Significant Interactions between Adipokines and Vitamin D Combined with the Estimated Glomerular Filtration Rate: A Geriatric Case Study

Vitamin D deficiency is an important issue in the worldwide population, especially in older people. According to the World Health Organization data, in 2030, 1 in 6 people in the world will be 60 years old or older. The main storage site for vitamin D is adipose tissue. Further, 25(OH)D regulates the expression of adipogenic genes and apoptosis of adipocytes and directly influences the secretion of the appetite-regulating hormone-leptin. Thus, we investigated the impact of the serum concentrations of leptin, adiponectin, omentin, ghrelin, visfatin, and biochemical parameters on vitamin D and estimated glomerular filtration rate (eGFR) in geriatric females. Our studies indicate that the leptin, visfatin and ghrelin are linked with vitamin D concentration and the eGFR rate in the geriatric females. (1) Background: Vitamin D deficiency is common in older people, and researchers are looking for a link between vitamin D deficiency and the occurrence of diseases in advanced age. The study aimed to evaluate the association between serum 25(OH)D levels and clinical variables in older females. (2) Methods: We investigated the impact of the serum concentrations of leptin, adiponectin, omentin, ghrelin, visfatin, and biochemical parameters on vitamin D and estimated the glomerular filtration rate (eGFR) in 74 geriatric females. (3) Results: We observed a significantly higher concentration of creatinine and visfatin in the G2 stage (eGFR = 60-89 mL/min./1.73 m(2)). We performed an additional analysis to exclude the effect of vitamin D supplementation and obtained a significantly higher vitamin D concentration in the G2 stage. We found significantly lower vitamin D concentrations in older people. In addition, in a person with low levels of vitamin D, we observed significantly lower levels of albumin and ghrelin. Older patients (80 to 89 years old) had significantly lower levels of vitamin D, albumin, insulin, HOMA-IR, and ghrelin than younger patients (60 to 69 years old). Spearman's correlations performed to examine the relationship between clinical variables seemed to confirm previous results. According to ROC curve analysis, leptin concentration was the strongest predictor of vitamin D fluctuations (the area under the curve, AUC = 0.685; with 79.5% sensitivity and 51.4% specificity; p = 0.0291). However, visfatin reached the most accurate AUC(ROC) = 0.651 with 84.2% sensitivity and 49.1% specificity for predicting effects on eGFR. (4) Conclusions: The results suggest that serum levels of leptin, visfatin, and ghrelin are linked with vitamin D concentration and the eGFR rate in the population of geriatric females.