Association of Body Mass Index with Risk of Lung Cancer: Evidence from a Middle-Aged male Cohort in Shanghai, China

OBJECTIVE To investigate the relationship between body mass index (BMI) and lung cancer risk among men in urban Shanghai, China.

METHODS Between January 1, 1986 and September 30, 1989, a total of 18,244 male residents of urban Shanghai were recruited in the prospective cohort study. The eligible study subjects were those aged 45 to 64 years and without history of cancer. Through July 10^th, 2003 (17 years follow-up), 467 new cases of lung cancer were identified in the cohort. Cox regression models were used to estimate the adjusted relative risks (RRs) and 95% confidence intervals (CIs).

RESULTS The risk of lung cancer decreased with increasing in BMI. After adjustment for some potential confounding factors, a relative risk of 0.6 (highest versus lowest quintile of BMI) was observed (P-trend =0.01). Stratified by smoking status, an inverse association of body mass index with lung cancer risk still existed among current smokers. There were too few cases of lung cancer to draw a valid result among men who never smoked. The results also showed that the association of BMI with the risk of lung adenocarcinoma was more apparent than with other histological subtypes.

CONCLUSION An inverse association of BMI with lung cancer risk may exist among men in Shanghai.