BMI trajectories and risk of overall and grade‐specific prostate cancer: An observational cohort study among men seen for prostatic conditions

BACKGROUND: Dynamic longitudinal patterns in body mass index (BMI) have been suggested to better predict health outcomes than static measures. Effects of BMI trajectories on prostate cancer (PCa) risk have not been thoroughly explored. METHODS: Cohort data were derived from electronic medical records of patients who were admitted to a tertiary‐care hospital in the Southeastern USA during 1994‐2016. Patients with a history of urologic clinic visit because of any prostatic condition and with repeatedly measured BMI (n = 4857) were included. BMI trajectories prior to PCa diagnosis were assessed using the developmental trajectory analysis method. Cox proportional hazards regression modeling was used to estimate adjusted hazard ratio (aHR) with 95% confidence intervals (CIs) for overall and grade‐specific PCa. RESULTS: The median age (interquartile range, IQR) of the participants at baseline was 63 (54, 72) years. Over a median follow‐up (IQR) of 8.0 (2.0, 13.0) years, 714 (14.7%, 714/4857) were diagnosed with PCa. Men with growing BMI trajectory progressing from normal weight to overweight/obese had a 76% increased PCa risk (aHR = 1.76; 95% CI: 1.25, 2.48), and men being obese and experiencing progressive weight gain had 3.72‐fold increased PCa risk (aHR = 3.72; 95% CI: 1.60, 8.66), compared to men with persistently normal BMI. The associations were more pronounced for PCa with Gleason score ≥7. No significant association of decreasing BMI trajectory progressing from obese to normal BMI was found with PCa risk. CONCLUSIONS: Progressively body weight gain during middle‐to‐late adulthood was associated with increased PCa risk for both normal weight and overweight men. Further studies are warranted to confirm this finding.