Indexed in MEDLINE, SCI & KoreaMed
pISSN 1011-8934   eISSN 1598-6357
Open Access, Peer-reviewed, Weekly
    J Korean Med Sci. 2023 Aug 07;38(31):e241. English.
    Published online Jul 19, 2023.
    https://doi.org/10.3346/jkms.2023.38.e241
    © 2023 The Korean Academy of Medical Sciences.
    Original Article

    Association Between Oral Health and Airflow Limitation: Analysis Using a Nationwide Survey in Korea

    Sun-Hyung Kim,1,* Seonhye Gu,2,* Jung-Ae Kim,3 YoHan Im,4 Jun Yeun Cho,1 Youlim Kim,5 Yoon Mi Shin,1 Eung-Gook Kim,6 Ki Man Lee,1 Kang Hyeon Choe,1 Hyun Lee,7 and Bumhee Yang1
      • 1Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Chungbuk National University Hospital, Chungbuk National University College of Medicine, Cheongju, Korea.
      • 2Department of Epidemiology and Health Informatics, Korea University, Seoul, Korea.
      • 3Department of Conservative Dentistry, Chungbuk National University Hospital, Cheongju, Korea.
      • 4Department of Internal Medicine, Chungbuk National University Hospital, Cheongju, Korea.
      • 5Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Korea.
      • 6Department of Biochemistry, Chungbuk National University College of Medicine, Cheongju, Korea.
      • 7Division of Pulmonary Medicine and Allergy, Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Korea.
    • Address for Correspondence: Bumhee Yang, MD, PhD. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Chungbuk National University Hospital, Chungbuk National University College of Medicine, 776 1sunhwan-ro, Seowon-gu, Cheongju 28644, Republic of Korea. Email: ybhworld0415@gmail.com
      Address for Correspondence: Hyun Lee, MD, PhD. Division of Pulmonary Medicine and Allergy, Department of Internal Medicine, Hanyang University College of Medicine, 222-1 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea. Email: namuhanayeyo@hanyang.ac.kr

      *Sun-Hyung Kim and Seonhye Gu contributed equally to this work as first author.
    Received November 16, 2022; Accepted April 03, 2023.

    This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

    Abstract

    Background

    Although poor oral health is a common comorbidity in individuals with airflow limitation (AFL), few studies have comprehensively evaluated this association. Furthermore, the association between oral health and the severity of AFL has not been well elucidated.

    Methods

    Using a population-based nationwide survey, we classified individuals according to the presence or absence of AFL defined as pre-bronchodilator forced expiratory volume in 1 second/forced vital capacity < 0.7. Using multivariable logistic regression analyses, we evaluated the association between AFL severity and the number of remaining teeth; the presence of periodontitis; the Decayed, Missing, and Filled Teeth (DMFT) index; and denture wearing.

    Results

    Among the 31,839 participants, 14% had AFL. Compared with the control group, the AFL group had a higher proportion of periodontitis (88.8% vs. 79.4%), complete denture (6.2% vs. 1.6%), and high DMFT index (37.3% vs. 27.8%) (P < 0.001 for all). In multivariable analyses, denture status: removable partial denture (adjusted odds ratio [aOR], 1.12; 95% confidence interval [95% CI], 1.04–1.20) and complete denture (aOR, 1.52; 95% CI, 1.01–2.05), high DMFT index (aOR, 1.13; 95% CI, 1.02–1.24), and fewer permanent teeth (0–19; aOR, 1.32; 95% CI, 1.12–1.52) were significantly associated with AFL. Furthermore, those with severe to very severe AFL had a significantly higher proportion of complete denture (aOR, 2.41; 95% CI, 1.11–3.71) and fewer remaining teeth (0–19; aOR, 2.29; 95% CI, 1.57–3.01).

    Conclusion

    Denture wearing, high DMFT index, and fewer permanent teeth are significantly associated with AFL. Furthermore, a reduced number of permanent teeth (0–19) was significantly related to the severity of AFL. Therefore, physicians should pay attention to oral health in managing patients with AFL, such as chronic obstructive pulmonary disease.

