Influence of level of highest BMI on the age of onset of cancer

Obesity has been implicated as a risk factor for several types of cancer. This research examined whether the level of body mass index (BMI) at the time of the highest weight in one's life had an influence on the age of onset of cancer. The study focused on a subgroup of adults (89 males, 67 females) from the National Health and Nutrition Examination Survey 2007-2008 sample who were diagnosed with cancer (excluding skin cancer) after they had attained their highest BMI. Women were diagnosed with cancer 13.60 years after attaining their highest BMI, men were diagnosed 20.28 years later (t = 2.71, p < .01). Unadjusted means comparison indicated the onset of cancer was 14.27 years after attaining their highest BMI for those who were obese at their highest BMI, while the onset was 20.99 years later for people who were not obese. In multiple regression analysis, BMI (continuous variable) was negatively associated with the time lag for the onset of cancer (Beta = -.22, p < .05), controlling for gender, race, education, language at interview, income, and smoking. Treating BMI as a categorical variable, analysis of covariance indicated that people who were obese or overweight were likely to have cancer sooner compared to people with highest BMI < 25. Race and obesity had an interaction effect such that the onset age of cancer was sooner in the case of obese whites. Findings indicate the importance of level of highest BMI in a cancer patient's life for the onset age.