TABLE 5.
Multivariate-adjusted hazard ratios* for the relation between change in weight from age 18 years to baseline and risk of lung cancer, by smoking status, in the Women's Health Initiative (Observational Study only), 1998–2006
| Weight change from age 18 years to baseline | No. of cases† | Person-years of follow-up | Hazard ratio | 95% confidence interval |
| Current smokers (n = 202) | ||||
| Weight loss of ≥10 pounds (≥4.5 kg) | 19 | 34,486 | 1.03 | 0.59, 1.80 |
| Weight change of <10 pounds (±<4.5 kg) | 53 | 78,514 | 1.00 | Reference |
| Weight gain | ||||
| 10–<20 pounds (4.5–9 kg) | 33 | 59,945 | 0.84 | 0.54, 1.33 |
| 20–<30 pounds (9.1–13.5 kg) | 29 | 40,478 | 0.69 | 0.43, 1.10 |
| ≥30 pounds (≥13.6 kg) | 64 | 112,615 | 0.63 | 0.43, 0.93 |
| p for trend | 0.009 | |||
| Former smokers (n = 431) | ||||
| Weight loss of ≥10 pounds (≥4.5 kg) | 18 | 24,069 | 0.97 | 0.55, 1.71 |
| Weight change of <10 pounds (±<4.5 kg) | 63 | 94,449 | 1.00 | Reference |
| Weight gain | ||||
| 10–<20 pounds (4.5–9 kg) | 58 | 96,641 | 0.82 | 0.56, 1.21 |
| 20–<30 pounds (9.1–13.5 kg) | 76 | 115,988 | 1.05 | 0.76, 1.50 |
| ≥30 pounds (≥13.6 kg) | 216 | 336,250 | 0.76 | 0.56, 1.03 |
| p for trend | 0.09 | |||
| Never smokers (n = 120) | ||||
| Weight loss of ≥10 pounds (≥4.5 kg) | 6 | 9,695 | 1.53 | 0.62, 3.80 |
| Weight change of <10 pounds (±<4.5 kg) | 23 | 32,929 | 1.00 | Reference |
| Weight gain | ||||
| 10–<20 pounds (4.5–9 kg) | 18 | 29,821 | 0.86 | 0.45, 1.64 |
| 20–<30 pounds (9.1–13.5 kg) | 19 | 28,923 | 0.99 | 0.53, 1.84 |
| ≥30 pounds (≥13.6 kg) | 54 | 85,725 | 0.76 | 0.45, 1.30 |
| p for trend | 0.24 | |||
All models included age (years—continuous), education (less than high school graduation, high school graduation, some college, college graduation, or postcollege), ethnicity (White, Black, or other), use of hormone replacement therapy (never/ever), intakes of total fat (g/day), fruits (servings/day), vegetables (servings/day), alcohol (drinks/week), and total calories (kcal/day) (all continuous), and physical activity (metabolic equivalents per week—continuous). Models for former smokers included the additional variables pack-years of smoking (>0–<20, 20–<40, 40–<60, or ≥60), age at quitting smoking (<35, 35–44, 45–49, 50–54, 55–59, or ≥60 years), and whether the participant had quit smoking because of a health problem (yes/no). Models for current smokers included pack-years of smoking in addition to the variables listed above for never smokers.
Numbers of cases were reduced because participants were asked about weight at age 18 years in the Observational Study only.