Evaluation of Association Between Obesity and Health of Periodontium in the Indian Population - A Randomized Cross-Sectional Study

Introduction

Obesity, defined as body mass index (BMI) greater than 30.0 kg/m² is the fastest growing health-related problem in the world.¹ A common metabolic and nutritional disorder, obesity is an intricate and multifactorial chronic disease that arises from an interaction of genotype and the environment.² The worldwide prevalence of obesity is a considerable source of concern given its potential impact on morbidity, mortality and the cost of health care.³ World Health Organization (WHO) has recognized obesity as a predisposing factor to major chronic diseases ranging from cardiovascular disease to cancer. Obesity has been acknowledged as a noteworthy risk factor for several conditions like hyperlipidemia, diabetes mellitus, hypertension, cholelithiasis, osteoarthritis, respiratory disorders, non-alcoholic fatty liver, cardiovascular and cerebrovascular disease.⁴ Obesity markedly diminishes quality of life by increasing the years of life lost to illness especially among younger age and lower socioeconomic groups.^5-6

Obesity is often associated with increased lipid and blood glucose levels which may have deleterious consequences on the host response leading to alterations in T cells and monocytes/macrophages as well as an increased cytokine production.⁷ Adipose tissue, especially the visceral adipose tissue, is an important reservoir of several bioactive substances known as adipocytokines. They play varied roles such as hormone like proteins (e.g. leptin and adiponectin), classical cytokines (e.g. tumor necrosis factor-α and interleukin-6), proteins involved in vascular hemostasis (e.g. plasminogen activator inhibitor-1, tissue factor), regulators of blood pressure (angiotensinogen), promoters of angiogenesis (e.g. vascular endothelial growth factor), and acute phase respondents (C- reactive peptide).⁸ These may act locally or may be released in circulation where they act as signaling molecules to the liver, muscles and endothelium.

Adipokines modulates the immune system and inflammatory responses in such a manner that it predisposes the host to increased risk of tissue destruction and periodontal disease e.g. TNF-α mediates endotoxin induced injury in various organs including periodontal tissues, thus enhancing periodontal tissue degradation.⁹

Periodontal disease is one of the most common chronic diseases in the world that affects the gingiva and cause damage to the supporting tissues and bone.¹⁰ Various factors related to host, pathogen and environment affect the incidence and the rate of exacerbation of periodontal disease.^11-13 It is a disease of inflammatory origin characterized by a shift in the microbial ecology of subgingival plaque biofilms and the progressive host mediated destruction of tooth supporting structures.¹⁴ Several systemic factors are associated with increased risk of periodontal disease viz. smoking, diabetes, osteoporosis, stress and age.¹⁵

Third National Health and Nutrition Examination Survey (NHANES III) found a positive co-relation between obesity and peridontitis.¹⁶ Based on this, the present study was carried out to scrutinize this hypothesis and to find out if prevalence of periodontitis is greater in obese people than in people of normal weight in adult population in Amritsar district in the state of Punjab, India.

Materials and Methods

Study sample

A total of 200 subjects aged 20-60 years were selected randomly for this study. These subjects were selected using a simple random sampling method from a larger sample representative of people reporting to Sri Guru Ram Das Institute of Dental Sciences and Research in Amritsar in the state of Punjab from January 2022 to April 2022.

Inclusion criteria

• Dentate persons of age 20 years and above.
• Obese patients without history of any systemic disease viz. diabetes, hypertension etc.

Exclusion criteria

• Pregnant women.

All subjects were informed about the nature of the study and verbal consent was obtained.

Clinical variables

Obesity variables

Indicators of obesity were BMI (body mass index) and WC (waist circumference). BMI was calculated by dividing weight (measured in kilograms) by the square of height (measured in meters). The WHO criteria were used in categorizing the subjects into three groups: 1) underweight (≤18.5 kg/m²); 2) normal weight (18.5 to 24.9 kg/m² ); 3) overweight (25 to 29.9 kg/m² ); and 4) obese (≥30 kg/m² ).¹⁷

WC was measured at midpoint between the lower border of the rib cage and the iliac crest by the WHO method.¹⁸ For categorizing the subjects by WC, we used guidelines by WHO. WC cutoff points were >102 cm for males and >88 cm for females.

Periodontal examination

A single examiner performed the periodontal examination. The WHO community periodontal index (CPI)¹⁹ was used to assess periodontal condition. The CPI was scored as follows: 0 = healthy; 1 = bleeding; 2 = supragingival or subgingival calculus with or without bleeding; 3 = a probing depth of 4 to 5 mm; 4 = a probing depth of ≥ 6 mm.

