Pre-diagnosis recreational physical activity and lung cancer survival within the California teachers study

Although physical activity (PA) levels have been linked to decreased lung cancer mortality, the magnitude of associations and delineation of biological and behavioral risk factors are often inconsistent. Our study aims to address this gap by elucidating the associations of lung cancer survival while considering duration and intensity of prediagnosis PA levels.

We evaluated lung cancer-specific survival among 1768 women diagnosed with lung cancer in the California Teachers Study (1995-2019). PA was assessed at baseline and included lifetime PA (cumulative activity from high school through age 54) and recent PA (activity during the 3 years prior to enrollment), each quantified separately for moderate and strenuous intensity. These measures capture both long-term duration and short-term duration of PA at different intensities before diagnosis. Multivariable Cox proportional hazards models using age as the time scale were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for lung cancer-specific mortality.

Similar risks of lung cancer-specific mortality were observed across most PA variables. Among ever and/or former smokers, higher levels of moderate, lifetime PA were associated with lower lung cancer mortality (HR_ever = 0.77; HR_former = 0.63). In contrast, ever and/or current smokers who engaged in intermediate to high levels of strenuous, lifetime PA had higher mortality risk (intermediate: HR_ever = 1.24; HR_former = 1.39). Among never smokers, higher strenuous, lifetime PA was associated with lower mortality risk (HR = 0.69, 95% CI = 0.49-0.97), while intermediate levels of strenuous, recent PA were associated with higher mortality (HR = 1.62, 95% CI = 1.12-2.34).

The results of this study suggest that smoking significantly modifies the association between physical activity and lung cancer‑specific survival. The mechanisms underlying these patterns remain uncertain, and additional research is needed to clarify how physical activity duration and intensity relate to lung cancer prognosis across smoking histories.