TABLE 2.
Association between baseline body mass index (BMI) and risk of COPD
| BMI kg·m−2 | ||||
| <18.5 | 18.5–<24.0 | 24.0–<28.0 | ≥28.0 | |
| Total n | 452 259 | |||
| Cases n | 1173 | 5809 | 2859 | 898 |
| Rate per 1000 person-years | 7.08 | 2.49 | 1.89 | 1.90 |
| Model 1 | 1.86 (1.75–1.99) | 1.00 | 0.95 (0.91–1.00) | 1.12 (1.04–1.20) |
| Model 2 | 1.75 (1.64–1.86) | 1.00 | 0.97 (0.93–1.02) | 1.10 (1.02–1.19) |
| Model 3 | 1.78 (1.66–1.89) | 1.00 | 0.89 (0.84–0.95) | 0.95 (0.87–1.05) |
| Males n | 182 209 | |||
| Cases n | 651 | 3099 | 1208 | 255 |
| Rate per 1000 person-years | 10.46 | 3.26 | 2.01 | 1.56 |
| Model 1 | 2.05 (1.88–2.23) | 1.00 | 0.86 (0.80–0.92) | 0.85 (0.75–0.97) |
| Model 2 | 1.90 (1.74–2.07) | 1.00 | 0.89 (0.83–0.95) | 0.88 (0.77–1.00) |
| Model 3 | 1.91 (1.75–2.08) | 1.00 | 0.84 (0.77–0.90) | 0.76 (0.65–0.90) |
| Female n | 270 050 | |||
| Cases n | 522 | 2710 | 1651 | 643 |
| Rate per 1000 person-years | 5.05 | 1.96 | 1.82 | 2.08 |
| Model 1 | 1.67 (1.52–1.84) | 1.00 | 1.02 (0.96–1.09) | 1.27 (1.16–1.39) |
| Model 2 | 1.59 (1.44–1.75) | 1.00 | 1.02 (0.96–1.09) | 1.23 (1.12–1.34) |
| Model 3 | 1.64 (1.49–1.81) | 1.00 | 0.92 (0.85–1.00) | 1.05 (0.93–1.18) |
Data are presented as HR (95% CI), unless otherwise stated. Models were adjusted as follows. Model 1: sex (only in total population); model 2: additionally included education (none or primary school, middle or high school, college or university), marital status (married, widowed, divorced or separated, never married), smoking (never or occasional, former and having quit <5 years or ≥5 years, current smoking <15 years, 15–24 years or ≥25 cigarettes·day−1), passive smoking (never lived with smoker, lived with smoker for <20 years, lived with smoker for ≥20 years and exposure <20 h·week−1, lived with smoker for ≥20 years and exposure ≥20 h·week−1), cooking and heating fuel type (coal, wood/charcoal, cleaner fuel, other fuels, no cooking/heating), alcohol drinking (non-drinker, occasional drinker, former drinker, regular drinker), intake frequencies of red meat, fresh fruit and vegetables (daily, 4–6 days·week−1, 1–3 days·week−1, monthly, rarely or never), physical activity (MET-h·day−1) and respiratory symptoms (presence or absence); model 3: additionally adjusted for waist circumference. p-value for interaction between sex and BMI <0.001.