Table 2.
Standardised stroke incidence rates per 10 000 person-years and adjusted HRs by baseline BMI among people without previous stroke or ischaemic heart disease
|
Ischaemic stroke |
Intracerebral haemorrhage |
Subarachnoid haemorrhage |
Unspecified stroke |
All stroke |
||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Events | Rate* | HR (95% CI)† | Events | Rate* | HR (95% CI)† | Events | Rate* | HR (95% CI)† | Events | Rate* | HR (95% CI)† | Events | Rate* | HR (95% CI)† | ||
| BMI<18·0 | 590 | 49·3 | 1·00 (0·92–1·09) | 253 | 15·8 | 1·00 (0·88–1·13) | 10 | 1·2 | 1·00 (0·53–1·87) | 37 | 2·3 | 1·00 (0·72–1·39) | 890 | 68·6 | 1·00 (0·94–1·07) | |
| BMI 18·0–20·4 | 2740 | 50·4 | 1·10 (1.05–1·14) | 980 | 13·5 | 0·97 (0·91–1·03) | 71 | 1·1 | 1·53 (1·20–1·94) | 207 | 3·5 | 1·41 (1·23–1·63) | 3998 | 68·5 | 1·08 (1·04–1·11) | |
| BMI 20·5–22·9 | 5790 | 59·6 | 1·33 (1·29–1·36) | 1494 | 13·7 | 1·01 (0·96–1·06) | 127 | 1·3 | 1·57 (1·32–1·87) | 349 | 3·4 | 1·47 (1·32–1·63) | 7760 | 78·0 | 1·24 (1·22–1·27) | |
| BMI 23·0–24·9 | 5600 | 67·5 | 1·51 (1·47–1·55) | 1020 | 12·9 | 0·95 (0·90–1·02) | 81 | 1·0 | 1·25 (1·01–1·56) | 306 | 3·8 | 1·61 (1·44–1·80) | 7007 | 85·2 | 1·37 (1·33–1·40) | |
| BMI 25·0–27·4 | 5946 | 78·6 | 1·75 (1·70–1·79) | 960 | 14·6 | 1·11 (1·04–1·18) | 89 | 1·2 | 1·57 (1·28–1·94) | 289 | 4·0 | 1·75 (1·56–1·97) | 7284 | 98·4 | 1·58 (1·54–1·62) | |
| BMI 27·5–29·9 | 3038 | 86·6 | 1·90 (1·84–1·97) | 464 | 17·7 | 1·24 (1·13–1·36) | 43 | 1·3 | 1·66 (1·22–2·25) | 150 | 4·5 | 2·03 (1·73–2·39) | 3695 | 110·1 | 1·73 (1·68–1·79) | |
| BMI≥30·0 | 1506 | 96·7 | 2·03 (1·92–2·13) | 209 | 19·5 | 1·32 (1·15–1·51) | 13 | 1·2 | 1·05 (0·60–1·82) | 86 | 6·9 | 2·60 (2·09–3·22) | 1814 | 124·3 | 1·85 (1·76–1·94) | |
| Overall | 25 210 | 65·5 | .. | 5380 | 14·0 | .. | 434 | 1·1 | .. | 1424 | 3·7 | .. | 32 448 | 84·3 | .. | |
| ptrend | .. | .. | <0·0001 | .. | .. | <0·0001‡ | .. | .. | 0·9686 | .. | .. | <0·0001 | .. | .. | <0·0001 | |
| HRs per 5 kg/m2 | ||||||||||||||||
| Observed | .. | .. | 1·30 (1·28–1·33) | .. | .. | 1·11 (1·07–1·16) | .. | .. | 0·96 (0·83–1·11) | .. | .. | 1·28 (1·18–1·38) | .. | .. | 1·27 (1·25–1·29) | |
| Expected¶ | .. | .. | 1·25 (1·24–1·26) | .. | .. | 1·48 (1·46–1·50) | .. | .. | 1·17 (1·11–1·24) | .. | .. | 1·31 (1·27–1·35) | .. | .. | 1·29 (1·29–1·30) | |
Body-mass index (BMI) unit is kg/m2. HR=hazard ratio. ..=not applicable.
*
Per 10 000 person-years. Standardised to age, sex, and study area structure of the China Kadoorie Biobank population.
†
Stratified by age, sex, and study area and adjusted for education, smoking, alcohol consumption, physical activity, and self-rated health status.
‡
p value <0·0001 both for trend test and for test of non-linearity across seven groups.
¶
Estimated according to the corresponding difference in usual systolic blood pressure (8·3 mm Hg) and its associated stroke risk.