Solar ultraviolet-B radiation and vitamin D: a cross-sectional population-based study using data from the 2007 to 2009 Canadian Health Measures Survey

Background: Exposure to solar ultraviolet-B (UV-B) radiation is a major source of vitamin D3. Chemistry climate models project decreases in ground-level solar erythemal UV over the current century. It is unclear what impact this will have on vitamin D status at the population level. The purpose of this study was to measure the association between ground-level solar UV-B and serum concentrations of 25-hydroxyvitamin D (25(OH)D) using a secondary analysis of the 2007 to 2009 Canadian Health Measures Survey (CHMS). Methods: Blood samples collected from individuals aged 12 to 79 years sampled across Canada were analyzed for 25(OH)D (n=4,398). Solar UV-B irradiance was calculated for the 15 CHMS collection sites using the Tropospheric Ultraviolet and Visible Radiation Model. Multivariable linear regression was used to evaluate the association between 25(OH)D and solar UV-B adjusted for other predictors and to explore effect modification. Results: Cumulative solar UV-B irradiance averaged over 91 days (91-day UV-B) prior to blood draw correlated significantly with 25(OH)D. Independent of other predictors, a 1 kJ/m 2 increase in 91-day UV-B was associated with a significant 0.5 nmol/L (95% CI 0.3-0.8) increase in mean 25(OH)D (P =0.0001). The relationship was stronger among younger individuals and those spending more time outdoors. Based on current projections of decreases in ground-level solar UV-B, we predict less than a 1 nmol/L decrease in mean 25(OH)D for the population. Conclusions: In Canada, cumulative exposure to ambient solar UV-B has a small but significant association with 25(OH)D concentrations. Public health messages to improve vitamin D status should target safe sun exposure with sunscreen use, and also enhanced dietary and supplemental intake and maintenance of a healthy body weight

A Validated Age-Related Normative Model for Male Total Testosterone Shows Increasing Variance but No Decline after Age 40 Years

The diagnosis of hypogonadism in human males includes identification of low serum testosterone levels, and hence there is an underlying assumption that normal ranges of testosterone for the healthy population are known for all ages. However, to our knowledge, no such reference model exists in the literature, and hence the availability of an applicable biochemical reference range would be helpful for the clinical assessment of hypogonadal men. In this study, using model selection and validation analysis of data identified and extracted from thirteen studies, we derive and validate a normative model of total testosterone across the lifespan in healthy men. We show that total testosterone peaks [mean (2.5-97.5 percentile)] at 15.4 (7.2-31.1) nmol/L at an average age of 19 years, and falls in the average case [mean (2.5-97.5 percentile)] to 13.0 (6.6-25.3) nmol/L by age 40 years, but we find no evidence for a further fall in mean total testosterone with increasing age through to old age. However we do show that there is an increased variation in total testosterone levels with advancing age after age 40 years. This model provides the age related reference ranges needed to support research and clinical decision making in males who have symptoms that may be due to hypogonadism.Publisher PDFPeer reviewe

Weight status and perception of body image in children: the effect of maternal immigrant status

<p>Abstract</p> <p>Background</p> <p>Recent studies have shown that body image perception is an important factor in weight control and may be influenced by culture and ethnicity. The aim of the present study was to assess the relationship between immigrant status of the mother and weight status and body image perception of the child.</p> <p>Methods</p> <p>In total, 2706 schoolchildren (1405 boys and 1301 girls) aged 8–9 years and their mothers participated in a cross-sectional survey in Emilia-Romagna region (northern Italy). Weight and height of the children were measured and Body Mass Index (BMI) was calculated. Actual and ideal body image perception by the children and by the mothers with respect to their children was evaluated according to Collins’ body image silhouettes.</p> <p>Results</p> <p>The BMI values were significantly lower in children of immigrants than in children of Italian mothers (F:17.27 vs 17.99 kg/m²; M:17.77 vs 18.13 kg/m²). The prevalence of overweight/obesity was lower, and the prevalence of underweight higher, in children of immigrant mothers than in those of Italian mothers (overweight- F:21.3 vs 29.1%; M. 28.3 vs 31.4%; underweight- F:5.16 vs 3.84%; M:6.63 vs 2.82%). The children's body image perception was consistent with the differing pattern of nutritional status. In the comparison between actual and ideal figures, the Feel-Ideal Difference Index (FID) scores resulted different between the subsample with foreign-born mother in comparison to the native one (significantly lower in daughters of immigrants) (FID- F: 0.31 vs 0.57; M: 0.35 vs 0.32). There were significant differences in the choice of the ideal figure of the child between immigrant mothers and Italian mothers (FID- F: -0.05 vs 0.19; M: -0.35 vs −0.03): the ideal figure values were higher in the immigrant mothers of male children and lower in the Italian mothers of female children.</p> <p>Conclusion</p> <p>Our results suggest that cultural and behavioral factors linked to ethnicity play an important role in the nutritional status of children and in the perceived and ideal body image.</p

An exploration of third parties’ preference for compensation over punishment: six experimental demonstrations

Research suggests that to restore equity, third parties prefer compensation of a victim over the punishment of a perpetrator. It remains unclear, however, whether this preference for compensation is stable or specific to certain situations. In six exper- imental studies, we find that adjustments in the characteristics of the situation or in the available behavioral options hardly modify the preference of compensation over punishment. This preference for compensation was found even in cases where pun- ishment might refrain a perpetrator from acting unfairly again in the future, and even when punishment has a greater impact in restoring equity than compensation does. Thus, the preference of compensation over punishment appears to be quite robust. Implications and ideas for future research are discussed