Background: The association between body mass index (BMI) and prostate cancer (Pca) remains a controversial subject. Despite Pca being common in Tanzania, there is a scarcity of data on the role of BMI on Pca risk. This study aimed to assess the association between Pca and BMI among African men in Tanzania.

Methods: This analysis included Tanzanian men aged ≥40 years who underwent prostate biopsy for the elevated prostate-specific antigen of >4 ng/mL during community-based Pca screening. Gleason scores of all Pca cases were determined by an experienced pathologist. BMI was calculated by dividing weight in kilograms by height in metre square. Participants were categorised into four BMI categories as follows: underweight (<18.5 kg/m²), normal weight (18.5–24.9 kg/m²), overweight (25.0–29.9 kg/m²) and obese (≥30 kg/m²). A high Gleason score refers to any score of ≥4+3. Logistic regression was used to estimate the odd ratio of each BMI category for the risk of Pca and high Gleason score.

Results: A total of 572 men underwent prostate biopsy after being found to have an elevated prostate-specific antigen of >4 ng/mL during screening. Of these, normal BMI accounted for 233 (40.7%), while overweight and obesity accounted for 153 (26.7%) and 141 (24.7%), respectively. In multivariate analysis, overweight men had significantly higher odds of being diagnosed with Pca (OR 6.95, 95% CI; 3.43–14.06) as compared to their normal-weight counterparts. The strength of the association became stronger among obese participants (OR 23.65, 95%CI; 11.45–48.87). Similarly, there was a significant increase in the odds of being diagnosed with high Gleason score Pca among obese men (OR 3.63, 95%CI; 1.52–8.70).

Conclusion: Tanzanian men with elevated prostate-specific antigen and a high BMI have a significant risk of being diagnosed with Pca, mostly with a high Gleason score. Normal BMI maintenance might help in reducing the risk of developing Pca.