High Prevalence and Low Awareness of Mild Cognitive Impairment in a Suburban Community in Shanghai
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.333524
Source of Support: None, Conflict of Interest: None
Keywords: Alzheimer's disease, awareness, dementia, mild cognitive impairment, prevalence
Mild cognitive impairment (MCI) is the previous stage of Alzheimer's disease(AD) which as a significant cognitive deficit has not been qualified as dementia reference. Especially, about 38.2% of MCI patients developed AD within 5–10 years, while 2017 meta-analysis found that 5–15% of those who were aged over 65 and had MCI (amnestic MCI) developed AD every year. AD was also be predicted by amyloid PET, tau PET, MRI cortical thickness, and gene,,, but none of which could replace MCI. So, in recent years, many opinions trend to treat AD at stage of MCI because there was no effective drug for AD.
Therefore, it is imperative that we know the prevalence of MCI in the first place. In China, there is a dearth of literature on the prevalence of MCI in the suburban community residents in China.
Accordingly, the high prevalence rate of MCI should evoke proper intervention and treatment, which, however, depend on the awareness of MCI symptoms and risks, for the low awareness can hamper the interventions. So, assessing public's knowledge and understanding about MCI and identifying what lay people know would be the basis of designing awareness-raising campaigns and educational programs. In fact, MCI patients underestimated their MCI, being unaware of their memory deficits., Cahill et al. identified current Alzheimer's disease knowledge level and status, and areas of misconceptions and knowledge gaps among Vietnamese Americans, calling for urgent needs for educational outreach to improve knowledge about Alzheimer's disease among Vietnamese Americans. In the United States, Healthy People 2020 aims to increase AD diagnosis disclosure by 10% from a baseline of 34.8% of adults aged ≥65 with a dementia diagnosis, which reflected that the diagnosis ratio was not enough and low diagnosis ratio impacted by low awareness of these diseases. A French study found 95% informants are unable to recognize early stages of AD.
Furthermore, few reports have been made on the awareness rate of MCI symptoms and risks in the populations at large. Twenty years ago, a study in Japan demonstrated that 52% of family informants failed to recognize the significant memory problem of dementia in the subjects and that 53% failed to receive a medical evaluation for the medical problem. Today, although there was no exact number of the awareness of MCI, however, to address the needs of care among a growing aging population, Japan implemented an insurance program and long-term care approach in 2000 that focused on consistent evaluation of the elderly and increased care and financial support for family caregivers, which convinced the enhancement of awareness. Such data indicated that the awareness rate of MCI was low in patients and families, thereby inducing the low rate of medical evaluation. But the problem is that little is known about the current awareness rate of MCI in China.
Thus, the aim of the current study was to investigate the prevalence of MCI of the residents aged ≥65 in the suburban communities of Shanghai, China, and examine the awareness rate of MCI in terms of symptom, prevention and intervention.
This study was approved by the Medical Ethics Committee of Shanghai Pudong New Area People's Hospital, Shanghai, China. Written informed consent was obtained from all participants or their legally acceptable representatives. The date of the approval was 05-08-2018.
Beside the Functional Activities Questionnaire (FAQ), Clinical Dementia Rating (CDR), and Montreal Cognitive Assessment (MoCA), our questionnaire was designed to survey the awareness rate of MCI knowledge (QAMK), which was composed of 18 questions covering 5 dimensions: The family's concern for MCI symptoms in elderly (three Qs), the awareness rate of MCI symptoms (four Qs), the awareness rate of MCI prevention (four Qs), the doctor's concern for MCI symptoms in elderly (three Qs), and the rate of taking MCI elderly family member to the doctor (four Qs).
The subjects were chosen from the Heqing Community, which is located in Shanghai. The embranchment in the Pudong government stipulates that annual physical examination be offered to the community-dwellers aged ≥45. QAMKs were used to assess the awareness rate of MCI based on the oral questions to those who had no cognition impairment. FAQ, CDR, and MoCA were used to assess MCI and dementia in individuals aged ≥65 without schizophrenia or mental retardation on their medical record or Parkinson disease and stroke or other disease-induced difficulty of assessment. These tests were voluntarily performed as part of the medical exam.
Medical and neurologic examination
Questionnaire survey and score calculations were performed by the five physicians independently, who had been trained to be unified. The demographic data referred to age, gender, education, being widowed and living with the next generation, and the medical history involved hypertension, diabetes, and heart disease.
