Assessment of the Composite Dietary Antioxidant Index and Its Association With Overweight and Obesity Among Adolescents: A Cross-Sectional Study in Mangalagiri, Guntur, Andhra Pradesh.

Background and objectives Adolescence is a critical window for establishing lifelong dietary and cardiometabolic risk, and low- and middle-income countries increasingly face a double burden of malnutrition. Obesity is characterised by chronic low-grade oxidative stress, and dietary antioxidants may modulate this milieu; the Composite Dietary Antioxidant Index (CDAI) summarises overall antioxidant intake from six nutrients. Data on CDAI among Indian adolescents are sparse. We aimed to estimate the prevalence of overweight and obesity, to estimate the CDAI, and to examine its association with nutritional status among adolescents attending an adolescent health clinic in Guntur, Andhra Pradesh. Methods This facility-based cross-sectional study was conducted at the State Adolescent Health Resource Centre, All India Institute of Medical Sciences (AIIMS), Mangalagiri (October 2025-March 2026). A total of 109 adolescents aged 10-19 years were enrolled by systematic sampling. A pre-tested questionnaire captured sociodemographic, physical activity, and substance-use data; dietary intake used a single 24-hour recall. The CDAI was computed as the sum of within-sample standardised (z-score) intakes of vitamins A, C, and E, selenium, zinc, and carotenoids. BMI-for-age z-scores used the WHO 2007 growth reference. Analyses used the Shapiro-Wilk test, Wilson 95% CI, chi-square, Kruskal-Wallis, Mann-Whitney U, Spearman correlation, and binary logistic regression (unadjusted; adjusted for age, sex, and physical activity; and for socioeconomic status), with p < 0.05 considered significant. Results Participants had a mean age of 16.0 ± 1.9 years and 62.4% (68/109) were female. The prevalence of thinness was 17.4% (19/109; 95% CI: 11.5%-25.6%), overweight 11.9% (13/109; 95% CI: 7.1%-19.3%), and obesity 12.8% (14/109; 95% CI: 7.8%-20.4%); combined overweight/obesity was 24.8% (27/109; 95% CI: 17.6%-33.6%), coexisting with thinness and reflecting a double burden of malnutrition. The median CDAI was -0.83 (IQR: -2.32 to 1.53), and vitamin A had the highest proportion of zero intakes at 31.2% (34/109). CDAI did not differ across nutritional-status categories (p = 0.723) and was not correlated with BMI-for-age z-score (Spearman ρ = 0.065, p = 0.505); it remained a non-significant predictor of overweight/obesity after adjustment for socioeconomic status (adjusted OR = 1.08, 95% CI: 0.96-1.22, p = 0.181). Carbohydrate intake was higher in overweight/obese than in normal/thin adolescents (p = 0.032), whereas energy, protein, and fat did not differ. Conclusion A double burden of malnutrition was evident, with overweight/obesity affecting 24.8% and thinness 17.4% of participants. Diet quality was poor: the median CDAI was below the sample average and 31.2% consumed no vitamin A on the recall day, yet antioxidant intake was not associated with nutritional status. Adolescent nutrition programmes should therefore address under- and overnutrition together: promoting vitamin A- and carotenoid-rich foods rather than supplements; counselling on balanced diets; and routine BMI-for-age screening and nutrition education within existing platforms (Rashtriya Kishor Swasthya Karyakram, mid-day meal, and Anganwadi services), with staple-food fortification to close micronutrient gaps.