Leisure-Time Physical Activity And Lung Cancer Risk: A Systematic Review And Meta-Analysis
Darren BRENNER, Alberta Health Services, Canada
YANNITSOS D. 1,2
, FARRIS M. 1,2
, JOHANSSON M. 4
, CHRISTINE F. 1,2,3
1 Department of Cancer Epidemiology and Prevention Research, Alberta Health Services, Calgary, Alberta, Canada
2 Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
3 Department of Oncology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
4 Section of Genetics, International Agency for Research on Cancer, Lyon France
Purpose: To examine the association between recreational physical activity and lung cancer risk to update previous analyses and to examine population subgroups of interest defined by smoking status and histology we conducted a systematic review and meta-analysis.
Methods: We searched the PubMed and MEDLINE databases for studies up to May 2015. Individual study characteristics were abstracted including study design, number of cases, assessment of recreational physical activity and type and level of adjustment for confounding factors. Combined effect estimates were calculated for the overall associations and across subgroups of interest.
Results: We identified 28 studies that were eligible for inclusion in the meta-analysis. The overall analysis indicated an inverse association between recreational physical activity and lung cancer risk (Relative Risk (RR), 0.76; 95% Confidence Interval (CI), 0.69-0.85, p-value: <0.001). Similar inverse associations with risk were also noted for all evaluated histological subtypes, including adenocarcinoma (RR, 0.80; 95% CI, 0.72-0.88), squamous (RR, 0.80; 95% CI, 0.71-0.90) and small cell (RR, 0.79; 95% CI, 0.66-0.94). When we examined effects by smoking status, inverse associations between recreational physical activity and lung cancer risk were observed among former (RR, 0.77; 95% CI, 0.69-0.85) and current smokers (RR, 0.77; 95% CI, 0.72-0.83), but not among never smokers (RR, 0.96; 95% CI, 0.79-1.18).
Conclusions: Results from this meta-analysis suggest that regular recreational physical activity is associated with reduced risk of lung cancer. Only four studies examining never smokers were identified, suggesting the need for additional research in this population.
Funding Source: None to declare.