1776P - Body composition in adult life and prostate cancer (PCa) incidence and mortality: The PROCA-life study

Background

The global increase in obesity parallels the increase in PCa incidence, but the role of excess weight and weight change throughout adult life and their implications for PCa risk and prognosis are still under debate. We studied whether pre-diagnostic body mass index (BMI) and weight change is linked to PCa risk and prognosis.

Methods

A total of 16 879 healthy men were included to study PCa risk and prognosis in the Prostate Cancer Study throughout life (PROCA-life), based on those who participated in the prospective cohort Tromsø Study (1994-2016). Pre-diagnostic BMI and weight change (relative weight change in percent of baseline weight between two waves of the Tromsø study) during follow-up were measured. Detailed information from histopathological and clinical medical records for PCa cases were obtained. Cox proportional hazard and logistic regression models were used to estimate hazard ratios (HRs) and odds ratios (ORs) for the associations between pre-diagnostic measurements of BMI and weight change during follow-up, and PCa risk and overall and PCa specific mortality. Regression models were used to evaluate incidence rate ratios (IRR).

Results

Overall, the participants had a median age at study entry of 44 years, 46.0% were overweight and 13.8% were obese. In total 904 men developed PCa during follow-up, with a median age at diagnosis of 68 years. The incidence rates for PCa increased from 1995 to 2019 (overall IRR 2.27, 95% CI 1.82-2.83). We observed that men with a pre-diagnostic BMI ≥ 30kg/m² at study entry, and who had a weight gain > 5% during follow-up, had a three-fold increased risk for incident PCa (HR 2.94, 95% CI 1.36-6.36). Overweight was associated with lower Gleason grade (OR 0.64, 95% CI 0.43-0.96) and lower Prostate Specific Antigen (OR 0.69, 95% CI 0.48-0.99). Overall, 311 PCa cases died, of whom 154 was PCa related deaths (17%). Pre-diagnostic obesity was associated with PCa-specific death (HR 1.73, 95% CI 1.03-2.91).

Conclusions

Our observation that weight gain in adult pre-diagnostic obese men was associated with increased risk for incident PCa, and that pre-diagnostic obesity increased the risk of PCa-mortality, support the importance to combat excess weight gain in the general population.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Data protection office at University Hospital of North-Norway (UNN).

Funding

University of Tromsø.

Disclosure

All authors have declared no conflicts of interest.