Anthropometric measures and physical activity and the risk of lung cancer in never-smokers: a prospective cohort study.
Worldwide, lung cancer in never-smokers is ranked the seventh most common cause of cancer death; however, the etiology of lung cancer in never-smokers is unclear. We investigated associations for body mass index (BMI) at various ages, waist circumference, hip circumference, and physical activity with lung cancer in 158,415 never-smokers of the NIH-AARP Diet and Health Study. Multivariable hazard ratios (HR) and 95% confidence intervals (CI) were estimated from Cox proportional hazards models. Over 11 years of follow-up, 532 lung cancer cases occurred. The risk estimate for obese (BMI ≥ 30 kg/m(2)) participants at baseline was 1.21 (95%CI = 0.95-1.53) relative to those with a normal BMI between 18.5 ≤ BMI<25.0. Overweight (25.0 ≤ BMI<30.0) at age 18 (HR(overweight-vs-normal) = 1.51;95%CI = 1.01-2.26) and time spent sitting (HR(≥ 3 hrs-vs-<3 hrs) = 1.32;95%CI = 1.00-1.73) was each associated with lung cancer after adjustment for baseline BMI, as was waist (HR(Q4-vs-Q1) = 1.75;95%CI = 1.09-2.79) and hip circumference (HRQ4-vs-Q1 = 0.62;95%CI = 0.39-0.99), after mutual adjustment for each other and baseline BMI. No associations were observed for vigorous activity or television watching. In summary, using a large prospective cohort study, we found no evidence that BMI at baseline or middle age was associated with decreased lung cancer risk in never smokers. If anything, we observed some evidence for positive associations with a larger BMI or waist circumference.
Genetic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, Maryland, United States of America. lamt@mail.nih.gov
Tram Kim
TK
Lam
Steve C
SC
Moore
Louise A
LA
Brinton
Llewellyn
L
Smith
Albert R
AR
Hollenbeck
Gretchen L
GL
Gierach
Neal D
ND
Freedman
D000230:Adenocarcinoma / Q000453:epidemiology* / Q000209:etiology; D000368:Aged; D015992:Body Mass Index; D015444:Exercise; D005260:Female; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000453:epidemiology* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D050177:Overweight / Q000150:complications; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D055105:Waist Circumference