The following is a summary of “Household Income, Cortisol, and Obesity During Early Childhood: A Prospective Longitudinal Study,” published in the JANUARY 2023 issue of Pediatrics by Kunin-Batson, et al.

For a study, researchers sought to investigate prospectively, over 3 years in early childhood, the trajectory of children’s cortisol, body mass index (BMI), and household income.

In the Now Everyone Together for Amazing and Healthful Kids (NET-Works) Study (n = 534, children ages 2-4 years, and baseline household income <$65,000/year), household income, child hair cortisol levels, and BMI were assessed at baseline, 12-, 24-, and 36-month follow-up visits. With the help of adjusted linear growth curve modeling, relationships were looked at between very low household income (<$25 000/year) at baseline, income status over time (remaining <$25 000/year or having increasing income), cortisol accumulation from hair samples, & BMI percent of the 95th percentile (BMIp95) trajectories. The reference group for all analyses consisted of households with an annual baseline income between $25,000 and $65,000.

Children in reference group families experienced lower yearly changes in BMIp95 (0.40 vs. 0.62 percentage units/year) than children from extremely low-income households at baseline (P< .001). As compared to the reference group (-0.61 percentage units/year), children from families with growing income (P =.01,.51 percentage units/year) and those with meager income (P <.01,.34 percentage units/year) experienced more significant annual increases in BMIp95. Children from very low-income households had higher hair cortisol accumulations (0.22 pg/mg, P =.02) than children in the reference group. In contrast, the hair cortisol concentrations of children from households with rising income (0.03 pg/mg) were not significantly different from those of the reference group. BMIp95 and cortisol were unrelated.

A family’s financial situation may impact children’s BMI trajectories and developmental stress systems, but these processes may occur independently.