Causal relationship between periodontitis and chronic obstructive pulmonary disease.

CONTEXT: Recently, it has been recognized that oral infection, especially periodontitis, may affect the course and pathogenesis of a number of systemic diseases. An association between periodontal disease and chronic obstructive pulmonary disease (COPD) has been observed. AIMS: The aim of the present study was to evaluate the potential association between periodontal health and COPD and to assess the potential health status of patients with and without COPD. SETTINGS AND
DESIGN: In this observational study, the association between periodontal disease and COPD has been assessed.
MATERIALS AND METHODS: HUNDRED PATIENTS WERE CHOSEN FOR THE STUDY: group A comprising 50 COPD patients and group B consisting of 50 patients without COPD. Gingival Index (GI) and Papilla Bleeding Index (PBI) were used to assess the gingival status. Periodontal indices included Russell's Periodontal Index (PI) and Periodontal Index for Risk of Infectiousness (PIRI), which were assessed in all 100 patients. Analysis of covariance (ANCOVA) was the statistical analysis used.
RESULTS: After eliminating age affects using ANCOVA, the mean indices of all variables between groups were found to be highly significant (P<0.001). The scores were highly significant in COPD group than in non-COPD group.
CONCLUSIONS: The findings of the present study show that there is an association between periodontal disease and COPD. It is suggested that periodontitis is one of the risk factors for COPD.

INTRODUCTION

The relationship between periodontal health or disease and systemic health or disease has given rise to a discipline in Peridontology termed “Periodontal Medicine,” aptly termed and proposed by Offenbacher[1] at the 1996 World workshop in Periodontics. Throughout the history of mankind, it has been believed that diseases and maladies which affect the mouth, such as periodontal disease, can have an effect on the rest of the body. Over the centuries, writings from the ancient Egyptians, Hebrews, Assyrians, Greeks and Romans, have all noted the importance of the mouth in overall health and well-being. Thus, one could say that the concept of linking periodontitis and systemic diseases could be traced back to the beginning of recorded history and medicine.[2]

Certain systemic diseases, such as osteoporosis, diabetes and immune disorders, may increase the risk for periodontal disease.[3] However, until recently, less attention has been devoted to the role of chronic oral diseases on systemic health. It has been hypothesized that oral conditions such as periodontal infections may be risk factors or indicators for important medical outcomes like diabetes mellitus, respiratory diseases like pneumonia and chronic obstructive pulmonary disease (COPD), heart diseases and preterm low birth weight babies [Figures 1 and 2].[45] The recent research increasingly substantiates a role for periodontitis in affecting systemic health, which has brought the term periodontal medicine to the forefront, and as such has fostered a new branch of periodontology. The word periodontal medicine was first suggested by Offenbacher,[3] who defined this term as “a rapidly emerging branch of periodontology focusing on the wealth of new data establishing a strong relationship between periodontal health or diseases and systemic health or disease.”

Figure 1

Possible mechanism of action of infection

Figure 2

Mechanism of tissue destruction in periodontal disease and emphysema

In individuals with periodontitis, bacteria present in the gingival sulcus or the subsequently formed periodontal pockets, may have easy access to the blood vessels. The microorganisms may also enter the lungs by inhalation, but the most common route of infection is aspiration of oropharyngeal secretions. Therefore, it is plausible that oral microorganisms might infect the respiratory tract, causing COPD.

A posse of professionals, group of clinicians and scientists worked for years together to draw a relationship of periodontal diseases and systemic diseases. Yet, the controversy on whether the relation is true or not continues to baffle academia. Therefore, an attempt to find out the relation between periodontal diseases and COPD has been made.

MATERIALS AND METHODS

In this observational study, 100 patients were selected on purposive selection criteria from the Outpatient Department of General Medicine. The patients were in the age range 30–60 years, of whom 50 patients belonged to group A (test group) and 50 belonged to group B (control group). Both the groups comprised age- and sex-matched individuals. Group A comprised 50 patients diagnosed as COPD. Group B comprised 50 patients without disease.

