The Efficacy and Safety of Metformin Intervention in Elderly Overweight or Obesity With Mild Cognitive Impairment by a Single-center, Randomized, Placebo-controlled Interventional Study (Include Elderly Patients With Obesity or Overweight)
Phase: PHASE1
Conditions: Mild Cognitive Impairment, Overweight or Obesity, Elderly
Sponsor: Fudan University

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Title 
The efficacy and safety of metformin intervention in elderly 
overweight or obesity with mild cognitive impairment 
 
study protocol 
 
Scheme Design Institute: Huadong Hospital, Fudan University 
Main Research Institution: Huadong Hospital, Fudan University 
 
 
Main Investigator: Tao Xiaoming 
 
Clinical Research Department: Endocrine Department 
Sponsor: none 
Ethical Review Number:2025K299 
NCT number ：Not yet assigned 
Protocol Version: 01, August 7, 2025 
 
 
 
 
 
 
                                                     Signature of principal investigator: 
Date: 
                                                               Contact information of main researcher: 
 
 
 

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Huadong Hospital, Fudan University 
Name: Tao Xiaoming 
Title: chief physician 
Address: Room 204, No.168 Yan 'an West Road, Shanghai            postal code: 200040 
Telephone number 
021-62483180-720230 
mobile phone 
13042190822 
email  
t983166@163.com 
 
Contact information for study group members 
Huadong Hospital, Fudan University 
Name: Jiang Cuiping 
Title: associate chief physician 
Address: Endocrinology Department, 9th Floor, Building 6, No.221 Yan 'an West Road, 
Shanghai                                                postal code: 200040 
Telephone number 
021-62483180-560903 
mobile phone 
18964612712 
email  
litthat@126.com 
 
Name: Lu Bin 
Title: chief physician 
Address: Endocrinology Department, 9th Floor, Building 6, No.221 Yan 'an West Road, 
Shanghai                                                postal code: 200040 
Telephone number 
021-62483180-560903 
mobile phone 
18121186716 
email  
lubinfd@126.com 
 
Name: Huang Yuxin 
Title: associate chief physician 
Address: Endocrinology Department, 9th Floor, Building 6, No.221 Yan 'an West Road, 
Shanghai 200040                                    postal code: 200040 
Telephone number 
021-62483180-560903 
mobile phone 
13816972588 
email  
mhc_2@sina.com 
 
Name: Yi Na 
Title: attending physician 
Address: Endocrinology Department, 9th Floor, Building 6, No.221 Yan 'an West Road, 
Shanghai                                                postal code: 200040 
Telephone number 
021-62483180-560903 
mobile phone 
 
email  
 
 

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Name: Xu Yuanyuan 
Title: associate chief physician 
Address: Endocrinology Department, 9th Floor, Building 6, No.221 Yan 'an West Road, 
Shanghai 200040                                 postal code: 200040 
Telephone number 
021-62483180-560903 
mobile phone 
13636320720 
email  
yaya19860223@126.com 
 
Name: Lou Xudan 
Title: attending physician 
Address: Endocrinology Department, 9th Floor, Building 6, No.221 Yan 'an West Road, 
Shanghai                                              postal code: 200040 
Telephone number 
021-62483180-560903 
mobile phone 
18818201196 
email 
lxdreddy@126.com 
 
Name: Qiu JieyuZhen 
Title: attending physician 
Address: Endocrinology Department, 9th Floor, Building 6, No.221 Yan 'an West Road, 
Shanghai                                              postal code: 200040 
Telephone number 
021-62483180-560903 
mobile phone 
13761687328 
email  
jqiu8966@163.com 
 
Name: Wei Chuanli 
Title: Doctor 
Address: Endocrinology Department, 9th Floor, Building 6, No.221 Yan 'an West Road, 
Shanghai                                               postal code: 200040 
Telephone number 
021-62483180-560903 
mobile phone 
17852664537 
email  
17852664537@163.com 
 
 
Name: Zhou Yiping 
Title: attending physician 
Address: Neurology Department, 11th Floor, Building 6, No.221 Yan 'an West Road, 
Shanghai                                               postal code: 200040 
Telephone number 
021-62483180-561103 
mobile phone 
13816439877 
email  
375504653@qq.com 
 

