Circulating 25-hydroxyvitamin D (25(OH)D), a marker for vitamin D status, is associated with bone health and possibly cancers and other diseases; yet, the determinants of 25(OH)D status, particularly ultraviolet radiation (UVR) exposure, are poorly understood. Determinants of 25(OH)D were analyzed in a subcohort of 1,500 participants of the US Radiologic Technologists (USRT) Study that included whites (n = 842), blacks (n = 646), and people of other races/ethnicities (n = 12). Participants were recruited monthly (2008-2009) across age, sex, race, and ambient UVR level groups. Questionnaires addressing UVR and other exposures were generally completed within 9 days of blood collection. The relation between potential determinants and 25(OH)D levels was examined through regression analysis in a random two-thirds sample and validated in the remaining one third. In the regression model for the full study population, age, race, body mass index, some seasons, hours outdoors being physically active, and vitamin D supplement use were associated with 25(OH)D levels. In whites, generally, the same factors were explanatory. In blacks, only age and vitamin D supplement use predicted 25(OH)D concentrations. In the full population, determinants accounted for 25% of circulating 25(OH)D variability, with similar correlations for subgroups. Despite detailed data on UVR and other factors near the time of blood collection, the ability to explain 25(OH)D was modest.

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We observed no association between working in a PFOS-exposed job and several cancers, common health conditions, and birth weight.

We examined the risk of childhood cancer (o20 years) among 105 950 offspring born in 1921 -1984 to US radiologic technologist (USRT) cohort members. Parental occupational in utero and preconception ionising radiation (IR) testis or ovary doses were estimated from work history data, badge dose data, and literature doses (the latter doses before 1960). Female and male RTs reported a total of 111 and 34 haematopoietic malignancies and 115 and 34 solid tumours, respectively, in their offspring. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression. Leukaemia (n ¼ 63) and solid tumours (n ¼ 115) in offspring were not associated with maternal in utero or preconception radiation exposure. Risks for lymphoma (n ¼ 44) in those with estimated doses of o0.2, 0.2 -1.0, and 41.0 mGy vs no exposure were non-significantly elevated with HRs of 2.3, 1.8, and 2.7. Paternal preconception exposure to estimated cumulative doses above the 95th percentile (X82 mGy, n ¼ 6 cases) was associated with a non-significant risk of childhood cancer of 1.8 (95% CI 0.7 -4.6). In conclusion, we found no convincing evidence of an increased risk of childhood cancer in the offspring of RTs in association with parental occupational radiation exposure. British Journal of Cancer (2008) Exposure to in utero diagnostic ionising radiation (IR) is generally considered to increase the risk of childhood cancer, including solid and haematological malignancies (Brenner et al, 2003; Wakeford, 2004). Although cohort studies of medical radiation workers have reported increases in the incidence and mortality of skin cancer, breast cancer, and leukaemia, especially in individuals who started working before 1950 when both radiation doses and permitted levels of exposure were higher (Yoshinaga et al, 2004), the risk of cancer in their offspring associated with parental occupational exposure is unclear (Brenner et al, 2003). Radiation could increase offspring cancer risk through germline or in utero somatic mutations (Doll and Wakeford, 1997; UNSCEAR, 2001;Prasad et al, 2004). The only study of childhood cancer incidence in the offspring of medical radiographers found no significant excess (Roman et al, 1996).The US radiologic technologist (USRT) cohort is one of the largest groups of occupationally exposed medical personnel assembled for study. As 73% USRT cohort participants are female, both preconception and in utero occupational radiation exposure effects on offspring cancer risk could be studied. In addition, much effort was devoted to reconstructing probable dose levels during periods when workers were not routinely monitored (Simon et al, 2006), allowing quantitative evaluation of parental exposures. To date, this is the largest study of childhood cancer risk in RT offspring. METHODSThe University of Minnesota Institutional Review Board and the United States National Cancer Institute approved all protocols for data use. Complete study details have been described elsewhere (Boice et al, 1992;Doody et ...