The criteria of MCI included the elements as follows: Cognitive impairment in one or more domains (scored at least 1.5 standard deviations below the norm in memory, executive function, language, or visuoconstructive skill), global CDR score of 0.5 or less, preserved ability to perform daily activities and social functions, and absence of dementia. The participants were first screened by MoCA translated into Chinese (Montreal Cognitive Assessment Beijing Version 26 August, 2006, translated by Wei Wang and Hengge Xie; the reliability and validity being good enough to have alpha value of 0.862), and the score of 23 was the threshold of normal and MCI. The cutoff score was adjusted for education year, the score plus 1 if the education years were ≤12. A diagnose was made of dementia according to the Diagnostic and Statistical Manual of Mental Disorders, the fourth edition (DSM-IV) criteria for dementia. Activity of Daily Living (ADL) scale was used to elicit physical self-maintenance and instrumental activities of daily living, including eating, using the telephone, preparing meals, handling money, and completing chores. The participants were considered to be functionally intact if their ADL score was > 16. QAMKs were attached in appendix-table.
Statistical Package for the Social Sciences version 19.0 (SPSS Inc., Chicago, IL) was applied to the current statistical analysis. Descriptive statistics was used to calculate by percentage the sociodemographic characteristics of the study populations and the prevalence ratios of the suburban populations calculated. The χ2 test was used to assess the differences between different subgroups in terms of sex, age, education, being widowed, living with the next generation, and the diseases of hypertension, diabetes, and heart disease. The reliability and validity of the QAMKs were tested using reliability analysis and factor analysis. Multiple regression analysis was applied to QAMKs to assess the effect of sex, age, education, and occupation on the five dimensions, respectively.
As shown in [Figure 1], 925 community dwellers implemented the assessment of MCI, 103 (11.1%) having dementia, 276 (29.8%) having MCI, and 546 (59%) being normal, with the mean age 71.16 ± 4.41.
An analysis was made of the association of the prevalence of MCI and dementia with different demographic characteristics [Table 1] and [Figure 2]. The ages were divided into five categories: 65, 66–70, 71–75, 76–80, and >80. Significant differences were observed among the three groups of people of dementia, MCI, and normal in each category of age and education (P < 0.001). The degree of cognitive impairment was linearly correlated with age (P < 0.001). There was a significant difference among the three groups in different gender, being widowed, and living without the next generation (P < 0.001), the females: OR = 1.72, 95% CI: 1.32–2.25; being widowed: OR = 1.5, 95% CI: 1.09–2.05; and living without the next generation: OR = 1.43, 95% CI: 09–1.89.
Designed for the responses of the participants to yes/no questions pertaining to the five dimensions, the statistical analysis of QAMKs showed that the reliability and validity of the questionnaire were good, the reliability analysis indicating that alpha value was 0.734, the factor analysis indicating that Kaiser–Meyer–Olkin test value was 0.760, and Bartlett test of sphericity was P < 0.001. As indicated in [Figure 3], the rotated component matrix reflected the five dimensions.
QAMKs were delivered to the elderly who could complete it on their own, and also to their younger accompanies if they were willing to do it. As indicated in [Table 2], a total of 600 questionnaires were collected, the majority of which were accomplished by the younger accompanies of the elderly.
In occupation, they were educational workers, medical workers, company employees, and suburban farmers. Their educational level ranged from being illiterate to holding a master's degree. The rates of the five dimensions for the negative answers were high, the no-attention rate for MCI symptoms in the elderly being 40%, the unawareness rate of MCI symptom being 74.5%, the unawareness rate of MCI prevention being 84.5%, the rate of physician's no-asking for MCI symptoms being 98%, and the rate of no-taking MCI elderly family member to the doctor being 68%.
As indicated in [Table 3] and [Table 4], the factors were listed which impacted the rate of the five dimensions. The medical workers were more likely to pay attention to MCI symptoms in the elderly than other groups (OR = 0.49; 95% CI: 0.26–0.96), having a higher awareness rate than other groups (OR = 0.253; 95% CI: 0.10–0.64), and the participants who had received ≤12 years of education had a lower awareness rate (OR = 2.18; 95% CI: 1.15–4.14). In the dimension of the awareness rate of MCI prevention, significant differences were found between genders (P < 0.001) and in educational level (P < 0.05), the females having a lower awareness rate of MCI prevention than the males (OR = 2.78; 95% CI: 1.66–4.66) and those of ≤12 educational years having a lower awareness rate of MCI prevention (OR = 2.75; 95% CI: 1.23–6.14).
