Obesity is a chronic disease with the global epidemic spread. The worldwide prevalence of obesity is a considerable source of concern given its potential impact on morbidity, mortality, and cost of health care. The World Health Organization (WHO) has recognized obesity as a predisposing factor to measure chronic diseases ranging from cardiovascular diseases to cancer. Once considered a problem only in wealthy countries, the WHO estimates show that overweight and obesity are now dramatically on the rise in low- and middle-income countries. The disturbing sequelae of this increased trajectory of overweight populations are the parallel increases in chronic diseases that are comorbidities of obesity. Primary health-care providers, including dental professionals, are well positioned to address this public health problem at the patient level. Dental professionals must be aware of the increasing numbers of the obese patients and of the significance of obesity as a multiple risk factor syndrome for oral and overall health. Thus, it seems that dental health is becoming a global health concern and further, multinational and cultural studies are needed. Although the relationship between obesity and periodontitis needs further investigation, dentist should counsel obese individuals regarding the possible oral complications to diminish morbidity for such individuals.
Keywords: Body mass index, obesity, periodontal disease
Obesity is a chronic disease with global epidemic spread. The worldwide prevalence of obesity is a considerable source of concern given its potential impact on morbidity, mortality, and cost of health care. The World Health Organization (WHO) has recognized obesity as a predisposing factor to measure chronic diseases ranging from cardiovascular diseases (CVDs) to cancer. Once considered a problem only in wealthy countries, the WHO estimates show that overweight and obesity are now dramatically on the rise in low- and middle-income countries. The WHO estimates that over one billion people are overweight globally and that if current trends continue, this number will increase to 1.5 billion by 2015. This is due to a number of factors including a global shift in diet and a trend toward decreased physical activity due to the sedentary nature of modern work and transportation and increasing urbanization. The disturbing sequelae of this increased trajectory of overweight populations are the parallel increases in chronic diseases that are comorbidities of obesity. According to the WHO, obesity can be defined as an abnormal or excessive level of fat accumulation that may impair health. Like many chronic diseases, obesity has significant associated morbidity, mortality, and economic impact and is largely preventable. Primary health-care providers, including dental professionals, are well positioned to address this public health problem at the patient level. It is increasingly evident that the dental profession is a stakeholder in the weight status of its patients and can be part of a coordinated effort to prevent and intervene in obesity problem. In 2010, the WHO reported that approximately 43 million children younger than 5 years were overweight and that the distribution was no longer heavily skewed toward high-income countries. Nearly 35 million overweight children are part of the developing world and 8 million are in developed nations. The same report states that 65% of the world’s population live in countries where overweight and obesity kill more people than underweight conditions. The onset of Type 2 diabetes (DM) in young children aged 6 to 11 has doubled in past 20 years. Internationally, it was estimated in 2008 that 1.5 billion adults, aged 20 and older, were overweight. Of these, over 200 million men and nearly 300 million women were obese. It was concluded that more than 1 in 10 of the global adult population is considered obese, a trend that has developed in the past decade. Demographically, 13.9% of people meet the adult classification of obesity with a body mass index (BMI) of ≥30. Furthermore, a study by Ritchie et al. found that a child who was overweight at any one point during the elementary school years was 25 times more likely to be overweight at age 12 than a child who was never previously overweight. It is predicted that 70% of overweight children become obese adults with all the chronic disease implications attached which underscores the importance of early intervention efforts. The National Health and Nutrition Examination Survey (NHANES) results from 2009 to 2010 found that more than one-third of adults were obese and there were no significant differences found between genders.
BMI is defined as an individual’s body mass divided by the square of his or her height. The formulae universally used in medicine produce a unit of measure of kg/m 2.
BMI = Mass (kg)/(height [m])2
The WHO regards a BMI <18.5 as underweight and may indicate malnutrition, an eating disorder, or some other health problems, while BMI >25 is considered overweight and >30 is considered obese. These ranges of BMI values are valid only as statistical categories.
