Co-Residence with Grandparents and the Body Mass Index (BMI) during Adolescence and Early Adulthood

Purpose: Adolescent obesity is a major public health issue in the United States (US) that has increased in significance over the past three decades. Concurrently, three-generation households have become more prevalent in the United States as well. Given these trends, this study examines (a) whether the presence of a grandparent in one and two parent households is associated with differences in body mass index (BMI) trajectories as adolescents age into emerging adulthood in single- or two- parent households, and (b) to what extent adolescent race/ethnicity helps explain variations in BMI trajectories in single- or two- parent households.

Methods: The data come from the National Longitudinal Study of Adolescent Health and the analytic sample consists of 10,086 adolescents who belonged to one and two-parent households with and without a grandparent present. The dependent variable is self-reported BMI from waves 1-3. The independent variable is an experience living with a grandparent under 19 years old. Adolescents and family characteristics (e.g., gender, ethnicity, family income, parental education, maternal employment, adolescent’s immigrant status), and health behavior characteristics (e.g., vigorous physical activity, intake of fruits and vegetables, and sedentary activity) were included as control variables. Growth curve models were used to evaluate the trajectory for changes in BMI. Missing data was imputed using chained equations to generate 5 sets of imputed data.

Results: For the first model adjusted for ethnicity, there were no differences in BMI trajectories between those adolescents who had co-residence with a grandparent and those who did not in all types of family structure. When the model was then stratified by ethnicity, we found that Hispanic adolescents who lived with grandparents in two-parent households have significantly slower rates of BMI growth compared to those who have not lived with grandparents during adolescence (b= -0.12, p<0.01). The associations were not found among other ethnic groups.

Implications: These results suggest that co-residence with a grandparent may play an important role in reducing long-term obesity risk among Hispanic adolescents in two-parent households. This study offers insight into ways that co-residence with grandparents may slow dietary acculturation and adaptation of associated with mainstream culture. Therefore, Hispanic grandparents may help their grandchildren develop a healthy diet intake. These findings suggest that providing effective resources and supports which are designed to meet the varying needs of grandparents in three-generational families will enable grandchildren to become healthy and contributing adults.