Bisphenol A and other environmental risk factors for prostate cancer in Hong Kong

Background: Environmental exposures are contributing factors to prostate cancer etiology, but these remain unclear. We aimed to document the associations between environmental risk factors and prostate cancer in Chinese, with special reference to bisphenol A (BPA).

Methods: We recruited 431 newly diagnosed prostate cancer cases and 402 age-matched controls from Prince of Wales Hospital in Hong Kong. We obtained each participant's clinical data and epidemiological information on chronic BPA exposure and other environmental risk factors (e.g., dietary habits, occupation and shift work) using a standard questionnaire. A new assessment tool of environmental BPA exposure was developed and replicated. Multiple logistic regression analysis was performed to examine odds ratio (OR) and 95% confidence interval (95% CI) for the association of prostate cancer with a novel cumulative BPA exposure index (CBPAI) and other environmental risk factors.

Results: Weekly consumption of deep fried food (OR=1.85, 95% CI: 1.15-2.95) and pickled vegetable (OR=1.87, 95% CI: 1.07-3.28) was significantly associated with excessive prostate cancer risk. Prostate cancer was positively associated with nightshift work (OR=1.76, 95% CI: 1.07-2.89) and it was negatively associated with green tea drinking (OR=0.56, 95% CI: 0.34-0.91). There was a positive exposure-response relationship between CBPAI and prostate cancer, with the greatest and significant risk in the high versus reference category (OR=1.57, 95% CI: 1.01-2.44).

Conclusions: Frequent consumption of deep fried food and pickled vegetable, non-habitual green tea drinking and nightshift work are the contributing risk factors to prostate cancer in Hong Kong Chinese. More importantly, this study provides the first epidemiological evidence on carcinogenicity of BPA on the human prostate.