Vitamin D Levels and Diabetes Mellitus: A Study on Age, Sex, and Body Mass Index

Abstract

Objective: The correlation between Body Mass Index (BMI) and vitamin D levels has garnered considerable attention in contemporary medical investigations. Vitamin D, an essential fat-soluble micronutrient, significantly influences bone health, immune system functionality, and various other physiological functions. The bioavailability of vitamin D may be affected by adiposity, which might result in possible deficits in persons with elevated body mass indices. The objective of this retrospective study conducted at a single center was to examine the potential relationship between BMI and diabetes mellitus (DM) with vitamin D serum levels in a cohort of 680 individuals, comprising 511 females and 169 males. Methods: The present study utilized a methodology in which medical records from a single facility were comprehensively reviewed to collect relevant information on BMI and blood 25-hydroxyvitamin D [25(OH)D] levels. The participants were classified into four distinct groups based on their BMI categories, which included normal weight, overweight, obese, and morbidly obese. Statistical methods were employed to investigate the relationship between BMI, diabetes mellitus (DM), age, and 25-hydroxyvitamin D (25(OH)D) levels. Furthermore, multivariate regression analysis was conducted to account for potential confounding variables such as age and gender. Results: The study included a sample of 680 individuals, comprising 511 women (75.1%) with an average age of 41 (±12) and 169 men (24.9%) with an average age of 38 (±13). Vitamin D levels in women were found to be 14±7 ng/mL, while in men, the levels measured at 16.6±7 ng/mL. The study identified a statistically significant difference in vitamin D levels between women and men (p<0.001). The study's findings indicate that there was no significant correlation between vitamin D levels and age among all individuals (p=0.258). However, a significant albeit weak correlation was observed between vitamin D levels and BMI (p=0.002, R2=0.0141). The vitamin D levels of the obese group were measured to be 14±7 ng/mL, while the non-obese group had levels of 16±7 ng/mL. Statistical analysis revealed that vitamin D levels in the obese group were significantly lower compared to the non-obese group (p=0.012). When comparing vitamin D levels between individuals with and without diabetes mellitus (DM), it was observed that the mean vitamin D level was 13.8±6.3 ng/mL in the non-DM group and 16.6±7.6 ng/mL in the DM group. Statistical analysis revealed that vitamin D levels were significantly higher in the DM group (p=0.012). Conclusion: Our study's findings suggest a potential connection between low vitamin D levels and obesity, while factors such as diabetes, age, and gender do not seem to significantly impact this association.