C.E. Yen*, S.W. Hu** *Department of Early Childhood Development and Education, Chaoyang University of Technology, Taichung, Taiwan **Institute of Oral Sciences, College of Oral Medicine, Chung Shan Medical University, Taichung, Taiwan Department of Dentistry, Chung Shan Medical University Hospital, Taichung, Taiwan e-mail:
[email protected]
Association between dental caries and obesity in preschool children abstract Aim The purpose of this study was to investigate the association between dental caries and obesity in preschool children. Materials and methods A total of 329 preschool children were recruited from nine day care centers. A qualified dentist examined the oral health of each child and a caries score was recorded. Anthropometric measurements included body weight, height, triceps skinfold thickness, and body fat. Body mass index, and weight-for-height index were calculated. Parents or guardians answered a questionnaire regarding their children’s dietary patterns, oral hygiene habits, and medical history, as well as parental practices and attitudes towards their children’s oral health. Results The prevalence of dental caries was 73% in this study. Fourteen percent of the children were overweight or obese. The caries scores were not significantly different according to weight-for-height index categories. After taking into account important factors in the multiple regression models, body mass index and weight-for-height index, respectively, were not significantly associated with dental caries. Conclusion This study showed that obesity was not significantly associated with dental caries in preschool children.
Keywords Body Mass Index; Dental caries; Obesity; Preschool children; Weight-for-height Index.
European Journal of Paediatric Dentistry vol. 14/3-2013
Introduction Dental caries is one of the common public health problems among preschool children worldwide. Dental caries can lead to pain, chewing difficulty, general health disorders, and can affect growth and development [Sheiham, 2005]. In Taiwan, caries is a serious public health problem. A study reported that the prevalence of dental caries was as high as 88% in preschool children [Tsai et al., 2000]. Yet, a national diet and nutrition survey showed that the prevalence of dental caries was 37% in 4-6 years old in the United Kingdom [Walker et al., 2000]. Forty percent of preschool children presented dental caries in Brazil [Ferreira et al., 2007]. In Mexico, the prevalence of dental caries was 18% in preschool children [Vázquez-Nava et al., 2010]. Obesity is currently one of the most common health problems in numerous countries. A cross-sectional study showed that the obesity prevalence among 4-year-old US children was 18% [Anderson & Whitaker, 2009]. According to one survey, the prevalence of obesity varied from 4% to 17% in Taiwanese children aged 3-19 years [Chen, 1997]. Obese children are more likely to become obese adults [Freedman et al., 2001]. There has been a growing interest in the relationship between dental caries and childhood obesity. The studies have found a positive association between these two conditions and have suggested that obese children are at an increased risk for dental caries [Willerhausen et al., 2004; Willerhausen et al., 2007] or, on the contrary, preschool children with a low body mass index (BMI) have significantly higher dental caries [Norberg et al., 2012]. Yet, other studies have shown no association between dental caries and childhood obesity [GranvilleGarcia et al., 2008; Chen et al., 1998]. Some studies have found that children with early childhood caries have lower weight [Ayhan et al., 1996; Acs et al., 1999]. In a recent systematic review, dental caries was reported to be associated with both high and low BMI in children [Hooley et al., 2012a]. Previous studies have demonstrated inconsistent results because the association between dental caries and obesity is complicated. Both conditions are complex with multiple contributing factors, including biological, genetic, socioeconomic, cultural, dietary, environmental, and lifestyle factors [Granville-Garcia et al., 2008; Hong et al., 2008]. Nevertheless, childhood caries and obesity may share some common risk factors. Energy-dense and highly refined foods (i.e. soda, cake, candy) have been identified as potential contributors to obesity [Nicklas et al., 2001]. Also, these foods are considered highly cariogenic; the increased consumption of sugars leads to an increased risk of caries [Marshall et al., 2005]. The relationship between dental caries and obesity in preschool children has not been thoroughly investigated, and the results are inconsistent. The purpose of this study was to examine the relationship between dental caries and obesity among preschool children.
185
Yen C.E. and Hu S.W.