Body mass index for children
Overweight and obesity are defined differently for children and teens than for adults. Children are still growing and boys and girls mature at different rates. BMIs for children and teens compared their heights and weights against growth charts that take age and sex into account recognized as BMI-for-age percentile. A child or teen’s BMI-for-age percentile shows how his or her BMI compared with other boys and girls of the same age. Instead of set thresholds for underweight and overweight, the BMI percentile allows comparison with children of the same sex and age. A BMI, that is, less than the 5th percentile is considered underweight and above the 95th percentile is considered obese for people 20 and under. People under 20 with a BMI between the 85th and 95th percentile are considered to be overweight.
Calculations and interpretation of BMI: BMI is calculated the same way for both adults and children. The calculation is based on the formulae shown in [Table 1].
Health consequences of obesity on general health
Overweight individuals are at increased risk for many diseases and health conditions including hypertension, dyslipidemia (for example, high low-density lipoprotein cholesterol, low high-density lipoproteins cholesterol, or high levels of triglycerides), Type 2 DM, coronary heart disease, stroke, gallbladder disease, osteoarthritis, sleep apnea and respiratory problems, and some cancers (especially endometrial, breast, and colon). Moreover, obesity also has psychological, social, and economical as well as oral health consequences. The only positive effect of obesity is a reduced risk of developing premenopausal breast cancer and osteoporosis in females. Obesity is a systemic disease that predisposes to a variety of comorbidities and complications that not only affect the overall health but also influence oral health.
The most common health consequences of obesity on oral health include obesity which is related to several aspects of oral health, such as caries, periodontitis, and xerostomia. In addition, obesity may have implications for the dental treatment plan. Children who are obese and overweight prefer sweet and fatty foods more frequently compared to children with normal weight. Hence, there is higher prevalence of dental caries in overweight and obese children in both the primary and permanent teeth. Elevated BMI is associated with an increased incidence of permanent molar interproximal caries. Several recent studies suggest that periodontitis occurs more frequently in obese individuals than in individuals with a normal body weight. The obese individuals exhibited significantly greater mean pocket depth and a higher percentage of sites exhibiting visible plaque. Obesity has emerged as a risk indicator of periodontal disease and studies have reported that individuals with periodontitis had higher blood pressure than individuals without periodontitis. Furthermore, many studies have reported that periodontitis is more prevalent in persons with diabetes and that individuals with periodontitis have abnormal lipid metabolism. Recently, obesity has emerged as one of the major risk indicators of periodontal disease, and conversely, the remote effects of periodontal disease on various systemic diseases have been proposed. Among the systemic health disorders, Type 2 DM and CVD are established obesity-related diseases. If obesity is a true risk factor for periodontal disease, the association among periodontal disease, obesity, and Type 2 DM or CVD must be very complex because each is a confounding factor for the other. In addition, several studies have suggested that periodontal disease affects both glucose and lipid metabolism which are themselves very important factors in the development of both Type 2 DM and CVD. Hormonal changes in the obese patients may affect mineral metabolism. The metabolic changes caused by obesity that have an impact on bone growth also affect tooth eruption. Children with a high BMI had higher eruption rates. There is a well-described connection between periodontal disease and diabetes with implications that the relationship may be bidirectional. Periodontal disease and obesity are associated with inflammatory stress and increased production of pro-inflammatory cytokines. Clearly, these associations should be the reasons for the dental profession to intervene in the rise of obesity. There are various methods to measure body fat which includes skin fold thickness measurements, underwater weighing, bioelectrical impedance, dual-energy X-ray absorptiometry scans, and isotope dilution methods. However, these methods are not always readily available and they are either expensive or need highly trained personnel. Furthermore, many of these methods can be difficult to standardize across observers or machines complicating comparisons across studies and time periods. Obtaining BMI and BMI percentile measurements can be a feasible addition to the dental protocol as it is noninvasive and requires a small time commitment and minimal cost. Accepting the premise that weight status is associated with oral health, weight screening, obesity prevention, and intervention in dental offices can be advocated as part of the comprehensive dental assessment and treatment. Calculating BMI is one of the best methods for population assessment of overweight and obesity. The BMI or Quetelet Index is actually a proxy for human body fat based on an individual’s weight and height. Because calculation requires only height and weight, it is inexpensive and easy to use for the clinicians. It is a fairly reliable indicator of body fat for most adults. Numerous research studies have related BMI, especially the degree of overweight to an increased risk of developing various diseases as well as premature death. Given the tremendous increase in the prevalence of obesity, dental professionals should promote a healthy diet not only to prevent dental decay but also to reduce the risk of obesity. In the future preventive programs, the importance of nutrition should not only be emphasized with respect to general diseases but also with regard to carious lesions, periodontal diseases, oral cancers, and various other oral diseases. Dental professionals should participate in multidisciplinary medical teams managing obese individuals. Obesity is a complex disease and its relationship to oral health has been realized in recent years, and therefore, the purpose of the study was to undertake a systematic review of the relationship between BMI and oral health.
