Janet A. Foote

Several studies have investigated the potential role of selenium (Se) in the development of type 2 diabetes (T2D) with disparate findings. We conducted a systematic review and meta-analysis to synthesize the evidence of any association between Se and T2D. PubMed, Embase, and Scopus were searched following the Preferred Reporting Items for Systematic Reviews and Meta-analysis Approach (PRISMA). Sixteen studies from 15 papers met inclusion criteria defined for this review. Of the 13 observational studies included, 8 demonstrated a statistically significant positive association between concentrations of Se and odds for T2D, with odds ratios (95% confidence intervals) ranging from 1.52 (1.01–2.28) to 7.64 (3.34–17.46), and a summary odds ratio (OR) (95% confidence interval (CI)) of 2.03 (1.51–2.72). In contrast, among randomized clinical trials (RCTs) of Se, a higher risk of T2D was not observed for those who received Se compared to a placebo (OR = 1.18, 95% CI 0.95–1.47). Taken together, the results for the relationship between Se and T2D differ between observational studies and randomized clinical trials (RCTs). It remains unclear whether these differences are the result of uncontrolled confounding in the observational studies, or whether there is a modest effect of Se on the risk for T2D that may vary by duration of exposure. Further investigations on the effects of Se on glucose metabolism are needed.

Background. The level of systemic inflammation as measured by circulating levels of C-reactive protein (CRP) and interleukin-6 (IL-6) is linked to an increased risk for cardiovascular diseases (CVD) and cancer.Methods. We recruited 154 current and former smokers between 40 and 80 years of age with 25 or more pack-years of smoking history to study the relationship between inflammatory markers (CRP and IL-6) and smoking status.Results. Our results show that male smokers had significantly higher levels of serum IL-6 compared to male former smokers. We did not find any gender specific differences for smoking and CRP levels but the IL-6 levels were slightly lower in females compared to males. Additionally, our results show that CRP is significantly associated with IL-6 regardless of smoking status. Modelling indicates that the significant predictors of CRP levels were biomarkers of the metabolic syndrome while the significant predictors of IL-6 levels were age and plasma triglycerides among former smokers and the numbers of smoked packs of cigarettes per year among smokers.Conclusions. In conclusion, our study showed that CRP levels were not associated with markers of smoking intensity. However, IL-6 levels were significantly associated with smoking especially among current smokers.

Prior research shows that topical application of free, nonfatty acid–conjugated vitamin E (dl-α-tocopherol) prevents skin cancer in mice, as well as immunosuppression induced by UVB radiation. This study investigated the chemopreventive potential of dl-α-tocopherol in humans through monitoring surrogate end point biomarkers in sun-damaged skin. Contralateral arms of healthy human volunteers with actinic keratoses (AK) were randomly assigned to receive either 12.5% dl-α-tocopherol or placebo in a crème base for 6 months. Changes in number of AKs, levels of p53 protein expression, proliferating cell nuclear antigen, and polyamines were assessed along with skin and systemic vitamin E levels. Following treatment, plasma concentration levels of dl-α-tocopherol were unchanged, but skin levels were highly elevated (P < 0.001). Levels of p53 and proliferating cell nuclear antigen did not change significantly, whereas number of AKs declined insignificantly in both placebo and treatment arms. Regression models showed significant decreases in putrescine, spermidine, spermine, and total polyamine concentrations following treatment. Topically applied dl-α-tocopherol was substantially absorbed in skin, but the 6-month application did not significantly reduce numbers of preexisting AKs on moderately to severely sun-damaged forearms. Increases in polyamine synthesis are expected during tumor initiation and promotion; conversely, the significant reductions in polyamine levels resulting from the topical dl-α-tocopherol application are consistent with reductions in tumorigenesis potential. Topical tocopherol did not normalize established sun-induced lesions, but dl-α-tocopherol–induced reductions in polyamine metabolism are consistent with the inhibition of skin squamous cell carcinogenesis as seen in previous human trials and animal models.