The Association between Mild Cognitive Impairment (MCI) and Traditional Chinese Medicine (TCM) Constitution among Community-Dwelling Elderly in Japan

Dementia has become a significant global health concern, with over 55 million people affected worldwide. It is estimated that by 2030, the number of people with dementia will reach approximately 78 million, and by 2050, it will rise to around 139 million [1]. Dementia ranks as the seventh leading cause of death among all diseases and is a primary factor contributing to disability and dependency among the elderly. With the rapid aging of societies, particularly in countries like Japan, addressing dementia has become an increasingly critical issue. 

Mild Cognitive Impairment (MCI) represents an intermediate stage between normal cognitive aging and dementia, particularly Alzheimer’s disease (AD). 

Studies [2] have shown that more than half of individuals with MCI develop dementia within five years, whereas [3]. Appropriate intervention can facilitate recovery to normal cognitive function in 46% of cases. According to the Japanese Neurological Society (2017) [4], the annual conversion rate from MCI to dementia ranges from 5% to 15%, while the probability of returning to normal cognitive function with proper intervention ranges from 16% to 41%. These findings highlight the importance of early detection and intervention in MCI management to delay or prevent its progression to AD. 

Currently, there is no definitive cure for dementia, making prevention and delaying its onset a priority. While modern medicine primarily focuses on the neurological aspects of dementia, Traditional Chinese Medicine (TCM) has drawn increasing attention as a complementary approach. In TCM, dementia is classified under (dull syndrome) and (depressive syndrome), while MCI is described using terms such as (forgetfulness) and (habitual forgetfulness). TCM views the human body as an interconnected system in which organ imbalances affect overall health. From this perspective, modifying an individual’s constitution is crucial for preventing and managing MCI. 

Recent studies have explored the relationship between MCI and TCM-based constitutions. Research in China has reported a high prevalence of certain constitutions, such as blood stasis, phlegm-damp, and yang deficiency, among MCI patients [5-7]. However, there is no unified consensus on this relationship, necessitating further large-scale studies. In Japan, research on the correlation between MCI and TCM-based constitution remains limited, presenting an opportunity for future exploration.

Several TCM-based interventions, including acupuncture, herbal medicine, qigong exercises (e.g., Ba duan Jin), emotional therapy, and dietary therapy, have shown promise in improving cognitive function in MCI patients [8-10]. Given the potential benefits of TCM in MCI management, further research and clinical applications should be encouraged to enhance dementia prevention strategies, particularly in aging societies like Japan.

• Research subjects and duration 

Four hundred elderly persons aged 65 years or older living in a community in S ward, K city, Japan. A cross-sectional survey was conducted using a self-administered, anonymous questionnaire. This study was approved by the Research Ethics Review Committee of Kyoto Koka Women's University (Approval No. 22MM01) and was conducted until November 2023. 

• Survey contents 

Basic Attributes of the Elderly: Background information including age, gender, chronic disease status (whether the participant had a chronic disease and the specific name of the disease), and presence of cohabitants (yes or no) were collected using a checklist. 

• Japanese version of the Questionnaire on Chinese Medicine Constitution (CCMQ-J 

Criteria for determining TCM constitution (Chinese Society of Traditional Chinese Medicine 2009) [11] (Table 1) 

Table 1: Formula for calculating the Chugai constitution = [(total score of items - number of items)/number of items x 4] x 100

(* Items 2, 7, 8, 9, 22, and 53 are inverted items when calculating the number of peace pledges.)

In this study, to analyze the results statistically, the constitution with a tendency to ο ο was also judged as ο ο constitution.

Those with a score of

In this study, an individual may have a single constitution or several constitutions at the same time, but the constitution with the highest score was determined as the constitution of the study subject. 

Dementia Assessment Sheet for Community-based Integrated Care System 21 items (DAS C-21): The DASC-21 is an assessment sheet consisting of an introductory section (A and B) and items 1 to 21, with each item rated on a 4-point scale (1 to 4). When evaluating using this 4-point scale, anchor points are placed between 1-2 and 3-4, with scores of 1 and 2 considered within the normal range, and scores of 3 and 4 indicating possible impairment. The total score ranges from 21 to 84 points, with a score of 31 or higher suggesting a potential risk of dementia. The severity of dementia is assessed based on patterns in the subcategories of remote memory, spatial cognition, social awareness, and physical ADL, with severity classified into four levels: (1) none, (2) mild, (3) moderate, and (4) severe. 

