Prognostic value of different maternal obesity phenotypes in predicting offspring obesity in a family-based cohort study.

Background: Parental weight is studied as an important determinant of childhood obesity; however, obesity-related metabolic abnormalities have been less considered as determinants of childhood obesity. This study aimed to investigate the association between maternal obesity phenotypes and incidence of obesity in their offspring.

Methods: This longitudinal study was conducted within the framework of the Tehran Lipid and Glucose Study. A total of 2151 non-obese children who had complete parental information were followed for incidence of obesity over a mean of 148.7 ± 34.7 months. Obesity in children was defined using the World Health Organization criteria. Maternal body mass index (BMI) was classified into three categories: normal weight, overweight and obese. Dysmetabolic status was considered as having metabolic syndrome or diabetes. Metabolic syndrome and diabetes were defined according to the Joint Interim Statement and American diabetes association criteria, respectively. Considering maternal BMI categories and metabolic status, six obesity phenotypes were defined as followed: 1) normal weight and normal metabolic status, 2) overweight and normal metabolic status, 3) obese and normal metabolic status, 4) normal weight and dysmetabolic status, 5) overweight and dysmetabolic status, and 6) obese and dysmetabolic status. The association between maternal obesity phenotypes and incidence of obesity in children was studied using Cox proportional regression hazard model.

Results: In male offspring, the risk of incidence of obesity significantly increased in those with maternal obesity phenotypes including overweight/normal metabolic: 1.75(95% CI: 1.10-2.79), obese/normal metabolic: 2.60(95%CI: 1.51-4.48), overweight/dysmetabolic: 2.34(95%CI: 1.35-4.03) and obese/dysmetabolic: 3.21(95%CI: 1.94-5.03) compared to the normal weight/normal metabolic phenotype. Similarly, in girls, the risk of incidence of obesity significantly increased in offspring with maternal obesity phenotypes including overweight/normal metabolic: 2.39(95%CI: 1.46-3.90), obese/normal metabolic: 3.55(95%CI: 1.94-6.46), overweight/dysmetabolic: 1.92(95%CI: 1.04-3.52) and obese/dysmetabolic: 3.89(95%CI: 2.28-6.64) compared to normal weight/normal metabolic phenotype. However, maternal normal weight/dysmetabolic phenotype did not significantly change the risk of obesity in both male and female offspring.

Conclusion: Except for normal weight/dysmetabolic phenotype, all maternal obesity phenotypes had significant prognostic values for incidence of offspring obesity with the highest risk for obese/dysmetabolic phenotype. This study provides valuable findings for identifying the first line target groups for planning interventions to prevent childhood obesity.