To research the connection between exercise and cancer of the lung among smokers and whether this relationship differed based on exercise intensity, smoking status, and gender.
A mechanical bibliographical search was conducted in five databases. Study inclusion criteria were: (i) the research population wasn’t identified as having cancer of the lung at baseline (ii) the research provided information in regards to the effect size exercise on the chance of developing cancer of the lung in smokers and (iii) the research distinguished different exercise intensity levels. Two authors individually extracted data and assessed the methodological quality. Pooled rate ratios (RR) were calculated for those data, as well as for subgroups of exercise intensity, smoking status, and gender.
Pooled RRs of seven cohort studies demonstrated that exercise was connected having a reduced chance of cancer of the lung in smokers (RR = 0.82, 95% CI = 0.77 .87). We didn’t find obvious dose–response relationship regarding exercise or smoking intensity, i.e. high amounts of exercise didn’t show a greater risk reduction than moderate exercise levels, and also the association between exercise and risk reduction didn’t differ between heavy and lightweight smokers. The lower risk connected with exercise was greater in females compared to men (p = 0.03), however this finding took it’s origin from just one study that reported data on women.
Outcomes of this meta-analysis indicate that free time exercise is connected with reduced chance of developing cancer of the lung among smokers. Future studies ought to provide understanding of a possible dose–response relationship, and really should use reliable and valid exercise measurements.