Group A: Inclusion criteria

Fifty patients diagnosed as COPD by the physician

Dentate patients

Age group 30–60 years

Group A: Exclusion criteria

Edentulous patients

If patients had undergone periodontal therapy for last 3 months

Patients on medications (antibiotics) known to influence the periodontal tissues for last 6–8 weeks

Patients with any other systemic diseases

Group B: Inclusion criteria

Fifty patients without respiratory diseases

Dentate patients

Group B: Exclusion criteria

Edentulous patients

If patients had undergone periodontal therapy for last 3 months

Patients on antibiotic therapy for last 6–8 weeks

All the patients’ detailed case history was taken and examined by physician. All the patients underwent routine investigations depending upon their provisional diagnosis.

Respiratory disease/condition

The physician made the diagnosis of respiratory diseases and non-respiratory diseases. A detailed case history, physical examination and investigations like chest X-ray and Pulmonary Function Test, complete blood count, urine examination, and sputum examinations were done. After confirmation of COPD as diagnosis, these patients were taken for the study.

Demographic variables included age, gender, socioeconomic status, frequency of dental visits, and use of oral physiotherapeutic aids, which also have been considered in this study. Lifestyle characteristics examined included history of smoking and alcohol consumption. A thorough medical history of each patient was recorded. In addition, any patient found with other chronic systemic diseases was excluded from the study.

All 100 patients of groups A and B were examined for gingival and periodontal status by recording the following indices:

Gingival Index (GI) (Loe and sillness)[67]

Papilla Bleeding Index (PBI) (Muhlemann's)[8-10]

Periodontal Index (PI) (Russell's)[910]

Periodontal Index for Risk of Infectiousness (PIRI)[11]

The mean values of the respective indices were calculated in both the groups and the potential association of periodontal condition to respiratory status was assessed with the help of statistical package for social science (SPSS) windows version 10.0.

RESULTS

The chi-square test was used to analyze the association between two discrete variables.

The mean values of all indices like G.I, PBI, Russell's Index (RI), and PIRI were compared between the two groups using Student's t test.

COPD patients with mean age of 56.3 ± 3.8 years presented significantly higher P value (<0.001) [Table 1] when compared to patients aged 47.4 ± 4.9 years in the control group. In COPD group, majority of the subjects belonged to low-income group (Rs. <5000/year) and were illiterates. Majority of the patients were males and most of them were chronic smokers and alcoholics. Subjects with COPD had more significant GI and PBI values than the subjects without COPD (GI: 2.01 ± 0.49, P<0.001 and 95% CI 0.81–0.45; PBI: 2.89 ± 0.41, P<0.001 and 95% CI 0.94–0.60). Subjects with COPD were also showing more significant RI and PIRI values. The RI in COPD group was 4.96 ± 0.83 with P< 0.001 and 95% CI was from -1.89 to -1.34, and PIRI in COPD was 5.80 ± 1.79, P< 0.001 and 95% CI was from -3.72 to -2.52.

Table 1

Age distribution of the study population

After eliminating age affects using analysis of covariance (ANCOVA), the mean indices of all variables between groups were found to be highly significant (P< 0.001). The scores were highly significant in COPD group than in non-COPD group.

DISCUSSION

Systemic health has often been closely linked to the state of the oral cavity: Many systemic diseases and conditions have oral manifestations.[3] Therefore, in the recent past, there has been greater concern in understanding the association of periodontal disease with many systemic conditions. Likewise, oral microbiological infections may also affect one's general health status. Indeed, animal- and population-based studies[12] now suggest that periodontal diseases may be linked with systemic diseases including cardiovascular diseases, diabetes, respiratory diseases, adverse pregnancy outcomes and osteoporosis.[13] Better understanding of this correlation will help both the dental and medical professionals to determine the best approach to patient care.

