Prospective Studies of Body Mass Index with Head and Neck Cancer Incidence and Mortality
A partir des données des cohortes américaines "Cancer Prevention Study-II" et "Nutrition cohort" incluant 1 059 153 participants, cette étude évalue l'association entre l'indice de masse corporelle et le risque de cancer de la tête et du cou ainsi que la mortalité des patients
Background: Results of a pooled analysis of case-control studies show a higher risk of head and neck cancer (HNC) associated with a low body mass index (BMI) and a lower risk associated with being overweight or obese, compared to being normal weight. However, these results are prone to bias due to residual confounding by smoking, a strong risk factor, and possible weight loss prior to diagnosis. Using prospectively collected data from the Cancer Prevention Study-II cohort and the Nutrition cohort, we examined the association of BMI with HNC mortality and incidence, overall and by smoking status. Methods: Mortality analyses included 1,383 cases among 1,059,153 participants; incidence analyses included 340 cases among 150,262 participants. Multivariable Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association of BMI with HNC incidence and mortality. Results: Overall, compared to the category of BMI 22.5-24.9 kg/m2, the categories of BMI 25.0-29.9 kg/m2 and ≥30.0 kg/m2 were associated with a lower risk of HNC mortality but not incidence. In never smokers, there were no associations of BMI with HNC incidence or mortality. In smokers, BMI <22.5 kg/m2 was associated with a higher risk of HNC mortality (HR=1.42, 95% CI 1.20, 1.67). Conclusions: In this prospective cohort, there was no association between BMI and HNC incidence, although BMI was inversely associated with HNC mortality in smokers. Impact: These suggest that there is no etiological relationship between BMI and HNC.