Having multifactorial causes, obesity is largely attributed to the systemic energy imbalance created by excessive caloric intake and inadequate levels of physical activity. Since the 1970s, diets have shifted toward processed foods and beverages. Furthermore, the advent of new technologies has allowed for markedly more sedentary lifestyles. Some of the key factors associated with obesity risk include socioeconomic factors, minority status, geographic location, access to education, cultural beliefs, and genetic influences.,
Burden of disease
Obesity has both physical and psychological complications. Physiologically, it increases the risk of Type 2 DM, sleep apnea, orthopedic complications, certain cancers, periodontal disease, high blood lipids, hypertension, and other cardiovascular risk factors., A recent study indicates that obesity may affect children from birth linking maternal obesity and diabetes with autism spectrum disorders and development delays. Psychosocially, obesity may have a long-term negative impact leaving the patient vulnerable to the development of depression, anxiety, social isolation, discrimination, a lower quality of life, and stigmatism. It has also been associated with unemployment, absenteeism, and the potential for lower wages in comparison with nonobese employees.
Body mass index and periodontal disease
Overweight and obesity are increasing as health problems at global level. Developed and developing countries are facing an obesity epidemic with various health consequences. Few studies have addressed the relationship between obesity and periodontal health. An epidemiological study revealed that obesity is an independent risk factor for periodontal disease. Obesity and Type 2 DM were associated with many metabolic disorders including insulin resistance, dyslipidemia, hypertension, and atherosclerosis. Chronic subclinical inflammation has been declared a part of the insulin resistance syndrome. The study hypothesized that periodontal disease is one such subclinical inflammation. It summarized the current knowledge supporting this concept primarily based on the data obtained from other studies and proposed a new concept that periodontal disease should be considered as part of the insulin resistance syndrome. The global obesity epidemic has been described by the WHO, 2002 as one of the most blatantly visible but yet, most neglected, public health problems that threatens to overwhelm both more or less developed countries. There is a concern for public health as obesity is, now, the sixth most important risk factor contributing to disease worldwide and increased level of obesity may result in a decline in life expectancy in the future. Besides being a risk factor for CVD, certain cancers, and Type 2 DM, obesity has also been suggested to be a risk factor for periodontitis. Obesity may be considered as a low-grade systemic inflammatory disease. Obese children and adults have elevated serum levels of C-reactive proteins (CRPs), interleukin-6, tumor necrosis factor-alpha, and leptins which are known as markers of inflammation and are closely associated with chronic inflammatory diseases. Therefore, these findings indicate rationalized bases for association between obesity and periodontal disease which is also an inflammatory disease resulting from a complex interaction between pathogenic microbes and the host immune response. Saito et al. used the community periodontal index of treatment needs and reported a strong association between BMI and periodontal disease. In the United States, where obesity has a high prevalence, 30% of the individuals with periodontitis were found to be obese as against 12% of the periodontally healthy individuals. The obese individuals exhibited significantly greater mean pocket depth and a higher percentage of sites exhibiting visible plaque. The relationship between obesity and periodontitis seems to be affected by both gender and age. In an adult Brazilian population, obese