The relationship between metabolic disorders and oxidative stress is still controversial in the child population. The present cross-sectional study aimed to analyze the associations between obesity, cardiometabolic traits, serum level of carbonylated proteins (CPs), malondialdehyde (MDA), and the enzyme activity of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) in children from Mexico City (normal weight: 120; obesity: 81). Obesity resulted in being positively associated with CAT (β = 0.05 ± 0.01, p = 5.0 × 10⁻³) and GPx (β = 0.13 ± 0.01, p = 3.7 × 10⁻¹⁹) enzyme activity. A significant interaction between obesity and sex was observed in MDA and SOD enzymatic activity (P_MDA = 0.03; P_SOD = 0.04). The associations between obesity, MDA level, and SOD enzyme activity were only significant in boys (boys: P_MDA = 3.0 × 10⁻³; P_SOD = 7.0 × 10⁻³; girls: p ≥ 0.79). In both children with normal weight and those with obesity, CP levels were positively associated with SOD enzyme activity (P_{Normal-weight} = 2.2 × 10⁻³; P_Obesity = 0.03). In conclusion, in Mexican children, obesity is positively associated with CAT and GPx enzyme activity, and its associations with MDA levels and SOD enzyme activity are sex-specific. Therefore, CP level is positively related to SOD enzyme activity independently of body weight.

Background/Objective: This study is aimed to assess the link between oxidative stress markers and incident hyperglycemia in women with gestational diabetes mellitus (GDM) during an educational intervention. Methods: The study used a prospective cohort. Pregnant women with GDM who were 18–40 years old (n = 201) participated in an 18-month postpartum educational intervention emphasizing healthy practices (nutrition, breastfeeding, physical activity, and psychosocial support). GDM women were tested with an oral glucose tolerance test (OGTT) after the third month postpartum, and were classified as follows: (1) incident hyperglycemia (IHypergly) (n = 86) if they had a fasting plasma glucose (FPG) of 100–125 mg/dL, and impaired glucose tolerance of 2 h (140–199 mg/dL), or type 2 diabetes (T2D) with an FPG ≥ 126 or ≥200 mg/dL (2 h); and (2) without incident hyperglycemia (n = 115) if they had an FPG < 100 mg/dL and <140 mg/dL 2 h post-OGTT. Participants were evaluated at the end of pregnancy and post-intervention. Clinical, biochemical, anthropometric, dietary, and oxidative stress markers data (malondialdehyde, reduced glutathione, antioxidant capacity, carbonylated proteins, and adiponectin) were recorded. Multivariate logistic regression analysis identified an association between oxidative stress markers and incident hyperglycemia in women with GDM. Results: A total of 6% progressed to T2D, and 36.8% to prediabetes. At baseline, Ihypergly women exhibited elevated oxidative stress markers and adiponectin, and lower antioxidant capacity. Post-intervention, they showed higher antioxidant capacity, GSH, and adiponectin, and lower MDA. Basal malondialdehyde, pregestational BMI, HbA1c, and sugary food consumption positively correlated with Ihypergly. A high intake of antioxidants inversely correlated with incident hyperglycemia. Conclusions: Higher concentrations of plasma markers of oxidative stress are associated with postpartum incident hyperglycemia in women with gestational diabetes.