Cancer risks of police officers: the retrospective cohort mortality study of police, Buffalo, NY 1950 to 2005.
Little is known about the long term cancer risks police officers face. Police officers work long, irregular shifts which often include stressful situations. In 2007, the International Agency for Research on Cancer listed shift work that involves circadian disruption as a probable carcinogen to humans. The police cohort consisted of male officers (n = 3,049) who worked a minimum of 5 years for the Buffalo Police Department, New York, between January 1, 1950 and December 31, 2005. Female officers (n = 298), officers who did not have either birth data or hire date (n = 44), and officers who worked < 5 years (n = 33) were excluded from this analysis (N = 3,424). As of December 31, 2005, 50% of the population had died, 46% were alive, 4% were lost to follow-up. Mortality from all causes of death combined for police officers was significantly higher than expected (SMR = 1.20; 95% confidence interval (CI) = 1.14-1.26). Significantly increased mortality was also seen for all malignant neoplasms combined (SMR = 1.32; 1.19-1.46), all benign neoplasms combined (SMR = 2.48; 1.17-4.89), and all diseases of the circulatory system combined (SMR = 1.10; 1.02-1.19). The elevated mortality for all malignant neoplasms was primarily due to statistically significant excesses in cancers of the esophagus (SMR = 1.93; 1.08-3.18), colon (SMR = 1.83; 1.35-2.42), respiratory system (SMR = 1.24; 1.03-1.48), as well as Hodgkin's disease (SMR = 3.38; 1.23-7.36) and leukemia (SMR = 1.77; 1.08-2.73). Differences in cancer risk are noted for years employed and latency and other factors. Implications for future research on the effects of shift work and stress and prevention will be discussed.