Relationship between Environmental Noise Exposure in Hospitals and Respiratory Infections in Elderly Individuals with Cognitive Decline: A Retrospective Analysis.
Long-term environmental noise exposure is associated with an increased risk of respiratory tract infections in the elderly with cognitive decline, with cognitive impairment potentially aggravating this association by affecting behavioral adaptation and physiological stress responses.
Key Findings
Results
High environmental noise exposure significantly increased respiratory infection risk in elderly patients with cognitive decline.
Odds ratio = 1.092 (95% confidence interval: 1.009–1.182; P < 0.005) for respiratory tract infection associated with high noise exposure
Participants were stratified by WHO guidelines into high-noise (Lnight ≥ 55 dB, n = 46) and low-noise (Lnight < 55 dB, n = 46) groups
Total cohort comprised 92 elderly patients with cognitive decline (Mini-Mental State Examination ≤ 24)
Multivariate logistic regression was used to analyze the relationship between noise exposure and respiratory tract infection outcome
Results
The high-noise group demonstrated significantly elevated inflammatory markers compared to the low-noise group.
Inflammatory markers assessed included high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and neutrophil-to-lymphocyte ratio (NLR)
All inflammatory marker differences between groups were statistically significant (P < 0.05)
Spearman's rank correlation was used to evaluate the strength of association between Lnight and each inflammatory marker
Elevated inflammatory markers may represent a mechanistic pathway linking noise exposure to increased infection susceptibility
Results
The high-noise group showed poorer sleep quality as measured by the Pittsburgh Sleep Quality Index.
Sleep quality difference between high-noise and low-noise groups was statistically significant (P < 0.05)
Sleep disruption was identified as one potential mechanism through which noise may affect respiratory health
Pittsburgh Sleep Quality Index (PSQI) was the instrument used to assess sleep quality
The study enrolled elderly patients with cognitive decline, a population potentially more vulnerable to sleep disruption from noise
Results
High noise exposure was associated with higher systolic blood pressure and reduced autonomic function (heart rate variability) in elderly patients with cognitive decline.
Differences in systolic blood pressure and heart rate variability between high-noise and low-noise groups were statistically significant (P < 0.05)
Heart rate variability was used as a measure of autonomic nervous system function
Reduced heart rate variability in the high-noise group indicates diminished autonomic function
These cardiovascular and autonomic changes may contribute to increased physiological stress responses in this population
Results
High noise exposure was associated with reduced lung function in elderly patients with cognitive decline.
Lung function was measured as forced expiratory volume in 1 second to forced vital capacity ratio (FEV1/FVC%)
The difference in lung function between high-noise and low-noise groups was statistically significant (P < 0.05)
Reduced lung function in the high-noise group may contribute to increased vulnerability to respiratory tract infections
This is a retrospective cohort study, so causal directionality cannot be definitively established
Discussion
Cognitive impairment may aggravate the association between noise exposure and respiratory infection risk by affecting behavioral adaptation and physiological stress responses.
All study participants had cognitive decline defined by Mini-Mental State Examination score ≤ 24
The study was specifically designed to examine this vulnerable population, which may have reduced capacity to behaviorally adapt to noise (e.g., using earplugs or relocating)
Cognitive impairment was hypothesized to amplify the noise-infection association through impaired behavioral and physiological stress response mechanisms
This retrospective study design limits the ability to establish the independent contribution of cognitive impairment versus noise exposure
What This Means
This research suggests that elderly hospital patients who already have some degree of cognitive decline (memory or thinking problems) and are exposed to higher nighttime noise levels — defined as 55 decibels or more — face a meaningfully greater chance of developing respiratory infections compared to those in quieter environments. The study followed 92 such patients and found that those in noisy environments also had higher levels of inflammation markers in their blood, worse sleep, higher blood pressure, poorer lung function, and less stable heart rate patterns. All of these differences were statistically significant.
The researchers propose that noise may harm respiratory health through multiple pathways: disrupting sleep (which weakens the immune system), triggering chronic low-grade inflammation, and stressing the cardiovascular and nervous systems. For elderly people with cognitive decline specifically, the problem may be worse because they are less able to take steps to protect themselves from noise — such as using earplugs, asking for a quieter room, or recognizing and reporting disturbance — and their bodies may also respond to stress less effectively.
This research suggests that hospital noise management could be an important and underappreciated factor in preventing infections among cognitively impaired elderly patients. However, because this was a retrospective study (looking back at existing records rather than conducting a controlled experiment), it cannot definitively prove that noise directly causes respiratory infections — only that the two are associated. Future prospective studies and interventions to reduce hospital noise in wards housing cognitively impaired elderly patients would help clarify whether noise reduction could meaningfully lower infection rates in this group.
Zhang D, Yuan L. (2026). Relationship between Environmental Noise Exposure in Hospitals and Respiratory Infections in Elderly Individuals with Cognitive Decline: A Retrospective Analysis.. Noise & health. https://doi.org/10.4103/nah.nah_208_25