Major Depression and Obesity in Parents and Adolescent Offspring: A Community-Based Study

Introduction: Major depressive disorder (MDD) and obesity are associated within individuals, but little is known about the association between MDD and obesity within families. The purpose of this study was to examine the association between MDD in parents and obesity in their late-adolescent offspring, and between obesity in parents and MDD in their late-adolescent offspring. We expected that MDD in parents would be associated with obesity in offspring and that obesity in parents would be associated with MDD in offspring.

Methods: Participants were drawn from the community-based Minnesota Twin Family Study (total n=7307, 17-year-old n=3774). Parents and their 17-year-old offspring were assessed for MDD using a structured diagnostic interview, and direct assessments of height and weight were conducted (and BMI derived from these measurements). Obesity was coded using the CDC cutoff of 30 for adults and the 95^th percentile cutoff for 17-year-olds (30 for females, 28.9 for males). Analyses were conducted using generalized estimating equations to appropriately account for the nested nature of the data (twins within families).

Results: Parental MDD was associated with offspring obesity (OR=1.74, CI=1.24-2.46). Odds ratios for the risk associated with maternal (1.42) and paternal (1.40) MDD were similar. This effect remained significant when parental obesity and offspring MDD were adjusted for. Results for parental obesity were more complex, with maternal obesity being associated with increased risk for MDD in offspring (OR=1.32, CI=1.06-1.64) and paternal obesity being associated with decreased risk for MDD among offspring (OR=.70, CI=.54-.91). These effects remained significant when parental MDD and offspring obesity were adjusted for. There were no differences in these findings by offspring gender.

Conclusions: There are significant cross-disorder associations between MDD and obesity in parents and offspring. The pattern of findings was complex, with parental MDD being associated with increased risk for obesity among offspring and maternal obesity being associated with increased risk for MDD among offspring, but paternal obesity being associated with decreased risk for obesity among offspring. There are many possible explanations for these findings. Parents may contribute to risk for this comorbidity by providing unhealthy food as an antidote to “feeling bad.” Obese mothers may model poor self-esteem, which could contribute to MDD symptoms in offspring. Stressors that affect the family (e.g., poverty) and/or common biological factors (e.g., HPA axis disruption) could also contribute to the co-occurrence of these disorders across family members. The reduced risk for MDD among offspring of obese fathers was unexpected; future research examining this association would be useful.