Cardiovascular diseases remain the leading cause of morbidity and mortality worldwide. In India, the burden of cardiovascular disease has increased substantially due to rapid urbanization, lifestyle changes, and a rising prevalence of metabolic disorders. While traditional risk factors such as hypertension, diabetes mellitus, dyslipidemia, and smoking are well established, chronic low-grade inflammation has emerged as a central mechanism linking these conditions to atherosclerosis and cardiovascular events.

High-sensitivity C-reactive protein (hs-CRP) is a widely used biomarker of systemic inflammation and an independent predictor of cardiovascular risk. Elevated hs-CRP levels are associated with endothelial dysfunction, plaque instability, and increased incidence of myocardial infarction and stroke. Identification of modifiable factors influencing inflammatory burden may therefore offer opportunities for cardiovascular risk reduction.

Vitamin D, a fat-soluble secosteroid hormone, has been increasingly recognized for its extra-skeletal effects. Vitamin D receptors are expressed in immune cells, vascular smooth muscle cells, and endothelial cells, suggesting a role in immune regulation and vascular health. Vitamin D exerts anti-inflammatory effects by suppressing pro-inflammatory cytokines and inhibiting nuclear factor-kappa B signaling pathways.

Despite abundant sunlight, vitamin D deficiency is highly prevalent in India, with reported prevalence rates exceeding 70% in several studies. Limited sun exposure, darker skin pigmentation, dietary insufficiency, and lack of food fortification contribute to widespread deficiency. Observational studies have suggested an inverse relationship between vitamin D levels and inflammatory markers; however, Indian data correlating vitamin D status with systemic inflammation and cardiovascular risk stratification are limited.

The present study was undertaken to evaluate the association between vitamin D status, systemic inflammation measured by hs-CRP, and overall cardiovascular risk among adults attending a tertiary care hospital.

This hospital-based cross-sectional analytical study was conducted in the Department of Medicine in collaboration with the Department of Biochemistry at a tertiary care teaching hospital over a period of 24 months.

Study Population

A total of 200 adults aged 18–65 years attending outpatient or inpatient services were enrolled after obtaining written informed consent.

Inclusion Criteria

• Adults aged 18–65 years
• Both males and females
• Willingness to participate in the study

Exclusion Criteria

• Chronic kidney disease, chronic liver disease, or malabsorption syndromes
• Acute infections, malignancy, or autoimmune disorders
• Pregnant or lactating women
• Recent vitamin D or calcium supplementation
• Long-term steroid therapy

Data Collection

Demographic and clinical details were recorded using a structured case record form. Blood pressure and anthropometric measurements were obtained using standard protocols.

Laboratory Investigations

Fasting venous blood samples were collected. Serum 25-hydroxyvitamin D levels were measured using chemiluminescent immunoassay. hs-CRP levels were estimated using a high-sensitivity immunoturbidimetric method.

Vitamin D status was categorized as:

• Deficient: <20 ng/mL
• Insufficient: 20–29 ng/mL
• Sufficient: ≥30 ng/mL

Cardiovascular Risk Stratification

Participants were classified into low, moderate, and high cardiovascular risk categories based on the presence of multiple cardiometabolic risk factors.

Statistical Analysis

Data were analyzed using SPSS version 26. Continuous variables were expressed as mean ± standard deviation. Group comparisons were performed using Student’s t-test and ANOVA. Pearson’s correlation coefficient was used to assess associations. A p-value <0.05 was considered statistically significant.

Vitamin D deficiency was present in 64% of participants, while only 13% had sufficient vitamin D levels. Mean hs-CRP levels were significantly higher in vitamin D deficient participants compared to vitamin D sufficient participants (4.8 ± 1.6 vs 2.1 ± 0.9 mg/L; p < 0.001), indicating increased systemic inflammation.

A significant inverse correlation was observed between serum vitamin D levels and hs-CRP concentrations (r = −0.49; p < 0.001). This finding suggests that lower vitamin D levels are associated with greater inflammatory burden.

Cardiovascular risk stratification revealed that nearly half (48%) of vitamin D deficient participants were categorized as high cardiovascular risk, compared to only 20% of vitamin D sufficient participants. Low-risk profiles were more commonly observed in individuals with adequate vitamin D levels.

Table 1. Baseline Clinical Characteristics of Study Participants (n = 200)

The study population comprised middle-aged adults with a moderate prevalence of lifestyle-related cardiovascular risk factors.

Table 2. Distribution of Participants According to Vitamin D Status

Vitamin D deficiency was highly prevalent, affecting nearly two-thirds of the study population.

Table 3. hs-CRP Levels According to Vitamin D Status

hs-CRP levels were significantly higher in vitamin D deficient individuals, indicating increased systemic inflammation.

Table 4. Cardiovascular Risk Stratification by Vitamin D Status

A substantially higher proportion of vitamin D deficient participants fell into the high cardiovascular risk category.

Table 5. Prevalence of Inflammatory and Cardiometabolic Risk Factors

Vitamin D deficiency was associated with clustering of inflammatory and cardiometabolic risk factors.

Table 6. Correlation Between Serum Vitamin D and Inflammatory/Cardiovascular Parameters

Serum vitamin D levels showed significant inverse correlations with inflammatory burden and overall cardiovascular risk.

Table 7. Odds of High Cardiovascular Risk According to Vitamin D Status

Vitamin D deficient individuals had more than three-fold higher odds of being classified as high cardiovascular risk.

The present study demonstrates a strong association between vitamin D deficiency, elevated systemic  inflammation, and increased cardiovascular risk. The high prevalence of vitamin D deficiency observed is consistent with previous Indian studies, reinforcing hypovitaminosis D as a major public health concern.

Elevated hs-CRP levels among vitamin D deficient individuals support the immunomodulatory role of vitamin D. Vitamin D suppresses inflammatory cytokines and reduces oxidative stress, and deficiency may promote a pro-inflammatory state conducive to atherosclerosis.

The clustering of multiple cardiovascular risk factors in vitamin D deficient participants highlights the multifactorial contribution of vitamin D deficiency to cardiovascular disease. Similar findings have been reported in international cohort studies demonstrating increased cardiovascular events among individuals with low vitamin D levels.

Although large randomized trials have shown mixed results regarding vitamin D supplementation and cardiovascular outcomes, benefits may be more pronounced in individuals with baseline deficiency, emphasizing the importance of targeted interventions.

Vitamin D deficiency is significantly associated with increased systemic inflammation and higher cardiovascular risk. Serum vitamin D levels may serve as a useful adjunct biomarker for cardiovascular risk assessment. Screening and correction of vitamin D deficiency in high-risk individuals may contribute to improved cardiovascular prevention strategies.

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