Background

Growing evidence links unhealthy food environments with diet quality and overweight/obesity in adults. Studies in children are scant. Using two food environment indicators, we examined whether the availability of unhealthy food outlets around schools affects diet quality and weight of school-aged children.

Methods

Dietary intake from 851 grade 5 students (10-11 years) from 39 schools in Alberta, Canada was collected in 2014, using the Harvard Food Frequency Questionnaire (FFQ) for Children and Youth. Youth Healthy Eating Index was derived from FFQ data. Measured height and weight provided body mass index (BMI, kg/m2). Food outlets were: (1) classified as healthy or unhealthy according to the CDC’s Modified Retail Food Environment Index (mRFEI) and (2) ranked by a Registered Dietician (RD) as healthy, somewhat healthy or unhealthy based on the menus/offerings in relation to the provincial pediatric nutrition guidelines. Multilevel mixed-effects regression models tested the effect of absolute (number) and relative (proportion) densities of unhealthy food outlets within one mile buffers around schools on diet quality and weight.

Results

Overall, the proportion of unhealthy food outlets (based on the RD-ranked indicator) was not significantly associated with diet quality or BMI. For students attending schools with a higher number (36+) of unhealthy food outlets within one mile, every 10% increase in the proportion of unhealthy food outlets (based on the RD-ranked indicator) was associated with 3.9 lower diet quality score and 0.4 kg/m2 higher BMI. Every 10% increase in the proportion of unhealthy food outlets (based on the mRFEI) was associated with 0.5 kg/m2 higher BMI (p<0.05).

Conclusions

Attending a school in an area with a higher proportion of unhealthy food outlets is linked with lower diet quality and higher BMI, particularly in areas where the number of unhealthy food outlets is also high.