Table 5.
Associations of risk factors with diabetes: sex-specific crude and adjusted risk ratios
|
Men (n=11 062) |
Women (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) | 2·76 (2·12–3·59) | 2·07 (1·42–3·05) | 1·87 (1·28–2·74) | 2·57 (2·06–3·20) | 1·45 (1·04–2·02) | 1·24 (0·89–1·72) |
| Age group, years | ||||||
| 18–29 | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) |
| 30–39 | 3·66 (2·05–6·50) | 3·86 (2·08–7·16) | 3·22 (1·73–5·99) | 3·48 (2·19–5·54) | 3·52 (2·17–5·70) | 2·45 (1·48–4·04) |
| 40–49 | 7·57 (4·33–13·23) | 7·58 (4·17–13·77) | 5·87 (3·21–10·74) | 10·73 (6·92–16·60) | 12·26 (7·61–19·73) | 8·01 (4·90–13·10) |
| 50–59 | 14·83 (8·61–25·54) | 17·55 (9·76–31·55) | 13·55 (7·51–24·48) | 17·56 (11·37–27·14) | 21·51 (14·04–36·08) | 13·00 (7·90–21·39) |
| 60–69 | 19·90 (11·40–34·74) | 22·17 (12·58–39·08) | 16·29 (9·16–28·99) | 22·72 (14·47–35·67) | 34·00 (21·22–54·50) | 19·19 (11·71–31·45) |
| ≥70 | 15·75 (8·76–28·31) | 28·75 (15·45–53·47) | 20·98 (11·20–39·27) | 20·07 (12·23–32·95) | 37·66 (21·67–65·44) | 21·85 (12·39–38·51) |
| 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 | 1·20 (0·65–2·23) | 1·10 (0·59–2·03) | 1·19 (0·59–2·00) | 1·49 (0·94–2·37) | 1·43 (0·90–2·28) | 1·48 (0·91–2·38) |
| Third | 1·57 (0·86–2·89) | 1·25 (0·69–2·28) | 1·19 (0·66–2·17) | 1·80 (1·14–2·86) | 1·48 (0·93–2·35) | 1·38 (0·86–2·22) |
| Fourth | 2·73 (1·56–4·79) | 1·80 (1·03–3·16) | 1·62 (0·92–2·85) | 3·17 (2·09–4·80) | 2·18 (1·42–3·36) | 1·95 (1·24–3·04) |
| Wealthiest | 5·21 (3·03–8·96) | 2·73 (1·57–4·76) | 2·20 (1·24–3·89) | 5·28 (3·52–7·01) | 3·07 (1·97–4·77) | 2·37 (1·50–3·75) |
| p value for trend | <0·0001 | <0·0001 | 0·0012 | <0·0001 | <0·0001 | 0·0002 |
| Education | ||||||
| None | 0·20 (0·028–1·39) | 0·20 (0·028–1·43) | 0·21 (0·029–1·48) | 0·54 (0·34–0·86) | 0·61 (0·39–0·97) | 0·74 (0·47–1·15) |
| Standard 1–5 | 0·73 (0·40–1·33) | 0·76 (0·42–1·40) | 0·77 (0·42–1·41) | 0·67 (0·48–0·92) | 0·74 (0·54–1·07) | 0·81 (0·59–1·12) |
| Standard 5–8 | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) |
| Secondary | 1·80 (1·27–2·55) | 1·40 (0·97–2·04) | 1·27 (0·88–1·85) | 1·75 (1·34–2·29) | 1·12 (0·84–1·50) | 1·05 (0·78–1·42) |
| Post secondary | 4·15 (2·87–6·00) | 2·16 (1·40–3·34) | 1·84 (1·17–2·89) | 3·11 (2·25–4·30) | 1·44 (0·97–2·15) | 1·24 (0·83–1·87) |
| p value for trend | <0·0001 | <0·0001 | 0·0006 | <0·0001 | 0·0015 | 0·0552 |
| Employment | ||||||
| Not working | 1·12 (0·74–1·69) | 0·84 (0·55–1·29 | 0·92 (0·23–1·39) | 1·02 (0·71–1·46) | 0·84 (0·59–1·20) | 0·87 (0·60–1·25) |
