Reduction of parathyroid hormone with vitamin D supplementation in blacks: A randomized controlled trial

BACKGROUND: Response of parathyroid hormone (PTH) to vitamin D supplementation is determined by the baseline PTH level and change in vitamin D status. Conflicting reports in Blacks exist on the PTH response to vitamin D to supplementation. METHODS: During 3 winters from 2007-2010, 328 healthy Blacks (median age, 51 years) living in Boston, MA were randomized into a 4-arm, double-blind trial for 3 months of placebo, 1000, 2000, or 4000 IU of vitamin D3. PTH was measured in 254 participants at baseline and at the end of vitamin D supplementation period. RESULTS: The differences in PTH between baseline and 3 months were 3.93 pg/mL for those receiving placebo, -3.37 pg/mL for those receiving 1000 IU/d, -6.76 pg/mL for those receiving 2000 IU/d, and -8.99 pg/mL for those receiving 4000 IU/d ( -2.98 pg/mL for each additional 1000 IU/d of vitamin D3; p<0.001). CONCLUSION: We found a significant decrease in PTH with increasing doses of vitamin D supplementation up to intakes of 4000 IU/d in Blacks. Clinical Trials.gov: NCT0058563

How Many Varieties of Capitalism? Comparing the Comparative Institutional Analyses of Capitalist Diversity

This essay reviews the development of approaches within the comparative capitalisms (CC) literature and points to three theoretical innovations which, taken together, define and distinguish these approaches as a group. First, national economies are characterized by distinct institutional configurations that generate a particular systemic 'logic' of economic action. Second, the CC literature suggests a theory of comparative institutional advantage in which different institutional arrangements have distinct strengths and weaknesses for different kinds of economic activity. Third, the literature has been interpreted to imply a theory of institutional path dependence. Behind these unifying characteristics of the literature, however, lie a variety of analytical frameworks and typologies of capitalism. This paper reviews and compares these different frameworks by highlighting the fundamental distinctions among them and drawing out their respective contributions and limitations in explaining economic performance and institutional dynamics. The paper concludes that the way forward for this literature lies in developing a more dynamic view of individual institutions, the linkages between domains, and the role of politics and power.In diesem Discussion Paper werden Ansätze der Comparative-Capitalism-Diskussion vorgestellt. Sie haben drei theoretische Innovationen gemein. Erstens: Nationale Ökonomien werden durch institutionelle Konfigurationen geprägt, die auf jeweils eigene "systemische Logiken" wirtschaftlichen Handelns hinwirken. Zweitens: Die Comparative-Capitalism-Literatur beinhaltet eine Theorie der komparativen institutionellen Vorteile, der zufolge institutionellen Konfigurationen spezifische Wettbewerbsvorteile zugeordnet werden können. Zudem, drittens, beinhaltet die Comparative-Capitalism-Literatur auch eine implizite Theorie der Pfadabhängigkeit. Trotz dieser Gemeinsamkeiten unterscheiden sich die Ansätze hinsichtlich analytischer Zugriffe und Vorschläge zur Typologisierung nationaler Kapitalismen. Beim Vergleich dieser Ansätze werden besonders deren Stärken und Schwächen bei der Analyse wirtschaftlicher Performanz und institutioneller Entwicklungsdynamiken hervorgehoben. Der Aufsatz kommt zu dem Schluss, dass die Comparative-Capitalism-Literatur in dreierlei Hinsicht der Weiterentwicklung bedarf: hinsichtlich einer dynamischeren Modellierung von Institutionen, einem besseren Verständnis der Interaktion institutioneller Domänen und der Berücksichtigung von Macht und Politik in der Analyse von Produktionsregimen

The Biology of Veganism: Plasma Metabolomics Analysis Reveals Distinct Profiles of Vegans and Non-Vegetarians in the Adventist Health Study-2 Cohort

