PurposeTo give a systematic review of the development of noise-induced hearing loss (NIHL) in working life.MethodsA literature search in MEDLINE, Embase, Web of Science, Scopus, and Health and Safety Abstracts, with appropriate keywords on noise in the workplace and health, revealed 22,413 articles which were screened by six researchers. A total of 698 articles were reviewed in full text and scored with a checklist, and 187 articles were found to be relevant and of sufficient quality for further analysis.ResultsOccupational noise exposure causes between 7 and 21 % of the hearing loss among workers, lowest in the industrialized countries, where the incidence is going down, and highest in the developing countries. It is difficult to distinguish between NIHL and age-related hearing loss at an individual level. Most of the hearing loss is age related. Men lose hearing more than women do. Heredity also plays a part. Socioeconomic position, ethnicity and other factors, such as smoking, high blood pressure, diabetes, vibration and chemical substances, may also affect hearing. The use of firearms may be harmful to hearing, whereas most other sources of leisure-time noise seem to be less important. Impulse noise seems to be more deleterious to hearing than continuous noise. Occupational groups at high risk of NIHL are the military, construction workers, agriculture and others with high noise exposure.ConclusionThe prevalence of NIHL is declining in most industrialized countries, probably due to preventive measures. Hearing loss is mainly related to increasing age.Electronic supplementary materialThe online version of this article (doi:10.1007/s00420-015-1083-5) contains supplementary material, which is available to authorized users.

No abstract

Objective To study the prognosis for pelvic girdle pain, and to explore the association between presence of emotional distress during pregnancy and pelvic girdle syndrome 6 months after delivery.Design Longitudinal population study. Main outcome measure Pelvic girdle syndrome 6 months after delivery, defined as pain in the anterior pelvis and on both sides in the posterior pelvis.Results Six months after delivery, 78.0% of the women had recovered, 18.5% reported persistent pain in one or two pelvic locations, 3.0% reported pelvic girdle syndrome and 0.5% reported severe pelvic girdle syndrome. The recovery rates decreased with increasing levels of pain severity in pregnancy. Being emotionally distressed at two time points during pregnancy was associated with the presence of pelvic girdle syndrome (adjusted OR 1.5, 95% CI 1.2-1.9) and severe pelvic girdle syndrome (adjusted OR 1.9, 95% CI 1.1-3.1), after adjustment for pain severity in pregnancy, other medical conditions, body mass index, age at menarche, previous low back pain, and smoking during pregnancy.Conclusions In this follow-up of women with pelvic girdle pain in pregnancy, the recovery rates after delivery were high. Our findings suggest that the presence of emotional distress during pregnancy is independently associated with the persistence of pelvic girdle pain after delivery.Keywords Emotional distress, pelvic girdle pain, pregnancy, prognostic factors, prospective cohort, the Norwegian Mother and Child Cohort Study.Please cite this paper as: Bjelland E, Stuge B, Engdahl B, Eberhard-Gran M. The effect of emotional distress on persistent pelvic girdle pain after delivery: a longitudinal population study . BJOG 2013;120:32-40.

The effect of noise exposure on amplitude and phase of distortion product otoacoustic emissions (DPOAEs) was examined by five different paradigms: across a wideband of frequency, microstructure, input/output function, primary frequency ratio tuning curve, and group delay. The aim was to investigate the vulnerability of these different features to moderate levels of noise exposure. Nine subjects were exposed to third-octave-band noise. The DPOAE amplitude was reduced frequency specifically with the greatest reduction approximately half an octave above the frequency of the noise. The degree of amplitude reduction was greatest at low stimulus levels. There were no observed effects on the shape of the primary ratio tuning curve. A weak tendency to a decrease was seen in group delays. Distinct microstructure was seen in the amplitude against frequency of five out of seven subjects. The maximum to minimum ratio of the microstructure decreased, and the whole pattern shifted toward lower frequencies after noise exposure. Evidence of multiple internal reflection or interference was seen in the periodicity of the microstructure. Using a simple model of the microstructure based on multiple reflections, the noise-induced changes were reevaluated. A reduction in maximum to minimum microstructure ratio could be interpreted as a decrease in the internal reflection coefficient. The implications of these observations for the interpretation of the DPOAE measurements are considered.

No abstract

Engdahl B, Tambs K. Occupation and the risk of hearing impairment -results from the Nord-Trøndelag study on hearing loss. Scand J Work Environ Health. 2010;36(3):250-257.Objectives We studied the effect of occupation on hearing and if it remained after adjustment for noise exposure, education, income, and other risk factors.Methods Audiometry and a questionnaire concerning exposure was administered to a general adult population sample in Norway (N=49 948). Information on occupation, education, and income was obtained from population census registers.Results Occupation had marked effects on hearing loss. Occupation explained 2-3% of the variance in hearing loss among men ≥45 years in addition to the hearing loss due to age (10-19%). Occupation explained ≤1% of hearing loss among women of all ages and young men. Controlling for self-reported occupational noise exposure reduced the occupational effect by 20-40% in men ≥45 years. Controlling for leisure-time noise, ear infections, and head injuries did not change the effect of occupation, which was slightly reduced after controlling for education and income. The most elevated hearing thresholds in men were observed among: wood workers; miners; linemen and cable jointers; construction carpenters and workers; seamen; and workshop mechanics. ConclusionsThere was a moderate association between occupation and hearing loss. Unbiased estimates of occupational hearing loss may help identify high-risk occupations, for which interventions are needed, and identify individuals with hearing loss.

This cohort study indicates that, although many cardiovascular risk factors are associated with hearing loss, the effects are small and of doubtful clinical relevance.

The aim of the study was to compare the frequency-specific effects of noise on hearing acuity across the range 250-8000 Hz and the extent to which the patterns of frequency-specific threshold shifts differ between occupational noise and impulse noise. Pure-tone audiometry was administered to an adult general population sample with 51 975 subjects who also provided questionnaire information about noise exposure and other risk factors. Threshold shifts induced by life-long occupational noise and impulse noise (mostly shooting) were estimated separately in six age and sex groups for eight frequencies. Reported noise exposure, as well as observed threshold shifts, were moderate among women. Threshold shifts averaged over both ears among subjects in the higher 2% of exposure to occupational noise, reached 13 dB (3000 Hz, age 65 years + ) among men and were generally largest at 3000-4000 Hz. The shifts induced by impulse noise reached approximately 8 dB among men 45-64 years and men 65 years+. The effects of impulse noise were strongest at 3000-8000 Hz and varied little within this frequency range.