Patients had an average age of 62 years, 63 per cent were male and 88 per cent were white. 38 per cent of patients had a BMI of 30 or more, which is classified as obese, and this figure rose to 42 per cent in the patients with clear-cell RCC. By contrast, only 31 per cent of the patients with benign tumours were obese.67 per cent of the obese patients had malignant tumours with clear-cell RCC, compared with 57 per cent of the non-obese patients. The rates for the other kinds of malignant tumours - including papillary, chromophobe and collecting duct - were similar between the obese and non-obese patients.

"We also looked at other health and lifestyle factors, like diabetes, hypertension and smoking" adds Dr Lowrance. "This showed that the only other factors that were independent predictors of clear-cell RCC were male gender and tumour size."

The researchers conclude that BMI is an independent predictor of clear-cell RCC and that as BMI increases, the odds of having a clear-cell RCC also increases.

"Although we still need to find out more about the pathology of clear-cell RCC, this study is useful as it provides individual predictors of the chance of developing this form of cancer" concludes Dr Lowrance. "Of these, obesity provides the strongest association."

The article forms part of a free sample issue, which can be accessed online at: www3.interscience.wiley/journal/123215319/issue

Notes to editors

Obesity is associated with a higher risk of clear-cell renal cell carcinoma than with other histologies. Lowrance et al. BJUI. 105, pp16-20. (January 2010). DOI: 10.1111/j.1464-410X.2009.08706.x

Source: Wiley-Blackwell