Occupational noise exposure and its association with incident hyperglycaemia: a retrospective cohort study

Aircraft and road traffic noise, insulin resistance, and diabetes: The role of neighborhood socioeconomic status in San Diego County

Evidence linking traffic noise to insulin resistance and diabetes is limited and unanswered questions remain regarding the potential effect modification by neighborhood socioeconomic status (nSES). We aimed to assess socioeconomic inequalities in noise exposure, whether road and aircraft noise exposures were associated with insulin resistance or diabetes, and whether nSES modified these relationships. Among the Community of Mine Study in San Diego County, road and aircraft noise exposure at enrollment was calculated based on the static (participant's administrative boundary, and circular buffer around participant homes), and dynamic (mobility data by global positioning system, GPS) spatio-temporal aggregation methods. Associations of noise with insulin resistance (HOMA-IR) or type 2 diabetes (T2DM) were quantified using generalized estimating equation models adjusted for sex, age, ethnicity, individual income, and air pollution (nitrogen dioxide) exposure. Additive interaction between noise and nSES was assessed. Among 573 participants (mean age 58.7 y), participants living in low nSES were exposed to higher levels of aircraft and road noise using noise level at the census tract, circular buffer, or Kernel Density Estimation (KDE) of GPS data. Participants exposed to road noise greater or equal to the median (53 dB(A)) at the census tract and living in low nSES had an increased level of insulin resistance (β = 0.15, 95%CI: -0.04, 0.34) and higher odds of T2DM (Odds Ratio = 2.34, 95%CI: 1.12, 4.90). A positive additive interaction was found as participants living in low nSES had higher odds of T2DM. The impact of noise exposure on insulin resistance and T2DM differs substantially by nSES. Public health benefits of reducing exposure to road or aircraft noise would be larger in individuals living in low nSES.

Evaluating Risk of Noise-Induced Hearing Loss in Otologic Surgery

OBJECTIVES

To evaluate risk for noise-induced hearing damage from otologic surgery-related noise exposure, given recent research indicating that noise levels previously believed to be safe and without long-term consequence may result in cochlear synaptopathy with subsequent degeneration of spiral ganglion neurons, degradation of neural transmission in response to suprathreshold acoustic stimuli, and difficulty understanding in background noise.

METHODS

A prospective observational study of surgeon noise exposure during otologic and neurotologic procedures was performed in a tertiary care center. Surgeon noise exposure was recorded in A- and C-weighted decibel scales (dBA, dBC), including average equivalent (LA_eq) and peak (LA_peak, LC_peak) levels and noise dose.

RESULTS

Sound measurements taken at the ear with continuous recording equipment during cadaveric otologic surgery demonstrated LA_eq 80-83 dBA, LA_peaks of 105 dBA, LC_peaks of 127 dBC, with noise doses of 0.9% to 6.7%. Sound level measurements during live surgery translabyrinthine approaches yielded lower LAeq of 72 to 74 dBA and lower noise doses compared with temporal bone lab measurements. Raw sound recordings during live surgery demonstrated narrow band, high frequency, high amplitude spikes between 4 and 12 kHz.

CONCLUSION

Noise exposure to surgeons, staff, and patients in the operating room is acceptable per NIOSH recommendations. Temporal bone lab noise exposures are greater, possibly due to poorly maintained drill systems and lack of noise shielding from microscope bulk, yet are also within NIOSH recommended levels.

Relationship Between Chronic Noise Exposure, Cognitive Impairment, and Degenerative Dementia: Update on the Experimental and Epidemiological Evidence and Prospects for Further Research

Degenerative dementia, of which Alzheimer's disease is the most common form, is characterized by the gradual deterioration of cognitive function. The events that trigger and promote degenerative dementia are not clear, and treatment options are limited. Experimental and epidemiological studies have revealed chronic noise exposure (CNE) as a potential risk factor for cognitive impairment and degenerative dementia. Experimental studies have indicated that long-term exposure to noise might accelerate cognitive dysfunction, amyloid-β deposition, and tau hyperphosphorylation in different brain regions such as the hippocampus and cortex. Epidemiological studies are increasingly examining the possible association between external noise exposure and dementia. In this review, we sought to construct a comprehensive summary of the relationship between CNE, cognitive dysfunction, and degenerative dementia. We also present the limitations of existing evidence as a guide regarding important prospects for future research.

Occupational Noise Exposure and Incidence of High Fasting Blood Glucose: A 3-Year, Multicenter, Retrospective Study

The role of hazardous occupational noise exposure on the development of prediabetes is not well researched. We aimed to elucidate exposure to hazardous occupational noise as an independent risk factor for high fasting blood glucose (FBG). Participants exposed/non-exposed to occupational noise were recruited from the Common Data Model cohorts of 2013/2014 from two centers and were followed-up for 3 years. Multivariate time-dependent Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) and were adjusted for various covariates. Pooled HRs were calculated. Among the 43,858 participants of this retrospective cohort study, 37.64% developed high FBG. The mean (standard deviation) age in the cohort was 40.91 (9.71) years. In the fully adjusted models, the HRs of high FBG in the two centers were 1.35 (95% CI: 1.24-1.48) and 1.22 (95% CI: 1.17-1.28), and the pooled HR was 1.28 (95% CI: 1.16-1.41). A Kaplan-Meier plot of high FBG incidence by occupational noise exposure showed significant results (p < 0.001). We found that occupational noise exposure is significantly associated with high FBG. Preventing exposure to hazardous noise in the work environment may help reduce the risk for prediabetes among workers.

The Association between Noise Exposure and Metabolic Syndrome: A Longitudinal Cohort Study in Taiwan

Metabolic syndrome is becoming more common worldwide. Studies suggest environmental pollution, including traffic noise, might be linked with metabolic syndrome. This study sought to evaluate how noise exposure is linked to the development of metabolic syndrome and its components in Taiwan. Using data from a cohort of 42,509 participants and Cox proportional hazards regression models, the effects of noise exposure on metabolic syndrome and its components were quantified. After adjustment for covariates (age, gender, body mass index, and physical activity), the hazard ratio for metabolic syndrome was 1.13 (95% CI: 1.04–1.22) for medium noise exposure and 1.24 (95% CI: 1.13–1.36) for high noise exposure. Noise exposure was also positively associated with all of metabolic syndrome’s components. This finding suggests noise exposure might contribute to metabolic syndrome and its components. Policies aiming to reduce noise pollution might reduce the risks of metabolic syndrome and its components.