Particulate matter and their interaction of physical activity on ovarian cancer survival: A prospective cohort study

Insufficient data exists regarding the trade-off between the survival benefits of exercise in patients with ovarian cancer (OC) and the potential risks associated with increased particulate matter (PM) exposure during physical activity (PA). This study included 822 individuals newly diagnosed with OC. The total PA and subtypes (occupational [OPA], traffic [TPA], household [HPA], leisure-time [LTPA]) were assessed for the year preceding diagnosis using the Physical Activity Questionnaire of the China Kadoorie Biobank. The residential average PM concentrations 1-year before the date of OC diagnosis were assessed by random forest models at a 1 km × 1 km resolution. The comprehensive exposure to three types of PM was evaluated using a PM score (PMS). In addition, we further examined interaction of PMS with different types of PA on OC survival. Cox proportional hazard models were employed to determine hazard ratios (HRs) and their corresponding 95 % confidence intervals (CIs). Through a median follow-up of 44.95 months, 373 deaths were documented. The highest tertile of the total PA (HR = 0.68, 95 %CI = 0.53, 0.87), TPA (HR = 0.66, 95 %CI = 0.47, 0.95), HPA (HR = 0.41, 95 %CI = 0.25, 0.67), and LTPA (HR = 0.02, 95 %CI = 0.01, 0.05) showed improved overall survival (OS) compared with the lowest tertile, OPA decreased OS (HR = 1.50, 95 %CI = 1.17, 1.92). Additionally, a 34 % reduction in OC survival was observed with each standard deviation rise in PMS (95 %CI = 1.10, 1.63). Notably, OPA intensified PMS-related OS reductions, while total PA, HPA, and LTPA attenuated this association. We revealed that joint exposure to comprehensive PM was significantly linked to decreased OS of patients with OC, particularly for those primarily engaged in OPA. However, the long-term benefits of total PA, HPA, and LTPA may ameliorate the adverse effects of comprehensive PM exposure during PA.