Maternal Vitamin D Supplementation and Infantile Rickets: Secondary Analysis of a Randomized Trial.

BACKGROUND: The role of maternal vitamin D supplementation in the prevention of infantile rickets is unknown, particularly in low- and middle-income countries without routine infant vitamin D supplementation. Through secondary analysis of a randomized, placebo-controlled trial in Bangladesh, we examined the dose-ranging effects of maternal vitamin D supplementation on the risk of biochemical rickets at 6 to 12 months of age. METHODS: Pregnant women (n = 1300) were randomized into 5 groups: placebo, or vitamin D 4200 IU/week, 16 800 IU/week, or 28 000 IU/week from second trimester to delivery and placebo until 6 months postpartum; or 28 000 IU/week prenatally and until 6 months postpartum. Infants underwent biochemical rickets screening from 6 to 12 months of age (n = 790). Relative risks (RR) and 95% confidence intervals (95% CI) of biochemical rickets were estimated for each group versus placebo. RESULTS: Overall, 39/790 (4.9%) infants had biochemical rickets. Prevalence was highest in the placebo group (7.8%), and the risk was significantly lower among infants whose mothers received combined prenatal and postpartum vitamin D at 28 000 IU/week (1.3%; RR, 0.16; 95% CI, 0.03-0.72). Risks among infants whose mothers received only prenatal supplementation (4200 IU, 16 800 IU, 28 000 IU weekly) were not significantly different from placebo: 3.8% (RR, 0.48; 95% CI, 0.19-1.22), 5.8% (RR, 0.74; 95% CI, 0.33-1.69), and 5.7% (RR, 0.73; 95% CI, 0.32-1.65), respectively. CONCLUSIONS: Maternal vitamin D supplementation (28 000 IU/week) during the third trimester of pregnancy until 6 months postpartum reduced the risk of infantile biochemical rickets. Further research is needed to define optimal postpartum supplementation dosing during lactation.

Adolescent Gender Identity, Sexual Orientation, and Cannabis Use: Potential Mediations by Internalizing Disorder Risk.

BACKGROUND/AIMS: Adolescents who identify as nonbinary gender or as not heterosexual report higher levels of mental illness than their counterparts. Cannabis use is a commonly employed strategy to cope with mental illness symptoms among adolescents; however, cannabis use can have many deleterious health consequences for youth. Within the frame of minority stress theory, this study investigates the relationships between gender identity and sexual orientation, internalizing disorder symptoms, and cannabis use among adolescents. METHOD: A national cross-sectional survey of a generalizable sample of high school students in Canada from the 2017 wave (N = 15,191) of the Cancer Risk Assessment in Youth Survey was analyzed in spring 2019. Mediation analyses were completed to examine risk of internalizing disorder symptoms as a potential mediator of the association between (1) gender identity and (2) sexual orientation, and cannabis use. RESULTS: Indirect effects in all models show significantly higher levels of reported internalizing disorder symptoms for female (OR = 3.44, 95% CI [2.84, 4.18]) and nonbinary gender (OR = 3.75, 95% CI [2.16, 6.51]) compared with male students. Sexual minority adolescents had higher odds of internalizing disorder risk relative to non-sexual minority adolescents (OR = 3.13, 95% CI [2.63, 3.74]). Students who reported higher rates of internalizing disorder symptoms were more likely to have ever used cannabis. Patterns of partial mediation are also present among all groups. DISCUSSION/CONCLUSIONS: Findings can be used to better inform mental health interventions for adolescents. Future study should explore specific mental health stressors of vulnerable adolescent groups with respect to cannabis use as a coping mechanism.

Cannabis use and stigma among Canadian high school students: Results from the 2015 and 2017 Cancer Risk Assessment in Youth Survey.

BACKGROUND: Adolescent cannabis use is perceived as a risky behavior, has been linked with many negative health outcomes, and is increasingly being connected with stigma. METHODS: The purpose of this study is to investigate how cannabis use is associated with potentially stigmatizing markers of identity among adolescents two waves of a repeat cross-sectional survey (2015 N = 12,110; 2017 N = 15,191) of high schools students in seven Canadian provinces. Students were asked about ever use of cannabis, as well as "stigma markers", including their current living arrangement, mother's education, and ethnicity. Multivariable logistic regression models were used to examine associations between cannabis use and stigma markers. RESULTS: After adjusting models for grade, gender, and province of residence, students who did not live with their mothers had higher odds of cannabis use relative to students living with their mothers [OR = 1.94, 95% CI 1.62-2.31]. Low maternal education was also significantly associated with cannabis use, as was ethnicity (students who identified as Indigenous had 3.38 (95% CI 2.29-4.99) times higher odds of using cannabis compared to students who identified as "white" in 2017). Findings related to attending school in a rural (vs. urban) area (2015 OR = 1.33 95% CI 0.99-1.78; 2017 OR = 1.44 95% CI 0.9 to -2.15) and low SES (2015 OR = 0.99, 95% 0.98-1.00; 2017 OR = 1.00, 95% CI 0.98-1.01) were more marginal. CONCLUSIONS: Future research should explore cannabis initiation experiences among vulnerable groups to better understand potential stigma triggers.