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Kiuchi S, Cooray U, Aida J, Osaka K, Chan A, Malhotra R, Peres MA. Effect of Tooth Loss on Cognitive Function among Older Adults in Singapore. J Dent Res 2023:220345231172109. [PMID: 37278356 DOI: 10.1177/00220345231172109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023] Open
Abstract
Evidence suggests a longitudinal association between tooth loss and cognitive function. However, the temporality of this association is not well understood. We investigated the effect of several emulated tooth loss prevention scenarios on cognitive function. We used data from 3 waves (baseline: 2009, second wave: 2011-2012, and third wave: 2015) of the Panel on Health and Ageing of Singaporean Elderly (PHASE). PHASE targeted older adults, aged ≥60 y, in Singapore. Number of teeth was used as a time-varying exposure (baseline, second wave). Cognitive function (Short Portable Mental Status Questionnaire score) in the third wave was assessed as the outcome. Multiple time-invariant (baseline) and time-varying (baseline and second wave) covariates were included. The "longitudinal modified treatment policy approach" combined with targeted minimum loss-based estimation was used to define and estimate additive effects of emulated tooth loss prevention scenarios. Emulated scenarios were the following: what if edentate people retained 1 to 4 teeth (scenario 1), what if those with <5 teeth retained 5 to 9 teeth (scenario 2), what if those with <10 teeth retained 10 to 19 teeth (scenario 3), and what if everyone retained ≥20 teeth (scenario 4)? A total of 1,516 participants, excluding those with severe cognitive impairment, were included (male: 41.6%). The mean age at baseline was 70.6 y (SD = 7.1). The mean SPMSQ score at baseline was 2.06 (SD = 0.02) for edentulous, 1.55 (SD = 0.04) for 1 to 4 teeth, 1.61 (SD = 0.03) for 5 to 9 teeth, 1.73 (SD = 0.02) for 10 to 19 teeth, and 1.71 (SD = 0.02) for ≥20 teeth. Additive effect of hypothetical intervention gradually increased with intensity of prevention from scenario 1 to scenario 4 (scenario 1: -0.02 [95% CI, -0.08 to 0.04], scenario 2: -0.05 [95% CI, -0.11 to -0.00], scenario 3: -0.07 [95% CI, -0.14 to -0.00], scenario 4: -0.15 [95% CI, -0.23 to -0.06]). Emulated tooth loss prevention interventions were associated with better cognitive function score. Therefore, preventing tooth loss could potentially benefit maintenance of cognitive function among older adults.
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Affiliation(s)
- S Kiuchi
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Aoba-ku, Sendai, Japan
- Department of International and Community Oral Health, Tohoku University Graduate School of Dentistry, Aoba-ku, Sendai, Japan
| | - U Cooray
- Department of International and Community Oral Health, Tohoku University Graduate School of Dentistry, Aoba-ku, Sendai, Japan
| | - J Aida
- Department of Oral Health Promotion, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - K Osaka
- Department of International and Community Oral Health, Tohoku University Graduate School of Dentistry, Aoba-ku, Sendai, Japan
| | - A Chan
- Centre for Ageing Research and Education, Duke-NUS Medical School, Singapore
- Health Services and Systems Research, Duke-NUS Medical School, Singapore
| | - R Malhotra
- Centre for Ageing Research and Education, Duke-NUS Medical School, Singapore
- Health Services and Systems Research, Duke-NUS Medical School, Singapore
| | - M A Peres
- National Dental Research Institute Singapore, National Dental Centre Singapore, Singapore
- Oral Health ACP, Health Services and Systems Research Programme, Duke-NUS Medical School, Singapore
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Cooray U, Tsakos G, Heilmann A, Watt RG, Takeuchi K, Kondo K, Osaka K, Aida J. Impact of Teeth on Social Participation: Modified Treatment Policy Approach. J Dent Res 2023:220345231164106. [PMID: 37085984 DOI: 10.1177/00220345231164106] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023] Open
Abstract
Social participation prevents social isolation and loneliness among older adults while having numerous positive effects on their health and well-being in rapidly aging societies. We aimed to estimate the effect of retaining more natural teeth on social participation among older adults in Japan. The analysis used longitudinal data from 24,872 participants in the Japan Gerontological Evaluation Study (2010, 2013, and 2016). We employed a longitudinal modified treatment policy approach to determine the effect of several hypothetical scenarios (preventive scenarios and tooth loss scenarios) on frequent social participation (1 = at least once a week/0 = less than once a week) after a 6-y follow-up. The corresponding statistical parameters were estimated using targeted minimum loss-based estimation (TMLE) method. Number of teeth category (edentate/1-9/10-19/≥20) was treated as a time-varying exposure, and the outcome estimates were adjusted for time-varying (income, self-rated health, marital status, instrumental activities of daily living, vision loss, hearing loss, major comorbidities, and number of household members) and time-invariant covariates (age, sex, education, baseline social participation). Less frequent social participation was associated with older age, male sex, lower income, low educational attainment, and poor self-rated health at the baseline. Social participation improved when tooth loss prevention scenarios were emulated. The best preventive scenario (i.e., maintaining ≥20 teeth among each participant) improved social participation by 8% (risk ratio [RR] = 1.08; 95% confidence interval [CI], 1.05-1.11). Emulated tooth loss scenarios gradually decreased social participation. A hypothetical scenario in which all the participants were edentate throughout the follow-up period resulted in a 11% (RR = 0.89; 95% CI, 0.84-0.94) reduction in social participation. Subsequent tooth loss scenarios showed 8% (RR = 0.92; 95% CI, 0.88-0.95), 6% (RR = 0.94; 95% CI, 0.91-0.97), and 4% (RR = 0.96; 95% CI, 0.93-0.98) reductions, respectively. Thus, among Japanese older adults, retaining a higher number of teeth positively affects their social participation, whereas being edentate or having a relatively lower number of teeth negatively affects their social participation.
