Occupational noise exposure and noise-induced hearing loss are associated with work-related injuries leading to admission to hospital.

OBJECTIVE: This study focuses on work-related injuries that required admission to hospital in a population of male workers exposed to occupational noise (≥80 dBA) which some displayed a hearing loss due to their exposure. METHODS: The study population count 46 550 male workers, 1670 (3.6%) of whom incurred at least one work-related injury requiring admission to hospital within a period of 5 years following hearing tests conducted between 1987 and 2005. The noise exposure and hearing loss-related data were gathered during occupational noise-induced hearing loss (NIHL) screening. The hospital data were used to identify all members of the study population who were admitted, and the reason for admission. Finally, access to the death-related data made it possible to identify participants who died during the course of the study. Cox proportional hazards model taking into account hearing status, noise levels, age and cumulative duration of noise exposure at the time of the hearing test established the risk of work-related injuries leading to admission to hospital. RESULTS: For each dB of hearing loss, a statistically significant risk increase was observed (HR=1.01 dB 95% CI 1.006 to 1.01). An association (HR=2.36 95% CI 2.01 to 2.77) was also found between working in an occupational ambient noise ≥100 dBA and the risk of injury. CONCLUSIONS: From a safety perspective, this issue is highly relevant; especially when workers are exposed to intense ambient noise and NIHL.

Cardiovascular disease mortality among retired workers chronically exposed to intense occupational noise.

OBJECTIVE: The aim of this study, conducted among retired workers (≥65 years), is to estimate the association between long-term risk of cardiovascular disease (CVD) death and (1) duration of occupational noise exposure in career and (2) noise-induced hearing loss (NIHL), the latter being used as an indicator of adverse effects for long-term exposure to occupational noise. METHODS: Data from screening activities of occupational NIHL were paired to data from death records and were used for this study. A nested case-control analysis was performed. Each case was matched with three controls for length of follow-up and economic sector. A total of 161 CVD deaths occured during an average follow-up of 6.8 years. Conditional logistic regression models were used to estimate the risk (OR) of CVD death by tertiles of duration of noise exposure and of NIHL. RESULTS: Conditional logistic regression models indicated that prolonged duration of noise exposure (≥36.5 years) (3rd tertile) was associated with an increased risk of CVD death (OR 1.70; 95 % CI 1.10-2.62), as compared with shorter duration (<27 years) (first tertile). Moderate NIHL (2nd tertile) (OR 1.64; 95 % CI 1.04-2.6) and severe NIHL (3rd tertile) (OR 1.66; 95 % CI 1.06-2.60) were also associated with an increase in risk of CVD death. CONCLUSIONS: Results are consistent with recent findings on the chronic effects of occupational noise exposure persisting after retirement although it is less than during active working life.

Falls risk and hospitalization among retired workers with occupational noise-induced hearing loss.

This study sought to ascertain whether occupational noise-induced hearing loss (NIHL) increased the risk of falls requiring hospitalization among retired workers. The study population consisted of males (age ≥ 65) with an average occupational noise exposure of 30.6 years and whose mean bilateral hearing loss was 42.2 dB HL at 3, 4, and 6 kHz. Seventy-two retired workers admitted to hospitals after a fall were matched with 216 controls from the same industrial sectors. Conditional logistic regression models were used to estimate the risk (odds ratio; [OR]) of falls leading to hospitalization by NIHL categories. Results showed a relationship between severe NIHL (≥ 52.5 dB HL) and the occurrence of a fall (OR: 1.97, CI95%: 1.001-3.876). Reducing falls among seniors fosters the maintenance of their autonomy. There is a definite need to acquire knowledge about harmful effects of occupational noise to support the prevention of NIHL and ensure healthier workplaces.

The impact of drinking water, indoor dust and paint on blood lead levels of children aged 1-5 years in Montréal (Québec, Canada).

Lead is neurotoxic at very low dose and there is a need to better characterize the impact of domestic sources of lead on the biological exposure of young children. A cross-sectional survey evaluated the contribution of drinking water, house dust and paint to blood lead levels (BLLs) of young children living in old boroughs of Montréal (Canada). Three hundred and six children aged 1 to 5 years and currently drinking tap water participated in the study. For each participant, residential lead was measured in kitchen tap water, floor dust, windowsill dust and house paint and a venous blood sample was analyzed. Multivariate logistic regression was used to evaluate the association between elevated BLL in the children (≥ 75th percentile) and indoor lead contamination by means of odds ratios (OR) using 95% confidence intervals (CI). There was an association between BLL ≥75th percentile (1.78 µg/dL) and water lead when the mean water concentration was >3.3 µg/L: adjusted OR=4.7 (95% CI: 2.1-10.2). Windowsill dust loading >14.1 µg/ft(2) was also associated with BLL ≥1.78 µg/dL: adjusted OR=3.2 (95% CI: 1.3-7.8). Despite relatively low BLLs, tap water and house dust lead contribute to an increase of BLLs in exposed young children.

Biomarkers of arsenic exposure and effects in a Canadian rural population exposed through groundwater consumption.

Drinking water intake of arsenic (As) from private wells may represent a significant exposure pathway and induce oxidative DNA damage. We measured total As concentrations in hair and nails, and concentrations of the different species of As and its metabolites as well as 8-OHdG in urine of 110 non-smoking adults living in a rural region of the Province of Quebec, Canada. Significant differences in exposure biomarker levels were observed between individuals consuming drinking water with As levels of≤1.0,>1.0 -≤10 and>10 µg/l. Multivariate linear regression analysis also showed a significant relationship between estimated daily drinking water intakes of As and biomarker levels. Conversely, 8-OHdG levels were not significantly related to daily drinking water intakes of As or to hair, nail or urinary exposure biomarker levels, according to multivariate linear regression analysis. Even at the relatively low levels of As found in well water of our participants, water consumption significantly increases their body load of As, as confirmed by multiple matrix measurements, which reflected exposure over different time frames. However, this increased internal As dose was not associated with higher oxidative damage to DNA as reflected by urinary 8-OHdG levels.