    Graphical Abstract

    Keywords
    Oral Health; Chronic Obstructive Pulmonary Disease; Airflow Limitation; DMFT Index

    INTRODUCTION

    Chronic obstructive pulmonary disease (COPD) is defined as a preventable and treatable airway disease characterized by airflow obstruction due to an enhanced chronic inflammatory response within the airways.1 COPD causes substantial morbidity and mortality, and due to the aging of the population, the economic burden of COPD is continuously increasing.2, 3 Smoking is a known major cause of COPD, and, like noxious particles or gases, causes an inflammatory response in the lungs that leads to airway damage and destruction of the lung parenchyma. This inflammatory response involves not only the airways, but also other chronic diseases such as cardiovascular, metabolic, and other inflammatory comorbidities.4, 5, 6, 7

    Poor oral health (e.g., periodontal disease, dental caries) is a common comorbidity in individuals with COPD.8, 9 For example, poor dental and periodontal health was shown to increase the risk of developing COPD.10 Periodontal diseases can also increase the risk of acute COPD exacerbations by increasing the risk of lower respiratory tract infections.11 Furthermore, edentulous individuals with COPD were shown to be at an increased risk of hospitalization and mortality.12 However, most previous studies have evaluated the association between a specific condition of poor oral health (e.g., periodontitis) and COPD, and few studies have comprehensively evaluated the association between general oral health (including periodontitis, dental caries, denture wearing, number of existing permanent teeth, and tooth brushing habits) and COPD.11, 13, 14 Furthermore, the association between oral health and the severity of COPD has not been well elucidated.12 Therefore, this study aimed to evaluate the association between poor oral health and airflow limitation (AFL), particularly in terms of the severity of AFL.

    METHODS

    Study population

    The Korea National Health and Nutritional Survey (KNHANES) is a population-based nationwide survey to assess the health and nutritional status of the noninstitutionalized population of Korea conducted by the Korea Centers for Disease Control and Prevention (KCDC). We used data from the KNHANES IV (2007–2009), V (2010–2012), VI (2013–2015), VII (2016–2018), and VIII (2019). The KNHANES analyses are periodically conducted to assess Korea’s health and nutritional status. Thus, the KNHANES is a nationally representative cross-sectional study conducted by KCDC. The study population was investigated based on a stratified multi-stage sampling method. During the 12 years, 57,417 participants aged 40 years or older underwent pulmonary function tests. Of these, participants with missing weighted variables or pulmonary function variables (n = 25,578) were excluded, and 31,839 individuals were included in the analysis. Of the eligible individuals, we allocated participants to one of two groups according to the presence or absence of AFL (pre-bronchodilator forced expiratory volume in 1 second [FEV1]/forced vital capacity [FVC] < 0.7) (Fig. 1).15 Since post-bronchodilator spirometry was not performed in KHANES, AFL was defined using pre-bronchodilator spirometry. The spirometry equation used in the KHANES data is a Korean spirometry standard equation that meets the requirements recommended by the American Thoracic Society.16, 17

    Fig. 1
    Flow chart of subjected participants. AFL was defined as pre-bronchodilator forced expiratory volume in 1 second/forced vital capacity < 0.7.
    KNHANES = Korea National Health and Nutritional Survey, AFL = airflow limitation.

    Classification of severity of AFL

    The exposure was AFL, and the severity of AFL was classified as mild (FEV1 ≥ 80% predicted), moderate (50% ≤ FEV1 < 80% predicted), or severe to very severe (FEV1 < 50% predicted).18

    The measurement of oral health

    Oral health conditions were evaluated using the number of remaining teeth, presence of periodontitis, Decayed, Missing, and Filled Teeth (DMFT) index, and denture use.

