Waist circumference, waist-hip ratio, body mass index, and prostate cancer risk: results from the North-American case-control study Prostate Cancer & Environment Study

INTRODUCTION: The evidence on the association between anthropometric measures quantifying body fatness and prostate cancer (PCa) risk is not entirely consistent. Associations among waist circumference (WC), waist-hip ratio, body mass index (BMI), and PCa risk were assessed in a population-based case-control study.

PATIENTS AND METHODS: The study included 1933 incident PCa cases diagnosed between 2005 and 2009. Population controls were 1994 age-matched (±5y) Montreal residents selected from electoral lists. Information on sociodemographics, medical history including PCa screening, height, weight, and waist and hip circumferences was collected through interviews. Logistic regression was used to assess odds ratios (ORs) for the association between anthropometric measures, and overall and grade-specific PCa.

RESULTS: After adjustment for BMI, an excess risk of high-grade PCa (Gleason≥7) was associated with a WC ≥102cm (OR = 1.47 [1.22-1.78]) and with a waist-hip ratio >1.0 (OR = 1.20 [1.01-1.43]). Men with a BMI≥30kg/m(2) had a lower risk of PCa, regardless of grade. Restricting to subjects recently screened for PCa did not alter findings.

CONCLUSION: Elevated BMI was associated with a lower risk of PCa, regardless of grade. Contrastingly, abdominal obesity, when adjusted for BMI, yielded results in the opposite direction. Taken together, our observations suggest that the specific body fat distribution (abdominal), for a given BMI, is a predictor of PCa risk, whereas BMI alone is not. BMI and abdominal obesity, especially when measured by the WC, should be examined conjointly in future studies on this issue and may require consideration at patient counseling.