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Obese or Overweight Children Do Not Have a Higher Risk of Dental Caries
ETIOLOGY/OTHER
ARTICLE ANALYSIS & EVALUATION ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION Caries status and overweight in 2- to 18-year-old US children: findings from national surveys. Kopycka-Kedzierawski DT, Auinger P, Billings RJ, Weitzman M. Community Dent Oral Epidemiol 2008;36(2):157-67.
REVIEWER
Obese or Overweight Children Do Not Have a Higher Risk of Dental Caries SUMMARY Subjects This analysis included data from 2 sequential nationwide surveys, namely the NHANES III (1988-1994) and NHANES 1999-2002. The analysis targeted children ages from 2 to 18 years in each dataset who completed dental examination and height and weight measurement. The NHANES III sample included 10,180 children and NHANES 99-02 included 7568 children.
Woosung Sohn, DDS, PhD, DrPH
Key Risk/Study Factor PURPOSE/QUESTION The authors analyzed nationally representative samples of children (2 to 18 years old) to investigate the relationship between obesity/ overweight and dental caries status.
The key risk factor in this analysis is body mass index (BMI) percentile based on the age and sex-specific 2000 Centers for Disease Control and Prevention (CDC) growth chart. Children’s weight status was defined based on BMI percentile as (1) overweight: at or above 95th percentile, (2) at risk for overweight: at or above 85th percentile and less than 95th percentile, and (3) normal weight: less than 85th percentile.
Main Outcome Measure SOURCE OF FUNDING None
TYPE OF STUDY/DESIGN (Sequential) Cross-sectional study
LEVEL OF EVIDENCE Level 3: Other evidence
STRENGTH OF RECOMMENDATION GRADE Not applicable
J Evid Base Dent Pract 2009;9:97-98 1532-3382/$34.00 Ó 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.jebdp.2009.03.013
The main outcome measure was dental caries experience in the primary (dfs) for 2- to 5-year-old children, and permanent dentition (DMFS) for 12- to 18-year-old children. For 6- to 11-year-old children, caries experience in both primary (dfs) and permanent dentition (DMFS) were recorded. In the analysis, the caries experience measure was dichotomized as either having caries experience (dfs > 0 or DMFS > 0) or having no caries experience (dfs = 0 and DMFS = 0). Examinations for dental caries were conducted based on the modified Radike’s criteria (ie, disease is defined as dentinal cavitated lesion using a sharp #23 sickle-shaped explorer).
Main Results The results from the analyses of 2 sequential cross-sectional datasets (NHANES III 1988-1994 and NHANES 1999-2002) suggest that there is no association between caries experience in the primary dentition and body weight status (normal weight, at risk for overweight, or overweight) among 2- to 5-year-old children in the United States. For older children, the results are not consistent in the 2 nationwide datasets. The results from NHANES III indicate that there is a negative association between caries experience in the primary dentition and body weight status among 6- to 11-year-old children (ie, overweight and at risk for overweight children are less likely to have caries experience in the primary dentition than normal weight children). In the permanent dentition (both 6- to 11- and 12- to 18-year-old children), a negative association is significant only between overweight children and normal weight children. These negative associations, however, are not significant in the NHANES 1999-2002; ie, for children 6 to 11 years of age and 12 to 18 years of age, there are no differences in having caries experience among normal, at risk for overweight, and overweight children.
JOURNAL OF EVIDENCE-BASED DENTAL PRACTICE
Conclusions The authors concluded that there is no evidence to suggest that overweight children are at an increased risk for dental caries based on the analysis of data from NHANES III and NHANES 1999-2002. The authors also suggested, based on some of the NHANES III results, that being overweight may be associated with decreased rates of caries in older children (6 to 18 years old).
