Obesity and abnormal glucose tolerance in offspring of diabetic mothers: A systematic review and meta-analysis

BACKGROUND Rising prevalence of childhood obesity and type 2 diabetes mellitus (T2DM) is an emerging public health issue. OBJECTIVES To investigate the association of maternal hyperglycemia exposure during pregnancy with obesity and abnormal glucose tolerance in offspring, and the age at occurrence. METHODS We searched MEDLINE and EMBASE for observational studies on obesity and diabetes in offspring of diabetic mothers (gestational diabetes mellitus (GDM), type 1 diabetes mellitus (T1DM) and T2DM), and those on non-diabetic mothers. We performed fixed effect meta-analysis for all studies except when heterogeneity was detected. The quality of studies was evaluated using the Risk of Bias Assessment Tool for Nonrandomized Studies (RoBANS). RESULTS Twenty observational studies were included involving a total of 26,509 children. Offspring of GDM mother had higher BMI z-score in childhood (pooled MD: 0.14, 95%CI: 0.04-0.24, seven studies, 21,691children, low quality of evidence). Offspring of T1DM mothers had higher BMI z-score from prepubertal to adolescent (pooled MD: 0.35, 95% CI: 0.13-0.58, three studies, 844 children, low quality of evidence) compared with control. After adjustment for maternal pre-pregnancy BMI, this association remained in offspring of T1DM, but disappeared in those of GDM mothers. Offspring of GDM mother had higher 2-hour plasma glucose from prepubertal to early adulthood (pooled MD: 0.43 mmol/L, 95% CI: 0.18-0.69, five studies, 890 children), while those of T1DM mothers had higher rate of T2DM in 2-5 years old to early adulthood (pooled odds ratio [OR], 6.10: 95% CI: 1.23-30.37, two studies, 448 children, very low quality of evidence) compared with control. As there was only one study with offspring of T2DM mothers, evidence is sparse. LIMITATIONS Only observational studies were included, with a few adequately adjusted for covariables. CONCLUSIONS Exposure to maternal hyperglycemia was associated with offspring obesity and abnormal glucose tolerance especially in offspring of T1DM mothers, but the evidence relies on observational studies with low quality of evidence only.