INTERNATIONAL RENAL-CELL CANCER STUDY .3. ROLE OF WEIGHT, HEIGHT, PHYSICAL-ACTIVITY, AND USE OF AMPHETAMINES

Although numerous studies have identified obesity or high relative wei ght as a risk factor for renal-cell cancer in women, the degree to whi ch this effect is present in men remains unclear. A multicenter popula tion-based case-control study concerning incident cases of histologica lly verified renal-cell cancer (n = 1,732) and age- and sex-matched co ntrols (n = 2,309) was conducted in Australia, Denmark, Germany (2 cen ters), Sweden and the United States. Relative weight was estimated by the body mass index, and the association between this factor and other factors, such as height, physical activity and use of amphetamines, w as measured by the relative risk estimated in logistic regression mode ls. Body mass index was found to be a risk factor among women and, to a lesser extent, among men. A 3-fold increased risk (RR = 3.6, 95% CI = 2.3-5.7) was observed for women with a relative weight in the top 5% compared with those in the lowest quartile. Rate of weight change (es timated as weight change per annum in kilograms) appeared to be an ind ependent risk factor among women but not among men. Physical activity and height were unrelated to risk of renal-cell cancer regardless of l evel of BMI, while use of amphetamines was associated with an increase d risk among men, although no dose or duration effect was seen. Our fi ndings verify the link between high relative weight and risk of renal- cell cancer, particularly among women. The mechanism that underlies th is association is, however, still unclear, although the rate of weight change may play a role. (C) 1995 Wiley-Liss, Inc.