Nine-year-old children exposed to more sociodemographic, physical and psychosocial risks tend to have poorer self-regulatory behaviour and are more likely to show an increase in BMI during the next 4 years
- Correspondence to Robert H Bradley
School of Social & Family Dynamics, Arizona State University, 951 S. Cady Mall, Tempe, Arizona 85287, USA;
Implications for practice and research
■ A focus on improving children's self-regulatory skills can be an effective component of interventions aimed at reducing obesity.
■ Future research should consider additional attitudinal and motivational pathways through which high-risk children can improve eating and activity patterns that protect against obesity.
Approximately 17% of US children are classified as obese, with low-income children showing higher rates of obesity than middle income children.1 The International Association for the Study of Obesity estimates that 20% of school-age children in Europe are overweight: a marker of accelerating problems with obesity worldwide.2 Being overweight in childhood increases the risk of a broad array of health problems, and so there is great concern for identifying mechanisms responsible for weight gain. Some of these have been reasonably well characterised, but there remain gaps in knowledge pertaining to processes connected to obesity for children who live in adversity. The chronic stress associated with cumulative risk produces physiologic perturbations and maladaptive behaviour patterns that may increase potential for obesity.3
Evans et al used data from 244 children (out of an original sample of 339) living in rural communities in New York. About half were from low-income families at the time of recruitment. Parents provided information on nine sociodemographic risk indicators (eg, poverty, substandard housing, family turmoil). Each risk factor was scored dichotomously (0/1) based on statistical or theoretical criteria. From these a cumulative risk index was composed (0/9). Height and weight data were gathered at ages 9 and 13. Children's self-regulatory competence was assessed at age 9 using a delay of gratification task.4 Structural equation modelling was used to test a series of path models connecting cumulative risk to body mass index (BMI) at age 13.
Cumulative risk at age 9 was associated with lower levels of self-regulation at age 9 and BMI at age 13, controlling for BMI at age 9. The most parsimonious model showed significant indirect paths between cumulative risk at age 9 and BMI at age 13 via self-regulation at age 9 and BMI at age 9.
Finding that self-regulatory competence mediates relations between cumulative risk and obesity for young adolescents has major implications for interventions aimed at overweight in children who live in conditions of chronic adversity. The findings are noteworthy even though the sample was restricted to European Americans from rural areas in New York and there were not measures of cumulative risk, self-regulatory competence and BMI gathered from early childhood onwards. The findings gybe with research showing that chronic stress is connected to poor dietary habits via physiological mechanisms connected to the prefrontal cortex.5 Chronic stress appears to undermine a child's ability to delay gratification and, in so doing, leads to overeating. A clear implication of the findings is that dietary interventions aimed at low-income children should probably include components aimed at helping them manage stress.
Although the study points to a potentially important pathway through which cumulative risk influences weight gain, one aspect of the findings suggests that the overall model tested was underspecified; specifically, the finding that cumulative risk at age 9 was connected to BMI at age 13 via BMI at age 9. Indeed, the correlation between BMI at age 9 and BMI at age 13 was 75. Prior studies show that cumulative risk can undermine cognitive development and the development of positive motivational tendencies. Toxic stress appears to result in permanent changes in both brain structure and function and can lead to functional differences in learning, memory and executive functioning.6 Consequently, poor and traumatised children less likely know about what they should eat or how best to approach eating. Moreover, cumulative stress tends to undermine parenting processes, including such critical functions as the management of daily routines, food preparation and the socialisation of eating in children. Future research needs to consider how these and like mechanisms should be considered in planning interventions for low-income children beginning in elementary school.