An investigation of aircraft worker anemia: medical surveillance interpretation in an aging workforce.

OBJECTIVE: To identify exposures possibly contributing to anemia cases among hexavalent chromium medical surveillance program enrollees. METHODS: An investigation encompassed metals surveillance programs, extensive workplace sampling and remediation, consultation, evaluation of laboratory accuracy, and follow-up of anemic individuals. RESULTS: Workers had underlying medical conditions that affected surveillance results. There was a systemic error in classification based on hematocrit value. The prevalence of anemia in a workforce averaging 52 years old was 16%. CONCLUSIONS: Anemia may be more prevalent in middle-aged workers than expected. Modern laboratories generally report a calculated hematocrit value, and using hemoglobin for most classification purposes is preferred. Characteristics of a specific workforce, including age, health, hobbies, and diet, should be taken into account when interpreting medical surveillance program findings. The value of a team approach in addressing occupational health problems was demonstrated.

Navy Asbestos Medical Surveillance Program (1984-1990): linear regression analysis for effect of asbestos exposure on pulmonary function testing.

This study examined records from the Navy Asbestos Medical Surveillance Program for 1984 through 1990 for Caucasian men (N = 129,598) using a population-based, cross-sectional, linear regression model. Continuous dependent variables were forced expiratory volume in 1 s and forced vital capacity (FVC), and continuous independent variables were age, height, weight, and tobacco use. A mid-period estimate of asbestos exposure was used because those values were reported as categorical variables. With asbestos exposure, forced expiratory volume in 1 s changed -3.2 cm3/year (t = -8.6, p = 0.000), and forced vital capacity changed -5.1 cm3/year (t = -11.8, p = 0.00). Those with more than 5 years of asbestos exposure demonstrated impairment over those with less exposure, and those with more than 15 years of exposure demonstrated even more impairment. These findings support the association of pulmonary function impairment with asbestos exposure for workers studied during this period.

Navy Asbestos Medical Surveillance Program (1991-1999): linear regression analysis for the effect of asbestos exposure on pulmonary function testing.

The effect of asbestos exposure on pulmonary function was studied using data from the Navy Asbestos Medical Surveillance Program. Records were selected for Caucasian men from 1991 to 1999 (N = 89,318) and were analyzed using a cross-sectional, linear regression model. Dependent variables were forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC), with independent continuous variables of age, height, weight, smoking, and asbestos history. Overall, the continuous variable for asbestos exposure demonstrated significant protection of +1.1 cm3/year (t = 3.278, p = 0.001) for FEV1 and +1.6 cm3/year (t = 4.225, p = 0.000) for FVC. There was significant interaction between asbestos exposure and smoking history (FEV1, -0.09 cm3/year2, t = -6.467, p = 0.000; FVC, -0.097 cm3/year2, t = -5.663, p = 0.000). This study suggests that workers within the program demonstrated minimal additional pulmonary function changes during the period, particularly if they do not smoke tobacco. The study also supports continuing smoking cessation efforts for all asbestos-exposed workers.

Navy Hearing Conservation Program: 1995-1999 retrospective analysis of threshold shifts for age, sex, and officer/enlisted status.

This study provides a cross-sectional, population-based analysis of significant threshold shifts (STS) from over 83,000 audiograms on active duty members in the Navy Hearing Conservation Program Database for 1995-1999. Crude STS rates were lower for women than men (odds ration [OR], 0.82; 95% confidence interval [CI], 0.76-0.89; p = 0.0000) and lower for officer than enlisted (OR, 0.71; 95% CI, 0.66-0.76; p = 0.000000). STS rates also increased significantly with increasing age (chi2 for trend, 134; p = 0.0000). Compared with historical information, STS rates for officers were significantly lower (OR, 0.23; 95% CI, 0.18-0.27; p = 0.00000). Adjustment by logistic regression found STS rates were lower for women (OR, 0.837; 95% CI, 0.773-0.905; p = 0.000) and officer status (OR, 0.670; 95% CI, 0.619-0.725; p = 0.0000), and increased significantly with age. These findings warrant further investigation because they have programmatic implications on Navy hearing conservation and force health protection.

U.S. Navy and Marine Corps Hearing Conservation Program, 1995-1999: mean hearing thresholds for enlisted personnel by gender and age groups.

This study presents mean hearing thresholds from a cross-sectional study of 68,632 monitoring audiograms submitted to the Navy Environmental Health Center for 1995 to 1999. Records included U.S. Navy and U.S. Marine Corps enlisted personnel (Navy men = 51,643; Navy women = 4,184; Marine Corps men = 12,251: Marine Corps women = 554). Mean hearing thresholds were calculated for age groups (17-24, 25-29, 30-34, 35-39, 40-44, 45-49, and 50 years and older), gender (male/female), and service (Navy/Marine Corps). Although hearing thresholds worsened with increasing age, as expected, Navy and Marine Corps men have worse levels than Occupational Safety and Health Administration age-corrected values throughout most of their careers, whereas women were closer to the Occupational Safety and Health Administration values. Hearing thresholds in the Navy have not improved appreciably from historical reports. Threshold variability, as revealed by standard deviations, increased with age and paralleled threshold levels. This epidemiological information suggests that hearing conservation continues to be an important force health protection issue.

Navy Hearing Conservation Program: threshold shifts in enlisted personnel, 1995-1999.

This study presents audiometric information from 54,057 Navy enlisted personnel in the Navy and Marine Corps Hearing Conservation Program database from 1995 to 1999. The purpose was to compare current threshold shift patterns for Navy enlisted population with historical literature and review programmatic effectiveness issues. The data suggest that 82% of the population did not display significant threshold shift (STS) on the "annual" and "termination" audiograms, which increased to 94% after the "follow-up 2" examination. Compared with historical data, STS rates were significantly lower for the most junior enlisted personnel (E1-E3) (odds ratio = 0.34, p = 0.00, 95% confidence interval = 0.30-0.39) but not significantly different for more senior enlisted personnel (odds ratio = 0.96, p = 0.22, 95% confidence interval = 0.90-1.03). STS rates did not appear to correlate with expected "high" and "low" noise exposure Navy enlisted occupations. This suggests further investigation to readdress the possible risk factors other than noise intensity/duration.