High fitness levels offset the increased risk of chronic obstructive pulmonary disease due to low socioeconomic status: A cohort study

Abstract

Objective Evidence suggests that higher cardiorespiratory fitness (CRF) levels can offset the increased risk of adverse outcomes due to other risk factors. The impact of high CRF levels on the increased risk of chronic obstructive pulmonary disease (COPD) due to low socioeconomic status (SES) is unknown. We aimed to assess the combined effects of SES and CRF on the future risk of COPD.

Methods We employed a prospective cohort of 2312 Finnish men aged 42–61 years at study entry. Socioeconomic status was self-reported and CRF was objectively assessed using respiratory gas exchange analyzers. Both exposures were categorized as low and high based on median cutoffs. Multivariable-adjusted hazard ratios (HRs) with confidence intervals (CIs) were estimated.

Results During 26.0 years median follow-up, 120 COPD cases occurred. Low SES was associated with increased COPD risk and high CRF was associated with reduced COPD risk. Compared with high SES-low CRF, low SES-low CRF was associated with an increased COPD risk 2.36 (95% CI: 1.44–3.87), with no evidence of an association for low SES-high CRF and COPD risk 1.46 (95% CI:0.82–2.60).

Conclusion In middle-aged Finnish men, SES and CRF are each independently associated with COPD risk. However, high CRF levels offset the increased COPD risk related to low SES.