Background: Given the rapid pace of urbanization and Westernization and the increasing prevalence of obesity, there is a need for research to better understand the influence of the built environment on overweight and obesity in world's developing regions. Culturally-specific food environment survey instruments are important tools for studying changing food availability and pricing. Here, we present findings from an effort to develop and evaluate food environment survey instruments for use in a rapidly developing city in southwest China.
Methods: We developed two survey instruments (for stores and restaurants), each designed to be completed within 10 minutes. Two pairs of researchers surveyed a pre-selected 1-km stretch of street in each of three socio-demographically different neighborhoods to assess inter-rater reliability. Construct validity was assessed by comparing the food environments of the neighborhoods to cross-sectional height and weight data obtained on 575 adolescents in the corresponding regions of the city.
Results: 273 food establishments (163 restaurants and 110 stores) were surveyed. Sit-down, take-out, and fast food restaurants accounted for 40%, 21% and 19% of all restaurants surveyed. Tobacco and alcohol shops, convenience stores and supermarkets accounted for 25%, 12% and 11%, respectively, of all stores surveyed. We found a high percentage of agreement between teams (>75%) for all categorical variables with moderate kappa scores (0.4-0.6), and no statistically significant differences between teams for any of the continuous variables. More developed inner city neighborhoods had a higher number of fast food restaurants and convenience stores than surrounding neighborhoods. Adolescents who lived in the more developed inner neighborhoods also had a higher percentage of overweight, indicating well-founded construct validity. Depending on the cutoff used, 19% to 36% of male and 10% to 22% of female 16-year old adolescents were found to be overweight.
Conclusions: The prevalence of overweight Chinese adolescents, and the food environments they are exposed to, deserve immediate attention. To our knowledge, these are the first food environment surveys developed specifically to assess changing food availability, accessibility, and pricing in China. These instruments may be useful in future systematic longitudinal assessments of the changing food environment and its health impact in China.