Birth size and subsequent risk for prostate cancer: a prospective population-based study in Norway

Studies on birth size characteristics and adult risk for prostate cancer have been few and inconclusive. We prospectively examined the association between birth size and risk for prostate cancer with particular emphasis on metastatic disease. A total of 19,681 singleton males born between 1920 and 1958, whose birth records were kept at St. Olav's University Hospital (Trondheim, Norway), were followed up for prostate cancer by linkage to the Norwegian Cancer Registry. A total of 159 cases of prostate cancer were diagnosed during follow-up; 33 had metastases at diagnosis. Overall, there was little evidence for any association between birth size and prostate cancer risk; however, there was a positive association for birth size and metastatic disease. Men in the highest quartile of birth length (> or =53 cm) had a relative risk of 2.5 (95% CI 1.0-6.3) compared to men in the lowest quartile (<51 cm). Further, men in the highest quartile of both birth weight and birth length had a relative risk of 3.8 (95% CI 1.2-12.0) for metastatic prostate cancer compared to men in the lowest category of both factors. These results support the hypothesis that factors that determine intrauterine growth could be important for aggressive forms of prostate cancer in adulthood.