Edward F Krieg’s research while affiliated with National Institute of Occupational Safety and Health JAPAN and other places

The National Institute for Occupational Safety and Health (NIOSH) evaluated continuous and impact noise exposures and hearing loss among workers at a hammer forge company. Full-shift personal noise exposure measurements were collected on forge workers across 15 different job titles; impact noise characteristics and one-third octave band noise levels were assessed at the forge hammers; and 4,750 historic audiometric test records for 483 workers were evaluated for hearing loss trends. Nearly all workers' noise exposures exceeded regulatory and/or recommended exposure limits. Workers working in jobs at or near the hammers had full-shift time-weighted average noise exposures above 100 decibels, A-weighted. Impact noise at the hammers reached up to 148 decibels. Analysis of audiometric test records showed that 82% of workers had experienced a significant threshold shift, as defined by NIOSH, and 63% had experienced a standard threshold shift, as defined by the Occupational Safety and Health Administration (OSHA). All workers with an OSHA standard threshold shift had a preceding NIOSH significant threshold shift which occurred, on average, about 7 years prior. This evaluation highlights forge workers' exposures to high levels of noise, including impact noise, and how their hearing worsened with age and length of employment.

This study aimed to assess temporary and permanent auditory effects associated with occupational coexposure to low levels of noise and solvents. Cross-sectional study with 25 printing industry workers simultaneously exposed to low noise (<80 dBA TWA) and low levels of solvents. The control group consisted of 29 industry workers without the selected exposures. Participants answered a questionnaire and underwent auditory tests. Auditory fatigue was measured by comparing the acoustic reflex threshold before and after the workday. Workers coexposed to solvents and noise showed significantly worse results in auditory tests in comparison with the participants in the control group. Auditory brainstem response results showed differences in III–V interpeak intervals (p = 0.046 in right ear; p = 0.039 in left ear). Mean dichotic digits scores (exposed = 89.5 ± 13.33; controls = 96.40 ± 4.46) were only different in the left ear (p = 0.054). The comparison of pre and postacoustic reflex testing indicated mean differences (p = 0.032) between the exposed (4.58 ± 6.8) and controls (0 ± 4.62) groups. This study provides evidence of a possible temporary effect (hearing fatigue) at the level of the acoustic reflex of the stapedius muscle. The permanent effects were identified mainly at the level of the high brainstem and in the auditory ability of binaural integration.

Introduction The effect of combined exposures to noise and solvents on hearing has been studied for decades, but the characterization of the risk is incomplete. Objective To assess the temporary and permanent auditory effects associated with occupational co-exposures to low levels of solvents and noise. Method Cross-sectional study with 25 printing industry workers (mean age 36.2 years) simultaneously exposed to low levels of solvents and noise ( < 8 0 dBA TWA). The control group composed of 29 industry workers (mean age 36.7 years) without exposure to noise and/or solvents. Participants answered a questionnaire and underwent pure-tone audiometry (PTA), acoustic immittance tests, auditory brainstem response (ABR), dichotic digit test (DD). We examined auditory fatigue through the EchoScan test. Results Exposed workers had worse thresholds bilaterally at 4 kHz (p=0.0253 in right ear - RE; p=0.0436 in left ear - LE). Ipsilateral acoustic reflex levels were different between groups at the frequencies of 500 Hz (p=0.02 in RE; p=0.04 in LE) and 1 kHz (p=0.04 in LE). The only differences detected by the ABR was for the interpeak interval III-V (p=0.03 in RE; p=0.02 in LE). DD means (exposed= 89.5±13.33; control= 96.40±4.46), were only different in the LE (p=0.05). Echoscan detected a difference (p=0.0317) between the means of the exposed (4.58±6.8) and control (0±4.62) groups, indicating possible hearing fatigue in the exposed group. Conclusion Each of the hearing tests indicated differences between the groups, suggesting that occupational co-exposure to low noise and low concentrations of solvents can be harmful to hearing functions. The temporary effect of the exposure was detected by the EchoScan and the acoustic reflex of the stapedius muscle. The permanent effects were identified mainly at the level of the high brainstem and in the auditory ability of binaural integration. The EchoScan, can facilitate the early identification of auditory effects, while these are still temporary.

Objective This prospective study assessed the risk of developing rotator cuff syndrome (RCS) with separate or specific combinations of biomechanical exposures measures, controlling for individual confounders. Background Compared with other musculoskeletal disorders, rates of work-related shoulder musculoskeletal disorders have been declining more slowly. Method We conducted up to 2 years of individual, annual assessments of covariates, exposures, and health outcomes for 393 U.S. manufacturing and healthcare workers without RCS at baseline. Task-level biomechanical exposures assessed exposure to forceful exertions (level, exertion rates, duty cycles), vibration, and upper arm postures (flexion, abduction). Hazard ratios (HRs) were calculated with Cox proportional hazard models. Results We observed 39 incident RCS cases in 694 person-years (incidence rate = 5.62 per 100 person-years). Adjusting for confounders, we found increased risk of incident RCS associated with forceful hand exertions per minute for three upper arm posture tertiles: flexion ≥45° (≥28.2% time, HR = 1.11, CI [1.01, 1.22]), abduction ≥30° (11.9–21.2%-time, HR = 1.18, CI [1.04, 1.34]), and abduction >60° (≥4.8% time, HR = 1.16, CI [1.04, 1.29]). We failed to observe statistically significant effects for other interactions or any separate measures of biomechanical exposure. Conclusion This study highlights the importance of assessing combinations of exposure to forceful repetition and upper arm elevation when developing interventions for preventing RCS. Application Based on these results, interventions that reduce exposure to forceful repetition (i.e., lower force levels and/or slower exertion rates) may reduce the risk of RCS, especially when upper arm elevation cannot be avoided.