    The number of existing natural teeth was investigated by a dentist trained in the examination criteria of the National Oral Health Survey. Of the 28 teeth excluding the third molars, the number of existing natural teeth was calculated by excluding teeth that had been lost due to caries, those lost for reasons unrelated to caries, and those with unerupted surfaces. Since previous studies suggested that people cannot chew foods when they have more than 20 teeth missing, which is known as functional dentition,19, 20 the number of existing natural teeth was categorized into one of three groups as follows: 0–19, 20–27, and 28.9, 21

    The World Health Organization (WHO) community periodontal index (CPI) was used to evaluate periodontitis.22 Based on the periodontal pocket measurements, the periodontal status was classified as Code 0 (normal), Code 1 (bleeding periodontal tissue), Code 2 (presence of calculus), Code 3 (shallow periodontal pocket [> 3.5 mm]), or Code 4 (deep periodontal pocket [> 5.5 mm]). The index tooth numbers were 11, 16, 17, 26, 27, 31, 36, 37, 46, and 47 according to the World Dental Federation (FDI) system.23 The CPI probe was used according to the WHO guideline.22 Codes 1 and 2 were classified as normal, and Codes 3 and 4 were classified as periodontitis.

    The DMFT index is the sum of an individual’s decayed, missing, and filled permanent teeth.24 The DMFT index has been used since the 1930s as a method for evaluating caries and is one of the simplest and most commonly used indicators in epidemiological investigations.25 The DMFT index was allocated into tertiles designated as 0–4, 5–9, and 10 or more. Denture use was classified into the group without dentures, the group with partial dentures, and the group with full dentures. Regarding habits related to periodontal diseases and oral health, the frequency of daily tooth brushing (categorized as ≤ 2 times/day or ≥ 3 times/day) and the history of dental clinic visits in the last year were evaluated.

    Other measurements

    Body mass index (BMI), calculated as weight in kilograms divided by height in meters squared, was categorized according to Asian-specific criteria: underweight (< 18.5 kg/m2), normal weight (18.5–22.9 kg/m2), overweight (23–24.9 kg/m2), and obese (25.0–29.9 kg/m2).26 Individuals who consumed more than 30 g/day of alcohol were considered heavy drinkers.

    Occupation type was categorized into one of five groups according to the 6th Korean Standard Classification of Occupation: manager, professional, office worker; service or sales worker; agriculture or fishery worker; skilled labor or machine operator; and manual laborer.27

    Comorbidities (pulmonary tuberculosis, asthma, cardiovascular disease including myocardial infarction or angina, osteoporosis, arthritis, and depression) were defined based on self-reported physician diagnosis.4, 14, 28, 29 Diabetes mellitus (DM) was defined as a fasting blood glucose concentration ≥ 7 mmol/L, the current use of anti-diabetic medications, or a self-reported physician diagnosis of DM.30 Hypertension was defined as a self-reported physician diagnosis, the use of antihypertensive medication, a systolic blood pressure ≥ 140 mmHg, or a diastolic blood pressure ≥ 90 mmHg.31 Dyslipidemia was defined as a serum total cholesterol concentration ≥ 6.22 mmol/L, a fasting triglyceride concentration ≥ 2.26 mmol/L, use of lipid-lowering medications, or a self-reported physician diagnosis of dyslipidemia.32

    Statistical analysis

    All analyses were performed using survey commands in STATA version 15.1 (StataCorp LP, College Station, TX, USA) to account for the complex sampling design and survey weights. All data are presented as weighted percentages with standard errors for categorical variables. Data were compared using Student’s t-test for continuous variables and Pearson’s χ2 test for categorical variables. To evaluate the association between oral health and AFL, multivariable logistic regression analyses were performed. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated after adjusting for potential confounding factors. All analyses were adjusted for age, sex, BMI group (underweight, normal, overweight, or obese), smoking status (never, current, or ex), and comorbidities (pulmonary tuberculosis, asthma, DM, hypertension, dyslipidemia, cardiovascular disease, osteoporosis, osteoarthritis or rheumatoid arthritis, depression). All tests were two-sided, with P values < 0.05 considered to be statistically significant.4

    Ethics statement

    The study protocol was approved by the Institutional Review Board of Chungbuk National University Hospital (application No. 2022-02-017). The KNHANES was approved by the relevant Institutional Review Boards; and written, informed consent was provided by all participants.

