Risk factors for prostate cancer: A national case-control study
Review of: Cox B, Sneyd MJ, Paul C, Skegg DC. Int. J. Cancer: 119, 1690–1694 (2006)
As reported in a recent issue of the International Journal of Cancer, a research group from New Zealand utilized the statutory notification of cancer in their country to investigate risk factors for prostate cancer in a large national population-based case-control study.
Data obtained from telephone interviews with 923 cases and 1,224 controls of European descent contain information about previous illnesses, smoking and alcohol consumption, PSA testing and digital rectal examination, previous urological symptoms and operations, a family history of cancer and sociodemographic characteristics. For inclusion in the study, all subjects had to have been married at some time and never married men were excluded to avoid inappropriate questioning about vasectomy. Control subjects were randomly selected from the general electoral roll and frequency matched in 5-year age groups to the cases of prostate cancer. Those with a history of prostate cancer were excluded.
An increased risk of prostate cancer was found among men with a history of prostate cancer in first degree relatives (RR 2.6; 95% CI, 1.9–3.7) and an increased risk of prostate cancer related to length of marriage among men married only once and still married at interview. Somewhat surprisingly, men less than or equal to 1.7 m in height at age 20 years had a lower risk of prostate cancer than men taller at that age according to analysis of a consecutive subgroup of 550 cases and 819 controls. The authors found no association between weight or body mass index and risk of prostate cancer.
In the last decade, a multitude of different risk factors for development of prostate cancer has been studied extensively, including obesity, height, weight, body mass index, physical activity, dietary factors, in particular intake of fat, vitamins and selenium with inconsistent results. One consistent finding, however, has been an increased risk among men with a strong family history of prostate cancer and this was also confirmed here in accordance with previous reports. More interestingly, the authors found an increase in the risk of prostate cancer with increasing length of marriage among men married only once and still married at interview. As the authors comment themselves, no biological reason has been identified to explain this association and further studies are needed to confirm if length of marriage is truly related to the risk of prostate cancer.