It is unclear how vegetarian dietary patterns influence plasma metabolites involved in biological processes regulating chronic diseases. We sought to identify plasma metabolic profiles distinguishing vegans (avoiding meat, eggs, dairy) from non-vegetarians (consuming ≥28 g/day red meat) of the Adventist Health Study-2 cohort using global metabolomics profiling with ultra-performance liquid chromatography mass spectrometry (UPLC-MS/MS). Differences in abundance of metabolites or biochemical subclasses were analyzed using linear regression models, adjusting for surrogate and confounding variables, with cross-validation to simulate results from an independent sample. Random forest was used as a learning tool for classification, and principal component analysis was used to identify clusters of related metabolites. Differences in covariate-adjusted metabolite abundance were identified in over 60% of metabolites (586/930), after adjustment for false discovery. The vast majority of differentially abundant metabolites or metabolite subclasses showed lower abundance in vegans, including xanthine, histidine, branched fatty acids, acetylated peptides, ceramides, and long-chain acylcarnitines, among others. Many of these metabolite subclasses have roles in insulin dysregulation, cardiometabolic phenotypes, and inflammation. Analysis of metabolic profiles in vegans and non-vegetarians revealed vast differences in these two dietary groups, reflecting differences in consumption of animal and plant products. These metabolites serve as biomarkers of food intake, many with potential pathophysiological consequences for cardiometabolic diseases

Association between Vitamin D Genetic Risk Score and Cancer Risk in a Large Cohort of U.S. Women

Some observational studies suggest an inverse association between circulating 25-hydroxyvitamin D (25OHD) and cancer incidence and mortality. We conducted a Mendelian randomization analysis of the relationship between a vitamin D genetic risk score (GRS, range 0–10), comprised of five single nucleotide polymorphisms (SNPs) of vitamin D status in the DHCR7, CYP2R1 and GC genes and cancer risk among women. Analysis was performed in the Women’s Genome Health Study (WGHS), including 23,294 women of European ancestry who were cancer-free at baseline and followed for 20 years for incident cancer. In a subgroup of 1782 WGHS participants with 25OHD measures at baseline, the GRS was associated with circulating 25OHD mean (SD) = 67.8 (26.1) nmol/L, 56.9 (18.7) nmol/L in the lowest versus 73.2 (27.9) nmol/L in the highest quintile of the GRS (p trend < 0.0001 across quintiles). However, in age-adjusted Cox proportional hazards models, higher GRS (reflecting higher 25OHD levels) was not associated (cases; Hazard Ratio (HR) (95% Confidence Interval (CI)), p-value) with incident total cancer: (n = 3985; 1.01 (1.00–1.03), p = 0.17), breast (n = 1560; 1.02 (0.99–1.05), p = 0.21), colorectal (n = 329; 1.06 (1.00–1.13), p = 0.07), lung (n = 330; 1.00 (0.94–1.06), p = 0.89) or total cancer death (n = 770; 1.00 (0.96–1.04), p = 0.90). Results were similar in fully-adjusted models. A GRS for higher circulating 25OHD was not associated with cancer incidence or mortality

Effects of Vitamin D Supplementation on C-peptide and 25-hydroxyvitamin D Concentrations at 3 and 6 Months

The link between African-Americans’ disproportionate rates of diabetes, obesity and vitamin D deficiency may be marked by C-peptide as an indicator of insulin secretion. We hypothesize that vitamin D supplementation will increase C-peptide, a marker of insulin secretion. During 3 winters from 2007-2010, 328 healthy African-Americans (median age, 51 years) living in Boston, MA were randomized into a 4-arm, double-blind trial for 3 months of placebo, 1000, 2000, or 4000 IU of vitamin D3. The differences in non-fasting C-peptide between baseline and 3 months were −0.44 ng/mL for those receiving placebo, −0.10 ng/mL for those receiving 1000 IU/d, 0 ng/mL for those receiving 2000 IU/d, 1.24 ng/mL for those receiving 4000 IU/d (C-peptide increased 0.42 ng/mL for each additional 1000 IU/d of vitamin D3, p < 0.001). Vitamin D supplementation increased C-peptide in overweight African-Americans and may be compatible with other recommendations for diabetes prevention and management including weight loss and increased physical activity