The Association of Weight Status with Dental Caries and Trachoma Among School Children in Cities of Changsha and Shenzhen, China

Abstract

Dental caries and trachoma are two common diseases among children in developing countries. To examine whether weight status is associated with these two diseases, we used data from two screening surveys conducted in Changsha and Shenzhen, two cities in China. The screening surveys were part of a case-control study examining risk factors related to childhood obesity. Approximately 5,900 children (3,794 from Changsha and 2,193 from Shenzhen) participated in the screening survey in which weight and height were measured. Decayed or filled tooth counts (primary dentition) and trachoma infection status were obtained from school general health examination records (SGER). After excluding those who had missing information on weight, height, and SGER, a total of 4,073 (2,185 boys and 1,888 girls) aged 5-9 years old were included in the analysis. Body mass index (BMI) was calculated as weight (kg) divided by height (m 2 ) and standardized for age and sex, then converted to a BMI z-score. Using BMI z-score, subjects were categorized into 4 groups as underweight (<-2), normal weight (~1.03), overweight (~1.64), or obese (>1.64). Overall, approximately 5.5% of children (6.2% girls and 4.6% boys) were underweight and 18% (11% girls and 23% boys) were overweight or obese. Comparing normal weight to underweight, overweight and obese subjects, after adjusting for age, gender, grade, and city of survey, the odds ratios (OR, [95% CI]) for dental caries were 1.12 (0.84-1.49), 0.70 (0.56-0.86), and 0.62 (0.48-0.79), (p for trends <0.001) while the ORs for trachoma were 1.65 (0.94-2.89), 0.90 (0.52-1.57), and 1.92 (1.20 -3.06). This suggests that weight status is associated with dental caries and trachoma among these Chinese children. Further study is warranted to explore the underlying mechanism(s).