According to a study [12], the average DASC-21 score among 17 MCI patients attending a memory clinic was 28.1 ± 3.9. Based on this, the current study defines MCI if the participant’s DASC-21 score is 28 or higher, and if the following criteria are met: 

• The individual is not diagnosed with dementia.
• The individual reports memory complaints.
• The individual is independent in activities of daily living (ADL).
• The DASC-21 score is 28 or higher. 

Statistical Methods 

Statistical analysis was performed using the Japanese version of SPSS 28.0 J. The Mann-Whitney U test and The Kruskal-Walli^’s chi-square test were performed. P values less than 0.05 were considered statistically significant.

• Participant Characteristics 

A total of 400 questionnaires were distributed, after excluding individuals with incomplete information, 323 participants were included. Due to incomplete entries on some forms, the total number of data points varied during analysis. Of the respondents, 251 were female (77.7%) and 72 were male (22.3%), with ages ranging from 65 to 90 years. Participant characteristics are shown in table 2. A total of 122 participants (37.8%) lived alone, while 201 (62.2%) did not. Additionally, 203 participants (62.8%) had chronic medical conditions, while 116 (35.9%) did not. 

Table 2: Participant's characteristics. 

• Distribution of TCM Constitutions

Among the collaborators, the results of the Traditional Chinese Medicine constitution distribution are shown in table 3. 

Table 3: Distribution of TCM constitution. 

• Differences in DASC-21 scores by TCM constitution: Biased and Balanced 

The subjects were divided into two groups based on their TCM constitutional types: the healthy Balanced constitution and the sub-healthy Biased constitution. The DASC-21 scores were examined using the Mann-Whitney U test. The results are shown in table 4. The average ranks for each item indicated that the scores for elderly individuals with the Bias constitution were significantly higher in "Total Score of DASC-21," "DASC-21 Item 1 - Memory," "DASC-21 Item 2 - Orientation," "DASC-21 Item 3 - Problem-Solving and Judgment," "DASC-21 Item 4 - IADL Outside the Home," "DASC-21 Item 5 - IADL Inside the Home," and "DASC-21 Item 6 - Physical ADL (1)." (P < 0.05) 

Table 4: Differences in DASC-21 scores by TCM constitution.

• Differences in DASC-21 scores Based on Gender 

The differences in DASC-21 scores between males and females were examined using the Mann-Whitney U test. The results are shown in table 5. The average rank for the total DASC-21 significantly higher for males (P < 0.05). Among the seven evaluation items, "DASC-21 Item 4 - IADL Outside the Home," "DASC-21 Item 5 - IADL Inside the Home," and "DASC-21 Item 7 - Physical ADL (2)" were also significantly higher for males (P < 0.05).

Table 5: The Differences in DASC-21 scores by Gender.

• Differences in DASC-21 scores Based on Chronic Diseases 

The subjects were divided into three groups based on their chronic disease status: none, single occurrence, and two or more comorbidities. The differences in DASC-21 scores among the groups were examined using the Kruskal-Walli^’s chi-squared test. The results are shown in table 6. A significant difference was observed in the average rank values of the Total Score of DASC-21 among the three groups. Among the seven items, a significant difference was noted in "DASC-21 Item 3 - Problem-Solving and Judgment" among the three groups (P < 0.05).

Table 6: Differences in DASC-21 scores Based on Chronic Diseases. 

Furthermore, to clarify which groups had significant differences, the LSD (L) multiple comparison method was used after the Kruskal- Walli^’s chi-squared test? As shown in table 7, a significant difference in the total DASC-21 score was found between the group with no chronic diseases and the group with two or more comorbidities (P < 0.05). A significant difference was also noted in "DASC-21 Item 3 - Problem-Solving and Judgment" between the no disease group and the two or more comorbidities group (P < 0.05).

Table 7: Multiple comparisons of DASC items showing significant differences in chronic diseases.

The average age of the study participants was 77.03 (SD ± 5.51) years. Among the participants, 22.3% were male and 77.7% were female, with a higher proportion of women, which aligns with trends in Japan where social activities are predominantly led by women. This suggests a need to encourage older men to engage more in social activities. 

The formation of TCM constitution is influenced by both genetic and environmental factors, including climate, region, social environment, diet, and lifestyle habits. In this study, 52.5% of participants had a healthy Peace Constitution. Previous studies in China and Japan reported [13-15] lower proportions of the Peace Constitution compared to this study, suggesting that the participants were healthier than the general population.

The participants were divided into two groups based on their TCM constitution: Peace Constitution (healthy) and Bias Constitution (pre-disease). Mann-Whitney U tests revealed that elderly individuals with a Peace Constitution had better cognitive function compared to those with a Bias Constitution. 

