SangWoo Tak

Exposure to hazardous workplace noise and use of hearing protection devices among US workers—NHANES, 1999–2004†‡

BACKGROUND To estimate the prevalence of workplace noise exposure and use of hearing protection devices (HPDs) at noisy work, NIOSH analyzed 1999-2004 data from the National Health and Nutrition Examination Survey (NHANES). METHODS A total of 9,275 currently employed workers aged > or =16 years were included in the weighted analysis. Hazardous workplace noise exposure was defined as self-reported exposure to noise at their current job that was so loud that the respondent had to speak in a raised voice to be heard. Industry and occupation were determined based on the respondents current place and type of work. RESULTS Twenty-two million US workers (17%) reported exposure to hazardous workplace noise. The weighted prevalence of workplace noise exposure was highest for mining (76%, SE = 7.0) followed by lumber/wood product manufacturing (55%, SE = 2.5). High-risk occupations included repair and maintenance, motor vehicle operators, and construction trades. Overall, 34% of the estimated 22 million US workers reporting hazardous workplace exposure reported non-use of HPDs. The proportion of noise-exposed workers who reported non-use of HPDs was highest for healthcare and social services (73.7%, SE = 8.1), followed by educational services (55.5%). DISCUSSION Hearing loss prevention and intervention programs should be targeted at those industries and occupations identified to have a high prevalence of workplace noise exposure and those industries with the highest proportion of noise-exposed workers who reported non-use of HPDs.

Hearing difficulty attributable to employment by industry and occupation: an analysis of the National Health Interview Survey--United States, 1997 to 2003.

Objective: To estimate the national burden of hearing difficulty among workers in US industries and occupations. Methods: Data on 130,102 employed National Health Interview Survey respondents between the ages of 18 to 65 years who were interviewed between 1997 and 2003 were analyzed to estimate the population prevalence, adjusted prevalence ratios, and fractions of hearing difficulty attributable to employment. Results: The estimated population prevalence of hearing difficulty was 11.4% (24% attributable to employment). The adjusted prevalence ratios of hearing difficulty were highest for railroads, mining, and primary metal manufacturing industry. Occupations with increased risk of hearing difficulty were mechanics/repairers, machine operators, and transportation equipment operators. Conclusions: Hearing difficulty was differentially distributed across various industries. In industries with high rates, employers and workers should take preventive action to reduce the risk of occupational hearing loss.

National income, self-reported wheezing and asthma diagnosis from the World Health Survey

The aims of this study were to quantify and describe the variations in respiratory symptoms and diagnosis prevalence across regions of the world according to national income. In 2002 and 2003, the World Health Organization implemented the World Health Survey (WHS), which used a standardised survey instrument to compile comprehensive baseline information on health and healthcare expenditure. We analysed the WHS data to assess the global patterns of self-reported wheeze and doctor-diagnosed asthma, two commonly reported measures of respiratory health. In total there were 308,218 participants with complete records, from 64 countries. The weighted mean age of the survey population was 43 yrs. Global prevalence of current wheezing symptoms ranged from 2.4% in Vietnam to 24% in Brazil; the prevalence of diagnosed asthma ranged from 1.8% in Vietnam to 32.8% in Australia. Overall, the prevalence of symptoms and diagnosis showed a U-shaped pattern with the largest prevalence reported in low- and high-income countries. The smallest prevalence was consistently found in middle-income countries. These WHS analyses have provided global prevalence estimates of wheeze and doctor-diagnosed asthma using data gathered simultaneously and consistently across six continents. These findings support the need for continued global respiratory illness surveillance for disease prevention, health policy and management.

The estimated national burden of physical ergonomic hazards among US workers.

