No abstract

The causal association between occupational noise exposure and permanent hearing loss is well-documented and well-founded primary preventive approaches have been developed. However, documentation of the impact on the present prevalence of noise-induced hearing loss in the working population is limited. This study reports on the prevalence of noise-induced hearing loss in a population sample of 788 workers from 11 trades with expected high noise exposure levels and a reference group examined according to the same protocol. Full-shift A-weighted equivalent sound levels were recorded and pure tone audiometric examinations were conducted at the work sites in soundproof booths. Data were analyzed with multivariate regression techniques and adjusted for age, sex, ear disease, smoking and environmental noise exposure. An overall two-fold increased risk of hearing handicap (hearing threshold above 20 dB averaged across 2, 3 and 4 kHz for either ear) was observed in the noise exposed workers [odds ratio (OR) 1.99, 95% confidence interval (CI) 0.91-4.34]. Workers exposed for more than 20 years to an exposure level above 85 dB(A) had a three-fold increased risk (OR 3.05, 95% CI 1.33-6.99). Workers starting in noisy work during the last 10-15 years or workers below 30 years of age showed no increased risk of hearing handicap. This indicates that preventive measures enforced during the past 10-15 years to reduce noise exposure may have borne fruit. Systematic surveillance of noise and hearing levels in appropriate populations should still be included in an efficient hearing conservation program.

Aims: To evaluate an epidemiological approach to a national noise hazard surveillance strategy, and report current exposure levels in the Danish workplace. Methods: A study base of 840 companies in 10 selected high risk industries in the largest county in Denmark was identified from a national register. Noise exposure was measured among manual workers recruited from a random sample of workplaces in each industry. For reference, financial companies and a sample of residents were investigated according to the same protocol. The A-weighted equivalent sound level (L Aeq ) for a full shift was measured by portable dosimeters worn by 830 workers employed at 91 workplaces (67% of 136 eligible companies). Results: The epidemiological design proved feasible and established a baseline for future noise surveillance. Substantial resources were needed to motivate workplaces to enlist and the final participation rate was less than optimal (66.9%). The L Aeq (8) values in the selected industries were highly elevated (mean 83.7 dB(A) (95% CI 83.3 to 84.1) in comparison with residents and office workers (mean 69.9 dB(A), 95% CI 68.8 to 71.0). Some 50% of the workers were exposed to more than 85 dB(A) and some 20% to more than 90 dB(A) in several industries. Conclusion: Noise levels in Danish high risk industries remain high. A substantial proportion of workers are exposed to noise levels above the current threshold limit of 85 dB(A). Ongoing surveillance of noise exposure using full shift dosimetry of workers in random samples of workplaces most at risk to high noise levels may help reinforce preventive measures. Such a programme would benefit from compulsory workplace participation.

The purpose was to investigate the relationship between noise exposure and tinnitus among workers with normal hearing and hearing loss, respectively. We conducted a cross-sectional survey of 752 workers employed at 91 workplaces, that were investigated by means of full work-shift noise levels, questionnaire data, and bilateral pure-tone audiometry. Tinnitus was not associated with the present noise level, the duration of noise exposure, or the cumulative noise exposure if participants had normal hearing. As expected, such trends were demonstrated if participants had a hearing handicap. Based on these data, we will be cautious in ascribing tinnitus to noise exposure in our patients' workplaces if they have a normal audiogram. Furthermore our data indicates no risk of noise-induced tinnitus at exposure levels where no hearing loss would be expected, e.g. as usually encountered in non-industrial workplaces.

This study aims to describe challenges in the management of HIV-infected university students focusing on their nutritional status and metabolic risk. Methods: A cross-sectional, descriptive study design was used to assess the anthropometry, food intake and clinical status of a cohort of known HIV-infected registered students at a South African university. Results: Participants (n = 63) had a mean CD4 cell count of 411 (SD = 219.9) cells/mm 3 , a mean body mass index (BMI) of 28.05 (SD = 7.9) kg/m 2 and only half of the participants (n = 31) were on antiretroviral therapy (ART). A higher BMI (> 25 kg/m 2) was significantly (p < 0.05; V = 0.32) associated with higher CD4 cell counts of > 350 cells/mm 3. Some 40% (n = 25) of students were at risk for metabolic complications based on their waist circumference and 11% (n = 7) had clinical signs of lipodystrophy. The 'obese' group consumed a mean energy intake of 24 kcal/kg bodyweight which was lower than the 'overweight' and normal weight groups. Conclusions: In total 51% of HIV-positive students in the sample presented with signs of metabolic complications. Side effects of ART can be prevented and/or treated by regular physical activity, adequate nutritional intake, monitoring of side effects and BMI, combined with optimal care and support.