False negative effect of high triglycerides concentration on vitamin D levels: A big data study.

Background: Inaccurate test results may be a reason why vitamin D deficiency is seen as a common problem worldwide. Interferences from the sample matrix during testing are the most important factors in measurement errors. In this study, the relationship between triglycerides and total cholesterol levels and vitamin D levels in Turkey was investigated.

Methods: The 25-hydroxyvitamin D test results and lipid test results studied in Turkey in 2021 were compared. Data were obtained from the Ministry of Health National Health Database. Simultaneously, 25-hydroxyvitamin D, triglyceride, and total cholesterol levels were studied, and 1,135,644 test results were taken as the basis.

Results: In the group of patients with total cholesterol levels between 0-10.33 mmol/L, the proportion of patients below 20 mg/L ranged from 56.8% to 61.8%. In the patient group with cholesterol between 10.36-259 mmol/L, the rate of patients with less than 20 mg/L was between 70.8-100%, while the rate of patients with cholesterol above 100 mg/L was 0%. The mean 25-hydroxyvitamin D level was 20.1 mg/L in the patient group with a total cholesterol level between 0-10.33 mmol/L, and 16 mg/L in the patient group with a cholesterol level above 10.36 mmol/L. The mean 25-hydroxyvitamin D level was 20.11 mg/L in the patient group with triglycerides 0-10.16 mmol/L, and the 25-hydroxyvitamin D level was 12.28 mg/L in the patient group with triglycerides 10.17-113 mmol/L. The proportion of patients with vitamin D levels above 100 mg/L was found to be 0% in the group of patients with triglycerides above 10.17-113 mmol/L.

Conclusions: According to this study, there is a risk of toxicity when administering vitamin D therapy in patients with high cholesterol and triglycerides levels. This study is the first of this size in the literature. High triglycerides and cholesterol levels can cause inaccurate measurement of vitamin D levels, so care should be taken when evaluating these tests.