PTH and obesity due to melanocortin 4 receptor deficiency: There was also an increasing focus on issues of obesity related to secondary hyperparathyroidism, as well as studies centered on body weight, parathyroid hormone, and hypovitaminosis D. In the years spanning 2010 to 2017, research focus shifted to the impact of insulin sensitivity and vitamin D insufficiency on the risk of coronary heart disease, and the study of the relationship between vitamin D insufficiency and obesity.