It’s long been known that African Americans have a higher incidence of diabetes than white Americans. Usually ascribed to racism in the economy and health treatment.
In an interesting new paper, Andersen et al. (2021) use the Putterman-Weil historical migration index to show that life-expectancy is lower in countries where a large proportion of that country’s population emigrated from places with more sunlight (UV-R). Ethiopians in Israel, Indians in the UK and blacks in the United States, for example, tend to have Vitamin D deficiency and higher levels of mortality and morbidity from a wide variety of diseases. The effect at the global level is small but significant, about the same order of magnitude as the effect of income, inequality, and schooling.
Vitamin D deficiency has been linked to the onset of diabetes. This review summarizes the role of Vitamin D in maintaining the normal release of insulin by the pancreatic beta cells (β-cells). Diabetes is initiated by the onset of insulin resistance. The β-cells can overcome this resistance by releasing more insulin, thus preventing hyperglycaemia. However, as this hyperactivity increases, the β-cells experience excessive Ca2+ and reactive oxygen species (ROS) signalling that results in cell death and the onset of diabetes. Vitamin D deficiency contributes to both the initial insulin resistance and the subsequent onset of diabetes caused by β-cell death. Vitamin D acts to reduce inflammation, which is a major process in inducing insulin resistance.