    RESULTS

    Study population

    The characteristics of the study population were summarized in Table 1. Of the 31,839 participants, approximately 14% (n = 4,477) had AFL (AFL group), while 86% (n = 27,362) did not (control group). Compared with the control group, the AFL group had a higher mean age (64.7 years vs. 54.8 years), a higher proportion of male participants (72.9% vs. 44.3%), a lower BMI (23.6 kg/m2 vs. 24.3 kg/m2), a higher proportion of smokers (68.6% vs. 40.9%), and a higher proportion of heavy drinkers (16.7% vs. 14.3%; P < 0.05 for all variables). Regarding socioeconomic characteristics, the AFL group had lower family income and a lower level of education than the control group (P < 0.001 for all variables). In addition, the proportion of participants working as service/sales workers was lower in the AFL group, while the proportion of participants working as skilled labor/machine operators was higher (P < 0.001). Regarding comorbidities, the AFL group had a higher proportion of asthma (8.7% vs. 1.9%), pulmonary tuberculosis (11.0% vs. 4.1%), DM (21.3% vs. 14.5%), hypertension (49.9% vs. 37.0%), and cardiovascular disease (6.7% vs. 3.7%) than the control group (P < 0.05).

    Table 1
    Characteristics of the study population

    Comparison of oral health between the AFL and control groups

    The comparison of oral health between the AFL and control groups is summarized in Table 2. Compared with the control group, the AFL group had a lower frequency of tooth brushing (62.4% vs. 52.9%, ≤ 2 times per day) but a higher proportion of periodontitis (88.8% vs. 79.4%), complete dentures (6.2% vs. 1.6%), and high DMFT index (37.3% vs. 27.8%; P < 0.001 for all variables). The number of permanent teeth was significantly lower in the AFL group than in the control group (15.2% vs. 35.5% in 28 permanent teeth; P < 0.001). However, the frequency of dental visits in the previous year did not differ between the two groups.

    Table 2
    Comparison of oral health between the AFL and control groups

    Association of oral health status with AFL severity

    The distribution of oral health according to the severity of AFL is shown in Fig. 2. As the severity of AFL increased, the number of permanent teeth decreased (P for trend < 0.001), whereas the proportions of high DMFT index and complete dentures increased (P for trend < 0.001). In contrast, there was no significant difference in the frequency of tooth brushing, or the prevalence of periodontitis based on the severity of AFL.

    Fig. 2
    Distribution of dental status in subjects with AFL according to the severity. (A) Natural teeth. (B) DMFT index. (C) Periodontitis. (D) Frequency of toothbrushing. (E) Denture Status. AFL was defined as pre-bronchodilator forced expiratory volume in 1 second/forced vital capacity < 0.7. Periodontitis: the World Health Organization CPI was used to assess periodontitis and when CPI code ≥ 3.
    AFL = airflow limitation, DMFT = decayed, missing, and filled teeth, CPI = community periodontal index.

    In multivariable analyses, denture status: removable partial denture (aOR, 1.12; 95% CI, 1.04–1.20), complete denture (aOR, 1.52; 95% CI, 1.01–2.05), high DMFT index (aOR, 1.13; 95% CI, 1.02–1.24), and lower number of existing permanent teeth (0–19; aOR, 1.32; 95% CI, 1.12–1.52) were factors significantly associated with AFL.

    Compared to the control group, the severe to very severe AFL group had a significantly higher proportion of complete dentures (aOR, 2.41; 95% CI, 1.11–3.71) and a lower number of permanent teeth (0–19; aOR, 2.29; 95% CI, 1.57–3.01). The moderate AFL group was more likely to have periodontitis (aOR, 1.03; 95% CI, 1.01–1.06), complete dentures (aOR, 1.81; 95% CI, 1.30–2.31), high DMFT index (≥ 10; aOR, 1.20; 95% CI, 1.10–1.30), and a lower number of permanent teeth (0–19; aOR, 1.54; 95% CI, 1.35–1.73) compared to the control group (Table 3).

    Table 3
    Adjusted odds ratios and 95% confidence intervals for oral health status by the severity of AFL

    Association of oral health status with respiratory symptoms in the AFL group

    Table 4 shows the association between oral health and respiratory symptoms in the AFL group. The AFL group with high DMFT index (≥ 10) were significantly associated with physical activity limitation (aOR, 1.42; 95% CI, 1.15–1.69), and those with fewer permanent teeth (0–19) were associated with dyspnea (aOR, 1.59; 95% CI, 1.05–2.14) and physical activity limitation (aOR, 1.27; 95% CI, 1.03–1.51).