females showed an 80% higher chance of having periodontitis than females of normal weight. No significant association was found between periodontitis and obesity among males, however, in this population. Analyses of data from the third NHANES demonstrated that in obese individuals aged 18–34 years, periodontitis was found 76% more frequent than in age-matched individuals with a normal body weight. In the middle and older age groups, no significant association was found between body weight and periodontal diseases. Under the age of 40 years, radiographic alveolar bone loss occurred significantly more frequently among obese than the nonobese individuals while over the age of 40 years, no difference was observed. The association between obesity and alveolar bone loss was stronger among females than males. The location of fat accumulation also plays a role since the increase in visceral fat is more important for the increase in clinical attachment level (CAL) and mean probing depth (PD) than the increase in BMI. Obesity appears to be a condition of relative leptin resistance with an elevated circulating level of leptin reported due to an enlarged fat mass. In periodontitis, there is a significant negative correlation between gingival crevicular fluid (GCF) and serum leptin concentration and these changes are significantly associated with increasing clinical attachment levels (CAL). A decreasing leptin level in GCF and gingival tissue is associated with a more deteriorated periodontal status. In adults, the mean PD was 3.1 times more likely to occur in overweight and 5.3 times more likely to occur in obese adults than in normal healthy weight adults with higher levels of the periodontal pathogen, Tannerella forsythia, found more frequently in obese individuals. At a simplistic level, the adipocytes of fat tissue which are surprisingly active in metabolic regulation produce both anti-inflammatory and pro-inflammatory mediators. The inflammatory mediators released from periodontal disease enhance the systemic inflammatory state. Periodontal therapy can reduce systemic inflammatory markers. For example, CRP is reduced by periodontal treatment which also has been shown to reduce serum levels of pro-inflammatory cytokines, leptin, and interleukin-6. However, this effect is nullified by the production of similar cytokines by the large number of adipocytes in obese individual. Both diabetes and obesity are accentuated by periodontal disease. GCF levels of pro-inflammatory cytokines, tumor necrosis factor-alpha, increase with BMI and metabolic syndrome and have been shown to be more prevalent in patients with radiographic evidence of periodontal bone loss. On acknowledging the common risk factors of obesity and periodontal disease, the converse, however, has not been adequately answered. Almost all studies conducted are cross-sectional, for which one cannot determine the directionality of association. The possibility that periodontal disease contributes to obesity is suggested by a prospective study that indicated that obesity develops more frequently in patients with periodontal pockets. In this study, 1023 adults were selected who were not obese and 205 had periodontal pockets. Four years later, 22 (10.7%) of those who had pockets were obese as compared with 6.2% who did not have pockets. An odds ratio of 1.7 indicated that it is almost twice as likely to develop obesity if patients have periodontal disease at the outset. Both periodontal disease and obesity are associated with inflammatory stress and increased production of pro-inflammatory cytokines. Although an association seems to have been well-established, there is no basis to recommend differences in dental treatment planning for obese patients; however, there is every reason to think that the dental professionals should be ready to participate in a weight management program for the overweight dental patients who may be adversely affected by their oral health status.