Objective: To update trends in prevalence of back and upper limb musculoskeletal symptoms and risk factors from the 2014 Quality of Work Life (QWL) Survey. Methods: Quadrennial QWL Surveys, 2002-2014 (with N = 1455, 1537, 1019, and 1124 in 2002, 2006, 2010, and 2014 surveys respectively) were analyzed for reports of back pain and pain in arms. Results: In the fourth analysis of this survey, twelve-year trends continue to show a decline in back pain and pain in arms. Key physical (heavy lifting, hand movements, very hard physical effort) and psychosocial/work organizational factors (low supervisor support, work is always stressful, not enough time to get work done) remain associated with back and arm pain, with the physical risk factors showing the strongest associations. Conclusion: Physical exposure risk factors continue to be strongly associated with low back and arm pain and should be the focus of intervention strategies.

Objective: To examine the auditory system of Brazilian gasoline station workers using an extensive audiological test battery. Design: This was a cross-sectional study. The audiological evaluation included a questionnaire, pure-tone audiometry, acoustic immittance tests, transient-evoked otoacoustic emissions (TEOAEs), distortion product otoacoustic emissions (DPOAEs), auditory brainstem response (ABR) and P300 auditory-evoked potentials. Study sample: A total of 77 Brazilian gasoline station workers were evaluated, and their results were compared with those of 36 participants who were not exposed to chemicals or noise at work. The gasoline station employees worked in 18 different gas stations, and the noise area measurements from all gas stations revealed time-weighted averages below 85 dBA. Results: Of the 77 gasoline station workers evaluated, 67.5% had audiometric results within the normal range, but 59.7% reported difficulties in communication in noisy places. Gasoline station workers showed significantly poorer results than non-exposed control participants in one or more conditions of each of the audiological tests used, except P300. Conclusions: The results suggest that the gasoline station workers have both peripheral and central auditory dysfunctions that could be partly explained by their exposure to gasoline.

Regression analysis was used to estimate and test for relationships between the blood lead concentration and the concentrations of serum thyroid stimulating hormone and serum total thyroxine in adults, 20 years and older, participating in the third National Health and Nutrition Examination Survey. No relationship was found between the blood lead level and the concentration of serum thyroid stimulating hormone. The serum total thyroxine concentration decreased as the blood lead level increased in women, but not in men. The lowest concentration of blood lead at which a relationship could be detected was 2.1 μg/dL and 3.9 μg/dL for the non-pregnant and pregnant women, respectively. Hypothetical mechanisms of the action of lead are discussed.

The NIOSH Health Hazard Evaluation program evaluated employee exposures to high level continuous and impact noise at a hammer forge company. Personal dosimetry data were collected from 38 employees and noise exposure recordings were collected during two facility visits. Extensive audiometric records were reviewed and trends for hearing loss, threshold shifts and risk of hearing loss were assessed. Hearing protector effectiveness was evaluated for hammer forging with an acoustic test fixture. A longitudinal analysis was conducted on the audiometric data set that included 4750 audiograms for 483 employees for the years 1981 to 2006. The analysis of the audiometric history for the employees showed that 82% had experienced a NIOSH-defined hearing threshold shift and 63% had experienced an OSHA-defined standard threshold shift. The mean number of years from a normal baseline audiogram to a threshold shift was about 5 years for a NIOSH threshold shift and was about 9 years for an OSHA threshold shift. Overall hearing levels among employees worsened with age and length of employment. The NIOSH audiometric test criteria in addition to OSHA threshold shift criteria to assess threshold shifts could provide an opportunity for early intervention to prevent future hearing loss. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health. Mention of any company or product does not constitute endorsement by NIOSH.

The NIOSH health hazard evaluation program evaluated employees’ exposures to high level continuous and impact noise at a hammer forge company. Personal dosimetry data were collected from 38 employees and noise exposure recordings were collected during two visits to the facility. Extensive audiometric records were reviewed and trends for hearing loss, threshold shifts and risk of hearing loss were assessed. The effectiveness of hearing protection devices for hammer forging was evaluated with an acoustic test fixture. A longitudinal analysis was conducted on the audiometricdata set that included 4750 audiograms for 483 employees for the years 1981 to 2006. The analysis of the audiometric history for the employees showed that 82% had experienced a NIOSH-defined hearing threshold shift and 63% had experienced an OSHA-defined standard threshold shift. The mean number of years from a normal baseline audiogram to a threshold shift was about 5 years for a NIOSH threshold shift and was about 9 years for an OSHA threshold shift. Overall hearing levels among employees worsened with age and length of employment. The NIOSH audiometric test criteria in addition to OSHA threshold shift criteria to assess threshold shifts could provide an opportunity for early intervention to prevent future hearing loss.