DIETARY RISK-FACTORS FOR RENAL-CELL CARCINOMA IN DENMARK

The role of diet in the aetiology of renal cell carcinoma was investig ated in a population-based case-control study in Denmark. Cases were 2 0-79 years old, with a histologically verified diagnosis of renal cell carcinoma. Controls were sampled from the general population and were frequency-matched on age and sex. A total of 351 cases (73% of the el igible) and 340 controls (68% of the eligible) were included in the st udy. Dietary information was obtained in a self-administered food freq uency questionaire and the information was confirmed in a subsequent i nterview performed by trained interviewers who also elicited informati on on other suspected risk factors such as smoking, occupation, medica l history, education and reproductive history. Logistic regression mod els were used to calculate the odds ratios, and, both frequency of con sumption of various food stuffs and computed nutrients were examined. A positive association was observed between risk of renal cell carcino ma and total energy intake (odds ratio, OR, for highest quartile compa red to lowest: 1.7 (95% confidence interval, CI, 1.0-3.0) for men, and 3.5 (95% CI 1.6-6.5) for women), fat intake (OR for highest quartile compared to lowest: 1.9 (95% CI 1.1-3.5) for men, and 3.3 (95% CI 1.6- 6.9) for women). For women, an effect was also seen for intake of carb ohydrates (OR for highest quartile compared to lowest: 3.2 (95% CI 1.5 -6.8), while no protective effect was seen for vegetables or fruit. Da iry products may be associated with risk of renal cell cancer (OR for women using thickly spread butter compared to thinly spread: 11.4 (95% CI 2.8-45), OR for women who drank more than one glass of milk with 3 .5% fat content compared to never drink milk: 3.7 (95% CI 1.2-11). As expected, total energy intake, intake of fat, protein and carbohydrate s were closely correlated making it difficult to identify one of the e nergy sources as more closely associated with risk of renal cell cance r than the other. Several energy sources have been identified as possi ble risk factors for renal cell. carcinoma. It is possible that a high energy intake as such rather than the individual sources are responsi ble for the increased risk. Furthermore, dairy fats may be associated with renal cell carcinoma risk. The observed associations appeared str onger in women, and did not explain the association with obesity and l ow socio-economic status previously found in Denmark. (C) 1996 Publish ed by Elsevier Science Ltd