Prior work has suggested that body size and fat content may influence certain carcinogen-DNA adduct levels measured in white blood cells because the parent compounds of the bulky aromatic adducts are lipid soluble and sequestered in fat stores making them unavailable to form adducts. Here we consider energy balance in a broader sense by assessing the impact of body mass index (BMI), physical activity and calorie intake on the presence of benzo[a]pyrene-DNA (BP-DNA) adducts in white blood cell DNA. Study subjects were part of a chemoprevention trial testing whether antioxidant micronutrient supplementation reduces genetic damage induced by cigarette smoking. Physical activity data were collected by the Paffenbarger questionnaire at 12 months of follow-up and food frequency data used to estimate calorie intake was collected at 15 months of follow-up. BP-DNA adduct levels were measured by HPLC in white blood cell samples collected at 12 months of follow-up. Complete data were available on 146 individuals. Logistic regression analyses showed that increasing in BMI was inversely associated with the presence of detectable adducts (OR=0.90 per one unit difference in BMI, P=0.02) and increasing hours of moderate intensity physical activity was associated with the presence of detectable adducts (OR=1.04 per one hour difference in activity, P=0.04). Hours of vigorous intensity activity and calorie intake were not associated with the presence of BP-DNA. These results provide further evidence that body fat content influences carcinogen-DNA adduct levels, probably by altering the distribution of the lipophilic parent compounds. Since cancer development and cancer treatment are often associated with changes in weight and fat mass, these findings have important implications for a number of published case-control studies of carcinogen-DNA adducts in which blood samples were drawn from cases at the time of, or after cancer diagnosis.

[Proc Amer Assoc Cancer Res, Volume 47, 2006]