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一、 Programme summary 
Protocol 
name 
The efficacy and safety of metformin intervention in elderly 
overweight or obesity with mild cognitive impairment 
Version 
number/ 
Version date 
V1.0 7 August, 2025 
Research 
objects 
Elderly overweight or obesity patients with mild cognitive 
impairment 
Research 
purposes 
To explore the efficacy and safety of metformin in sufficient amount 
in elderly overweight or obese patients with MCI. To provide 
reliable evidence for the elderly overweight or obese patients with 
MCI to delay and reverse the cognitive dysfunction. 
Research 
design 
This study was a prospective, randomized controlled, single-
center clinical cohort study. Elderly subjects who were overweight 
or obese with MCI and met the inclusion criteria and did not meet 
the exclusion criteria were included in this study with informed 
consent. The subjects were randomly divided into two groups using 
random number method. In the first group, subjects received 
metformin sustained-release tablets (1500mg once a day or reduced 
to the maximum tolerated dose if intolerable) and lifestyle 
intervention guidance. Subjects in the second group received only 
lifestyle intervention guidance. All subjects were followed for a 
period of 26 weeks. History collection, body measurement index 
evaluation, glycolipid metabolism biochemical test, medication 
record, and MoCA scale evaluation were conducted during the 
enrollment phase and the end of follow-up. The insulin sensitivity in 
central nervous system of subjects in the two groups before and after 
treatment was evaluated by nasal insulin inhalation combined with 
fMRI. 
Inclusion/ 
exclusion 
Inclusion criteria 

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criteria 
A. age: 60 -75 years; 
B. Body mass index: ≧24kg/m2; 
C. glycated hemoglobin < 8.5%; 
D. The scores of the MoCA scale are 20–26 (education > 10 
years) or 20–25 (education ≦10 years); 
E. sign informed consent forms; 
Exclusion criteria 
A. Anyone who takes any hypoglycemic drug within 8 weeks 
prior to enrollment; 
B. type 1 diabetes; 
C. Central nervous system magnetic resonance imaging cannot 
be completed; 
D. A history of alcohol or drug addiction; 
E. Severe gastrointestinal diseases, history of gastrointestinal 
surgery, severe cardiopulmonary dysfunction, malignant tumor and 
other diseases; 
F. Abnormal liver function (liver enzyme index is more than 
2.5 times the upper limit of the reference range) or renal function 
(estimated glomerular filtration rate < 45 mL/min); 
G. There were relevant situations that the investigator judged 
were not suitable for inclusion in the study. 
Study drug 
Drug name: metformin hydrochloride sustained-release tablets 
(Gehuazhi) 
Drug specification: 500mg 
Sample size 
The change in blood flow volume of cerebral regions shown by 
fMRI after nasal insulin inhalation was used as the research 
endpoint. According to the results of previous literature, the 
difference between groups after drug intervention was 20%, and the 
standard deviation was 20%. When the accuracy was 0.05 and the 
test efficiency 1-β was 0.8, the required sample size for each group 
was obtained from the sample size calculation formula: n1=n2=23. 
Considering the existence of a certain shedding ratio, and calculated 
based on the shedding rate of 15%, 54 patients, 27 in each group, 
were to be included in the study. 

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Statistical 
method 
SPSS 22.0 statistical analysis software was used for 
calculation. All statistical tests were performed using a two-sided 
test, and P≦0.05 was considered statistically significant for the 
difference tested. Enumeration data were described by constituent 
ratio, and measurement data were described by mean, standard 
deviation, median, and interquartile. Statistical analysis: Appropriate 
methods were used for analysis according to the types of indicators. 
T test or Wilcoxon rank sum test was used for inter-group 
comparison of quantitative data, and chi-square test was used for 
classified data. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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二、Contents 
一、 
Programme summary ........................................................................................................... 4 
二、 
Contents ............................................................................................................................... 7 
三、 
Version of the study protocol ............................................................................................... 8 
四、 
Research topic ...................................................................................................................... 8 
五、 
Research purposes ................................................................................................................ 8 
六、 
Research background ........................................................................................................... 8 
七、 
Research method ................................................................................................................ 10 
1. 
overall design ................................................................................................................. 10 
2. 
Study Population ............................................................................................................ 10 
八、 
Inclusion criteria, exclusion criteria and exit criteria of subjects ........................................ 11 
1. 
Inclusion criteria ............................................................................................................. 11 
2. 
Exclusion criteria ............................................................................................................ 11 
3. 
Exit criteria ..................................................................................................................... 11 
九、 
Sample size assessment ...................................................................................................... 12 
十、 
Study Endpoints .................................................................................................................. 12 
1. 
Effectiveness .................................................................................................................. 12 
2. 
Safety .............................................................................................................................. 12 
十一、 
Research process ............................................................................................................ 13 
十二、 
Serious adverse events ................................................................................................... 15 
十三、 
Statistical Analysis Plan................................................................................................... 16 
十四、 
Testing-related Ethics ..................................................................................................... 16 
十五、 
Informed consent ........................................................................................................... 17 
1. 
Subject informed consent ............................................................................................... 17 
2. 
Informed consent of the agent ........................................................................................ 17 
3. 
Withdrawal of informed consent .................................................................................... 17 
4. 
Confidentiality and privacy ............................................................................................ 18 
十六、 
Research progress planning ............................................................................................ 18 
十七、 
Safety Visit ...................................................................................................................... 18 
十八、 
Handling of subject information and biological samples ............................................... 18 
十九、 
Data and copyright ......................................................................................................... 19 
二十、 
References ...................................................................................................................... 21 
二十一、 Appendix ........................................................................................................................ 22 
 
