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Objective: We evaluated the effects of ozone on respiratory-related hospital admissions in three counties in Washington State from 1990 to 2006. We further examined vulnerability to ozone by key demographic factors., Method: Using linked hospital admission and ambient monitoring data, we estimated the age-, sex-, and health insurance-stratified associations between ozone (0 to 3 days' lag) and respiratory-related hospital admissions in King, Spokane, and Clark County, Washington., Results: The adjusted relative risk (RR) for a 10 ppb increase in ozone at 3 days' lag was 1.04 (95% confidence interval [CI]: 1.02, 1.07) for Clark County, 1.03 (95% CI: 1.01, 1.05) for Spokane County, and 1.02 (95% CI: 1.01, 1.03) for King County. There was consistent evidence of effect modification by age., Conclusion: Ozone at levels below federal standards contributes to respiratory morbidity among high-risk groups in Washington.

Objectives: Metabolites of estrogen (estrone-3-glucuronide [E1G]) and melatonin (6-hydroxymelatonin sulfate [6-OHMS]) were characterized among women living in a community with increased radiofrequency (RF) exposure from radio and television transmitters., Methods: RF spot measurements, and personal 60-Hz magnetic field and residential parameters were collected. Overnight urine samples were assayed for E1G and 6-OHMS excretion., Results: Among premenopausal women, there were no associations between RF or 60-Hz nonionizing radiation and E1G or 6-OHMS excretion. Among postmenopausal women, increased residential RF exposures, transmitter proximity and visibility, and temporally stable 60-Hz exposures were significantly associated with increased E1G excretion. This association was strongest among postmenopausal women with low overnight 6-OHMS levels., Conclusions: RF and temporally stable 60-Hz exposures were associated with increased E1G excretion among postmenopausal women. Women with reduced nocturnal 6-OHMS excretion may represent a sensitive subgroup.

Background: Night work is associated with disrupted circadian rhythms, fatigue, accidents, and chronic disease. Melatonin secretion helps regulate sleep and circadian rhythms., Objective: Melatonin, sleep disturbances, and symptoms (sleep, fatigue, mental) were compared among workers on permanent day, swing, and night shifts., Methods: Urinary 6-hydroxymelatonin sulfate (6-OHMS) was measured in postwork and postsleep samples. Disrupted circadian melatonin production was evaluated using the sleep:work 6-OHMS ratio. Wrist actigraphy characterized light exposures and sleep characteristics., Results: Night workers had altered melatonin, disrupted sleep, and elevated symptom prevalence. Subjects grouped by their sleep:work 6-OHMS ratio rather than shift had even greater symptom prevalence. Risks for two or more symptoms were 3.5 to 8 times greater among workers with sleep:work ratios < or =1 compared to those with ratios >1., Conclusions: This ratio may help identify workers at increased risk for accidents or injuries.

The effects of a 60-Hz magnetic field (MF) exposure on white blood cell ornithine decarboxylase (ODC) activity, natural killer (NK) cell activity, lymphocyte phenotypes, and differential cell counts were studied among 60 electric utility workers. Personal MF exposure monitoring over 3 consecutive workdays was followed by collection of a peripheral blood sample. There were no MF-related changes in NK activity or the number of circulating neutrophils, eosinophils, basophils, or T-lymphocytes (CD4, CD8, CD4:CD8 ratio). MF exposure intensity was associated with decreased ODC activity (P<0.01) and lower NK cell counts (P=0.04). Melatonin production, which stimulates the immune system, was quantified on the night preceding immune marker determinations. Exposure-related reductions in ODC activity, NK and B cells, and monocytes were strongest among workers with reduced melatonin production. The biological significance or long-term health consequences associated with these changes are not known.

This study assessed the relationship between occupational magnetic field exposure, the urinary melatonin metabolite 6-hydroxymelatonin sulfate (6-OHMS), and concentrations of blood-borne soluble amyloid beta (A beta), a protein associated with the hallmark lesions of Alzheimer's disease (AD). Blood and urine samples were obtained from male electric utility workers (n = 60) to quantify two lengths of the protein in plasma, A beta (amino acids 1-40) and A beta (1-42), and the urinary concentrations of 6-OHMS. Average A beta levels were positively associated with categories of magnetic field exposure, but this relationship was weak and did not achieve statistical significance. The melatonin metabolite was inversely correlated with A beta (1-42) and the ratio of A beta (1-42) to A beta (1-40). This observation is consistent with recent in vitro data and provides a plausible mechanism for the association between magnetic field exposure and AD that has been observed in some studies.