Methods This cross-sectional study was conducted in Taichung city, Taiwan. Preschool children aged 3-6 years were recruited from nine day care centers randomly selected from 80 registered day care centers in the city. Parents or guardians of all participating children gave written informed consent before participating in this study. The present study was approved by the Institutional Review Board of Chung Shan Medical University Hospital. A qualified dentist conducted the oral health examination of each study subject according to the guidelines of oral health surveys basic methods by the World Health Organization (WHO) [1997]. The WHO standard criteria were used to assess dental caries [WHO 1997]. The deft index (decayed, indicated for extraction, and filled primary teeth) was used to describe dental caries status for each child. The prevalence of dental caries was calculated as the percentage of children having caries (i.e. deft >= 1). The categories for the severity of caries were determined according to the 50th percentiles of the caries index distribution and were used as the cutoff points (deft < 4 and deft >= 4). A self-administered questionnaire was used to collected information from each participating child’s parent or guardian. The following variables were examined: (1) socio-demographic and family factors; (2) children’s dietary patterns: including food preference and dietary intake frequency; (3) children’s dental hygiene health habits: including frequency of tooth-brushing per day, using fluoride, and visits to the dentist; (4) parental practices and attitudes towards their children’s dental health; (5) children’s medical history. Body weight and height were measured in light clothing and without shoes. BMI was then calculated using the following formula: weight (kg)/height (m)2. The weight-for-height index (WHI) was also calculated as follows: WHI = [actual weight (kg) / actual height (cm)] / [50th percentile expected weight (kg) for age / 50th percentile expected height (cm) for age]. The children were categorised according to the BMI standard from the Department of Health in Taiwan as follows: “lean”, “underweight”, “normal weight”, “overweight”, and “obese”. A WHI less than 0.8 is considered lean, 0.80.89 is underweight, 0.9-1.09 is normal weight, 1.1-1.19 is overweight and >1.2 is obese in preschool children, following the standard of the Department of Health in Taiwan. Triceps skinfold thickness (TSF) was measured three times and the averages at the midpoint of the non-dominant upper posterior arm were determined using a Lange skinfold caliper (Cambridge). Body fat (%) was assessed using bioelectrical impedance analysis (BIA) (TANITA body fat monitor, TGF-531A, Japan). Data were analysed using the SPSS v. 12.0 software package (SPSS Inc., Chicago, IL, USA). The chi-squared test was used to compare frequencies of demographic variables between children with and without caries. The
186
difference in anthropometric measurements between caries groups and caries-free groups were compared using the Student’s t test. One-way analysis of variance (ANOVA) was used to compare means of caries indices among groups. Multiple regression analysis was applied to assess the relationship between BMI, WHI index and means of caries scores, with adjustment for potential confounding factors. Logistic regression analysis was conducted to evaluate the association between BMI, WHI index and presence of dental caries (yes vs. no), controlling for potential confounders. A p value of < 0.05 was considered statistically significant.
Results In total, 450 preschool children were invited to participate in this study and 329 of them had oral examination, anthropometric measurements, and questionnaire data, with a response rate of 73%. One hundred twenty-one children were not included in this study because they did not respond or did not have complete data. Table 1 shows the characteristics of participating children. The mean age of the caries group was significantly higher than the caries-free group and the prevalence of caries increased with increasing age. Birth order of children had a significant effect on dental caries. The caries-free children had a higher percentage of being the first born than did children with caries. Furthermore, there were no significant differences in frequencies of eating snacks, drinking carbonated beverages, and intake of fruits or vegetables, respectively, between the caries group and caries-free group (data not shown in table). Table 2 presents the anthropometric status of the children. The BMI, WHI index, body fat, and triceps skinfold were not significantly different between the caries-free group and the caries group or between the groups with different severities of caries. Table 3 shows that the distribution of WHI categories was not significantly different in children with different caries experience. Fourteen percent of the children were overweight or obese. The prevalence of dental caries was 73% in this study, and 55% of the children had severe caries (Table 4). The mean deft index of caries, prevalence of caries and severe caries significantly increased with age. There was no significant difference in the deft scores among children in different WHI index categories. Table 5 shows the relationship of the WHI index, BMI and dental caries in the multiple regression analysis. There was no significant association between the WHI index, BMI, respectively, and the caries score, after adjusting for age, gender, tooth-brushing habits, parent’s education level, birth order, age of toothbrushing began, frequency of vegetable and fruit intake, use of fluoride, and frequency of dental visits.
European Journal of Paediatric Dentistry vol. 14/3-2013
Dental caries and obesity
Variables
All children
329 n 4.91±0.86 Age (yr), mean±SD Age group, n (%) 18 (6) 3 yrs 79 (24) 4 yrs 146 (44) 5 yrs 86 (26) 6 yrs Sex, n (%) 175 (53) Male 154 (47) Female Birth order, n (%) 178 (56) First Second or later child 140 (44) Father's education, n (%) >=Graduate school 58 (19) 168 (53) University /College 89 (28)