 
 

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三、 Version of the study protocol 
Scenario history 
version number 
Version date 
Summary of revisions 
1.0 
7 August, 2025 
first edition 
四、 Research topic 
The efficacy and safety of metformin intervention in elderly overweight or obesity 
with mild cognitive impairment 
五、 Research purposes 
To explore the efficacy and safety of metformin in sufficient amount in elderly 
overweight or obese patients with MCI. To provide reliable evidence for the elderly 
overweight or obese patients with MCI to delay and reverse the cognitive dysfunction. 
 
六、 Research background 
1. The prevalence of cognitive impairment in elderly obese patients is high, and 
early intervention is of great value. 
Cognitive impairment refers to one or more impairments in learning and memory, 
language, executive function, sensorimotor function, complex attention and social 
cognition, which is often accompanied by mental, behavioral and personality 
abnormalities, including mild cognitive impairment (MCI) and dementia [1]. 
Epidemiological studies have shown that the prevalence of MCI in people over 60 
years old in China is 15.5%, and the number of people with MCI is 38 million [2]. 
More studies have confirmed the existence of a clear correlation between obesity and 
cognitive impairment [3]. Patients with MCI have less interference with cognitive 
deficits in daily life, but the proportion of patients progressing to dementia every year 
can reach 5-10%, which is much higher than the incidence rate of 1-2% of the general 
population every year [4]. 50% of patients with MCI can develop to dementia within 
five years [5], and 20-30% of patients with MCI can recover to normal cognition [6]. 

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Therefore, early detection of MCI and timely intervention for elderly obese patients 
have important clinical significance and value. 
2. Central nervous insulin resistance plays a role in the pathogenesis of 
cognitive dysfunction. Functional magnetic resonance imaging (fMRI) can 
evaluate cognitive dysfunction by observing central insulin resistance. 
At present, the mechanisms of cognitive dysfunction in elderly obese patients 
include the pathophysiological role of microvascular mechanisms and fat-derived 
factors [3]. Insulin not only regulates peripheral metabolism, but also acts on the 
central nervous system to regulate cognitive function. All cell types in the brain have 
insulin signaling pathways, and some studies have shown that insulin resistance in the 
brain can damage the plasticity and memory function of hippocampal synapses, 
leading to cognitive decline [7]. The Montreal Cognitive Assessment Scale (MoCA) 
is usually used for the evaluation of cognitive function, which includes multiple 
dimensions such as memory, attention, executive function and language function, 
with a full score of 30. The score considering the diagnosis of MCI is 20-26 
(education > 10 years) or 20-25 (education ≦10 years) [8]. However, in actual work, 
scale collection is affected by many factors. fMRI can display the changes of local 
cerebral blood flow and metabolic activities before the changes of brain structure, so 
as to understand the changes of brain function in depth. It is an important means for 
early diagnosis of cognitive dysfunction, efficacy monitoring and mechanism research 
[9]. The degree of central insulin resistance was assessed by fMRI combined with 
nasal insulin inhalation to observe the response of different brain regions to insulin. 
The absence of neuroimaging or neurophysiological reactions after nasal insulin 
inhalation is suggestive of central nervous system insulin resistance [7]. Previous 
studies have shown that improving central insulin resistance can delay or even reverse 
cognitive decline [10]. Therefore, the central insulin resistance observed by fMRI can 
be used as an objective basis for the assessment of cognitive function. 
3. Metformin may improve cognitive dysfunction by improving central insulin 
resistance in elderly obese patients. 
Metformin is widely used as the first-line medication for type 2 diabetes. Basic 
research showed that metformin had the potential to activate the 5'AMP-activated 
protein kinase (AMPK) pathway, which played a vital role in the pathogenesis of 
dementia [11]. Metformin can improve insulin resistance [12], reduce neuronal 
apoptosis [13], and reduce cerebral oxidative stress and inflammatory response [14]. 
Recent studies have shown that the use of metformin is associated with a significant 

