Assessment of the internal and external exposure risks to methylsiloxanes in communities near a petroleum refinery.

Methylsiloxanes (MSs) are widely used in industrial production and have attracted much attention due to their potential health risks to humans. MSs are present in emissions from petroleum refining, and it is therefore important to assess the health risks to residents living near refineries. In this study, we evaluated the pollution characteristics and human exposure risks of three cyclic MS (CMS) oligomers (D4-D6) in areas upwind and downwind of a petroleum refinery. The concentrations of total CMSs were 4-33 times higher in the downwind than upwind areas. At the same sampling site, the concentrations of CMSs were higher indoors than outdoors. The maximum concentration of CMSs was found in the indoor environment 200 m downwind of the petroleum refinery (75 µg/m3 in air and 2.3 µg/g in dust). The concentrations and detection rates of CMSs in plasma samples were higher in the downwind than upwind residents. Although residents living downwind of the petroleum refinery were a non-occupationally exposed population, they should be considered a highly CMS-exposed population because of their extremely high internal exposure doses. Inhalation exposure was the main source of CMSs in the plasma of these residents. When different exposure pathways were investigated, inhalation exposure was the major contributor to the average daily dose in residents of locations near the petroleum refinery, whereas the dermal absorption of personal care products was the major contributor at other sites. Although the overall risks of exposure to total CMSs were below the chronic reference dose for all exposure pathways, the combined joint toxic effects of various CMSs remain unclear. Further studies are therefore required to determine the exposure risks and subsequent health effects of CMSs for the residents of these areas.

Circulating concentrations of biomarkers and metabolites related to vitamin status, one-carbon and the kynurenine pathways in US, Nordic, Asian, and Australian populations.

Background: Circulating concentrations of biomarkers that are related to vitamin status vary by factors such as diet, fortification, and supplement use. Published biomarker concentrations have also been influenced by the variation across laboratories, which complicates a comparison of results from different studies.Objective: We robustly and comprehensively assessed differences in biomarkers that are related to vitamin status across geographic regions.Design: The trial was a cross-sectional study in which we investigated 38 biomarkers that are related to vitamin status and one-carbon and tryptophan metabolism in serum and plasma from 5314 healthy control subjects representing 20 cohorts recruited from the United States, Nordic countries, Asia, and Australia, participating in the Lung Cancer Cohort Consortium. All samples were analyzed in a centralized laboratory.Results: Circulating concentrations of riboflavin, pyridoxal 5'-phosphate, folate, vitamin B-12, all-trans retinol, 25-hydroxyvitamin D, and α-tocopherol as well as combined vitamin scores that were based on these nutrients showed that the general B-vitamin concentration was highest in the United States and that the B vitamins and lipid soluble vitamins were low in Asians. Conversely, circulating concentrations of metabolites that are inversely related to B vitamins involved in the one-carbon and kynurenine pathways were high in Asians. The high B-vitamin concentration in the United States appears to be driven mainly by multivitamin-supplement users.Conclusions: The observed differences likely reflect the variation in intake of vitamins and, in particular, the widespread multivitamin-supplement use in the United States. The results provide valuable information about the differences in biomarker concentrations in populations across continents.

Association of Coffee Consumption With Total and Cause-Specific Mortality in 3 Large Prospective Cohorts.

BACKGROUND: The association between consumption of caffeinated and decaffeinated coffee and risk of mortality remains inconclusive. METHODS AND RESULTS: We examined the associations of consumption of total, caffeinated, and decaffeinated coffee with risk of subsequent total and cause-specific mortality among 74,890 women in the Nurses' Health Study (NHS), 93,054 women in the Nurses' Health Study II, and 40,557 men in the Health Professionals Follow-up Study. Coffee consumption was assessed at baseline using a semiquantitative food frequency questionnaire. During 4,690,072 person-years of follow-up, 19,524 women and 12,432 men died. Consumption of total, caffeinated, and decaffeinated coffee were nonlinearly associated with mortality. Compared with nondrinkers, coffee consumption of 1 to 5 cups per day was associated with lower risk of mortality, whereas coffee consumption of more than 5 cups per day was not associated with risk of mortality. However, when restricting to never smokers compared with nondrinkers, the hazard ratios (and 95% confidence intervals) of mortality were 0.94 (0.89-0.99) for 1.0 or less cup per day, 0.92 (0.87-0.97) for 1.1 to 3.0 cups per day, 0.85 (0.79-0.92) for 3.1 to 5.0 cup per day, and 0.88 (0.78-0.99) for more than 5.0 cup per day (P value for nonlinearity = 0.32; P value for trend < 0.001). Significant inverse associations were observed for caffeinated (P value for trend < 0.001) and decaffeinated coffee (P value for trend = 0.022). Significant inverse associations were observed between coffee consumption and deaths attributed to cardiovascular disease, neurologic diseases, and suicide. No significant association between coffee consumption and total cancer mortality was found. CONCLUSIONS: Higher consumption of total coffee, caffeinated coffee, and decaffeinated coffee was associated with lower risk of total mortality.

