Health Equity and Childhood Obesity: A Longitudinal Analysis of Financial Stress and the Role of Parents on BMI Growth Curves

Background:

Family stress theory posits that familial resources (i.e., income) can impact a family’s coping response when faced with stressors. Adverse coping responses, such as engaging in poor health behaviors (e.g., overeating, increased consumption of comfort foods), have been identified as a common response among low-income adults (Jackson, 2010) and can lead to increased risk of obesity. However, little is known about the association between increased financial strain and parenting, and whether this is linked to increased risk for childhood obesity as children grow. This study hypothesizes that increased financial strain (i.e., lower income-to-needs ratio) will be associated with adverse parenting practices, which will be linked to a higher rate of growth in BMI among children between the ages of 3 and 15 years. 

Methods:

Data were collected from 3,730 families from the Fragile Families and Child Wellbeing Study to describe the trajectories of child weight status over 12 years when children were 3, 5, 9, and 15 years-old, and to examine the association of income-to-needs ratio on parenting aggravation and weight status over time. Weight status is measured as BMI z-scores based on 2000 CDC age and gender adjusted growth charts. Income-to-needs ratio is measured as household income, adjusted for household size and based on federal poverty guidelines. Parenting aggravation is based on average scores of a 4-item self-reported survey, with higher scores reflecting higher aggravation (e.g., being a parent is harder than I thought, I feel trapped by my responsibilities as a parent). Latent growth curve modeling (LGCM) was used to evaluate parenting aggravation as a mediator between income-to-needs ratio and initial/rate of change in BMI z-scores.

Results: On average, BMI z-scores increased from age 3 (.55) to age 9 (.91), but went down slightly at age 15 (.87). Average initial scores for parenting aggravation were between 2.77-3.00 (range 1-4) for all time points, and average initial income-to-needs ratio was between 1.88 and 2.51 (range 0-42) across all time points.

LGCM results revealed that higher initial income-to-needs ratio predicted higher initial parenting aggravation scores (β =.02, p=.01). Initial income-to-needs ratio predicted a significant and positive change (increase) in parenting aggravation over this same time period (β =.001, p=.009). Initial income-to-needs ratio predicted a negative rate of change in BMI z-score from 3 to 15 years, such that a higher income-to-needs ratio was associated with lower BMI z-scores over time (β =-.003, p=.02). There was no direct or indirect effect of parenting aggravation on BMI.

Conclusions:

Lower income-to-needs was associated with higher reports of parenting aggravation over time, as well as higher rates of change in BMI z-score. Parenting aggravation did not mediate the association between income-to-needs ratio and BMI. Implications of this study suggest that social work practitioners should address the role that financial strain may have on parenting as well as maintaining healthy weight and growth among children that are between 3 and 15-years-old. Future research should explore other potential parent-level factors that may mediate the relationship between financial strain and childhood BMI.