0·88–1·12) |
| Third | 1·34 (1·14–1·57) | 1·20 (1·03–1·41) | 1·15 (0·98–1·35) | 1·25 (1·12–1·40) | 1·13 (1·00–1·26) | 1·04 (0·92–1·16) |
| Fourth | 1·45 (1·25–1·69) | 1·18 (1·01–1·38) | 1·09 (0·93–1·28) | 1·54 (1·39–1·71) | 1·27 (1·13–1·42) | 1·14 (1·02–1·28) |
| Wealthiest | 1·84 (1·58–2·15) | 1·32 (1·11–1·56) | 1·10 (0·93–1·31) | 1·79 (1·60–2·00) | 1·34 (1·18–1·52) | 1·13 (0·99–1·28) |
| p value for trend | <0·0001 | 0·0076 | 0·396 | <0·0001 | 0·0001 | 0·061 |
| Education | ||||||
| None | 0·80 (0·61–1·06) | 0·78 (0·60–1·03) | 0·78 (0·59–1·04) | 1·08 (0·97–1·21) | 1·07 (0·96–1·20) | 1·12 (1·00–1·26) |
| Standard 1–5 | 0·87 (0·74–1·01) | 0·87 (0·74–1·02) | 0·88 (0·75–1·03) | 1·07 (0·97–1·18) | 1·09 (1·00–1·20) | 1·12 (1·01–1·23) |
| Standard 5–8 | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) |
| Secondary | 1·19 (1·07–1·33) | 1·05 (0·94–1·18) | 1·00 (0·89–1·12) | 1·44 (1·30–1·59) | 1·14 (1·02–1·26) | 1·11 (0·99–1·24) |
| Post secondary | 1·87 (1·64–2·13) | 1·41 (1·22–1·65) | 1·23 (1·06–1·44) | 1·79 (1·54–2·08) | 1·19 (0·99–1·42) | 1·13 (0·94–1·36) |
| p value for trend | <0·0001 | 0·0001 | 0·0112 | <0·0001 | 0·647 | 0·733 |
| Employment | ||||||
| Not working | 0·99 (0·85–1·15) | 0·90 (0·78–1·05) | 0·96 (0·83–1·12) | 0·98 (0·86–1·12) | 0·95 (0·83–1·08) | 0·99 (0·87–1·13) |
| Housework | 0·98 (0·76–1·26) | 0·91 (0·71–1·78) | 0·99 (0·77–1·27) | 1·06 (0·94–1·18) | 1·00 (0·89–1·12) | 1·04 (0·92–1·16) |
| Subsistence | 0·71 (0·62–0·81) | 0·92 (0·79–1·08) | 0·99 (0·85–1·16) | 0·59 (0·53–0·66) | 0·77 (0·68–0·88) | 0·85 (0·75–0·97) |
| Self-employed | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) |
| Salaried | 1·12 (0·98–1·29) | 0·97 (0·84–1·11) | 0·99 (0·86–1·14) | 1·25 (1·08–1·45) | 1·04 (0·88–1·22) | 1·08 (0·91–1·27) |
| Physical activity (WHO recommendation25) | ||||||
| Did not meet | 1·35 (1·20–1·51) | 1·15 (1·02–1·30) | ·· | 1·33 (1·20–1·47) | 1·16 (1·05–1·29) | ·· |
| Met recommendation | 1 (ref) | 1 (ref) | ·· | 1 (ref) | 1 (ref) | ·· |
| Smoking | ||||||
| Not current | 1 (ref) | 1 (ref) | ·· | 1 (ref) | 1 (ref) | ·· |
| Current | 0·74 (0·64–0·87) | 0·86 (0·73–1·00) | ·· | 0·78 (0·50–1·20) | 0·76 (0·49–1·18) | ·· |
| Alcohol consumption | ||||||
| Not in last year | 1 (ref) | 1 (ref) | ·· | 1 (ref) | 1 (ref) | ·· |
| In last year | 1·03 (0·94–1·13) | 1·11 (1·01–1·21) | ·· | 1·13 (0·97–1·33) | 1·11 (0·95–1·30) | ·· |
| Sugary drinks intake, teaspoons of sugar per day‡ | ||||||
| Fewer than six | 1 (ref) | 1 (ref) | ·· | 1 (ref) | 1 (ref) | ·· |
| Six or more | 0·87 (0·79–0·96) | 0·84 (0·76–0·93) | ·· | 0·85 (0·78–0·93) | 0·79 (0·72–0·87) | ·· |
| BMI, kg/m2 | ||||||
| <18·0 | 0·75 (0·60–0·94) | 0·76 (0·61–0·96) | ·· | 0·87 (0·73–1·05) | 0·90 (0·75–1·08) | ·· |
| 18·0–24·9 | 1 (ref) | 1 (ref) | ·· | 1 (ref) | 1 (ref) | ·· |
| 25·0–29·9 | 2·13 (1·92–2·36) | 1·89 (1·70–2·10) | ·· | 1·63 (1·49–1·78) | 1·49 (1·37–1·63) | ·· |
| ≥30·0 | 3·44 (3·00–3·95) | 2·80 (2·40–3·25) | ·· | 2·41 (2·22–2·63) | 2·02 (1·85–2·22) | ·· |
| Waist-to-hip ratio | ||||||
| Normal | 1 (ref) | 1 (ref) | ·· | 1 (ref) | 1 (ref) | ·· |
| High | 1·69 (1·53–1·86) | 1·59 (1·44–1·75) | ·· | 1·16 (1·07–1·24) | 1·31 (1·23–1·42) | ·· |
Data are risk ratios (95% CI). Hypertension is defined as systolic ≥140 mm Hg, diastolic ≥90 mm Hg, or on antihypertensive medication. We found no evidence of interaction between sex and age or site and risk for hypertension. We found evidence for significant interaction between age and sex (p<0·0001) and age and site (p=0·0003) in their associations with hypertension. Further stratified analyses (age-sex) and (age-site) are presented in the appendix.
Adjusted for distal factors: age, site, wealth, education, and occupation (see appendix p 2).
Additional BMI adjustment is added to adjustment for distal factors. We did not do additional BMI adjustment for lifestyle factors prone to change with changes in health and associated with BMI.
After adjusting for distal factors and excluding those with a previous diagnosis of diabetes, the odds ratio for association of at least six teaspoons of sugar daily and newly diagnosed diabetes was 0·78 (0·49–1·23) in men and 1·11 (0·77–1·61) in women.