Factors significantly related to cognitive function included gender and the presence of chronic diseases, consistent with findings from previous studies [16]. Several studies [8-10] reported improvements in cognitive function in MCI patients through acupuncture, acupressure, and traditional practices like Tai Chi and Baduanjin. In China, studies [5-7] indicated that MCI was more common in people with blood stasis, phlegm-dampness, and Yang deficiency constitutions. There is still no unified conclusion on the relationship between TCM constitution and MCI, suggesting the need for further research to explore its impact.

Due to the small sample size of the participants in the statistical analysis, there is a possibility of bias in the results. Therefore, it cannot be generalized to the characteristics of elderly people nationwide in Japan. Future studies should expand the target area and increase the number of participants to improve the research.

Factors significantly associated with DASC-21 scores included gender and the presence of chronic diseases. Older adults with a balanced constitution exhibited higher cognitive function than those with a biased constitution. TCM has the potential to restore sub-healthy constitutions to a healthy state. Improving biased constitutions may positively impact cognitive function and enhance overall community health and quality of life. Further large-scale studies are needed to clarify the relationship between these TCM constitutions and MCI.

The authors declare no conflicts of interest.

The authors would like to thank the Center for Community Care and Prevention, S ward, K city, Japan, and research collaborators for their cooperation. Special gratitude is extended to the professors for their guidance in planning, analysis, and writing of this study.

1. World Health Organization (2021) Global status report on the public health response to dementia: Executive summary. World Health Organization, Geneva, Switzerland.
2. Brodaty H, Connors MH, Ames D, Woodward M, PRIME study group (2014) Progression from mild cognitive impairment to dementia: a 3-year longitudinal study. Aust N Z J Psychiatry 48: 1137-1142.
3. Shimada H, Doi T, Lee S, Makizako H, Chen LK, et al. (2018) Cognitive Frailty Predicts Incident Dementia among Community-Dwelling Older People. J Clin Med 7: 250.
4. The Dementia Clinical Practice Guidelines Development Committee (2017) Dementia Clinical Practice Guidelines. I Medical Book Publishing, Tokyo, Japan.
5. Zeng C, Zhang W, Zhang E, Deng J., Lin M, et al. (2017) The correlation between mild cognitive impairment and traditional Chinese medicine constitution in elderly patients. Journal of Guangzhou Medical University 45: 31-34.
6. Zou M, Song Y, Luo D, Yang M, Wang M, et al (2022) A study on the correlation between traditional Chinese medicine constitution and mild cognitive impairment. Traditional Chinese Medicine Information 39: 48-52.
7. Wang L, Cong L, Liu K, Wang Y, Hou T, et al (2022) The association between mild cognitive impairment and constitution classification of traditional medicine. Chinese Journal of Alzheimer's Disease and Related Disorders 5: 109-114.
8. Lin Q (2016) The effect of Baduanjin exercise intervention on cognitive function in patients with mild cognitive impairment. Shandong Medical Journal 56: 50-51.
9. Zhu C, Cai S, Xu B, He C, Yang C, et al. (2015) Clinical Observation of Tongdu Vessel Regulating the Spirit Acupuncture Therapy in the Treatment of Amnestic Mild Cognitive Impairment.Journal of Anhui University of Chinese Medicine 34: 55-58.
10. Sun J, Zeng H, Pan L (2015) The effect of acupoint massage training on cognitive function in elderly individuals with mild cognitive impairment in the community. Chinese Journal of General Practice 18: 1057-1060.
11. Chinese Society of Traditional Chinese Medicine (2009) Classification and determination of traditional Chinese medicine constitution. China Traditional Chinese Medicine Press, China.
12. Fujita Y, Oba T, Miyake H, Nakano A, Sonoda K, et al. (2020) Understanding lifestyle needs and wishes of older adults with mild cognitive impairment and early dementia in regular outpatient care. Care of the Elderly and Behavioral Science 25: 84-98.
13. Li J, Yang L (2019) Analysis of traditional Chinese medicine constitution identification in elderly community residents in Changchun. Smart Health 19: 46-47.
14. Xia Y, Wang D, Zhou B, Sun Y, Dai H (2021) Analysis of traditional Chinese medicine constitution identification in elderly population in QingPu District, Shanghai. Henan Traditional Chinese Medicine, China.
15. Xu F, Kamata H, Zhu Y, Wang Q, Suzuki N, et al. (2020) Data analysis of health-related information of residents in the Kurobe area using traditional Chinese medicine constitution theory. Journal of the Japanese Society for Complementary and Alternative Medicine 17: 145-153.
16. Su X, Hua Q, Wang W (2016) A study on the correlation between mild cognitive impairment and chronic diseases in elderly community residents in Xi’an. Nursing Research 30: 323-325.