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reduction in the risk of dementia in elderly patients with type 2 diabetes [15][16], but 
these studies are all diabetes patients in a large database. Comparing the use of 
metformin to reach the conclusion is subject to more interference factors. Other early 
studies have shown that long-term use of metformin even increases the risk of 
dementia [17], which may be related to vitamin B12 deficiency, the duration of 
metformin use, and the course of diabetes. Short-term controlled studies with small 
samples have shown that metformin can penetrate the blood-brain barrier and improve 
learning, memory and attention in non-diabetic MCI patients [18]. 
In summary, as a widely used traditional hypoglycemic drug, metformin has 
been shown to improve central insulin resistance in basic studies and has been proved 
to be feasible in clinical studies of diabetic patients. However, there are few studies 
investigating the efficacy of metformin in improving cognitive function in elderly 
obese patients with MCI. 
七、 Research method 
1. 
overall design 
This study was a prospective, randomized controlled, single-center clinical 
cohort study. Those subjects who met the inclusion criteria were included in the study 
after they signed the informed consent. The study was conducted in the Drug Clinical 
Laboratory of Endocrinology Department, Huadong Hospital. The subjects were 
randomly divided into two groups using random number method. In the first group, 
subjects received metformin sustained-release tablets (1500mg once a day or reduced 
to the maximum tolerated dose if intolerable) and lifestyle intervention guidance. 
Subjects in the second group received only lifestyle intervention guidance. All 
subjects were followed up for 26 weeks with a diary card for dosing and adverse 
events and a telephone visit every 4 weeks 3 days after randomization. 
2. 
Study Population 
Any elderly subject who is overweight or obesity with mild cognitive 
impairment and is admitted to the study center may be considered for this study. The 
primary investigator bore the primary responsibility for subject enrollment. You can 
expect to limit the speed of grouping for the following reasons: 

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⚫ 
The number of outpatient visits and the number of subjects who met the inclusion 
and exclusion criteria; 
⚫ 
The willingness and informed consent of the subjects were evaluated at baseline. 
八、 Inclusion criteria, exclusion criteria and exit criteria of subjects 
1. 
Inclusion criteria 
A. age: 60 -75 years; 
B. Body mass index: ≧24kg/m2； 
C. glycated hemoglobin < 8.5%; 
D. The scores of the MoCA scale are 20–26 (education > 10 years) or 20–25 
(education ≦10 years); 
E. sign informed consent forms; 
2. 
Exclusion criteria 
A. Anyone who takes any hypoglycemic drug within 8 weeks prior to enrollment; 
B. type 1 diabetes; 
C. Central nervous system magnetic resonance imaging cannot be completed; 
D. A history of alcohol or drug addiction; 
E. Severe gastrointestinal diseases, history of gastrointestinal surgery, severe 
cardiopulmonary dysfunction, malignant tumor and other diseases; 
F. Abnormal liver function (liver enzyme index is more than 2.5 times the upper limit 
of the reference range) or renal function (estimated glomerular filtration rate < 45 
mL/min); 
G. There were relevant situations that the investigator judged were not suitable for 
inclusion in the study. 
3. 
Exit criteria 
All subjects had the right to withdraw from the study at any stage of the study 
and the investigator had the right to discontinue observation of subjects who: 
1) Continuing to participate in the seminar would cause unnecessary damages to the 
subjects; 
2) The subjects had poor compliance and did not cooperate with the researchers in 

