Longitudinal relationship between adiposity status and oral health among adolescents in Hong Kong

Abstract

Introduction: Adiposity and oral diseases share common risk factors. Most previous studies exploring the connection between obesity and oral health have focused on adulthood, while relatively few longitudinal studies have considered this relationship in children and adolescents. Objectives: This research aimed to (i) undertake two systematic reviews of oral health and anthropometric measurements (ii) investigate their relationship in a population-based cohort longitudinal project. Methods: Two systematic reviews were conducted to analyze the associations in children and adolescents between anthropometric measurements and (i) dental caries, and (ii) periodontal diseases. Data of obesity indices, caries experience, periodontal health, and socioeconomic status were obtained from a random cohort sample of Hong Kong adolescents at ages 12, 15 and 18 years old. Results: Inconclusive results were found in the two systematic reviews. In our longitudinal project, 282 students completed three rounds of survey. The percentage of underweight adolescents increased from 6.0% to 23.8% from age 12 to 18 years. The mean (SD) of DMFT was 0.46 (0.94), 1.57 (2.13) and 2.13 (2.48), respectively, for the three ages. At age 18 years, the mean DMFT of participants whose WHR at age 15 was below the median value was 29.3% lower than the DMFT of those whose WHR was above the median (P = 0.028). Participants with a higher DMFT at 15 years demonstrated significantly increased probability of having a WHR above the median (OR = 1.135; 95% CI: 1.01, 1.28; P = 0.041) at 18 years. About 20% of participants had healthy periodontal conditions at age 12, while the figures dropped to 10.3% at age 15 and 5.7% at age 18. The proportion of 15-year-old adolescents who brushed their teeth more than twice a day was significantly higher among participants belonging to the lower BMI, waist circumference, WHR, and WHtR category (P < 0.05). The fully adjusted model revealed that participants with a lower BMI at age 15 had higher probability of having more than 50% index teeth free from periodontal diseases at age 18 (OR = 2.78; 95% CI: 1.16, 6.64; P = 0.022). In the analysis of risk factors among participants at age 18, various significant factors – including gender, parents’ employment status, mouth rinse habit, frequency and amount of meat intake, frequency of oil intake, use of fluoride toothpaste and DMFT – were found in different final models of adiposity status. Conclusion: Evidence of the association between oral health and adiposity indices varied considerably in the systematic reviews. There is a dearth of prospective cohort studies with comprehensive potential variables. In our study, longitudinal association between WHR and caries experience was found among adolescents aged 15 to 18 years; higher BMI at 15 years was reported to be associated with more severe periodontal conditions at age 18; and various caries-related risk factors were significant to adiposity status. The findings point to the need for oral and diet health to be promoted among overweight/obese children and adolescents. Further longitudinal research projects are recommended to investigate genetic and environmental contributors.