Caffeine Intake, Coffee Consumption, and Risk of Cutaneous Malignant Melanoma.

BACKGROUND: Caffeine has been shown to prevent ultraviolet radiation-induced carcinogenesis and to inhibit growth of melanoma cells in experimental studies. We evaluated the association among caffeine intake, coffee consumption, and melanoma risk among three large cohort studies. METHODS: The analysis used data from 89,220 women in the Nurses' Health Study II (1991-2009), 74,666 women in the Nurses' Health Study (1980-2008), and 39,424 men in the Health Professionals Follow-up Study (1986-2008). We used Cox proportional hazards models to estimate the hazard ratios (HR) with 95% confidence intervals (CIs) of melanoma associated with dietary intakes. RESULTS: We documented 2,254 melanoma cases over 4 million person-years of follow-up. After adjustment for other risk factors, higher total caffeine intake was associated with a lower risk of melanoma (≥393 mg/day vs. <60 mg/day: HR = 0.78, 95% CI = 0.64, 0.96; Ptrend = 0.048). The association was more apparent in women (≥393 mg/day vs. <60 mg/day: HR = 0.70, 95% CI = 0.58, 0.85; Ptrend = 0.001) than in men (HR = 0.94, 95% CI = 0.75, 1.2; Ptrend = 0.81), and more apparent for melanomas occurring on body sites with higher continuous sun exposure (head, neck, and extremities; ≥393 mg/day vs. <60 mg/day: HR = 0.71, 95% CI = 0.59, 0.86; Ptrend = 0.001) than for melanomas occurring on body sites with lower continuous sun exposure (trunk including shoulder, back, hip, abdomen, and chest; HR = 0.90, 95% CI = 0.70, 1.2; Ptrend = 0.60). This pattern of association was similar to that for caffeinated coffee consumption, whereas no association was found for decaffeinated coffee consumption and melanoma risk. CONCLUSIONS: Increasing caffeine intake and caffeinated coffee consumption is associated with decreased risk of cutaneous malignant melanomas.

Psoriasis, psoriatic arthritis and risk of gout in US men and women.

BACKGROUND AND OBJECTIVE: Individuals with psoriasis have increased blood levels of uric acid. However, there is no prospective data on the association between psoriasis and uric acid levels and subsequent development of gout. In this study, we examined the risk of gout among individuals with psoriasis and psoriatic arthritis (PsA) in two cohorts of men and women, the Health Professionals Follow-up Study (HPFS) (1986-2010) and Nurses' Health Study (NHS) (1998-2010). METHODS: 27 751 men and 71 059 women were included in the analysis. Lifetime history of physician-diagnosed incident psoriasis and PsA was confirmed by validated supplementary questionnaires. Incident gout diagnoses were confirmed based on the American College of Rheumatology survey criteria. We used Cox proportional hazards models controlling for potential risk factors to calculate the HRs with 95% CIs of incident gout while simultaneously adjusting for several common risk factors. RESULTS: We documented 2217 incident cases of gout during follow-up. Psoriasis was associated with an increased risk of subsequent gout with a multivariate HR of 1.71 (95% CI 1.36 to 2.15) in the pooled analysis. Risk of gout was substantially augmented among those with psoriasis and concomitant PsA (pooled multivariate HR: 4.95, 95% CI 2.72 to 9.01) when compared to participants without psoriasis. CONCLUSIONS: In this prospective study of US women and men, psoriasis and PsA were associated with an increased risk of gout.

No association between vitamin D intake and incident psoriasis among US women.

We investigated the association between dietary, supplementary and total vitamin D intake and incident psoriasis in women. A prospective study was performed of 70,437 US female nurses aged 47-74 enrolled in the Nurses' Health Study who did not have psoriasis at baseline in 1994 and who completed semi-quantitative food frequency questionnaires in 1994, 1998, 2002 and 2006. The incidence of clinician-diagnosed psoriasis was ascertained and validated by self-reported questionnaires. 502 confirmed incident psoriasis cases were documented during 973,057 person-years of follow-up from 1994 June to 2008 June. Association between vitamin D intake and incident psoriasis was assessed using multivariable-adjusted cox regression analysis. After adjusting for age, smoking, body mass index, calorie intake, UV flux, exercise and alcohol use, there was no significant association between vitamin D intake (dietary, supplementary and total vitamin D) and the risk of incident psoriasis. Compared with women whose dietary vitamin D intake was <100 IU/day, multivariate relative risks for psoriasis was 1.13 (95 % CI 0.66-1.92) for ≥400 IU/day (P trend = 0.88). The multivariate relative risk for women who took supplementary vitamin D ≥400 IU/day was 1.18 (95 % CI 0.88-1.58) compared with women who did not take supplementary vitamin D. The multivariate risk for women who had total vitamin D intake of 300-399 IU/day was no different than at higher and lower doses of vitamin D intake. Our study does not support preventive roles of dietary or supplemental vitamin D intake for incident psoriasis.