Table 1 Characteristics of the study population at recruitment, and details of follow-up, by body mass index
From: Hospital admissions in relation to body mass index in UK women: a prospective cohort study
Body mass index: | ||||||
|---|---|---|---|---|---|---|
<22.5 | 22.5-24.9 | 25.0-29.9 | 30.0-34.9 | 35+ | All women | |
Number of women | 241,773 | 337,095 | 447,971 | 159,330 | 65,450 | 1,251,619 |
Median (interquartile range) BMI | 21.2 (1.6) | 23.8 (1.3) | 26.9 (2.3) | 31.7 (2.3) | 37.6 (4.3) | 25.4 (5.6) |
Mean (SD) age at recruitment | 55.8 (4.9) | 56.0 (4.9) | 56.4 (4.9) | 56.3 (4.8) | 55.8 (4.6) | 56.2 (4.9) |
Upper third of socioeconomic group (%) | 36.8 | 36.6 | 32.7 | 27.6 | 22.9 | 33.4 |
Mean (SD) number of children | 2.0 (1.2) | 2.1 (1.2) | 2.2 (1.2) | 2.3 (1.3) | 2.3 (1.4) | 2.1 (1.2) |
Strenuous physical activity > once a week (%) | 26.7 | 24.1 | 19.4 | 14.9 | 12.2 | 21.1 |
Mean (SD) alcohol intake (g/day) | 6.7 (8.0) | 6.6 (7.7) | 5.7 (7.4) | 4.6 (6.9) | 3.6 (6.3) | 5.9 (7.6) |
Current smoker (%) | 25.3 | 20.6 | 19.2 | 17.0 | 15.3 | 20.3 |
Current HRT user (%) | 37.4 | 35.8 | 32.9 | 29.4 | 24.7 | 33.7 |
Hysterectomy (%) | 21.1 | 23.5 | 26.6 | 29.0 | 27.2 | 25.0 |
Follow-up | ||||||
Woman-years of follow-up (1,000 s) | 2,231.4 | 3,122.7 | 4,130.1 | 1,460.7 | 594.1 | 11,539.0 |
Total number incident hospital admissions | 485,566 | 683,385 | 1,031,052 | 429,321 | 204,692 | 2,834,016 |
Woman-years of follow-up to first admission (1000 s) | 1,484.9 | 2,047.6 | 2,577.5 | 852.9 | 327.1 | 7,290.0 |
Number women with at least one incident admission | 138,740 | 197,724 | 281,238 | 107,813 | 47,160 | 772,675 |