A review of occupational knee disorders.

INTRODUCTION: Lower extremity knee disorders, like other cumulative disorders of the body, build up over time through cumulative exposures. 2006 data from the U.S. Bureau of Labor Statistics reveal that cumulative knee disorders account for 65% of lower extremity musculoskeletal disorders and 5% of total body musculoskeletal disorders. METHODS: The objective of the literature review was to find papers on work-related musculoskeletal disorders (WMSDs) common to the knee region. From these, symptoms of the disorders, affected industries, and potential risk factors were assessed. RESULTS: A review of the literature divulges that knee disorders primarily consist of bursitis, meniscal lesions or tears, and osteoarthritis. Though kneeling and squatting are considered to be two of the primary risk factors correlated to these knee disorders, 12 other risk factors should also be contemplated. These 14 contributing risk factors include both occupational (extrinsic) and personal (intrinsic) variables that affect the labor industries. Example industries include mining, construction, manufacturing, and custodial services where knee bending postural activities exist as a commonality. CONCLUSION: The understanding of the types of knee disorders, the affected occupations, and the job related risk factors will allow ergonomic practitioners and researchers to create and adjust work environments for the detection and lessening of knee work-related musculoskeletal risk. Further studies need to be conducted to (1) justify the presence of risk from certain risk factors and (2) enhance the understanding of risk factor dose-response levels and their temporal development.

Effect of aircraft-cabin altitude on passenger discomfort.

BACKGROUND: Acute mountain sickness occurs in some unacclimatized persons who travel to terrestrial altitudes at which barometric pressures are the same as those in commercial aircraft during flight. Whether the effects are similar in air travelers is unknown. METHODS: We conducted a prospective, single-blind, controlled hypobaric-chamber study of adult volunteers to determine the effect of barometric pressures equivalent to terrestrial altitudes of 650, 4000, 6000, 7000, and 8000 ft (198, 1219, 1829, 2134, and 2438 m, respectively) above sea level on arterial oxygen saturation and the occurrence of acute mountain sickness and discomfort as measured by responses to the Environmental Symptoms Questionnaire IV during a 20-hour simulated flight. RESULTS: Among the 502 study participants, the mean oxygen saturation decreased with increasing altitude, with a maximum decrease of 4.4 percentage points (95% confidence interval, 3.9 to 4.9) at 8000 ft. Overall, acute mountain sickness occurred in 7.4% of the participants, but its frequency did not vary significantly among the altitudes studied. The frequency of reported discomfort increased with increasing altitude and decreasing oxygen saturation and was greater at 7000 to 8000 ft than at all the lower altitudes combined. Differences became apparent after 3 to 9 hours of exposure. Persons older than 60 years of age were less likely than younger persons and men were less likely than women to report discomfort. Four serious adverse events, 1 of which may have been related to the study exposures, and 15 adverse events, 9 of which were related to study exposures, were reported. CONCLUSIONS: Ascent from ground level to the conditions of 7000 to 8000 ft lowered oxygen saturation by approximately 4 percentage points. This level of hypoxemia was insufficient to affect the occurrence of acute mountain sickness but did contribute to the increased frequency of reports of discomfort in unacclimatized participants after 3 to 9 hours. (ClinicalTrials.gov number, NCT00326703 [ClinicalTrials.gov].).

Prioritizing ergonomic research in aging for the 21st century American workforce.

The Bureau of Labor Statistics predicts that by 2008 Americans aged 55 and over will represent the greatest annual growth rate and will occupy 30% of the American population. Additionally, by 2008 civilian labor force participation rates for the 55 and older group will grow to 36.8%, a 6.5% increase over the participation rates for this group for 1996, with the 55 to 64 age group expected to add 7.3 million workers. The predicted median age of the labor force for 2008 is estimated at 40.7 years, an age not approached because the median age peaked at 40.5 years in 1962. Coupled with this aging profile, employment in professional specialty occupations will increase the fastest and add the most jobs in the decade leading to 2008. Within the professional specialty professions, the majority of the employment increases are expected to occur in the service industry division. The purpose of this paper is to merge demographic data with ergonomic and human factors data and predictions to explore areas of ergonomic research that will aid in keeping the aging workforce, and those with whom they interact, healthy in their jobs and keep the companies for whom they are employed competitive. Although some ergonomics research has been conducted in all the listed areas of expected growth, the paper reexamines the job demands in each sector, with a focus on the needs of the aging workforce.