A specially designed CPI probe with 0.5 mm ball tip that met WHO guidelines¹⁹ was used. The whole mouth was divided into six sextants. Examination of first and second molars and two incisors (upper right and lower left) was done as representative of each sextant. A sextant was examined only if it fulfilled the required conditions that there must be ≥2 teeth present, not scheduled for extraction. In case index teeth were not present in a particular sextant which qualified for assessment, then all other remaining teeth were evaluated and the highest score recorded was considered for that sextant. Periodontitis was defined as ≥ “code 3.”

Covariates

The selected variables were age, gender and smoking. The information about smoking was obtained from self-reported questionnaires. According to smoking status, the subjects were divided into three groups: 1) Non-smokers- those who had never smoked; 2) Current smokers- those who smoked currently and had smoked ≥ 100 cigarettes; and 3) Past smokers- those who had smoked 100 or more cigarettes during their life time but were not currently smoking.²⁰ The ethical approval was obtained from ethical committee for research of Sri Guru Ram Das Institute of Dental Sciences and Research and was in agreement with principles embodied in the Helsinki Declaration of 1975, as revised in 2013.

Statistical analysis

Chi-square test was used for the evaluation of significant differences (p <0.05) between groups. Any possible alliance of body mass index and periodontal disease was examined in a series of logistic regression models, and the odds ratio and 95% confidence interval were calculated. The Statistical Package for the Social Sciences (17.0 J for Windows; SPSS Japan, Tokyo, Japan) was used for the statistical analysis.

Results

Two hundred subjects, aged 20 to 60 years were recruited for the study, of which sixty eight percent were females and thirty two percent were males [Table 1]. Thirty eight percent were of normal weight, twelve percent were overweight and fifty percent were in the obese category [Figure 1].

The study samples were stratified into two age groups and the purpose of the present study was to appraise the correlation of BMI and WC with periodontal disease along with role of other confounding factors like age, gender etc.

Out of 200 subjects, 120 (60%) had normal waist circumference while 80 (40%) had high waist circumference according to the WHO criteria. Only six percent of them were current smokers. Prevalence of periodontitis among people enrolled was thirty nine percent.

As the study involved only local population of Amritsar district, the racial differences were negligible and hence are not reported.

A positive association was observed between BMI and periodontitis [Table 2, Figure 2] in both males and females. Statistically significant (p<0.01) higher prevalence of periodontitis was noticed in obese individuals rather than those with normal weight. Out of the total cases of periodontitis in males, 37.5% were in the obese category as compared to only 12.5% in the normal weight category. In case of females, out of the total cases of periodontitis, 68.89% were obese as compared to only 31.11% in the normal weight category.

No significant correlation was noticed between high WC and periodontitis in males [Table 3, Figure 3]. On contrary, in females, a significantly high (p<0.001) correlation was seen between high WC and periodontitis with 68.8% of females with periodontitis having a high WC. 

The univariable analysis [Table 4] showed that BMI and age were significantly associated with periodontitis irrespective of gender, whereas WC showed significant association with periodontitis only in females.

Males of age group 41-60 years had significant odds (2.50) of having periodontitis (p <0.05). Males with normal BMI had significantly less odds (0.25) of not having periodontitis (p <0.05). Whereas overweight and obese males had higher (2.00 and 1.50, respectively) but not significant odds of having periodontitis. No association was noticed between waist circumference and periodontitis in case of males.

Obese females had highly significant odds (3.44) of having periodontitis (p <0.001). Also, females in age group 20-40 years had significantly higher odds (2.17) of having periodontitis (p <0.05). Females with high waist circumference had highly significant odds (6.20) of having periodontitis (p <0.001).

Discussion

This study scrutinized the connection between obesity and the periodontal disease. The results show that obese females have significantly higher susceptibility to periodontitis than those with normal weight (OR= 3.44). A significant positive association was noticed between high waist circumference and periodontitis, only among the females. Since there were very few smokers present in our study, we excluded smoking as a variable in the univariable analysis.

