OBESITY AND RISK OF RENAL-CELL CANCER

In a population-based case control study including 449 directly interv iewed cases and 707 controls, we assessed the risk of renal cell cance r associated with height, weight, body mass index (BMI), and frequency of weight changes. Odds ratios and 95% confidence intervals were esti mated by using logistic regression models. Among women, risk increased with increasing usual BMI (P for trend < 0.001). A nearly 4-fold risk was found among the 10% of women with the highest usual BMI (odds rat io = 3.8; confidence interval = 1.7-8.4). Among men, no clear trend wa s observed with usual weight or BMI, although the highest risk (30-50% ) generally was seen among those in the upper deciles of weight or BMI . There was no clear indication that excess BMI early or late in life disproportionately affected risk. Risk also was not related to pattern s of weight fluctuations or use of diet pills. Our study supports prev ious observations linking renal cell cancer risk to increased BMI amon g women and suggests a weaker association in men. Given the increasing prevalence of obesity and the rising incidence of renal cell cancer i n the United States, additional studies are needed to disentangle the effects of BMI from various correlates and to identify the mechanisms by which obesity affects risk.