Our study found that the prevalence rate of MCI was up to 29.8% and the rate of dementia was 11.1% in the suburban community-dwellers aged ≥65. Especially, MCI was linearly correlated with age. The rate was higher than that previously reported of other two centers, which was approximately 20% in the urban and 23.4% in the rural community, respectively, and where the dementia prevalence rate was 6.05% in the rural and 4.40% in the urban community, respectively.,, This difference could be explained by the impacts of the participants' different ages and educational levels in the current study, where the mean age was over 70 and the educational level of the majority was under 12 years (97.39%). In fact, the prevalence rates of MCI or dementia were various in other countries. One study in San Salvador reported that the prevalence of MCI was set at 17.09% and in the elderly aged over 60. The prevalence of MCI in Indians increased with age, 15.7% in the ages of 60–64 to 30.1% in the ages of ≥80 years. In Germany Outpatient Health Care Sector, the prevalence rates of MCI were from 0.13% to 0.42% and it was 26.06% in South Indian aged over 60 years, 30% in Kazakhstan people aged 60 years old, 38.6% in Saudi Arabia aged over 60 years old, 15.3% in Greece aged over 65 years, and 21.6% in Italian aged over 65 years.
In the current study, it was found that the prevalence of MCI was higher in the females (OR = 1.72), which was consistent with the prevalence which was slightly higher in women than in men, the evidence which was reported by the study performed in Indian., However, a meta-analysis pointed that there were no statistically significant sex differences in prevalence or incidence of amnestic MCI. Behind the differences may exist some other confounding factors, as indicated by the report that men had a greater risk of developing MCI resulting from cerebrovascular disease.
Moreover, those who were widowed and living without the next generation were found to have a higher prevalence of MCI than those who were living with their spouses and next generation, respectively (OR = 1.5; OR = 1.43). Although few reports have been made on this correlation, this phenomenon has reasons to urge us to take extra care for the widowed and those who live without the next generation in China, where most of Chinese families used to live together with three or more generations. These two groups of the community dwellers can be sentimentally and socially vulnerable to depression, which can increase the risk of developing MCI in cognitively normal people.
Furthermore, those who had received ≤9 years of education have a higher prevalence of MCI and dementia than those who had >9 years, which was coincident with the previously reported evidence that education could be associated with the prevalence of MCI.,, A study from Finland found that the prevalence of MCI varied between education-adjusted (MCI = 9.3%) and unadjusted classifications (MCI = 22.3–41.3%), which indicated that education was an important factor for MCI.
But such factors as hypertension, diabetes, and heart disease were not found to be associated with the prevalence of MCI. Previous investigations, however, reported that poor disease course of hypertension, disease course of diabetes mellitus, and a low level of adiponectin in serum could be the risk factors in MCI development. The difference could be explained by the possible association with the course of hypertension, diabetes, and heart disease. As to the courses of hypertension, diabetes and heart disease were not known; in order to decrease bias, therefore, our future studies include a recruitment of subjects at a calculation of the courses of such medical problems.
The results as regard the awareness of MCI suggested a low rate of the five dimensions such as family's concern for MCI symptoms in elderly, awareness of MCI symptom, awareness of MCI prevention, and doctor's concern for MCI symptoms in elderly and taking MCI elderly family member to the doctor. In the three dimensions, the medical workers and the individuals of >12 educational years and female had a slightly higher rate awareness of MCI. In a previously reported study, the Informant Questionnaire on Cognitive Decline in the Elderly was used to assess the level of awareness, and the results showed a diminished awareness in MCI-patients. But our assessment was implemented in mostly normal people, not just in MCI patients themselves, which reflects the serious state of MCI awareness and is worth to have its enhancement in the whole society. A study of Israeli found that there is a need to improve the knowledge and awareness of the general public about AD, and particularly among men, which is consistent with our findings. General public perceptions and attitudes toward Alzheimer's disease from Chongqing in China found low awareness of AD remaindered that overall awareness of MCI was low no matter in a developed or undeveloped area. Moreover, a USA study made a questionnaire to investigate the awareness of AD. The questionnaire involved several dimensions such as perceived AD threat, perceived AD threat, knowledge about AD, family experience with AD, beliefs about AD risk factors, and beliefs about AD protective factors, which different to the dimensions of ours questionnaire.
All in all, the prevalence of MCI was higher in the suburban community dwellers aged ≥65 in Shanghai, China, but the awareness of MCI was significantly low, as indicated by the low attention by family members or doctors, insufficient knowledge of MCI symptoms, and prevention and low rate of receiving medical treatment. High prevalence and low awareness are enough to indicate the serious state of MCI in the aging city of Shanghai, China, with some significant implication for the aging cities of the country as a whole. It is necessary to educate the knowledge of MCI to overall people in china.
This study had registered on website in June (http://www.chictr.org.cn/index.aspx).
The registration number was ChiCTR1900024071.
This study was supported by the Science and Technology Development Fund of Shanghai Pudong New Area (No. PKJ2018-Y12).
Financial support and sponsorship
This study was supported by the Science and Technology Development Fund of Shanghai Pudong New Area (No. PKJ2018-Y12).
Conflicts of interest
There are no conflicts of interest.
Questionnaire to Survey the Awareness Rate of MCI Knowledge (QAMK)
What's your gender?
How old are you?
What's your education level?
What's your occupation?
[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4]