Statistical analysis

The prevalence of wasting, stunting, overweight, and obesity were reported at percentage (%) in each survey year. The differences between girls and boys were tested by Chi-square tests. To acquire the trend information across years, we conducted logistic regressions by using the probability of being overweight, obesity, wasting, and stunning as a function of the survey year and having the survey year as a numeric variable. We used “Maptools” package and the data of boundaries of China from the National Fundamental Geographic Information System of China to make a map showing the geographic location of Luoding city. All analyses were performed by using R software, version 3.3.0 (R Core Team). The p<0.05 (two-sided) was defined as statistically significant [25].