The present study is in harmony with various other studies that also reported a significantly positive association between obesity and periodontitis.^7,9-10,16,21 Al-Zahrani et al., found that the prevalence of destructive periodontal disease is 76% higher among young obese (BMI >30 kg/m2) individuals than in young but normal weight individuals^.21 Shimazaki et al., (2010) reported a significantly lower risk of severe periodontitis in subjects who were lean and had high levels of physical fitness.²² Saito et al., reported a strong alliance between BMI and periodontitis by using community periodontal index of treatment needs (CPITN) in Japanese population.²³ In Korea, Kim et al., found a positive connection between obesity and periodontitis using the WC criteria instead of BMI.¹⁰

In a study by Salekzamani et al. in 2011, 150 males aged 30-60 years were recruited. Among them, 31 had healthy periodontium, 45 were suffering from gingivitis, 39 from initial periodontitis, and 35 had reached the stage of established periodontitis. For the purpose of the study, every subject underwent an evaluation of BMI (body mass index), WC (waist circumference), and body composition parameters (body water, body fat, skeletal muscle and bone mass contents). Statistically significant difference was observed only between the stage of optimum periodontal health and established periodontitis. From the results, it was concluded that periodontal diseases influence the variables (BMI, WC, and body composition parameters) only in severe form. Hence indicative of the substantial association between severe variant of periodontal disease in males and their body composition.²⁴

We found that females belonging to age group 20- 40 years had significantly higher odds (OR=2.17) of having periodontitis than those belonging to age group of 40-60 years. Various other reports observed a positive connection between obesity, cardiovascular and chronic adult diseases in younger age groups.^25-28 Ageing is associated with an increase in body fat mass and this means that some older obese subjects gain weight as part of the ageing process.^29-30 The relationship between obesity and periodontitis could be more evident among younger than older adults because of the various confounding metabolic changes that may occur in later life.⁹

Few reports are available that explain the relationship between obesity and periodontal disease. It has been reported that obese-hypertensive rats are more likely to have periodontitis than normal rats and the periodontal blood vessels of these rats show intimal thickening indicating diminished blood flow.³¹ Recent studies indicate that adipose tissue, especially visceral adipose tissue, is an important organ that secretes several bioactive substances known as adipocytokines, which include tumor necrosis factor –α.^32-33 These may affect periodontal tissues directly. 

Leptin is the best known substance secreted from the adipose tissue. It stimulates the immune system, enhances cytokine production and phagocytosis by macrophages.⁹ Leptin is reported to be present within healthy and marginally inflamed gingival tissues and decreases in concentration as the adjacent probing depth increases.³⁴ Thus, it may play an imperative role in the development of periodontitis.

A recent study by Brownell et al., suggests that obesity levels in both children and adolescents are predictable in light of influential circumstances which encourage elevated consumption of the foods that are high in calories but poor in nutrient levels and discourage physical activity. By implementing the community level health approaches and targeting the situations causing obesity, reversal of the troubling trends can be anticipated.³⁵ This contemporary trend of rise in number of cases of obesity has been aggravated by the ease of availability of very pleasant but calorie-dense food which has occurred in concurrence with low physical activity in existing situation.³⁶

Another study by Bawadi et al., in 2011 showed that a low physical activity level and a poor diet were significantly associated with increased odds of periodontal disease.³⁷ In a study by Modeer et al., (2011) obese subjects exhibited greatly intensified gingival inflammation (p <0.001) with deeper pathological periodontal pockets (>4 mm) (p <0.001) but no incipient alveolar bone loss as compared to the normal weight subjects. Significantly elevated levels of IL-1β (p <0.001) and IL-8 (p=0.002) were also present in Gingival crevicular fluid (GCF) of obese subjects. The study thus suggests of an association between obesity and periodontal disease’s risk indicators in adolescent population, which on extending over a period of time may eventually lead to oral morbidity.³⁸

There are few limitations in this study. We scrutinized the periodontal status of enrolled population by CPI. Although, it is an easier way to evaluate the health of periodontium in community setting, since it examines only representative teeth, some of the deep periodontal pockets may have been overlooked and hence missed. This study also has limitations of small sample size and potential selection bias that may have led to overestimation of risk estimates.

Regardless of the accumulating evidences favoring considerable correlations, it is still doubtful if obesity in reality precedes periodontitis.

This is a preliminary epidemiological study to correlate obesity with periodontitis but prospective cohort studies will be required to address this concern.

Conclusion

This study shows that obese females with a higher waist circumference have significantly elevated chances of suffering from periodontitis as compared to females with normal weight. On the other hand, no similar significant association was observed in males. Bearing in mind the potentially negative outcome of obesity on both general and oral health, all health professionals, including the dental professionals, can provide a significant service to obese patients by educating them about the potential risk of developing periodontal disease and the significance of maintaining optimum oral hygiene. Screening of weight should be a fundamental element of periodontal risk evaluation on a regular basis. 

Conflicts of Interest

Nil