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relevant examinations and interventions; 
3) Subjects who were found not to meet the inclusion criteria after participating in the 
study; 
4) Subjects who were found to meet the exclusion criteria after participation in the 
study. 
九、 Sample size assessment 
The change in blood flow volume of cerebral regions shown by fMRI after nasal 
insulin inhalation was used as the research endpoint. According to the results of 
previous literature, the difference between groups after drug intervention was 20%, 
and the standard deviation was 20%. When the accuracy was 0.05 and the test 
efficiency 1-β was 0.8, the required sample size for each group was obtained from the 
sample size calculation formula: n1=n2=23. Considering the existence of a certain 
shedding ratio, and calculated based on the shedding rate of 15%, 54 patients, 27 in 
each group, were to be included in the study. 
十、 Study Endpoints 
1. Effectiveness 
The main evaluation indexes were the changes of cerebral blood flow shown by 
fMRI after nasal insulin inhalation. The secondary evaluation index was MoCA scale 
score. To explore the influence of metformin intervention on cognitive dysfunction 
under different glycosylated hemoglobin baselines. 
2. Safety 
Intestinal reaction, such as abdominal pain, diarrhea, abdominal distension; other 
uncomfortable symptoms or events affecting living activities. 

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十一、 
Research process 
1. Screening period: whether the screening met the inclusion criteria, and there was 
no exclusion criterion. 
2. V0: A total of 54 elderly subjects who were expected to be enrolled as overweight 
or obesity with MCI, taking medical history (previous illness, medication history and 
concomitant medication, smoking history, alcohol consumption history, and 
educational level), demographic data (gender, date of birth), comprehensive physical 
examination (height, weight, body temperature, heart rate, respiration, blood pressure, 
waist circumference, hip circumference, body composition, nervous system, and 
cardiopulmonary abdomen), Laboratory tests (fasting blood glucose, fasting insulin, 
fasting C-peptide, glycated hemoglobin, blood lipids, routine blood tests, liver and 
kidney function, and routine 12-lead electrocardiogram), MoCA scale evaluation, and 
nasal insulin inhalation combined with fMRI imaging were performed. 
54 patients were randomly divided into two groups. In the first group, subjects 
received metformin sustained-release tablets (1500mg once a day or reduced to the 
maximum tolerated dose if intolerable) and lifestyle intervention. Subjects in the 
second group received only lifestyle intervention guidance. All subjects were 
followed for a 26-week follow-up period and diary cards were issued to record dosing 
and adverse events. A 24-hour meal was recorded during the first week of 
intervention; Exercise instruction. 
3. V1 (intervention 4 weeks): The patient was interviewed by phone for any adverse 
events. 
4. V2 (eight weeks of intervention): The patient was interviewed by phone for any 
adverse events. 
5. V3 (intervention 12 weeks): The patient was interviewed by phone for any adverse 
events. 
6. V4 (intervention for 16 weeks): The patient was interviewed by phone for any 
adverse events. 

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7. V5 (intervention of 20 weeks): The patient was interviewed by phone for any 
adverse events. 
8. V6 (24 weeks of intervention): The patient was interviewed by phone for any 
adverse events. 
9. V7 (intervention for 26 weeks): Medical history (previous disease history, 
medication history and concomitant medication history, smoking history, drinking 
history, and educational level) demographic data (gender, date of birth), 
comprehensive physical examination (height, weight, temperature, heart rate, 
respiration, blood pressure, waist circumference, hip circumference, body 
composition, nervous system, and cardiopulmonary abdomen), laboratory tests 
(fasting blood glucose, fasting insulin, fasting C-peptide, glycated hemoglobin, blood 
lipid, blood routine, liver and kidney function, routine 12-lead electrocardiogram), 
MoCA scale evaluation, and nasal insulin inhalation combined with fMRI imaging 
were collected again. 
10. V8: A safety visit 4 weeks after the end of the intervention to ask the patient over 
the phone for any adverse events. The report was analyzed and recommendations 
were made for treatment protocol adjustments based on the report. 
 

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Figure 1 research flow chart 
 
Figure 2 Follow-up plan (duration and content of follow-up) 
Note: 
(1) After a 5-minute rest, systolic and diastolic blood pressure as well as pulse were measured by 
sitting quietly. Blood pressure, waist circumference, grip strength, and body function were 
assessed using the uniform method provided. The body composition was determined using Beijing 
Yueqi BIA-140. 
(2) All tests were performed in the test center. There were two blood tests in total, and 5ml venous 
whole blood was drawn each time. 
(3) ECG: 12 leads were used, and the same subject should be kept consistent. 
(4) Early withdrawal from trial visit: Participants who withdrew from the trial early should return 
to the study center on an empty stomach for the early withdrawal visit within 7 days after the 
investigator was informed. A repeat examination for the same item may be waived if the visit is 
less than 7 days from the date of the previous visit. 
(5) Dietary life guidance rules: during the formulation of nutrition treatment plan, attention should 
be paid to appropriately increase the protein and energy intake, to encourage the elderly subjects 
to choose regular exercise that can be insisted on for a long time, and to select the appropriate 
exercise mode (such as aerobic exercise and resistance training). 
 
