In this interview Mark A. Preston, MD, MPH, of Brigham and Women’s hospital sat down with Richard. R. Kerr, Urology Times content channel director, to discuss the association between obesity and incidence of total and fatal renal cell carcinoma in two prospective cohorts. The interview was conducted during the AUA annual meeting in New Orleans.
What did your study findings show about the effect of obesity on renal carcinoma incidence?
A number of recent studies have reported on the obesity paradox in kidney cancer, with the finding that obese people appear to be at higher risk for developing kidney cancer but at a lower risk of dying from kidney cancer. The reason for that is not entirely clear, but there is thought that maybe the obese milieu may provide some protective effects for death in kidney cancer.
We wanted to study that in more detail. At the Harvard School of Public Health, we have a number of very large and very long-running prospective cohorts, including the Nurses’ Health Study, which started in 1976, and the Health Professionals Follow-up Study, which started in 1986. We were able to combine these two cohorts, and we have over 170,000 people who were followed between 30 and 40 years, with surveys done every 2 years to ascertain BMI measurements and all lifestyle risk factors, diseases, food frequency, medications, etc. to get an overall assessment of these subjects over 30 to 40 years.
We specifically looked at the risk of developing kidney cancer, and we had over 500 cases of kidney cancer that developed during the follow-up period. We wanted to focus on the subset of kidney cancers that were actually fatal as well. The impact of BMI and how that resulted into kidney cancer was examined. We found there was an increased risk of not just kidney cancer, but death from kidney cancer, in people who had a BMI between 25 and 30 and especially if BMI was above 30, which contradicted a lot of those other studies.