A case-control study of risk factors for prostate cancer in Iran

Prostate cancer is a major cause of morbidity and mortality in Iran, yet there are few studies examining risk factors specific to the Iranian context. We conducted a case-control study to explore risk factors for prostate cancer in Mazandaran, Iran from 2005 to 2008. The cases were 137 men with clinicopathologically confirmed prostate cancer. Controls were 137 neighborhood and age match men without prostate cancer by PSA and digit examination. Analysis comprised an exploratory stage to identify potential risk factors, defined as variables associated with case status at the P < 0.20 level in conditional logistic regression. A second stage included all potential risk factors in multiple conditional logistic regression analysis, retaining those associated with prostate cancer at the P < 0.05 level. Potential risk factors for prostate cancer in exploratory analysis included family history of prostate cancer, history of other cancer, prostatitis, alcohol consumption, pipe or hookah smoking, walking to work, duration of occupational physical activity, intensity of occupational physical activity, body mass index, and older age. Multivariate analysis found intensity of occupational physical activity, prostatitis, and older age as independent predictors of increased risk for prostate cancer in this Iranian population. Our study confirms several recognized risk factors for prostate cancer, contributes evidence to the discussions of other hypothesized risk factors, and points to potentially new factors. Findings, along with confirmatory studies, can help guide efforts for early detection, treatment, and prevention for this common malignancy that is set to increase in Iran in future decades.