| Housework | 0·52 (0·19–1·45) | 0·49 (0·18–1·37) | 0·52 (0·19–1·44) | 0·75 (0·56–1·01) | 0·70 (0·51–0·95) | 0·73 (0·54–1·00) |
| Subsistence | 0·56 (0·38–0·83) | 1·29 (0·80–2·08) | 1·42 (0·88–2·30) | 0·36 (0·26–0·50) | 0·59 (0·40–0·87) | 0·70 (0·47–1·04) |
| Self-employed | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) | 1 (ref) |
| Salaried | 1·21 (0·82–1·78) | 0·86 (0·58–1·27) | 0·91 (0·61–1·35) | 1·28 (0·90–1·83) | 0·77 (0·52–1·13) | 0·82 (0·55–1·22) |
| Physical activity (WHO recommendation25) | ||||||
| Did not meet | 2·44 (1·77–3·37) | 1·53 (1·11–2·13) | ·· | 1·99 (1·32–3·02) | 1·55 (1·02–2·36) | ·· |
| Met recommendation | 1 (ref) | 1 (ref) | ·· | 1 (ref) | 1 (ref) | ·· |
| Smoking | ||||||
| Not current | 1 (ref) | 1 (ref) | ·· | 1 (ref) | 1 (ref) | 1 (ref) |
| Current | 0·60 (0·37–0·96) | 0·91 (0·56–1·29) | ·· | 0·76 (0·12–5·06) | 0·99 (0·19–5·22) | 1·38 (0·30–6·29) |
| Alcohol consumption | ||||||
| Not in last year | 1 (ref) | 1 (ref) | ·· | 1 (ref) | 1 (ref) | 1 (ref) |
| In last year | 0·72 (0·54–0·96) | 0·87 (0·66–1·18) | ·· | 1·20 (0·75–1·90) | 1·22 (0·78–1·91) | 1·11 (0·71–1·72) |
| Sugary drinks intake, teaspoons of sugar per day | ||||||
| Fewer than six | 1 (ref) | 1 (ref) | ·· | 1 (ref) | 1 (ref) | ·· |
| Six or more | 0·42 (0·30–0·59) | 0·37 (0·27–0·52)‡ | ·· | 0·89 (0·69–1·14) | 0·73 (0·57–0·95)‡ | ·· |
| BMI, kg/m2 | ||||||
| <18·0 | 0·52 (0·21–1·27) | 0·57 (0·23–1·39) | ·· | 0·76 (0·27–2·11) | 0·81 (0·29–2·25) | ·· |
| 18·0–24·9 | 1 (ref) | 1 (ref) | ·· | 1 (ref) | 1 (ref) | ·· |
| 25·0–29·9 | 3·11 (2·35–4·12) | 2·15 (1·57–2·93) | ·· | 3·04 (2·25–4·09) | 2·50 (1·86–3·37) | ·· |
| ≥30·0 | 5·34 (3·59–7·96) | 2·76 (1·72–4·42) | ·· | 6·47 (4·89–8·56) | 4·43 (3·29–5·97) | ·· |
| Waist-to-hip ratio | ||||||
| Normal | 1 (ref) | 1 (ref) | ·· | 1 (ref) | 1 (ref) | ·· |
| High | 3·86 (2·85–5·24) | 3·11 (2·27–4·27) | ·· | 2·11 (1·64–2·70) | 2·64 (2·06–3·37) | ·· |
Data are risk ratios (95% CI). We defined diabetes as fasting blood glucose >7·0 mmol/L or previous diagnosis. We found no evidence of interaction between sex and age or site and risk for diabetes. We found evidence for significant interaction between age-site (p=0·043). Additional stratifications are not presented because numbers are small.
*
Adjusted for 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 excluding those with a previous diagnosis, these values became 0·78 (0·49–1·23) for men and 1·11 (0·77–1·61) for women.