Relation between dietary acrylamide exposure and biomarkers of internal dose in Canadian teenagers.

Acrylamide (AA) is a probable human carcinogen found in several foods. Little information is available regarding exposure of adolescents, a subgroup potentially consuming more AA-rich foods. We investigated the relationship between dietary AA intake and levels of biomarkers of exposure (urinary metabolites and hemoglobin adducts) in 195 non-smoking teenagers of Montreal Island aged 10-17 years. Dietary habits and personal characteristics were documented by questionnaire. AA and its metabolites were quantified in 12-h urine collections by LC-MS/MS. Hemoglobin adducts from 165 blood samples were also analyzed by LC-MS/MS. Most prevalent urinary metabolites were NACP and NACP-S, with respective geometric mean concentrations of 31.2 and 14.2 µmol/mol creatinine. Geometric mean concentrations of AAVal and GAVal (hemoglobin adducts of AA and glycidamide (GA) with N-terminal valine residues) were 45.4 and 45.6 pmol/g globin, respectively. AA intake during the 2 days before urine collection was a significant predictor of NACP+NACP-S urinary concentrations (P<0.0001). AA intakes during the month before blood collection (P<0.0001) and passive smoking (P<0.05) were associated with adduct levels. Levels of hemoglobin adducts were above biomonitoring equivalent values corresponding to a 1 × 10(-4) excess cancer risk, which may indicate the need to reduce AA exposure in the population.

Dietary exposure to acrylamide in adolescents from a Canadian urban center.

The distribution of acrylamide in food items frequently consumed by Canadian adolescents was determined along with estimates of their contribution to the overall dietary intake of acrylamide. A total of 196 non-smoking adolescents (10-17 years old) were recruited in Montreal Island population, Canada. Participants were invited to fill out a 2-day food diary and a food frequency questionnaire over the last month. 146 samples of foods most frequently consumed by participants were analyzed for acrylamide contents. The highest acrylamide contents were measured in deep-fried french fries and potato chips (mean ± SD: 1053 ± 657 and 524 ± 276 ng/g respectively). On the basis of the 2-day food diary, median total daily intake of acrylamide was estimated at 0.29 µg/kg bw/d, as compared to 0.17 µg/kg bw/d on the basis of the food frequency questionnaire. These values are similar to those reported in comparable populations. Deep-fried french fries consumption contributed the most to daily acrylamide intake (50%) followed by potato chips (10%), oven-baked french fries (8%) and breakfast cereals (8%). Margins of exposure based on genotoxic benchmark dose limits were estimated to be low (≈<100) in high-consumer adolescents, indicating the need to continue efforts to reduce dietary acrylamide exposure.

Could driving safety be compromised by noise exposure at work and noise-induced hearing loss?

OBJECTIVE: A study was conducted to verify if there is an association between occupational noise exposure, noise-induced hearing loss and driving safety expanding on previous findings by Picard, et al. (2008) that the two factors did increase accident risk in the workplace. METHODS: This study was made possible when driving records of all Quebec drivers were made available by the Societe de l'assurance automobile du Quebec (SAAQ is the state monopoly responsible for the provision of motor vehicle insurance and the compensation of victims of traffic accidents). These records were linked with personal records maintained by the Quebec National Institute of Public Health as part of its mission to prevent noise induced hearing loss in the workplace. Individualized information on occupational noise exposure and hearing sensitivity was available for 46,030 male workers employed in noisy industries who also held a valid driver's permit. The observation period is of five years duration, starting with the most recent audiometric examination. The associations between occupational noise exposure levels, hearing status, and personal driving record were examined by log-binomial regression on data adjusted for age and duration of exposure. Daily noise exposures and bilateral average hearing threshold levels at 3, 4, and 6 kHz were used as independent variables while the dependent variables were 1) the number of motor vehicle accidents experienced by participants during the study period and 2) participants' records of registered traffic violations of the highway safety code. The findings are reported as prevalence ratios (PRs) with their 95% confidence intervals (CIs). Attributable numbers of events were computed with the relevant PRs, lesser-noise, exposed workers and those with normal hearing levels making the group of reference. RESULTS: Adjusting for age confirmed that experienced workers had fewer traffic accidents. The data show that occupational noise exposure and hearing loss have the same effect on driving safety record than that reported on the risk of accident in noisy industrial settings. Specifically, the risk of traffic accident (PR = 1.07 (CI 95% [1.01; 1.15]) is significantly associated with the daily occupational noise exposures >or= 100 dBA. For participants having a bilateral average hearing loss ranging from 16 to 30 dB, the PR of traffic accident is 1.06 (CI 95% [1.01; 1.11]) and reaches 1.31 (CI 95% [1.2; 1.42]) when the hearing loss exceeds of 50 dB. A reduction in the number of speeding violations occurred among workers occupationally exposed to noise levels >or= 90 dBA and those with noise-induced hearing loss >or=16 dB. By contrast, the same individuals had an increase in other violations of the Highway safety code. This suggests that noise-exposed workers might be less vigilant to other traffic hazards. CONCLUSION: Daily occupational noise exposures >or= 100 dBA and noise-induced hearing losses-even when just barely noticeable-may interfere with the safe operation of motor vehicles.