Obesity and dental caries among South Brazilian schoolchildren: a 2.5-year longitudinal study

Abstract The aim of this study was to assess the association between weight status and ΔDMFS among 12-year-old schoolchildren from South Brazil. A total of 801 12-year-old schoolchildren were followed-up for 2.5 ± 0.3 years. Data collection included questionnaire, recording of anthropometric measures (height and weight), and caries examination. The outcome was the difference between DMFS (number of decayed, missing or filled surfaces) at follow-up and baseline (ΔDMFS). Weight status, based on body mass index-for-age Z-scores, was considered the main predictor variable. Negative binomial regression models were used to model the association, and rate ratios and their 95% confidence intervals were estimated. A multivariable fractional polynomial model was used to further explore the relationship between obesity and dental caries. DMFS increased by 0.86 (95%CI = 0.65–1.07), 0.91 (95%CI = 0.59–1.23), and 0.42 (95%CI = 0.03–0.80) for normal weight, overweight, and obese schoolchildren, respectively. Obese adolescents had significantly lower ΔDMFS than normal weight ones (p < 0.05). No significant association between categories of weight status and ΔDMFS was found (overweight, IRR=0.92, 95%CI = 0.69–1.21, p = 0.54; obese IRR = 0.75, 95%CI = 0.51–1.12, p = 0.16). However, the multivariable fractional polynomial model showed an inverted U shaped relationship with a decreasing ΔDMFS with increasing BMI (p < 0.05). This population-based longitudinal study showed an inverse association between obesity and ΔDMFS over a 2.5-year period among South Brazilian adolescents.

摘要 本研究旨在探讨巴西南部12岁学龄儿童的体重状况与ΔDMFS（DMFS增量，即随访期与基线期龋、失、补牙面数(DMFS)的差值）之间的关联。本研究共纳入801名12岁学龄儿童，随访时长为2.5±0.3年。数据收集环节包含问卷调查、人体测量指标（身高与体重）记录以及口腔龋病检查。本研究的结局指标为随访期与基线期DMFS的差值，即ΔDMFS。以年龄别体质指数Z评分(BMI-for-age Z-scores)为依据划分的体重状况，被设为核心预测变量。本研究采用负二项回归模型分析该关联，并估算率比(rate ratios)及其95%置信区间。此外，本研究采用多变量分数多项式模型，进一步探讨肥胖与龋病之间的关联。体重正常、超重及肥胖学龄儿童的ΔDMFS分别增加0.86（95%CI=0.65~1.07）、0.91（95%CI=0.59~1.23）与0.42（95%CI=0.03~0.80）。肥胖青少年的ΔDMFS显著低于体重正常者（p<0.05）。未观察到体重状况分类与ΔDMFS间存在显著关联（超重组：IRR=0.92，95%CI=0.69~1.21，p=0.54；肥胖组：IRR=0.75，95%CI=0.51~1.12，p=0.16）。不过多变量分数多项式模型结果显示，二者呈倒U型关联：ΔDMFS随BMI升高先升后降（p<0.05）。这项基于人群的纵向研究显示，在巴西南部青少年群体中，肥胖与2.5年随访周期内的ΔDMFS呈负相关关系。