Job strain and autonomic indices of cardiovascular disease risk.

BACKGROUND: Despite the epidemiological evidence linking job strain to cardiovascular disease, more insight is needed into the etiologic mechanisms. This, in turn, would help to more precisely identify risk. METHODS: We measured Job Strain using the Job Content Questionnaire, 8/day diary reports, and nationally standardized occupational code linkage, as well as autonomic regulation utilizing heart rate variability including spectral-derived components and QT interval variability in 36 healthy mid-aged males with varying strain jobs. The subjects wore Holter-monitors for 48 hr; this included a work and rest day. RESULTS: Job strain (P = 0.02) and low decision latitude (P = 0.004) were associated with a reduction in cardiac vagal control (HFP) persisting throughout the 48 hr. Job strain was also associated with elevations in sympathetic control during working hours (P = 0.003). CONCLUSIONS: The disturbed cardiovascular regulatory pattern associated with job strain may help explain the increased risk of cardiovascular diseases linked with occupational exposure.

A case-control study of childhood leukemia in Woburn, Massachusetts: the relationship between leukemia incidence and exposure to public drinking water.

A 1981 Massachusetts Department of Public Health study confirmed a childhood leukemia cluster in Woburn, Massachusetts. Our follow-up investigation attempts to identify factors potentially responsible for the cluster. Woburn has a 130-year industrial history that resulted in significant local deposition of tannery and chemical manufacturing waste. In 1979, two of the city's eight municipal drinking water wells were closed when tests identified contamination with solvents including trichloroethylene. By 1986, 21 childhood leukemia cases had been observed (5.52 expected during the seventeen year period) and the case-control investigation discussed herein was begun. Nineteen cases and 37 matched controls comprised the study population. A water distribution model provided contaminated public water exposure estimates for subject residences. Results identified a non-significant association between potential for exposure to contaminated water during maternal pregnancy and leukemia diagnosis, (odds ratio = 8.33, 95% CI 0.73-94.67). However, a significant dose-response relationship (P < 0.05) was identified for this exposure period. In contrast, the child's potential for exposure from birth to diagnosis showed no association with leukemia risk. Wide confidence intervals suggest cautious interpretation of association magnitudes. Since 1986, expected incidence has been observed in Woburn including 8 consecutive years with no new childhood leukemia diagnoses.