    Table 4
    Adjusted odds ratios and 95% confidence intervals for oral health status by respiratory symptoms in participants with AFL

    DISCUSSION

    Using nationally representative data in Korea, the present study showed the association between oral health and AFL. Our study showed that denture status, high DMFT index, and decreased number of permanent teeth were factors significantly associated with AFL. Furthermore, high DMFT index and decreased number of permanent teeth (0–19) were significantly associated with the severity of AFL.

    The association between oral health and COPD has been investigated in recent decades. Most previous studies have focused on one or two indicators, such as periodontitis or the number of permanent teeth.9, 11, 21, 33, 34 Additionally, Gaeckle and colleagues35 recently showed that compared with healthy controls, participants with COPD had fewer teeth, a trend of a higher plaque index, and worse oral health-related quality of life. However, the study was limited by its small sample size. In contrast, using a nationwide survey, oral health was comprehensively evaluated using various indicators such as periodontitis, denture wearing, DMFT index, and number of permanent teeth. In addition, independent factors associated with AFL were investigated by adjusting for several factors. As a result, denture status, high DMFT index, and decreased number of permanent teeth were factors associated with AFL.

    Our study shows that the AFL group had a higher proportion of complete dentures, a higher DMFT index, and a decreased number of existing permanent teeth (0–19) than the control group. A prospective observational study also reported that the COPD group had poor oral hygiene and fewer teeth than the healthy control participants.35 Changes in oral health status due to dental caries and periodontitis lead to a decreased number of existing permanent teeth.9 The decreased number of existing permanent teeth as a result of dental caries and periodontal disease is a representative indicator of oral health and has significant clinical implications. In general, it is assumed that people wear dentures because of a small number of existing permanent teeth. The biofilm formed on the denture can provide shelter for bacteria, yeast, and mold. It is said to have a structure similar to that of natural teeth, and the type and number of microorganisms it contains are complex.36 Therefore, it was thought that the risk of COPD may increase in people who have lost more teeth due to denture-related accumulation of biofilm.

    Interestingly, our study showed that a high DMFT index and a decreased number of permanent teeth (0–19) were significantly associated with the severity of AFL. To our knowledge, this is the first study to show an oral health factor associated with AFL severity. The reason may be that the more advanced the AFL, the more severe the breathing difficulties and fatigue, making it difficult to perform daily activities.37 This is thought to deteriorate the ability to perform oral hygiene, resulting in the loss of permanent teeth and exacerbation of dental and periodontal diseases. In addition, participants with AFL who had a high DMFT index were associated with physical activity limitation, and those with decreased teeth (0–19) were associated with physical activity limitation as well as dyspnea. Although this phenomenon is not fully explainable, subjects with poor oral health may have poor oral intake, which can lead to poor nutrition and increased fatigue.38 Thus, these nutritional changes and increased fatigue might be a plausible explanation for physical activity limitation and dyspnea symptom in subjects with AFL who have poor oral health.

    The present study results have several important clinical implications. First, the AFL group showed a higher DMFT index, more extensive denture use, and a decreased number of permanent teeth than the control group. Dental caries is one of the main causes of tooth loss. As tooth loss progresses, the use of dentures increases. Aerobic and anaerobic microorganisms have been identified in the dentures. These pathogenic microorganisms are thought to affect dental health and cause greater tooth loss.14 In addition, aspiration of these microorganisms is believed to contribute to respiratory infection and COPD exacerbation. Therefore, clinicians must regularly assess the oral health of patients with COPD. Another important finding was that a decreased number of permanent teeth (0–19) was significantly associated with the severity of AFL. This is because the greater the number of teeth lost, the more difficult mastication becomes, which can lead to malnutrition. In addition, the more advanced the AFL, the more severe the breathing difficulties and fatigue, making it difficult to perform daily activities.37 This effect is believed to deteriorate the ability to perform oral hygiene, resulting in the loss of permanent teeth and exacerbation of dental and periodontal diseases. Thus, for COPD patients, the number of permanent teeth should be assessed, and the clinician should ensure that adequate nutrition is provided.

