Mortality among mine and mill workers exposed to respirable crystalline silica.

BACKGROUND: Millions of workers are potentially exposed to respirable crystalline silica (RCS) which has been associated with several diseases. We updated the mortality experience of a cohort of 2,650 mine and mill workers at four manufacturing facilities to assess cause-specific mortality risks associated with estimated cumulative RCS exposure. METHODS: Study eligibility was defined as any employee who had ≥1 year of service by 2000, with work history experience available from 1945 through 2004. Vital status and cause of death were ascertained from 1945 through 2015. RCS exposure was estimated across plant-, department-, job-, and time-dependent categories using historic industrial hygiene sampling data and professional judgment. Associations between cumulative RCS (mg/m3-years) and cause-specific mortality were examined using Cox proportional hazard regression models. RESULTS: In the exposure-response analysis defined on quartiles of cumulative RCS exposure, no increasing trend (ptrend = 0.37) in lung cancer mortality (n = 116 deaths) was observed (Hazard ratio (HR) = 1.00 (referent), 1.20, 1.85, 0.92). Mortality risk for non-malignant respiratory disease was increased across quartiles (HR = 1.00, 1.35, 1.89, 1.70; ptrend = 0.15), based on 83 deaths. Non-malignant renal disease mortality was increased across quartiles (HR = 1.00, 6.64, 3.79, 3.29; ptrend = 0.11), based on 26 deaths. CONCLUSIONS: After nearly seven decades of follow-up, the exposure-response analyses showed no evidence of a positive trend for lung cancer, and limited evidence of a trend for non-malignant respiratory disease, and non-malignant renal disease mortality as a result of cumulative RCS exposure in this occupational cohort.

Firefighters' physical activity: relation to fitness and cardiovascular disease risk.

PURPOSE: Cardiovascular disease (CVD) accounts for 44% of on-duty deaths among US firefighters with a markedly higher event risk during strenuous duties compared with nonemergencies. Sedentary persons are most susceptible to such CVD "event-triggering" due to irregular bouts of vigorous physical activity (PA). Conversely, regular PA and increased levels of cardiorespiratory fitness (CRF) protect against CVD triggering. Therefore, the present study evaluates PA measures in structural firefighters and their relationship to CRF and CVD risk factors. METHODS: Cross-sectional cohort study of 527 Midwestern career firefighters. PA frequency, duration, and intensity measures from a questionnaire along with total weekly aerobic exercise were analyzed. CRF was measured by maximal exercise tolerance testing. CVD risk parameters included body composition, blood pressure, and metabolic profiles. Group differences were compared using general linear models. RESULTS: Measures of increasing frequency, duration, intensity of PA, and total weekly exercise (min) were significantly associated with higher CRF (P < 0.001) after adjustment for age, body mass index (BMI), and smoking status. After multivariate adjustment, increasing PA frequency was significantly associated with reduced total cholesterol-HDL ratio, triglycerides, and glucose, as well as HDL increments. Increasing BMI category was associated with significant decrements in CRF and unfavorable dose-response trends in CVD risk factors (P < 0.001), even for those reporting very frequent, sustained, and intense PA. CONCLUSIONS: Increasing PA has beneficial independent effects on CRF, and PA frequency has similar favorable effects on CVD risk profiles. Whereas PA was beneficial regardless of BMI category, increasing BMI category had strong independent unfavorable effects. PA should be strongly encouraged for all firefighters with the highest priority given to PA frequency, followed by PA duration and intensity.

Obstructive sleep apnea screening during commercial driver medical examinations: a survey of ACOEM members.

OBJECTIVE: To survey American College of Occupational and Environmental Medicine (ACOEM) members regarding recent consensus guidelines for screening commercial drivers for Obstructive Sleep Apnea (OSA). METHODS: A brief survey instrument was distributed electronically by the American College of Occupational and Environmental Medicine to its members during February 2008 to April 2008. RESULTS: Most (92%) of the 552 examiners opined that screening commercial drivers for OSA was important. Nevertheless, only 42% reported screening using consensus guidelines or another specific protocol. Common reasons for not applying the guidelines included unaware (36%), too complicated (12%), client retention (10%), and driver inconvenience (10%). Most would consider using the guidelines going forward but 39% wanted additional evidence and another 21% only if they became the "community standard." CONCLUSIONS: More education regarding OSA and drivers is needed. A Federal mandate and eliminating "doctor shopping" would likely increase examiners' compliance with screening.

Screening for obstructive sleep apnea during commercial driver medical examinations.

OBJECTIVE: To evaluate consensus criteria for screening commercial drivers for obstructive sleep apnea (OSA). METHODS: Consecutive drivers underwent OSA screening using Joint Task Force consensus criteria at commercial driver medical examinations. Outcomes included: clinical yield of screening; and drivers' compliance with polysomnography (PSG) referrals and OSA treatment. RESULTS: Among 456 drivers, 53 (12%) were referred for PSG, and 20/20 were confirmed to have OSA, supporting a high positive predictive value. The other 33 drivers referred for PSG were lost to follow-up but demonstrated no significant differences from those with confirmed OSA. After diagnosis, only one of 20 drivers with confirmed OSA demonstrated treatment compliance. CONCLUSIONS: Drivers identified by the consensus criteria have a high likelihood of OSA. Drivers' poor compliance with PSGs and OSA treatment support federally mandated screening of commercial drivers.