The Relationship of Central Obesity to Vitamin D Levels in Medical Faculty Students of Udayana University in Year 2023

Abstract

Background: Central obesity is defined as the accumulation of excess fat in the abdomen as a result of an energy imbalance caused by genetic and environmental factors. Obesity may contribute to vitamin D deficiency (<20 ng/mL) and insufficiency (20–29.9 ng/mL). Vitamin D is an important vitamin for the body and is fat-soluble. It can be synthesized by exposure to ultraviolet B light by converting 7-dehydrocholesterol into 1,25-dihydroxyvitamin D3 through hydroxylation in the liver and kidneys and then binding to the vitamin D receptor to carry out its function. Based on previous research, the mechanism for decreasing vitamin D levels in obese people can be explained through three theories: volumetric dilution, sequestration theory, and degradation theory. Method: The purpose of this study is to determine the relationship between central obesity and vitamin D levels in college students at the Faculty of Medicine, Udayana University, in 2023. This study used a quantitative analytical methodology with a cross-sectional design. The study's dependent variable was waist circumference, while the independent variable was vitamin D levels. A total of 60 college students (28 men and 30 women) as research subjects were taken using a purposive sampling technique. The research was carried out by selecting and collecting identity and anthropometric data on research subjects through questionnaires. Then, research subjects who meet the criteria will have their blood samples taken and their waist circumference measured. Blood samples were examined for vitamin D levels using the BT Lab brand ELISA Kit at the Biochemistry Laboratory, Faculty of Medicine, Udayana University. The research lasted for 4 months, starting in November 2023 and ending in February 2024. Results: This research found a very weak but not significant positive correlation between body height and vitamin D levels (r = 0.035; p = 0.793). There is a very weak but not significant positive relationship between height and vitamin D levels (r = 0.036; p = 0.783). There is a very weak but not significant inverse relationship between BMI and vitamin D levels (r = -0.034; p = 0.796). In this study, there was an insignificant relationship and a very weak positive correlation between waist circumference, as an indicator of central obesity, and vitamin D levels (r = 0.001 and p = 0.992). Conclusion: In this study, it can be concluded that there is no relationship between central obesity and vitamin D levels. Apart from that, a correlation coefficient was obtained, which showed a very weak correlation and a directly proportional relationship. Keywords: central obesity, waist circumference, vitamin D deficiency, students at the Faculty of Medicine, Udayana University