Prevalência das Hemoglobinas S, C e ouras Hemoglobinas variiantes no estudo longitudinal de saúde do Adulto - ELSA- BRASIL

Abstract

The Brazilian population has a high degree of miscegenation, and its composition is the result of the mixture of Amerindian, African and European genes. Few multicenter studies have evaluated the prevalence of variant hemoglobin in Brazil, correlating with genetic ancestry. Knowing this prevalence is important to propose public health policies and actions aimed improve the diagnosis and monitoring of patients with these conditions. In addition, the presence of some variant hemoglobin may affect the accuracy of HbA1c measurements and directly impact the monitoring of patients with diabetes. Describe the prevalence of Hb S, C and other Hb Variants, detected by ion exchange HPLC used to determine HbA1c, among participants of the ELSA-Brasil baseline (2008 - 2010). Cross-sectional study with 15,089 participants aged between 35 and 74 years from ELSA-Brasil. Participants underwent blood collection by venipuncture for HbA1c analysis and DNA extraction for analysis of genetic ancestry. For quantitative variables, mean and standard deviation or median and interquartile range were used, Student's t-test for comparison of means and Mann-Whitney for medians. For categorical variables, frequency and the Chi-square test were used to compare groups. Differences were confirmed using the Chi-square test with Bonferroni correction. Analysis of the association with genetic ancestry was performed using the Mann-Whitney test. For quantitative variables, mean and standard deviation were used, and Student's t-test for comparison of means and Mann-Withney for medians. For categorical variables, the frequency and the chi-square test were used to compare the groups. Differences were confirmed using the chi-square test with Chiferroni corrections. The analysis of the association with genetic ancestry was performed using the Mann-Whitney test. The prevalence of Hb Variants was 7.3%, being 2.0% HbS, 1.5% HbC and 3.9% other Hb Variants. The frequency of HbS and C was significantly higher among black and brown individuals and participants with high school and elementary school. Participants with diabetes had a higher prevalence of HbS (3.6% vs. 1.6%, p <0.001). The prevalence of HbS and C in the Northeast of Brazil was significantly higher than South and Southeast (p≤0.001). Other Hb Variants were more prevalent in the northern region. This study showed the prevalence of S and C alleles and other Hb variants in different regions of the country, considering the distribution of race/color, according to the participants' genetic ancestry. In this study, individuals with diabetes had a higher prevalence of HbS, which highlights the importance of investigating variant hemoglobin in these individuals that may interfere with the accuracy of some tests for diagnosis and control of these individuals. Keywords: Hemoglobin Sickle; Hemoglobina C; Glicated Hemoglobin; Diabetes Mellitus Type 2; Heredity.