Statistical analysis of the results revealed that subjects with COPD belong to low-income group (i.e. ‘ <5000/year) [Table 2]. Occupationally, majority of the COPD subjects belonged to group 2 (i.e. white-collared workers, small farmers, small shopkeepers, sales representatives and teachers) [Table 3]. Majority of the COPD subjects were illiterates [Table 4] belonging to the lower socioeconomic status [Table 5]. Majority were males [Table 6]. Most of the COPD patients were chronic smokers and chronic alcoholics.

Table 2

Income distribution of the study population

Table 3

Occupational distribution of the study population

Table 4

Educational status of the study population

Table 5

Social status of the study population

Table 6

Gender distribution of the study population

Evaluation of the gingival status parameters revealed that GI and PBI scores had highly significant correlation in the COPD group. GI and PBI scores were highly significant in COPD group than in subjects without COPD. As per the results, the mean value of GI scores in non-COPD group was 1.38 ± 0.42 and in COPD group was 2.01 ± 0.49 [Table 7, Figure 3] (P value <0.001) and a highly significant difference was found between the two groups. The PBI score in non-COPD group was 2.12 ± 0.43 and in COPD group was 2.89 ± 0.41 [Table 8, Figure 4] (P value <0.001) and a highly significant difference was found between the two groups.

Table 7

Comparison of mean gingival index between COPD and non COPD groups

Figure 3

Comparison of Gingival Index in both groups

Table 8

Comparison of papilla bleeding index between COPD and non COPD groups

Figure 4

Comparison of Papilla Bleeding Index in both groups

Evaluation of the periodontal status parameters revealed that RI and PIRI scores had highly significant correlation in the COPD group. These scores were highly significant in the COPD group compared to non-COPD group. As per the results, the mean value of RI scores in non-COPD group was 3.34 ± 0.52 and in COPD group was 4.96 ± 0.83, which denotes a P value of <0.001 which is highly significant [Table 9, Figure 5]. The mean value of PIRI scores in non-COPD group was 2.68 ± 1.17 and in COPD group was 5.80 ± 1.79 (P< 0.001) and a highly significant difference was found between the two groups [Table 10, Figure 6].

Table 9

Comparison of Russell's index between COPD and non COPD groups

Figure 5

Comparison of Russell's Index between the two groups

Table 10

Comparison of periodontal index for risk of infectiousness between COPD and non COPD groups

Figure 6

Comparison of PIRI between two groups

A distinct trend was noted whereby more the severity of periodontal disease, greater was the association with COPD [Table 11, Figure 7]. These results positively correlate with the results obtained by Scannapieco and Genco.[14] Their results suggested that poor oral hygiene and periodontal attachment loss is an independent risk factor for COPD. These results also positively correlate with the results obtained by Scannapieco and Ho[1516] and Xiaojing et al.[17] Their studies also proved that more severe the mean attachment loss, greater is the association with COPD. However, these results are contradictory to the results obtained by Scannapieco et al.,[18] wherein there were no associations noted between the GI, PI and chronic respiratory disease. In addition, these results are contradictory to the results obtained by Scannapieco.[19] His results suggested that no associations were present between the PI and chronic respiratory diseases.

Table 11

Comparison of mean and standard deviation values of periodontal indices by groups

Figure 7

Comparison of all indices between COPD and non-COPD

Many studies[1520] [(large epidemiologic studies like National Health and Nutrition Examination survey – I, II and III (NHANES – I, II and III) and the Veterans Administration of Normative Aging Study (VANAS)] have found compelling evidence that periodontitis may be a risk factor for systemic conditions like COPD. Many bacteriological studies have proved that the same species of microorganisms are present in oral cavity as well as in lung infections. Further longitudinal and interventional studies are required to establish a positive correlation between periodontal health and development of COPD.[16]

The above results suggest that subjects in the COPD group had poorer periodontal health as evidenced by the greater bleeding scores and greater periodontal indices scores when compared to those in the non-COPD group. The results of this study suggest that there may be a possible association between periodontal diseases and COPD.