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Affiliation(s)
- U Cooray
- Department of International and Community Oral Health, Tohoku University Graduate School of Dentistry, Sendai, Japan
- Department of Oral and Maxillofacial Radiology, Faculty of Dental Medicine, Universitas Airlangga, Surabaya, Indonesia
| | - G Tsakos
- Department of Epidemiology and Public Health, University College London, London, UK
| | - A Heilmann
- Department of Epidemiology and Public Health, University College London, London, UK
| | - R G Watt
- Department of Epidemiology and Public Health, University College London, London, UK
| | - K Takeuchi
- Department of International and Community Oral Health, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - K Kondo
- Center for Preventive Medical Sciences, Chiba University, Chiba, Japan
- Center for Gerontology and Social Science, National Center for Geriatrics and Gerontology, Obu, Japan
| | - K Osaka
- Department of International and Community Oral Health, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - J Aida
- Department of Oral Health Promotion, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
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Kiuchi S, Cooray U, Kusama T, Yamamoto T, Abbas H, Nakazawa N, Kondo K, Osaka K, Aida J. Oral Status and Dementia Onset: Mediation of Nutritional and Social Factors. J Dent Res 2021; 101:420-427. [PMID: 34796750 DOI: 10.1177/00220345211049399] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Some modifiable risk factors for dementia are closely related to oral health. Although eating and speaking abilities are fundamental oral functions, limited studies have focused on the effect of malnutrition and lack of social interaction between oral health and dementia. We investigated the mediating effects of nutritional and social factors on the association between the number of teeth and the incidence of dementia. This 6-y cohort study used data from the Japan Gerontological Evaluation Study targeting older adults aged 65 y and above. The number of teeth (exposure) and covariates in 2010 (baseline survey), mediators (weight loss, vegetable and fruit intake, homeboundness, social network) in 2013, and the onset of dementia (outcome) between 2013 and 2016 were obtained. The Karlson-Holm-Breen mediation method was applied. A total of 35,744 participants were included (54.0% women). The mean age at baseline was 73.1 ± 5.5 y for men and 73.2 ± 5.5 y for women. A total of 1,776 participants (5.0%) had dementia during the follow-up period. There was a significant total effect of the number of teeth on the onset of dementia (hazard ratio, 1.14; 95% CI, 1.01-1.28). Controlling for nutritional and social mediators, the effect of the number of teeth was reduced to 1.10 (95% CI, 0.98-1.25), leaving an indirect effect of 1.03 (95% CI, 1.02-1.04). In the sex-stratified analysis, the proportion mediated by weight loss was 6.35% for men and 4.07% for women. The proportions mediated by vegetable and fruit intake and homeboundness were 4.44% and 4.83% for men and 8.45% and 0.93% for women, respectively. Furthermore, the proportion mediated by social networks was 13.79% for men and 4.00% for women. Tooth loss was associated with the onset of dementia. Nutritional and social factors partially mediated this association.