    Despite these clinical implications, our study has several limitations. First, it was performed using a representative sample from Korea. Therefore, our data may not be generalizable to other ethnic groups or populations. Second, the AFL group was defined based on pre-bronchodilator spirometric results, not by post-bronchodilator spirometry. Thus, the proportion of COPD in our study population could not be well evaluated. Although the KNHANES have a questionnaire about the presence of physician-diagnosed COPD, the physician-diagnosed COPD is known to be very low in Korea.39 Thus, previous studies evaluated the prevalence of COPD using pre-bronchodilator AFL.4, 39, 40 The actual prevalence of COPD seems to be between those two values; however, it is thought to be closer to the prevalence of AFL. Third, although we calculated the odds of AFL and AFL severity according to dental health status, a cause–effect relationship could not be determined due to the limitation of our cross-sectional study design. Thus, future studies are needed for this issue. Finally, this study included healthy participants with mild airflow obstruction rather than those with severe airflow obstruction. KNHANES data were obtained from participants in a nationwide survey; individuals admitted to hospitals or nursing homes were not included. Within these limitations, the KNHANES data represent the public health of the total population of Korea and are of considerable value in many respects.41

    In conclusion, our study showed that denture status, high DMFT index, and decreased number of permanent teeth were factors significantly associated with AFL. Furthermore, a reduced number of permanent teeth (0–19) was significantly related to the severity of AFL. Therefore, physicians should pay attention to oral health in managing patients with AFL, such as COPD.

    Notes

    Funding:This work was supported by grants from the National Research Foundation (NRF) of Korea (2020R1A5A2017476). This work was also supported by Chungbuk National University Hospital (2021).

    Disclosure:The authors have no potential conflicts of interest to disclose.

    Author Contributions:

    • Conceptualization: Lee H, Yang B.

    • Data curation: Gu S.

    • Formal analysis: Gu S, Yang B.

    • Funding acquisition: Kim EG, Yang B.

    • Investigation: Kim SH, Gu S, Yang B.

    • Methodology: Yang B.

    • Supervision: Kim JA.

    • Validation: Yang B.

    • Visualization: Kim SH, Yang B.

    • Writing - original draft: Kim SH, Gu S, Lee H, Yang B.

    • Writing - review & editing: Kim SH, Gu S, Kim JA, Im Y, Cho JY, Kim Y, Shin YM, Kim EG, Man Lee K, Choe KH, Lee H, Yang B.

