Association of age, birth weight, Tanner stage, age at menarche, and anthropometric measures with HbA1c levels among adolescent girls in Gairsain, Uttarakhand, India

Diabetes mellitus is a major public health concern in India, which is projected to affect over 134 million people by 2045. Early-life factors such as birth weight and pubertal development may influence metabolic health outcomes, including glycated hemoglobin (HbA1c). However, limited research has examined these determinants among adolescents in India. This study aims to assess the association of age, birth weight, Tanner staging, age at menarche, and anthropometric measures with HbA1c levels among adolescent girls in Gairsain, Uttarakhand, India. A cross-sectional study was conducted among 105 adolescent girls (13–19 years) enrolled in two schools in Gairsain, Uttarakhand, selected using simple random sampling. The sample size was calculated using n = Z2 p(1–p)/d2, with a 95% confidence level (Z = 1.96) and a 5% margin of error. Data were collected through a structured interview schedule, and HbA1c levels were measured using a Standard F Analyzer and HbA1c test kits. Statistical analysis was performed in SPSS, and descriptive statistics, chi-square tests, and linear and logistic regression were conducted, with statistical significance set at p < 0.05. A significant association was found between birth weight and HbA1c (p = 0.038). Adolescents with normal birth weight had lower odds of elevated HbA1c than those with low birth weight (OR = 0.312, 95% CI: 0.101–0.967, p = 0.044). No significant associations were observed with Tanner stage, age at menarche, BMI-for-age, or height-for-age. However, HbA1c levels showed a significant decline with increasing age during puberty (β = −0.052, 95% CI: −0.082 to −0.022, p < 0.001). These findings suggest that early-life factors such as birth weight and puberty-related hormonal changes may influence HbA1c levels among adolescent girls.