COMMENTARY AND ANALYSIS Obesity and dental caries share several common characteristics: both are complex conditions with multiple and multilevel risk factors, and both are more prevalent among low socioeconomic status (SES) and minority children. Furthermore, they seem to share a major common risk factor: diet and nutrition.1 A lingering question, derived mainly from speculation based on the common risk factor, has been whether obese children are at higher risk for dental caries development.2 The results from this analysis suggest that the answer is no. Based on the analysis of 2 consecutive national survey and examination datasets (NHANES III 1988-1994 and NHANES 1999-2002), the authors concluded that there is no evidence to suggest that overweight children are at an increased risk for dental caries. The results even suggested, although not consistent across the 2 datasets, that overweight children actually have reduced risk for dental caries in the permanent dentition compared with normal weight children. Given the limitations in drawing causality from crosssectional data, this analysis actually is an improvement over several previous studies: ie, enhanced statistical power, consistency of the finding over time (sequential analysis), and accounting for confounding such as gender, race/ethnicity, and SES. Although the overall conclusion of this analysis seems valid, it may not be applicable to specific subpopulation groups. Will the association (or lack thereof) between obesity and dental caries be uniform across all subgroups or conditions? The results indicate that the association is not uniform across different time points (1988-94 versus 1999-02), different age groups, and different dentitions. What other factors might influence or modify the association between the 2 conditions, and how? The literature provides no clear
98
answers to these questions. The results from Hong et al3 suggest differential association between caries and obesity among Black and Hispanic children. Marshall et al1 analyzed data of young children from rather homogeneous white families in rural areas and suggested a reverse-U-shape association; ie, children at risk for obesity may have higher caries risk compared with children with normal or overweight. Another question raised from this analysis is whether the findings would have been the same if they analyzed caries frequency (ie, severity) rather than prevalence. In summary, the findings of this analysis provide an overall snapshot view of the association between obesity and dental caries: the association seems flat, or may even be negative. This finding may have clinical implications; a clinician should not automatically assume an elevated caries risk among obese or overweight children. The evidence, however, is far from clear and specific enough for clinical application in individual cases. This relationship between obesity and caries requires further in-depth analyses of various effect modifications on the association, and studies with more rigorous research design. Until more evidence is available, BMI should not be considered in assessment of risk factors for caries diagnosis and treatment planning in children.
REFERENCES 1. Marshall TA, Eichenberger-Gilmore JM, Broffitt BA, Warren JJ, Levy SM. Dental caries and childhood obesity: roles of diet and socioeconomic status. Community Dent Oral Epidemiol 2007;35:449-58. 2. Willerhausen B, Blettner M, Kasaj A, Hehenfellner K. Association between body mass index and dental health in 1,290 children of elementary schools in a German city. Clin Oral Invest 2007;11:195-200. 3. Hong L, Ahmed A, McCunniff M, Overman P, Mathew M. Obesity and dental caries in children aged 2-6 years in the United States: National Health and Nutrition Examination Survey 1999-2002. J Public Health Dent 2008;68:227-33.
REVIEWER Woosung Sohn, DDS, PhD, DrPH Assistant Professor, University of Michigan School of Dentistry Department of Cariology, Restor. Sci. & Endo., 1011 N. University Ave., Ann Arbor, MI 48109 [email protected]
June 2009
ARTICLE ANALYSIS & EVALUATION ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION Caries status and overweight in 2- to 18-year-old US children: findings from national surveys. Kopycka-Kedzierawski DT, Auinger P, Billings RJ, Weitzman M. Community Dent Oral Epidemiol 2008;36(2):157-67.
REVIEWER
Obese or Overweight Children Do Not Have a Higher Risk of Dental Caries SUMMARY Subjects This analysis included data from 2 sequential nationwide surveys, namely the NHANES III (1988-1994) and NHANES 1999-2002. The analysis targeted children ages from 2 to 18 years in each dataset who completed dental examination and height and weight measurement. The NHANES III sample included 10,180 children and NHANES 99-02 included 7568 children.
Woosung Sohn, DDS, PhD, DrPH
Key Risk/Study Factor PURPOSE/QUESTION The authors analyzed nationally representative samples of children (2 to 18 years old) to investigate the relationship between obesity/ overweight and dental caries status.
The key risk factor in this analysis is body mass index (BMI) percentile based on the age and sex-specific 2000 Centers for Disease Control and Prevention (CDC) growth chart. Children’s weight status was defined based on BMI percentile as (1) overweight: at or above 95th percentile, (2) at risk for overweight: at or above 85th percentile and less than 95th percentile, and (3) normal weight: less than 85th percentile.
Main Outcome Measure SOURCE OF FUNDING None
TYPE OF STUDY/DESIGN (Sequential) Cross-sectional study
LEVEL OF EVIDENCE Level 3: Other evidence
STRENGTH OF RECOMMENDATION GRADE Not applicable
J Evid Base Dent Pract 2009;9:97-98 1532-3382/$34.00 Ó 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.jebdp.2009.03.013
The main outcome measure was dental caries experience in the primary (dfs) for 2- to 5-year-old children, and permanent dentition (DMFS) for 12- to 18-year-old children. For 6- to 11-year-old children, caries experience in both primary (dfs) and permanent dentition (DMFS) were recorded. In the analysis, the caries experience measure was dichotomized as either having caries experience (dfs > 0 or DMFS > 0) or having no caries experience (dfs = 0 and DMFS = 0). Examinations for dental caries were conducted based on the modified Radike’s criteria (ie, disease is defined as dentinal cavitated lesion using a sharp #23 sickle-shaped explorer).