In the present situation, where one has a highly prevalent (and preventable) condition such as periodontal disease which may act as a risk factor for a highly prevalent outcome such as COPD, even slight elevations in risk, if true, can have major implications. Such associations could also be accountable for the hypothesis that the co-occurrence of COPD and periodontal disease may be due to a common underlying host susceptibility factor. In such a case, periodontal status may serve as a useful risk marker to identify persons at higher risk for COPD.

Lacking demonstration and compelling evidence of temporal relationship between the exposure of interest (periodontal disease) and the outcome of interest (COPD), and the uni-directionality of the biologic mechanisms linking the two conditions, the conclusion from such cross-sectional data is that the association merits investigation using a study design more appropriate to assess directionality and causality. An ideal study design to pursue this question would be a randomized controlled trial in which an intervention to reduce or eliminate oral infection (e.g. plaque control, periodontal treatment) could be tested in regard to the ability to lower the risk of a respiratory disease outcome (e.g. aspiration pneumonia, exacerbation of COPD). Unfortunately, such studies are complex and expensive to undertake, as are large, prospective, well-controlled, cohort studies.

Bacteriological and clinic pathological studies may give accurate results to some extent, but these studies are not cost effective, are technique sensitive and difficult to perform in large populations.

However, yet there is no direct evidence for a causal relationship between periodontal diseases and respiratory diseases. In contrast, there is extensive evidence available indicating that a greater burden of oral infection (e.g. as indicated by plaque accumulation) in a particular susceptible host (e.g. medically compromised elders, ICU patients) may increase the risk for certain community-acquired or nosocomial pneumonias and for exacerbations of COPD.

Simply stated, it may be hypothesized that periodontium may serve as a reservoir for respiratory infection. Such oral systemic associations have been investigated through controlled interventional studies. However, now sufficient evidence exists to justify undertaking such definitive trials. For the perfection and greater accuracy, randomized controlled trials are required in order to address the question of causality and to understand better the biological basis of these epidemiological associations.

From these results, the author puts forward that there may be an association between periodontal disease and COPD. Therefore, periodontitis may act as an individual risk factor for COPD. This study did not include bacteriological examination which may be a limiting factor; also, a long-term follow-up would have better substantiated this study.

Some questions may arise from these results:

If periodontitis is the risk factor of COPD, why are all the periodontitis patients not prone to COPD? In addition, why do not all the COPD patients have periodontitis?

If we treat periodontal diseases, will the risk of COPD reduce?

Could it be possible that persons with COPD are more likely to have periodontal disease?

A positive correlation between poor periodontal health and risk of developing COPD has not been substantiated.

A definite cause and effect relationship has not been established for poor periodontal health.

All these questions have to be answered. Hence, further long-term studies are required for more accurate correlations between these diseases to be proved.

CONCLUSION

The results of the present analysis indicate that periodontal status, as assessed by GI, PBI, RI and PIRI, is associated with an increased risk for COPD. Worse periodontal health status was found to be associated with an increased risk of COPD.

It has been understood that poor oral health (periodontitis) alone is not responsible for COPD, rather poor oral health may work as an adjunct with other factors (such as continued smoking, environmental pollutants, viral infections, allergies and/or genetic factors) to promote the progression and/or exacerbation of COPD. Further longitudinal and interventional, molecular biologic studies will establish the role of oral health in the progression of COPD.

The future of dental practice will be dramatically altered if subsequent research confirms that periodontal disease is a true risk factor for systemic disease and that the initiation and progression of these medical conditions can be reduced by periodontal treatment. Dentists, especially periodontists, may be able to play a significant role in the prevention of respiratory diseases by redoubling their efforts to prevent periodontitis and arresting progression in patients who are already with existing periodontitis, which altogether will improve the quality of life in patients with periodontitis and COPD.

Presently, the major rationale for the treatment of periodontal disease is to prevent progression of the disease to preserve the dentition. The above discussion points out the potential impact of periodontal disease on systemic health. In future, an additional rationale for periodontal therapy may be to prevent untoward effects on systemic health. It is appropriate to conclude that the maintenance of oral health should receive topmost priority for leading a healthy and qualitative life.