BackgroundVitamin D deficiency has been associated with metabolic syndrome and its related outcomes, including type 2 diabetes mellitus, cardiovascular disease, myocardial infarction, and stroke. However, studies in Indian populations have provided conflicting results.MethodsThis single-center cross-sectional study was conducted in a tertiary care hospital in north India to determine the prevalence of vitamin D deficiency in patients with metabolic syndrome and to study the correlations of individual components of metabolic syndrome with 25 hydroxy vitamin D levels. The study included 235 patients aged between 30 to 70 years who met the criteria for metabolic syndrome. Patients with diabetes, hypothyroidism, Cushing's, and other disorders affecting vitamin D status, on supplements of vitamin D or anti-dyslipidaemic drugs were excluded. Information regarding socio-demographic characteristics, medical history, and anthropometric measurements were collected. Blood samples were collected to assess vitamin D levels.ResultsThe prevalence of vitamin D deficiency (<20 ng/ml) was 76% among the study population. There was a significant negative correlation between vitamin D levels and diastolic blood pressure (Spearman's rho: -0.134, 95% CI: -0.82,-0.260, p=0.040), fasting blood glucose (Spearman's rho: -0.142, 95% CI: -0.101,-0.269, p=0.029), A weak correlation was also found between vitamin D3 levels and total cholesterol (Spearman's rho: -0.246, 95% CI: -0.119,-0.367, p<0.001), triglyceride levels (Spearman's rho: -0.246, 95% CI: -0.118,-0.370, p<0.001) and low-density lipoprotein (LDL) levels (Spearman's rho: -0.229, 95% CI: -0.102,-0.351, p<0.001).ConclusionThe study findings suggest that vitamin D deficiency is prevalent among patients with metabolic syndrome in north India. There is a significant negative correlation between vitamin D levels and some components of metabolic syndrome. This highlights the need for further research to understand the underlying mechanisms and potential benefits of vitamin D supplementation in this population. Identification of high-risk individuals for hypovitaminosis D can aid in streamlining treatment guidelines and preventing unnecessary prescription of investigations in developing countries.