Introduction: Research has suggested that having low Vitamin D levels is associated with a higher likelihood of developing cardiovascular disease. Specifically, several observational studies have found that Vitamin D is linked to a decreased risk of coronary artery disease. Our study aimed to determine how prevalent Vitamin D deficiency is in Palestinian patients with acute coronary syndrome, a type of cardiovascular disease. Methods: This study used a cross-sectional design, which involved collecting 84 blood samples from patients diagnosed with acute coronary syndrome at two hospitals in Palestine. The blood samples were collected over approximately two months, from late January to late March 2021. They were analyzed to determine the patients' levels of vitamin 25(OH) D. The study also collected information on the patient's medical history, including any co-morbidities such as hypertension, diabetes mellitus, smoking, BMI, LDL, and TIA. The data was analyzed using point estimates, 95% confidence intervals, and frequency and proportion calculations for binary data. In addition, multivariate logistic regression analyses were performed to assess the factors associated with vitamin D status, including crude odd ratios and adjusted odd ratios for the relevant covariates. Results: In this study, it was found that 95% of the patients diagnosed with acute coronary syndrome had a deficiency in vitamin D. Of these patients, 50% had a severe deficiency, 32.14% had a moderate deficiency, and 8.33% had a mild deficiency. The study also found a significant relationship between male gender and vitamin D levels, with males having higher odds (OR: 7.07, 95% CI: 1.18–42.30, P = 0.03) of being deficient in vitamin D compared to females. Additionally, patients with a history of TIA (transient ischemic attack) were significantly associated with vitamin D deficiency (OR, 0.06, 95% CI, 0.-0.72). The study also showed that non-diabetic patients had higher levels of vitamin D compared to diabetic patients, and patients with hypertension (13.21±11.91 ng/ml) had slightly higher levels of vitamin D compared to those without hypertension (12.69±10.20 ng/ml). Non-smokers (14.36±13.97 ng/ml) and patients with low LDL (14.80±11 ng/ml) also had higher levels of vitamin D. Finally, patients who had suffered from TIA (24.40±25.03 ng/ml) had significantly higher levels of vitamin D compared to those who had not experienced a TIA (12.17±9.36 ng/ml). Conclusion: The findings of this study indicate that individuals diagnosed with ACS demonstrated a notable insufficiency of vitamin D. Although the number of studies on this topic is restricted, the outcomes of this research are largely consistent with prior investigations.

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