Abstract
A40
Background: Little is known about racial/ethnic differences in prostate cancer (PCa) epidemiological risk factors. Some previous studies conducted in predominantly white populations have reported working in job with sedentary or light physical activity to be associated with increased PCa risk. This study evaluated the role of occupational physical activity as a possible explanation for disparate PCa risk in minority populations with known differences in risk. African-American men have the highest incidence rate in the world, whereas incidence in Hispanic men is slightly lower than in white men. Methods: This case-control study included 485 Texas men with PCa (176 of Mexican descent and 309 African-Americans) along with 481 age- and ethnicity-matched controls (174 of Mexican descent and 307 African-Americans). Demographic, lifetime occupational history, family history of cancer, lifestyle (e.g., smoking, alcohol, diet, and recreational physical activity) and anthropometric information were collected by personal interviews. Occupational physical activity was determined using a job-exposure matrix for each reported job. Results: Multivariable logistic regression models adjusted for relevant covariates (i.e., education, family history of PCa, and screening history) were used to evaluate the independent effect of physical activity within each racial/ethnic group. Leisure-time physical activity and obesity were not associated with PCa risk in either group. Among participants of Mexican descent, cases were about 50% less likely to work in jobs with moderate/high occupational physical activity (OR = 0.5, P = 0.003) compared to controls. However, among African-Americans, physical activity was not associated with PCa risk (OR = 0.8, P = 0.2). Mexican-American cases and controls were more likely to have moderate/high levels of occupational physical activity (51.7% and 67.5%, respectively) compared to African-American cases and controls (45.8% and 52.3%, respectively). Conclusions: We found that working in occupations with high levels of physical activity remained protective against PCa among Mexican-Americans after adjusting for relevant covariates, but not among African-Americans. Since Mexican-Americans were more likely to be working in physically active jobs compared to African-Americans, it is possible that this difference may partially explain differences in PCa rates between these two groups. These results could be used for the development of future racially-/ethnically-tailored interventions to target physical activity as well as other modifiable factors, such as dietary intake, to decrease PCa risk in these understudied populations.
First AACR International Conference on the Science of Cancer Health Disparities-- Nov 27-30, 2007; Atlanta, GA