PURPOSE To estimate the national burden of physical ergonomic hazards among working adults in the US. METHODS We estimated the population prevalence of and the total number of workers who are exposed to physical ergonomic hazards, such as vibration, working in cramped space, kneeling, body bending or twisting, climbing, and repetitive motions using Occupational Information Network (O*NET) data and the Occupational Employment Statistics (OES) from the U.S. Bureau of Labor Statistics (BLS) stratified by occupation title. RESULTS Repetitive motion was the most prevalent of all ergonomic hazards (27% of US workers are estimated to be exposed continually). Bending or twisting of the body more than half their time at work was also common, involving over 32 million US workers (25% of US workforce). Kneeling, crouching, stooping, or crawling was another ergonomic hazard that 14 million US workers perform more than half their time at work. Almost 4 million workers climb ladders, scaffolds, poles, etc. for more than half their time at work. We estimate that over 13 million workers (10% of US workforce) were exposed to cramped workspace that requires getting into awkward positions every day. Finally, about 3.5 million workers (2.7% of US workforce) were estimated to be exposed to whole body vibration every day. CONCLUSION A large portion of the US work force is exposed to ergonomic hazards known to be associated with musculoskeletal disorders (MSDs). The occupations with the highest prevalence of each ergonomic hazard may be deserving of prompt efforts toward prevention of MSDs.

Occupational noise exposure assessment using O*NET and its application to a study of hearing loss in the US general population

Objectives Although occupational noise is a well known risk factor for hearing loss, little epidemiological evidence has been reported on its association with hearing loss in the general population, in part, because of the difficulty in exposure assessment. This study introduced a quantitative occupational noise exposure assessment tool using the Occupational Information Network (O*NET) database and evaluated its applicability for epidemiological research using data from the National Health and Nutrition Examination Survey (NHANES) 1999–2004. Methods The O*NET noise exposure data were assessed by questionnaires across numerous occupations, asking the frequency of exposure to sounds and noise levels that are distracting and uncomfortable (with five possible responses from ‘never’ to ‘every day’). Means of the O*NET noise scores were computed to correspond to NHANES occupational categories and assigned to 3828 adults aged 20–69 years, who participated in the 1999–2004 NHANES. Pure-tone averages (PTA) of hearing thresholds at 0.5, 1, 2 and 4 kHz were computed, and hearing loss was defined as a PTA >25 dB in either ear. Linear and logistic regression models with either continuous or quintiles of the O*NET noise scores were fitted on log-transformed PTA and binary hearing loss, respectively. Results Noise scores ranged from 1.80 to 4.37 with mean±SE of 3.06±0.02. After controlling for potential confounders, the highest (vs lowest) noise score quintile had a 22.5% (95% CI 11.0% to 35.2%) increase in PTA, and there was a linear dose-dependent trend across the quintiles of noise scores (p trend<0.0001). The adjusted OR for hearing loss comparing the highest with the lowest noise score quintiles was 2.1 (95% CI 1.2 to 3.6). Conclusion This study suggests that the O*NET noise score is a useful tool for examining occupational noise-induced health effects in the general population in the absence of actual occupational noise exposure assessment data.

Use of multiple data sources for surveillance of work-related amputations in Massachusetts, comparison with official estimates and implications for national surveillance.

BACKGROUND Accurate surveillance of work-related injuries is needed at national and state levels. We used multiple sources for surveillance of work-related amputations, compared findings with Survey of Occupational Injuries and Illnesses (SOII) estimates, and assessed generalizability to national surveillance. METHODS Three data sources were used to enumerate work-related amputations in Massachusetts, 2007-2008. SOII eligible amputations were compared with SOII estimates. RESULTS 787 amputations were enumerated, 52% ascertained through hospital records only, exceeding the SOII estimate (n = 210). The estimated SOII undercount was 48% (95% CI: 36-61%). Additional amputations were reported in SOII as other injuries, accounting for about half the undercount. Proportionately more SOII estimated than multisource cases were in manufacturing and fewer in smaller establishments. CONCLUSION Multisource surveillance enhanced our ability to document work-related amputations in Massachusetts. While not feasible to implement for work-related conditions nationwide, it is useful in states. Better understanding of potential biases in SOII is needed.

