HbA1c percentiles and the association between BMI, age, gender, puberty, and HbA1c levels in healthy German children and adolescents

Objective The measurement of glycated hemoglobin (HbA1c) represents one way to detect type 1 and 2 diabetes in children at an early stage. However, to date, variations in HbA1c levels are not fully understood, even in healthy children. With this in mind, the present study aimed to establish HbA1c reference values in healthy children and to investigate the influence of various independent variables. Study Design and Methods Two thousand four hundred fifty-five healthy children and adolescents aged between 0.5 and 18 years participated in the population-based cohort study LIFE Child, Germany. Age- and gender-dependent percentiles were estimated, enabling HbA1c values to be converted into standard deviation scores (SDS). Logistic regression models were applied to assess associations between HbA1c-SDS (as outcome) and age, gender, BMI, birth weight, physical activity, pubertal status, and socioeconomic status (SES; as explanatory variables). Results The mean HbA1c value was 31.79 mmol/mol or 5.06% (SD = 3.3 mmol/mol, SD = 0.3%). Positive associations with HbA1c values were identified for age (b = 0.09, p < 0.001), gender (b = 0.25, p = 0.007), and BMI-SDS (b = 0.06, p < 0.001). In addition, obesity was related to higher HbA1c values (b = 0.29, p < 0.001). Compared to prepuberty, the pubertal and postpubertal stages were associated with higher HbA1c levels. Furthermore, higher SES was associated with higher HbA1c-SDS (b = 0.01, p = 0.04). Conclusion The present study established HbA1c reference values based on a large sample of healthy German children and adolescents. Age, gender, SES, pubertal stage, and BMI were found to be associated with higher HbA1c levels.