Hypertension in adolescence is not an independent risk factor for renal cancer: A cohort study of 918,965 males

Background: Hypertension has been repeatedly linked to renal cell cancer, independent of overweight and anti-hypertensive drug use, but its role remains unclear, especially within the growing group of relatively young-middle aged renal cancer patients. In order to delineate the role of hypertension in early onset renal cancer, we examined the association of blood pressure measured at age 17 with the incidence of renal cancer. Methods: Sociodemographic and medical data of 918,965 adolescent males examined for fitness for military service from 1967 to 2005 were linked to the National Cancer Registry in this nationwide population-based cohort study (12,910,585 person years) to obtain cancer incidence. A single measurement of blood pressure at age 17 was stratified as optimal (<120/80), normal (>= 120/80 < 130/85), high normal (>= 130/85 < 140/90), or high (>= 140/90). We used Cox proportional hazards modeling to estimate the hazard ratio of the blood pressure categories for renal cancer, adjusted for year of birth, body mass index, origin of parents, and height. We also assessed the role of a clinical diagnosis of persistent hypertension (n = 4223, based on multiple measurements). Results: Of those who had their blood pressure recorded, 90 examinees developed renal cancer. In a multivariable model, the higher categories of blood pressure were associated with a decreased risk of renal cancer (hazard ratio, 0.32; 95% confidence interval, 0.12-0.84; P = .021 for blood pressure >= 140/90 vs < 120/80). Furthermore, there was no evidence of increased risk for those with an established diagnosis of hypertension (hazard ratio, 1.28; 95% confidence interval, 0.17-9.50; P = .81). Conclusions: It is unlikely that hypertension in adolescents carries an increased risk for renal cancer. (c) 2013 American Society of Hypertension. All rights reserved.