Neighbourhood socio-economic environment predicts adiposity and obesity risk in children under two

Abstract

Background: Neighbourhood socio-economic environment (SEE) is associated with obesity in older children and adults, but little is known about this relationship in younger children. Breastfeeding is an important preventative of adiposity in childhood, but its relationship with neighbourhood SEE is unknown.

Aims: We assessed differences in adiposity and obesity in children before age two by neighbourhood SEE, controlling for family socio-demographics and breastfeeding duration.

Materials and methods: Family socio-demographics, child body mass index z scores (BMIz), and breastfeeding duration were collected at periodic study visits from participants in PREVAIL (n = 245), a birth cohort in Cincinnati, OH. Addresses were assigned a Deprivation Index score, a validated measure of SEE, and dichotomized into highest SEE (least deprived quartile of scores) and not highest SEE (remaining quartiles). Longitudinal and Poisson models assessed differences in BMIz by SEE over the second year of life and obesity risk at age two, respectively (highest SEE, reference), while attenuation of obesity risk by breastfeeding duration was tested in mediation models.

Results: Residing outside of the highest SEE neighbourhoods was associated with an increased BMIz of 0.04 (95%CI 0.02, 0.06) per month of life and increased obesity risk at age two (aRR: 3.7, 95%CI 1.2, 16.2), controlling for family socio-demographics. Breastfeeding duration attenuated >9% of the obesity risk attributable to SEE (mediated RR: 3.4, 95%CI 1.1, 14.8).

Discussion: In the PREVAIL Cohort, residing outside of the highest SEE neighbourhoods predicted a significant increase in BMIz and obesity risk in children before age two, a relationship that was partially mediated by breastfeeding duration.

Conclusion: Breastfeeding support may play an important role in reducing obesity rates in children in lower SEE neighbourhoods.

Keywords: breastfeeding; child obesity; health disparities; social determinants of health; socio-economic environment.

FIGURE 1

Differences in body mass index z scores (BMIz) by census tract socio‐economic environment. BMIz in children 12, 18, and 24 months of age was calculated using data from the Pediatric Respiratory and Enteric Viral Acquisition and Immunogenesis Cohort (PREVAIL), a CDC‐funded birth cohort in Cincinnati, OH. Neighbourhood socio‐economic environment (SEE) was quantified using a validated measure of census tract material deprivation, the Deprivation Index. Quartiles of score were calculated and SEE was categorized as highest SEE (least deprived census tracts), high mid and low mid (intermediate levels of deprivation) and lowest SEE (most deprived census tracts). Comparisons were made among all categories (A) and by binary highest SEE vs all others (not highest SEE) (B). Comparisons of mean BMIz were made using ANOVA, with multiple comparisons adjusted using Tukey corrections.*p < 0.05, **p < 0.01, ***p < 0.001

FIGURE 2

Child weight and length were measured at each study visit in the Pediatric Respiratory and Enteric Viral Acquisition and Immunogenesis (PREVAIL) Cohort and BMIz was calculated using parameters supplied by the US Centers for Disease Control and Prevention. Obesity was defined as a BMIz ≥ 1.65 at age two. Census tract socio‐economic environment (SEE) was determined based on residing in the least deprived quartile of Deprivation Index score (highest SEE), a validated measure of neighbourhood material deprivation, or not (not highest SEE). Breastfeeding duration was self‐reported by the mother on quarterly study surveys and compared (model a) using a restricted mean survival time approach, controlling for family socio‐demographics variables (race, maternal age, marital status, family income, maternal education). Obesity risk by breastfeeding duration (model b), SEE (model c) and SEE + breastfeeding duration (model c’) was compared using Poisson regression while controlling for family socio‐demographics. Significant mediation by breastfeeding duration was defined as a significant effect of breastfeeding with a change in effect size or significance level of SEE in model c’