Cardiorespiratory fitness and risk of prostate cancer: findings from the Aerobics Center Longitudinal Study

Cancer Epidemiol. 2011 Feb;35(1):59-65. doi: 10.1016/j.canep.2010.07.013. Epub 2010 Aug 13.

Abstract

Objective: To examine the association between cardiorespiratory fitness (CRF) and risk of incident prostate cancer (PrCA).

Methods: Participants were 19,042 male subjects in the Aerobics Center Longitudinal Study (ACLS), ages 20-82years, who received a baseline medical examination including a maximal treadmill exercise test between 1976 and 2003. CRF levels were defined as low (lowest 20%), moderate (middle 40%), and high (upper 40%) according to age-specific distribution of treadmill duration from the overall ACLS population. PrCA was assessed from responses to mail-back health surveys during 1982-2004. Cox proportional hazards regression models, adjusted for potential confounders, were used to compute hazard ratios (HRs), 95% confidence intervals (95% CIs), and incidence rates (per 10,000 person-years of follow-up).

Results: A total of 634 men reported a diagnosis of incident PrCA during an average of 9.3 ± 7.1 years of follow-up. Adjusted HRs (95% CIs) in men with moderate and high CRF relative to low CRF were, 1.68 (1.13-2.48) and 1.74 (1.15-2.62), respectively. The positive association between CRF and PrCA was observed only in the strata of men who were not obese, had ≥ 1 follow-up examination, or who were diagnosed ≤ 1995.

Conclusions: Rather than revealing a causal relationship, the unexpected positive association observed between CRF and incident PrCA is most likely due to a screening/detection bias in more fit men who also are more health-conscious. Results have important implications for understanding the health-related factors that predispose men to receive PrCA screening that may lead to over-detection of indolent disease.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Body Mass Index
  • Cardiovascular Physiological Phenomena*
  • Exercise*
  • Follow-Up Studies
  • Humans
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Prostatic Neoplasms / epidemiology*
  • Respiratory Physiological Phenomena*
  • Risk Factors
  • Survival Rate
  • Young Adult