    References

      1. Yang B, Choi H, Lim JH, Park HY, Kang D, Cho J, et al. The disease burden of bronchiectasis in comparison with chronic obstructive pulmonary disease: a national database study in Korea. Ann Transl Med 2019;7(23):770.
      1. Sullivan SD, Ramsey SD, Lee TA. The economic burden of COPD. Chest 2000;117(2) Suppl:5S–9S.
      1. Chapman KR, Mannino DM, Soriano JB, Vermeire PA, Buist AS, Thun MJ, et al. Epidemiology and costs of chronic obstructive pulmonary disease. Eur Respir J 2006;27(1):188–207.
      1. Lee H, Shin SH, Gu S, Zhao D, Kang D, Joi YR, et al. Racial differences in comorbidity profile among patients with chronic obstructive pulmonary disease. BMC Med 2018;16(1):178.
      1. Negewo NA, Gibson PG, McDonald VM. COPD and its comorbidities: impact, measurement and mechanisms. Respirology 2015;20(8):1160–1171.
      1. Chen W, Thomas J, Sadatsafavi M, FitzGerald JM. Risk of cardiovascular comorbidity in patients with chronic obstructive pulmonary disease: a systematic review and meta-analysis. Lancet Respir Med 2015;3(8):631–639.
      1. Fabbri LM, Luppi F, Beghé B, Rabe KF. Complex chronic comorbidities of COPD. Eur Respir J 2008;31(1):204–212.
      1. Sapey E, Yonel Z, Edgar R, Parmar S, Hobbins S, Newby P, et al. The clinical and inflammatory relationships between periodontitis and chronic obstructive pulmonary disease. J Clin Periodontol 2020;47(9):1040–1052.
      1. Kim SW, Han K, Kim SY, Park CK, Rhee CK, Yoon HK. The relationship between the number of natural teeth and airflow obstruction: a cross-sectional study using data from the Korean National Health and Nutrition Examination Survey. Int J Chron Obstruct Pulmon Dis 2015;11:13–21.
      1. Hayes C, Sparrow D, Cohen M, Vokonas PS, Garcia RI. The association between alveolar bone loss and pulmonary function: the VA Dental Longitudinal Study. Ann Periodontol 1998;3(1):257–261.
      1. Scannapieco FA, Ho AW. Potential associations between chronic respiratory disease and periodontal disease: analysis of National Health and Nutrition Examination Survey III. J Periodontol 2001;72(1):50–56.
      1. Barros SP, Suruki R, Loewy ZG, Beck JD, Offenbacher S. A cohort study of the impact of tooth loss and periodontal disease on respiratory events among COPD subjects: modulatory role of systemic biomarkers of inflammation. PLoS One 2013;8(8):e68592
      1. Wang Z, Zhou X, Zhang J, Zhang L, Song Y, Hu FB, et al. Periodontal health, oral health behaviours, and chronic obstructive pulmonary disease. J Clin Periodontol 2009;36(9):750–755.
      1. Azarpazhooh A, Leake JL. Systematic review of the association between respiratory diseases and oral health. J Periodontol 2006;77(9):1465–1482.
      1. Lange P, Celli B, Agustí A, Boje Jensen G, Divo M, Faner R, et al. Lung-function trajectories leading to chronic obstructive pulmonary disease. N Engl J Med 2015;373(2):111–122.
      1. Choi JK, Paek D, Lee JO. Normal predictive values of spirometry in Korean population. Tuberc Respir Dis 2005;58(3):230–242.
      1. Graham BL, Steenbruggen I, Miller MR, Barjaktarevic IZ, Cooper BG, Hall GL, et al. Standardization of spirometry 2019 update. An official American Thoracic Society and European Respiratory Society technical statement. Am J Respir Crit Care Med 2019;200(8):e70–e88.
      1. Barnes PJ. Chronic obstructive pulmonary disease: effects beyond the lungs. PLoS Med 2010;7(3):e1000220
      1. A guide to the UK Adult Dental Health Survey 1998. Br Dent J 2001;Spec No:1–56.
      1. Sheiham A, Steele JG, Marcenes W, Finch S, Walls AW. The impact of oral health on stated ability to eat certain foods; findings from the National Diet and Nutrition Survey of Older People in Great Britain. Gerodontology 1999;16(1):11–20.
      1. Shin HS, Ahn YS, Lim DS. Association between the number of existing permanent teeth and chronic obstructive pulmonary disease. J Dent Hyg Sci 2016;16(3):217–224.
      1. World Health Organization. Oral Health Surveys: Basic Methods. Geneva, Switzerland: World Health Organization; 2013.
      1. Hancocks S. The FDI’s first ten years, 1900-1910. Fédération Dentaire Internationale. Int Dent J 2000;50(4):175–183.
