Relationship between Environmental Noise Exposure in Hospitals and Respiratory Infections in Elderly Individuals with...

Hospital noise pollution poses major health risks for elderly urban residents, particularly those with cognitive decline (Mini-Mental State Examination ≤24). While noise may affect respiratory health through inflammation and sleep disruption, its direct association with infection rates in this vulnerable population remains unclear.

This retrospective cohort study enrolled 92 elderly patients with cognitive decline. Participants were stratified by World Health Organization guidelines into high-noise [night equivalent sound level (Lnight) ≥55 dB, n = 46] and low-noise (Lnight < 55 dB, n = 46) groups. Annual respiratory infection rates, inflammatory markers (high-sensitivity C-reactive protein, interleukin-6, and neutrophil-to-lymphocyte ratio), Pittsburgh Sleep Quality Index, lung function (forced expiratory volume in 1 s/forced vital capacity%), blood pressure, and heart rate variability were assessed. Spearman's rank correlation was used to evaluate the strength of the association between Lnight and each of the detection indicators. A multivariate logistic regression model was employed to analyze the relationship between each factor and the outcome of respiratory tract infection.

Compared with the low-noise group, the high-noise group demonstrated significantly elevated inflammatory markers, poorer sleep quality, higher systolic blood pressure, and reduced lung and autonomic functions (all P < 0.05). High noise exposure significantly increased respiratory infection risk (odds ratio = 1.092, 95% confidence interval: 1.009-1.182; P < 0.005).

Results suggest that long-term environmental noise exposure is associated with an increased risk of respiratory tract infections in the elderly with cognitive decline. Cognitive impairment may aggravate this association to some extent by affecting behavioral adaptation and physiological stress responses.