In children aged 5–10 years born to mothers with gestational diabetes mellitus, is participation in a structured lifestyle intervention (dietary counseling plus supervised physical activity) associated with lower cardiometabolic risk markers (BMI z-score, fasting glucose, HOMA-IR, lipid profile) compared to usual care, over a 12-month follow-up period?

Children aged 5–10 years born to mothers with a documented history of GDM (diagnosed by IADPSG criteria during the index pregnancy), currently without a diagnosis of diabetes or established cardiovascular disease.

Single pediatric endocrinology or maternal-child health clinic affiliated with a tertiary hospital, leveraging existing GDM registries or obstetric records for identification of eligible offspring.

Purposive sampling from the hospital's GDM registry to identify mothers with confirmed GDM in their most recent pregnancy 5–10 years ago, followed by simple random sampling of eligible offspring (1:1 allocation to intervention vs. usual care) after informed consent.

Power calculation for a two-arm parallel RCT with a continuous primary outcome (HOMA-IR). Assuming a mean HOMA-IR of 2.1 (SD 0.9) in the usual-care arm based on pediatric GDM-offspring literature, a clinically meaningful difference of 0.5 units, alpha = 0.05, power = 0.80, the required n per group is approximately 52 (two-sample t-test formula: n = 2 × [(z_α/2 + z_β) × σ / δ]² = 2 × [(1.96 + 0.84) × 0.9 / 0.5]² ≈ 51). Adjusting for 20% attrition over 12 months: n ≈ 65 per group, total N ≈ 130.

Baseline and 12-month clinical assessments: anthropometric measurements (weight, height, waist circumference) by trained research nurses using standardized protocols; fasting venous blood samples analyzed for glucose (hexokinase method), insulin (electrochemiluminescence immunoassay), lipid panel (enzymatic colorimetric method) at the hospital laboratory; structured questionnaires for dietary intake (3-day food diary validated for pediatric use), physical activity (pedometer-measured steps over 7 days plus PAQ-C questionnaire), and sociodemographic data; maternal and perinatal data extracted from obstetric records (GDM diagnosis, treatment during pregnancy, pre-pregnancy BMI, birth weight, gestational age); intervention adherence tracked via attendance logs and pedometer data.

18–24 months total: 3–4 months for ethics approval and participant recruitment, 12 months for intervention and follow-up, 3–4 months for data analysis and write-up.

Moderate. Major costs include laboratory assays (~$40/participant × 2 timepoints × 130 = ~$10,400), physical activity session instructors (~$5,000 for 12 months), dietary counseling materials (~$1,500), pedometers (~$1,300), research nurse time (~$8,000), and participant transport reimbursement (~$2,600). Estimated total: ~$29,000–35,000, feasible with a national research grant or institutional seed funding.

Requires full IRB approval. Informed written consent from parents/guardians and age-appropriate assent from children aged 7–10. Key ethical considerations: (1) the intervention involves physical activity in children — must screen for contraindications via a pre-participation medical evaluation; (2) usual-care arm must not be denied standard pediatric care — they receive routine guidance and are offered the intervention materials after study completion; (3) any abnormal laboratory results (e.g., HbA1c suggestive of prediabetes/diabetes) trigger immediate referral to pediatric endocrinology per a pre-specified protocol; (4) data privacy for registry-based recruitment requires institutional data governance approval.