Adolescent obesity and paternal country of origin predict renal cell carcinoma: A cohort study of 1.1 million 16 to 19-year-old males

Purpose: The incidence of renal cell carcinoma has increased in recent decades, particularly among middle-aged adults. Early precursors of renal cancer remain unclear. We evaluated the association of body mass index and height determined in late adolescence, and paternal or grandpaternal country of origin with the risk of renal cell carcinoma. Materials and Methods: Health related data on 1,110,835 males at ages 16 to 19 years who were examined for fitness for military service between 1967 and 2005 were linked to the Israel National Cancer Registry in this nationwide, population based cohort study. We used Cox proportional hazards modeling to estimate the HR of renal cell carcinoma associated with birth year, body mass index, height, father country of origin and socioeconomic indicators. Results: During 19,576,635 person-years of followup renal cancer developed in 274 examinees. Substantial excess risk was conferred by a body mass index of greater than 27.5 kg/m² compared to less than 22.5 kg/m² (HR 2.43, 95% CI 1.54-3.83, p <0.0001). Asian or African origin was protective compared to European origin (African origin HR 0.67, 95% CI 0.49-0.92). Conclusions: Overweight in late adolescence is a substantial risk factor for renal cell carcinoma. European origin is independently associated with excess risk and it persists among Israeli born males. Preventing childhood obesity may be a promising target for decreasing the burden of renal cancer.