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Affiliation(s)
- S Kiuchi
- Department of International and Community Oral Health, Tohoku University, Graduate School of Dentistry, Miyagi, Japan
| | - U Cooray
- Department of International and Community Oral Health, Tohoku University, Graduate School of Dentistry, Miyagi, Japan
| | - T Kusama
- Department of International and Community Oral Health, Tohoku University, Graduate School of Dentistry, Miyagi, Japan.,Division for Regional Community Development, Liaison Center for Innovative Dentistry, Graduate School of Dentistry, Tohoku University, Miyagi, Japan
| | - T Yamamoto
- Department of Health Promotion, National Institute of Public Health, Saitama, Japan
| | - H Abbas
- Department of International and Community Oral Health, Tohoku University, Graduate School of Dentistry, Miyagi, Japan
| | - N Nakazawa
- Department of International and Community Oral Health, Tohoku University, Graduate School of Dentistry, Miyagi, Japan
| | - K Kondo
- Department of Social Preventive Medical Sciences, Center for Preventive Medical Sciences, Chiba University, Chiba, Japan.,Department of Gerontological Evaluation, Center for Gerontology and Social Science, National Center for Geriatrics and Gerontology, Aichi, Japan
| | - K Osaka
- Department of International and Community Oral Health, Tohoku University, Graduate School of Dentistry, Miyagi, Japan
| | - J Aida
- Division for Regional Community Development, Liaison Center for Innovative Dentistry, Graduate School of Dentistry, Tohoku University, Miyagi, Japan.,Department of Oral Health Promotion, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
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Cooray U, Aida J, Watt R, Tsakos G, Heilmann A, Kato H, Kiuchi S, Kondo K, Osaka K. Effect of Copayment on Dental Visits: A Regression Discontinuity Analysis. J Dent Res 2020; 99:1356-1362. [DOI: 10.1177/0022034520946022] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Despite their prevalence and burdens, oral diseases are neglected in universal health coverage. In Japan, a 30% copayment (out of pocket) by the user and a 70% contribution by Japan’s universal health insurance (JUHI) are required for dental and medical services. From the age of 70 y, an additional 10% is offered by JUHI (copayment, 20%; JUHI, 80%). This study aimed to investigate the effect of cost on dental service use among older adults under the current JUHI system. A regression discontinuity quasi-experimental method was used to investigate the causal effect of the JUHI discount policy on dental visits based on cross-sectional data. Data were derived from the 2016 Japan Gerontological Evaluation Study. This analysis contained 7,161 participants who used JUHI, were aged 68 to 73 y, and responded to questions regarding past dental visits. Analyses were controlled for age, sex, number of teeth, and equalized household income. Mean ± SD age was 72.1 ± 0.79 y for the discount-eligible group and 68.9 ± 0.78 y for the noneligible group. During the past 12 mo, significantly more discount-eligible participants had visited dental services than noneligible participants (66.0% vs. 62.1% for treatment visits, 57.7% vs. 53.1% for checkups). After controlling for covariates, the effect of discount eligibility was significant on dental treatment visits (odds ratio [OR], 1.36; 95% CI, 1.32 to 1.40) and dental checkups (OR, 1.49; 95% CI, 1.44 to 1.54) in the regression discontinuity analysis. Similar findings were observed in triangular kernel-weighted models (OR, 1.38 [95% CI, 1.34 to 1.44]; OR, 1.52 [95% CI, 1.47 to 1.56], respectively). JUHI copayment discount policy increases oral health service utilization among older Japanese. The price elasticity for dental checkup visits appears to be higher than for dental treatment visits. Hence, reforming the universal health coverage system to improve the affordability of relatively inexpensive preventive care could increase dental service utilization in Japan.
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Affiliation(s)
- U. Cooray
- Department of International and Community Oral Health, Graduate School of Dentistry, Tohoku University, Sendai, Japan
- Department of Epidemiology and Public Health, University College London, London, UK
| | - J. Aida
- Department of International and Community Oral Health, Graduate School of Dentistry, Tohoku University, Sendai, Japan
| | - R.G. Watt
- Department of Epidemiology and Public Health, University College London, London, UK
| | - G. Tsakos
- Department of Epidemiology and Public Health, University College London, London, UK
| | - A. Heilmann
- Department of Epidemiology and Public Health, University College London, London, UK
| | - H. Kato
- Graduate School of Business Administration, Keio University, Yokohama, Japan
| | - S. Kiuchi
- Department of International and Community Oral Health, Graduate School of Dentistry, Tohoku University, Sendai, Japan
| | - K. Kondo
- Center for Preventive Medical Sciences, Chiba University, Chiba, Japan
- Center for Gerontology and Social Science, National Center for Geriatrics and Gerontology, Obu, Japan
| | - K. Osaka
- Department of International and Community Oral Health, Graduate School of Dentistry, Tohoku University, Sendai, Japan
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