ODP129 Variation in 25(OH)D Levels, Measurement Methods and Prevalence of Vitamin D Deficiency: a Systematic Review and Meta-analysis

Vitamin D deficiency is a common disease with high morbidity. Although, there are several studies evaluating its prevalence in different Brazilian regions, its actual prevalence it not known. Furthermore, some research suggests that serum levels of 25-hydroxyvitamin D [25(OH)D] may vary according to the measurement technique. This variation may affect the results of the prevalence of vitamin D deficiency in Brazil, given that its diagnosis is made by measuring 25(OH)D, regardless of the technique used. Our study aimed to investigate whether 25(OH)D values vary according to the 25(OH)D measurement technique in Brazil. Therefore, a systematic review including controlled clinical trials, cohort studies, cross-sectional studies, and case-control studies was performed. Studies that included all participants with some underlying pathology were excluded. The bibliographic search was carried out in PubMed, BIREME, and EMBASE databases. Two protocol members independently performed the selection and extraction of data from the studies. A third member reviewed this selection and extraction. In total, 1,166 studies were found, of which 122 had their full texts evaluated, 34 studies evaluated the serum levels of 25(OH)D, and described the technique used to measure this hormone. A total of 356,565 participants with a mean age between 18 and 80 years were included in the analysis. The prevalence of vitamin D deficiency [25(OH)D < 20 ng/mL] and vitamin D insufficiency [25(OH)D < 30 ng/mL] in Brazil were, respectively, 29.7% (95%CI 25 .6 to 34.1%) and 65.2% (95%CI 62.5 to 87. 0%). Mean serum levels of 25(OH)D varied according to the technique and brand used to measure this hormone. The mean 25(OH)D values according to the technique used: chemiluminescence 25.5 ng/mL (95%CI 24. 0 to 27. 0 ng/mL); ELISA 41 (95%CI 37. 0 to 46.1 ng/ml); HPLC 28.7 ng/ml (95%CI 23.9 to 33.6 ng/ml) and radioimmunoassay 24.5 ng/ml (95%CI 20.2 to 28.8 ng/ml); p<0. 0001. This variation is associated with the heterogeneity of the pooled results of vitamin D prevalence in Brazil. In conclusion, these findings suggest that the prevalence of vitamin D in Brazil may vary according to the measurement technique used. Better standardization of the results of the 25(OH)D measurement assays becomes urgent that we can have a more precise estimate of this problem. Presentation: No date and time listed