Nested case-control study of occupational physical activity and prostate cancer among workers using a job exposure matrix

Abstract

Objective: We conducted a nested case-control study of 362 cases diagnosed between 1 January 1988 and 31 December 1999, and 1,805 matched controls to examine the association between occupational physical activity and prostate-cancer incidence among workers at a nuclear and rocket engine-testing facility in Southern California.

Methods: We obtained cancer incidence data from the California Cancer Registry and seven other state cancer registries. Data from company records were used to construct a job exposure matrix (JEM) for occupational physical activity during employment. Conditional logistic regression was used to estimate associations.

Results: With adjustment for occupational confounders, including socioeconomic status and trichloroethylene (TCE) exposure, high activity levels at work were inversely associated with prostate-cancer incidence among aerospace workers (odds ratio [OR] = 0.55; 95% CI = 0.32-0.95), but not among radiation workers (OR = 0.95; 95% CI = 0.43-2.1).

Conclusions: Our results suggest that adult men who are more continually active at work may have a decreased risk of prostate cancer.