Characterization of Lead in US Workplaces Using Data From OSHA's Integrated Management Information System

BACKGROUND Lead hazards continue to be encountered in the workplace. OSHAs Integrated Management Information System (IMIS) is the largest available database containing sampling results in US workplaces. METHODS Personal airborne lead sampling results in IMIS were extracted for years 1979-2008. Descriptive analyses, geographical mapping, and regression modeling of results were performed. RESULTS Seventy-nine percent of lead samples were in the manufacturing sector. Lead sample results were highest in the construction sector (median = 0.03 mg/m(3) ). NORA sector, year, OSHA region, number of employees at the worksite, federal/state OSHA plan, unionization, advance notification, and presence of an employee representative were statistically associated with having a lead sample result exceed the PEL. CONCLUSIONS Lead concentrations within construction have been higher than any other industry. Lead hazards have been most prevalent in the north and northeastern US. IMIS data can be useful as a surveillance tool and for targeting prevention efforts toward hazardous industries.

Lung cancer risk among construction workers in California, 1988–2007†‡

BACKGROUND Although lung cancer risks can vary by race/ethnicity and by construction occupation, these risks have not been examined extensively. METHODS This study analyzed 110,937 lung cancer cases identified from the California Cancer Registry between 1988 and 2007. Mean age at diagnosis, proportion diagnosed at an advanced stage, and proportion with 3-year survival were calculated for lung cancer cases employed in the construction industry. Case-control methodology was also used to assess the risk of lung cancer. Morbidity odds ratios (MORs) were estimated by conditional logistic regression. RESULTS Construction workers were found to have a significantly elevated risk for all lung cancer combined (MOR = 1.57) and for each lung cancer histologic subtype examined. All construction occupations, except managers/engineers and supervisors, had a significantly elevated risk for all lung cancer combined. Roofers and welders had the highest risks for total lung cancer and for each of the histologic subtypes. Construction workers in each of the four race/ethnicity groups also had significantly increased lung cancer risks. Compared to non-construction workers, construction workers were diagnosed at an earlier age, at a more advanced stage, and had significantly lower 3-year survival, though differences were modest. CONCLUSION These findings justify additional reductions in carcinogenic exposures in construction, and increased support for smoking cessation programs at construction sites.

Variability in Risk Factors for Knee Injury in Construction

This study investigated sources of variance in exposure to risk factors for knee pain in a variety of highway construction trades, operations, and tasks. Over 15,000 discrete observations of leg postures and weights handled were made on 120 construction workers in five construction trades, in nine operations over 79 days. The contributions of trade, operation, task, and worker to the variability in work time spent kneeling, squatting, and carrying loads were evaluated with multilevel random effects models. Construction operation and task explained about 20% to 30% of total variation in kneeling, squatting, and carrying loads. There was a large unexplained component of variance thought to represent day-to-day variability of exposure within task. Reliable assessments of knee exposures require multiple days to accommodate the high variability of exposures among operations and tasks and over time. These sources of variability should be carefully considered in efforts to estimate exposures to knee loading for epidemiologic or intervention studies. Homogenous exposure groups are not easily defined from the readily available organizational features of construction work.

Estimation of compressive forces on lumbar spine from categorical posture data

To combine estimates of trunk posture and force into an integrated measure of load on the low back, continuous variables for body angles were estimated by assuming specified distributions within corresponding posture categories with Monte-Carlo (MC) simulation. The estimated posture angles were compared with reference measurements from the Lumbar Motion Monitor and inclinometers. The lumbar compression estimates, generated from simulated posture angles and from direct measurement, were compared. Trunk flexion showed high correlation between direct measurements and simulated angles, as did L5/S1 compression. The MC approach to extracting continuous posture angles from categorized observations did not appear to introduce large error in the variables used to estimate spinal compressive forces. When instrumentation methods of postural assessment are not feasible, a simulation approach combined with biomechanical modelling could be used to integrate multiple external exposure variables into estimates of compressive forces acting on the low back.