Health Literacy
Relationship between child health literacy and body mass index in overweight children

https://doi.org/10.1016/j.pec.2009.07.035Get rights and content

Abstract

Objective

To test the relationship between child health literacy and body mass index (BMI) Z-score in overweight children.

Methods

Cross-sectional survey of overweight children and parents. Parent and child health literacy was measured by the Short Test of Functional Health Literacy (STOFHLA). Linear regression tested for predictors of childhood BMI Z-score, adjusting for confounders.

Results

Of 171 total children, 107 (62%) participated, of whom 78 (73%) had complete data for analysis. Mean child BMI Z-score (SD) was 2.3 (0.40); median child age (interquartile range) was 11.5 (10–16); 53% were female; 80% were Medicaid recipients. Mean child STOFHLA was 22.9 (9.0); mean parental STOFHLA was 29.1 (8.6). Child STOFHLA correlated negatively with BMI Z-score (r = −0.37, p = 0.0009) and positively with child eating self-efficacy (r = 0.40, p < 0.0001). After adjusting for confounders, child STOFHLA was independently associated with child BMI Z-score (standardized B = −0.43, p < 0.0001). Overall adjusted r-squared for the regression model was 38%. Child STOFHLA contributed 13% to the overall model.

Conclusions

Child health literacy was negatively correlated with BMI Z-scores in overweight children, suggesting the need to consider health literacy in the intersection between self-efficacy and behavior change when planning interventions that aim to improve child BMI.

Introduction

Better health literacy, an individual's ability to read and interpret health information needed to make health decisions [1], has been correlated with better health outcomes in adults [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34], [35], [36]. While some investigators have begun to explore the relationship between parental health literacy and child health outcomes [37], [38], no recent studies have evaluated the contribution of children's own health literacy to health outcomes.

While it is intuitive that children are under the influence and supervision of adults with regard to their own health care, there are a variety of instances where children's own health literacy – their ability to understand how to take medications, for example – may directly affect their health. Children even as young as 4 years old are involved in their own self-care [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50] and in one study, 9–12-year-old children with diabetes read carbohydrate details on food labels, estimated the amount of energy they would need for the next few hours, and calculated how much insulin they should inject [44]. Among children with asthma, a recent randomized trial indicated that group education of children ages 9–13 resulted in reduction of asthma morbidity in children, but education of their parents did not provide additional benefit [51].

The current epidemic of child obesity provides another important context for understanding the potential of health literacy as a contributor to health outcomes in children. For example, a study of a nationally representative sample of 2314 U.S. schoolchildren children reported that an average of 43% of children's meals were consumed in school [52]. Such information has been the impetus for school-based interventions to reduce the prevalence of overweight and obesity, through measures such as modifying the meals provided by school lunch, but also changing the options available in school vending machines. Such measures affirm the belief that children do in fact make unsupervised decisions that can affect their health. In support of this belief, studies looking at the effects of television exposure on children have shown that children exposed to television advertising for unhealthy foods are more likely to request unhealthy foods from their parents [53], eat fewer less fruits and vegetables [54], and eat more energy-dense foods [55], [56]. In fact, one study reported an increase of 167 kcal/d for each hour of television viewing, mediated by an increase in consumption of foods commonly advertised on television [56]. In the context of childhood obesity, we propose that children's own ability to obtain, use, and understand health information (food advertising, labeling) impacts their ability to understand the choices they face with regard to self-care (specifically, dietary intake), that in turn, impacts body mass index (BMI).

In response to the concerns about the relationship between literacy and childhood obesity, our research team was awarded a “Clear Health Communication” research grant from Pfizer to test whether an intervention to increase child and parental health literacy improved BMI among overweight children. The current report uses baseline data (before any intervention) from the study to examine the relationship between initial health literacy and a child's BMI Z-score. The a priori hypothesis was that higher health literacy scores (both parental and child) would be associated with better BMI scores.

Section snippets

Design/setting/participants

The parent study from which these baseline (pre-intervention) data were drawn enrolled children ages 6–19 with the following inclusion criteria: BMI at least 85th percentile for age and sex, and receiving primary care at the study site, an inner-city academic health center in the Bronx, New York. Children were enrolled with the one legal guardian who usually brought them to clinic visits. Children with diagnosed developmental impairment, hemo-dynamically significant heart disease, or

Results

Overall, 171 children were referred for participation in the obesity management program and study. Of these, 107 (62%) children agreed to participate. Seventy-eight (73%) children from 69 families had parental body mass index measured at baseline, and could therefore be included in this analysis. Children excluded for missing parental data had higher STOFHLA scores (Table 1). Overall, the study sample was representative of the health center population (largely Latino and African-American,

Discussion

A thorough review of the literature reveals one previous study of children with Type 1 diabetes, which found no relationship between children's literacy skill and their own health, as measured by hemoglobin A1C [67]. In contrast, we found, in this cross-sectional sample of overweight children, that higher literacy was significantly correlated with a lower body mass index, adjusted for age and gender.

We believe these results raise important questions for future research. First, the uncertainty

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    Presented in part at the annual meetings of the Pediatric Academic Societies in San Francisco, May 2006. Work supported in part by a “Clear Health Communication” research grant from Pfizer Pharmaceuticals, Inc. and by the Bronx Center for Reducing and Eliminating Health Disparities, Albert Einstein College of Medicine.

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