Abstract B08: Occupational and recreational physical activity in relation to prostate cancer aggressiveness: The North Carolina-Louisiana Prostate Cancer Project (PCaP)
Authors: Antwi Samuel , Steck Susan E. , Su L. Joseph , Blackard Bonny , Arp-Adams Swann , Hebert James R. , Fontham Elizabeth TH , Bensen Jeannette , Mohler James L. , Arab Lenore 
Published: May 2015

Background: Physical activity (PA) has been implicated in the etiology of prostate cancer (CaP). However, there are considerable inconsistencies in the epidemiological literature. This may be due to failure to examine associations by CaP aggressiveness. While most men will develop CaP if they live long enough, usually the disease is indolent; only aggressive disease is of prognostic relevance.

Methods: Associations of occupational and recreational PA in relation to CaP aggressiveness at diagnosis were examined in a large population-based, case-only study of incident CaP among African-American (n = 1,023) and European-American (n = 1,079) men (the North Carolina-Louisiana Prostate Cancer Project, PCaP). Men were classified as highly aggressive cases if Gleason sum =&gt; 8 or PSA &gt;20ng/ml or Gleason score =&gt; 7 and clinical stage T3-T4 (N = 370, 18%). All others (low and intermediate aggressive cases) were classified as the comparison group. Recreational PA was measured using a validated questionnaire and occupational PA was estimated based on current and longest-held job titles. Metabolic equivalents (MET) were estimated for recreational PA and job titles using the Compendium of Physical Activities. Associations between CaP aggressiveness at diagnosis and PA were assessed using logistic regression to calculate odds ratios (OR) and 95% confidence intervals (CI), adjusting for age, race, body mass index, CaP screening history, smoking status, and energy intake. Additional adjustment for educational status was done for the occupational PA models.

Results: Recreational PA, particularly walking for 75-150 minutes/week for exercise was associated with 33% lower odds of high aggressive CaP compared to no walking for exercise (OR= 0.67, 95% CI: 0.46-0.98). MET-hours/week from walking for exercise was inversely related to CaP aggressiveness, though did not reach statistical significance (OR= 0.77, 95% CI: 0.57-1.04, highest vs. lowest tertile; Ptrend = 0.08). PA at current job was associated with 28% lower odds of high aggressive CaP (OR= 0.72, 95% CI: 0.54-0.95, highest MET tertile vs. lowest). Conversely, the highest accumulation of PA at longest-held job (&gt;132 MET-years) was associated with 61% higher odds of presenting with high aggressive CaP compared to 60-90 MET-years (OR=1.61, 95% CI: 1.08-2.40). There was no evidence of interaction between PA and race on the association with aggressive CaP.

Conclusions: Walking for exercise and higher PA at current job were associated with reduced odds of high aggressive CaP. The positive association between highest PA at longest-held job and CaP aggressiveness may be influenced by residual confounding by low socioeconomic status, which often correlates with unhealthy lifestyle factors, such as poor diet.

Funding: PCaP is carried out as a collaborative study supported by the Department of Defense contract DAMD 17-03-2-0052.

Citation Format: Samuel Antwi, Susan E. Steck, L. Joseph Su, Bonny Blackard, Swann Arp-Adams, James R. Hebert, Elizabeth TH Fontham, Jeannette Bensen, James L. Mohler, Lenore Arab. Occupational and recreational physical activity in relation to prostate cancer aggressiveness: The North Carolina-Louisiana Prostate Cancer Project (PCaP). [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr B08. doi:10.1158/1538-7755.DISP13-B08