Main Results The results from the analyses of 2 sequential cross-sectional datasets (NHANES III 1988-1994 and NHANES 1999-2002) suggest that there is no association between caries experience in the primary dentition and body weight status (normal weight, at risk for overweight, or overweight) among 2- to 5-year-old children in the United States. For older children, the results are not consistent in the 2 nationwide datasets. The results from NHANES III indicate that there is a negative association between caries experience in the primary dentition and body weight status among 6- to 11-year-old children (ie, overweight and at risk for overweight children are less likely to have caries experience in the primary dentition than normal weight children). In the permanent dentition (both 6- to 11- and 12- to 18-year-old children), a negative association is significant only between overweight children and normal weight children. These negative associations, however, are not significant in the NHANES 1999-2002; ie, for children 6 to 11 years of age and 12 to 18 years of age, there are no differences in having caries experience among normal, at risk for overweight, and overweight children.
JOURNAL OF EVIDENCE-BASED DENTAL PRACTICE
Conclusions The authors concluded that there is no evidence to suggest that overweight children are at an increased risk for dental caries based on the analysis of data from NHANES III and NHANES 1999-2002. The authors also suggested, based on some of the NHANES III results, that being overweight may be associated with decreased rates of caries in older children (6 to 18 years old).
COMMENTARY AND ANALYSIS Obesity and dental caries share several common characteristics: both are complex conditions with multiple and multilevel risk factors, and both are more prevalent among low socioeconomic status (SES) and minority children. Furthermore, they seem to share a major common risk factor: diet and nutrition.1 A lingering question, derived mainly from speculation based on the common risk factor, has been whether obese children are at higher risk for dental caries development.2 The results from this analysis suggest that the answer is no. Based on the analysis of 2 consecutive national survey and examination datasets (NHANES III 1988-1994 and NHANES 1999-2002), the authors concluded that there is no evidence to suggest that overweight children are at an increased risk for dental caries. The results even suggested, although not consistent across the 2 datasets, that overweight children actually have reduced risk for dental caries in the permanent dentition compared with normal weight children. Given the limitations in drawing causality from crosssectional data, this analysis actually is an improvement over several previous studies: ie, enhanced statistical power, consistency of the finding over time (sequential analysis), and accounting for confounding such as gender, race/ethnicity, and SES. Although the overall conclusion of this analysis seems valid, it may not be applicable to specific subpopulation groups. Will the association (or lack thereof) between obesity and dental caries be uniform across all subgroups or conditions? The results indicate that the association is not uniform across different time points (1988-94 versus 1999-02), different age groups, and different dentitions. What other factors might influence or modify the association between the 2 conditions, and how? The literature provides no clear
98
answers to these questions. The results from Hong et al3 suggest differential association between caries and obesity among Black and Hispanic children. Marshall et al1 analyzed data of young children from rather homogeneous white families in rural areas and suggested a reverse-U-shape association; ie, children at risk for obesity may have higher caries risk compared with children with normal or overweight. Another question raised from this analysis is whether the findings would have been the same if they analyzed caries frequency (ie, severity) rather than prevalence. In summary, the findings of this analysis provide an overall snapshot view of the association between obesity and dental caries: the association seems flat, or may even be negative. This finding may have clinical implications; a clinician should not automatically assume an elevated caries risk among obese or overweight children. The evidence, however, is far from clear and specific enough for clinical application in individual cases. This relationship between obesity and caries requires further in-depth analyses of various effect modifications on the association, and studies with more rigorous research design. Until more evidence is available, BMI should not be considered in assessment of risk factors for caries diagnosis and treatment planning in children.
REFERENCES 1. Marshall TA, Eichenberger-Gilmore JM, Broffitt BA, Warren JJ, Levy SM. Dental caries and childhood obesity: roles of diet and socioeconomic status. Community Dent Oral Epidemiol 2007;35:449-58. 2. Willerhausen B, Blettner M, Kasaj A, Hehenfellner K. Association between body mass index and dental health in 1,290 children of elementary schools in a German city. Clin Oral Invest 2007;11:195-200. 3. Hong L, Ahmed A, McCunniff M, Overman P, Mathew M. Obesity and dental caries in children aged 2-6 years in the United States: National Health and Nutrition Examination Survey 1999-2002. J Public Health Dent 2008;68:227-33.
REVIEWER Woosung Sohn, DDS, PhD, DrPH Assistant Professor, University of Michigan School of Dentistry Department of Cariology, Restor. Sci. & Endo., 1011 N. University Ave., Ann Arbor, MI 48109 [email protected]
June 2009