Physical activity modifies the association between source-specific noise exposure and chronic pain: A cross-sectional analysis of NHANES 1999–2004

Background: Chronic pain is a prevalent public health problem, and environmental noise exposure has been implicated as a potential risk factor. However, evidence remains limited regarding different sources of noise exposure and whether lifestyle factors, such as physical activity, modify the association between noise exposure and chronic pain. Methods: We conducted a cross-sectional analysis of adults aged ≥18 years using data from the National Health and Nutrition Examination Survey (NHANES) 1999–2004. Noise exposure was assessed by self-reported occupational noise exposure, non-occupational noise exposure, and firearms noise exposure. Chronic pain was defined as self-reported pain lasting more than one year. Total physical activity was quantified as metabolic equivalent of task minutes per week (MET-min/week) and categorized into tertiles. Survey-weighted logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for demographic, socioeconomic, behavioral, and clinical covariates. Subgroup analyses and sensitivity analyses were performed to assess the robustness of the findings and potential effect modification. Results: Among 1,869 participants included in the analysis, 790 reported chronic pain. In fully adjusted models, firearms noise exposure was significantly associated with higher odds of chronic pain (OR 1.77, 95% CI 1.25–2.51; P = 0.003), whereas occupational and non-occupational noise exposures were not. Physical activity significantly modified the association between firearms noise exposure and chronic pain (P for interaction = 0.012). Stratified analyses showed that firearms noise exposure was strongly associated with chronic pain among individuals in the lowest physical activity tertile (OR 3.42, 95% CI 2.11–5.55; P