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Synopsis The population-based association between low vitamin D status and increased cancer risk can be inconsistent but is now generally accepted. These relationships link low serum 25 hydroxyvitamin D levels to cancer while cell-based studies show that the metabolite 1,25 dihydroxyvitamin D is the biologically active metabolite that works through vitamin D receptor to regulate gene transcription. Here we review the literature relevant to the molecular events that may account for the beneficial impact of vitamin D on cancer prevention or treatment. This data shows that while vitamin D-induced growth arrest and apoptosis of tumor cells or their non-neoplastic progenitors are plausible mechanisms, other chemoprotective mechanisms are also worthy of consideration. These alternative mechanisms include enhancing DNA repair, antioxidant protection, and immunomodulation. In addition, other cell targets such as the stromal cells, endothelial cells, and cells of the immune system may be regulated by 1,25 dihydroxyvitamin D and contribute to vitamin D mediated cancer prevention.

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Based on these findings, group-based comprehensive risk reduction was found to be an effective strategy to reduce adolescent pregnancy, HIV, and STIs. No conclusions could be drawn on the effectiveness of group-based abstinence education.

Context Children from low-income and racial or ethnic minority populations in the U.S. are less likely to have a conventional source of medical care and more likely to develop chronic health problems than are more-affluent and non-Hispanic white children. They are more often chronically stressed, tired, and hungry, and more likely to have impaired vision and hearing—obstacles to lifetime educational achievement and predictors of adult morbidity and premature mortality. If school-based health centers (SBHCs) can overcome educational obstacles and increase receipt of needed medical services in disadvantaged populations, they can advance health equity. Evidence acquisition A systematic literature search was conducted for papers published through July 2014. Using Community Guide systematic review methods, reviewers identified, abstracted, and summarized available evidence of the effectiveness of SBHCs on educational and health-related outcomes. Analyses were conducted in 2014–2015. Evidence synthesis Most of the 46 studies included in the review evaluated onsite clinics serving urban, low-income, and racial or ethnic minority high school students. The presence and use of SBHCs were associated with improved educational (i.e., grade point average, grade promotion, suspension, and non-completion rates) and health-related outcomes (i.e., vaccination and other preventive services, asthma morbidity, emergency department use and hospital admissions, contraceptive use among females, prenatal care, birth weight, illegal substance use, and alcohol consumption). More services and more hours of availability were associated with greater reductions in emergency department overuse. Conclusions Because SBHCs improve educational and health-related outcomes in disadvantaged students, they can be effective in advancing health equity.