It has been demonstrated that specific repeated messages from multiple resources are more likely to promote behavioral change than single source message. Primary care physicians and pediatricians are well equipped to address the obesity issue. The American Academy of Pediatrics recommends that the health-care providers should encourage healthy eating patterns and routine physical activity and discourage TV and video time by providing families with education and anticipatory guidance. However, evidence suggests that busy providers do not adequately follow these recommendations. Several studies have found that the detection of obesity during routine medical appointments is low and time constraints limit how much a clinician is willing or able to discuss with patients. Tools targeting specific behaviors may be helpful. Dental professionals are in a good position to be able to supplement and reinforce the information received in the medical setting as well as to initiate the conversation. Travares and Chomitz developed and tested the feasibility of a dental office-based tool for children targeting obesity risk behaviors. The healthy weight intervention based on the concepts of motivational interviewing was designed for children of all weights and requires approximately 10 min during the routine hygiene visit. Using standard, evidence-based recommendations for improving obesity risks, this preventive intervention does not require specialized training. The dental team is in a unique and favorable position to offer healthy weight intervention and obesity prevention. Most healthy patients visit dental professionals more frequently than a physician on an annual basis. Children and adolescents, in particular, follow the paradigm or annual medical and semiannual dental visits potentially allowing for twice the annual frequency of any intervention. In addition, it is already a standard practice for the dental professionals to promote dietary habits that avoid calorie and sugar-dense foods and beverages for caries prevention. They can easily expand their counseling to emphasize the implications of these dietary practices, in addition, to the positive effects of physical activity and other lifestyle changes on both oral and systemic health. For patients with suspected weight issues, the dentist can work alongside pediatricians, family physicians, and dieticians by providing referrals. Some dental settings, particularly, pediatric dental practices, already measure weight and height for other purposes, particularly for calculating dosages for local and general anesthesia. Obtaining BMI and BMI percentile measurements can be a feasible addition to the dental protocol as it is noninvasive and requires a small time commitment and minimal cost. Accepting the premise that weight status is associated with oral health, weight screening, obesity prevention, and intervention in dental offices can be advocated as part of the comprehensive dental assessment and treatment. There are strong links between obesity and oral health, particularly, with respect to diabetes and periodontal disease. Decreasing obesity risks through diet and lifestyle changes can have a positive impact on oral as well as systemic health. It is important for the dental team to consider all the key domains of obesity risk behaviors such as physical activity, screen time, and meal patterns, not only the diet.
Dental professionals must be aware of the increasing numbers of the obese patients and of the significance of obesity as a multiple risk factor syndrome for oral and overall health. Both obesity and dental caries have common determinants and require a comprehensive, integrated management approach by multidisciplinary medical teams. Dental professionals should promote healthy diets not only to prevent dental caries but also to reduce the risk of childhood obesity. Thus, it seems that dental health is becoming a global health concern, and further, multinational and cultural studies are needed. Although the relationship between obesity and periodontitis needs further investigation, dentist should counsel obese individuals regarding the possible oral complications to diminish morbidity for such individuals.
Dental professionals have a crucial role in the prevention and detection of many oral and systemic diseases because of their diagnostic and screening abilities as well as the frequency of patient visits. These invaluable skills and practice paradigms should be considered as part of the equation to solve one of the largest public health concerns of our time: the obesity epidemic. At present, the United States and many other nations are in the midst of this epidemic and its resulting implications. Chronic diseases, particularly diabetes and CVD, are the result of obesity. There is a well-described connection between periodontal disease and diabetes with implications that the relationship may be bidirectional. Periodontal disease and obesity are associated with inflammatory stress and increased production of pro-inflammatory cytokines. Clearly, these associations should be the reasons for the dental professionals to intervene in the rise of obesity. The rise of obesity and Type 2 DM in children is also of great concern. Once again, the dental profession can play a role in raising awareness of overweight status as well as obesity risk behaviors. Ultimately, a health condition as prevalent and serious as obesity must be approached by a concerted and collaborative effort of many disciplines and organizations. The dental profession should include itself in this collaboration using the tools and education opportunities available. Although the connection between oral health and obesity is critical to understand, it should not be the sole motivating factor for taking action. As Glick stated in his appeal to raise the awareness of the dental profession with respect to obesity, direct participation in changing this health problem will not be simple, but is this not a challenge we should consider?
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