      1. Cappelli DP, Mobley CC. In: Prevention in Clinical Oral Health Care. Amsterdam, The Netherlands: Elsevier Health Sciences; 2007.
      1. Klein H, Palmer C, Knutson J. Dental status and dental needs of elementary school children. Public Health Rep 1938;53:751–765.
      1. Kim MK, Lee WY, Kang JH, Kang JH, Kim BT, Kim SM, et al. 2014 clinical practice guidelines for overweight and obesity in Korea. Endocrinol Metab 2014;29(4):405–409.
      1. Shin SH, Park J, Cho J, Sin DD, Lee H, Park HY. Severity of airflow obstruction and work loss in a nationwide population of working age. Sci Rep 2018;8(1):9674.
      1. Lee H, Rhee CK, Lee BJ, Choi DC, Kim JA, Kim SH, et al. Impacts of coexisting bronchial asthma on severe exacerbations in mild-to-moderate COPD: results from a national database. Int J Chron Obstruct Pulmon Dis 2016;11:775–783.
      1. Yang B, Jang HJ, Chung SJ, Yoo SJ, Kim T, Kim SH, et al. Factors associated with bronchiectasis in Korea: a national database study. Ann Transl Med 2020;8(21):1350.
      1. Sacks DB, Bruns DE, Goldstein DE, Maclaren NK, McDonald JM, Parrott M. Guidelines and recommendations for laboratory analysis in the diagnosis and management of diabetes mellitus. Clin Chem 2002;48(3):436–472.
      1. Carey RM, Whelton PK. 2017 ACC/AHA Hypertension Guideline Writing Committee. Prevention, detection, evaluation, and management of high blood pressure in adults: synopsis of the 2017 American College of Cardiology/American Heart Association Hypertension guideline. Ann Intern Med 2018;168(5):351–358.
      1. Jellinger PS, Handelsman Y, Rosenblit PD, Bloomgarden ZT, Fonseca VA, Garber AJ, et al. American Association of Clinical Endocrinologists and American College of Endocrinology guidelines for management of dyslipidemia and prevention of cardiovascular disease. Endocr Pract 2017;23 Suppl 2:1–87.
      1. Chung JH, Hwang HJ, Kim SH, Kim TH. Associations between periodontitis and chronic obstructive pulmonary disease: the 2010 to 2012 Korean National Health and Nutrition Examination Survey. J Periodontol 2016;87(8):864–871.
      1. Khijmatgar S, Belur G, Venkataram R, Karobari MI, Marya A, Shetty V, et al. Oral candidal load and oral health status in chronic obstructive pulmonary disease (COPD) patients: a case-cohort study. Biomed Res Int 2021;2021:5548746
      1. Gaeckle NT, Heyman B, Criner AJ, Criner GJ. Markers of dental health correlate with daily respiratory symptoms in COPD. Chronic Obstr Pulm Dis 2018;5(2):97–105.
      1. Glass RT, Conrad RS, Bullard JW, Goodson LB, Mehta N, Lech SJ, et al. Evaluation of microbial flora found in previously worn prostheses from the Northeast and Southwest regions of the United States. J Prosthet Dent 2010;103(6):384–389.
      1. Ries AL, Bauldoff GS, Carlin BW, Casaburi R, Emery CF, Mahler DA, et al. Pulmonary rehabilitation: joint ACCP/AACVPR evidence-based clinical practice guidelines. Chest 2007;131(5) Suppl:4S–42S.
      1. Rahman N, Walls A. Chapter 12: nutrient deficiencies and oral health. Monogr Oral Sci 2020;28:114–124.
      1. Yoo KH, Kim YS, Sheen SS, Park JH, Hwang YI, Kim SH, et al. Prevalence of chronic obstructive pulmonary disease in Korea: the fourth Korean National Health and Nutrition Examination Survey, 2008. Respirology 2011;16(4):659–665.
      1. Kim DS, Kim YS, Jung KS, Chang JH, Lim CM, Lee JH, et al. Prevalence of chronic obstructive pulmonary disease in Korea: a population-based spirometry survey. Am J Respir Crit Care Med 2005;172(7):842–847.
      1. Kim Y. The Korea National Health and Nutrition Examination Survey (KNHANES): current status and challenges. Epidemiol Health 2014;36:e2014002
    MeSH Terms
    Comorbidity
    DMF Index
    Dental Restoration Wear
    Denture, Complete
    Denture, Partial, Removable
    Dentures
    Forced Expiratory Volume
    Humans
    Korea*
    Logistic Models
    Odds Ratio
    Oral Health*
    Periodontitis
    Pulmonary Disease, Chronic Obstructive
    Tooth
    Vital Capacity
    Metrics
    Share
    Links to
    Figures
    slide
    slide

    1 / 2

    Tables
    slide
    slide
    slide
    slide

    1 / 4

    ORCID IDs
    Funding Information
    PERMALINK