十二、 
Serious adverse events 
Definition of adverse event (AE): Any adverse medical event that occurred 
between the time the subject signed the informed consent and was enrolled in the 
study and the last visit, regardless of causality to study drug, was considered an 
adverse event. Serious adverse events (SAE) was a clinical event indicating a 
significant hazard, contraindication, side effect, or caution with respect to a test article 

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at any dose or at any time during observation. Adverse events are classified as serious 
adverse events if one or more of the following criteria are met: 1. Death 2. Life-
threatening (meaning that the patient in whom the event occurred was at risk of dying 
immediately at the time of the event; Does not include those events which, if more 
serious, could result in the death of the patient) 3. Lead to hospitalization or prolonged 
hospitalization 4. Lead to permanent or significant loss of labor or disability 5. 
Congenital malformations. Medical events that have not yet resulted in death, life risk, 
or hospitalization that, after appropriate medical judgment, may be hazardous to the 
patient or subject or require medical or surgical treatment to avoid such occurrences 
should also be considered SAE. 
If any adverse event occurs, the patient should report it to the researcher in time. 
The researcher should make a detailed record at the corresponding position on the 
case report form. The researcher should assist the patient to actively handle the 
adverse event and strive for the best prognosis while respecting the patient's will and 
choice. Meanwhile, possible adverse events are prevented and treated. As metformin 
was used in this study, it was expected that possible adverse events in this study 
would include: gastrointestinal reaction conditions, such as abdominal pain, diarrhea, 
and abdominal distension. In the case of serious adverse events, the Ethics Committee 
and relevant health authorities will be reported within 24 hours and the subject will be 
treated promptly. 
十三、 
Statistical Analysis Plan 
SPSS 22.0 statistical analysis software was used for calculation. All statistical 
tests were performed using a two-sided test, and P≦0.05 was considered statistically 
significant for the difference tested. Enumeration data were described by constituent 
ratio, and measurement data were described by mean, standard deviation, median, and 
interquartile. Statistical analysis: Appropriate methods were used for analysis 
according to the types of indicators. T test or Wilcoxon rank sum test was used for 
inter-group comparison of quantitative data, and chi-square test was used for 
classified data. 
十四、 
Testing-related Ethics 
1. compliance with the requirements of the declaration of helsinki and laws and 
regulations 

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2. Each subject should read the informed consent form before inclusion, and the 
patient should sign the informed consent form after the doctor answers all questions 
of the patient (see annex for the informed consent form). 
3. This study is a randomized controlled trial. The test drug metformin has been used 
clinically and can be used together with diet and exercise to improve blood glucose 
control of adult patients with type 2 diabetes. Lifestyle intervention was conducted in 
the control group in accordance with the principle of fairness and justice. All trials 
will be conducted after approval by the Ethics Committee of Huadong Hospital and 
accept supervision by the Ethics Committee of Huadong Hospital. 
十五、 
Informed consent 
The optional informed consent procedures in this study are described in detail 
below and should be in compliance with local ethics committee regulations. 
1. 
Subject informed consent 
Subjects should provide informed written consent whenever possible. Subjects 
were briefed by clinicians familiar with the protocol to explain consent to participate 
in the study. 
2. 
Informed consent of the agent 
If the subject is unable to provide informed consent, the subject's representative 
may provide informed consent on behalf of the subject. 
3. 
Withdrawal of informed consent 
Informed consent briefings provided to subjects and/or their agents clearly 
indicated that subjects could withdraw from the study at any time without explanation 
and that subjects would not be prejudiced or impaired thereby. This condition should 
be documented in the subject file. 

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4. 
Confidentiality and privacy 
Care should be taken to respect the privacy of subjects during the conduct of the 
study. To ensure subject privacy, submissions will be de-labeled. However, in 
monitoring the quality of the data and adherence to the study protocol, the auditor has 
access to the medical records at the hospitals participating in the study. 
十六、 
Research progress planning 
① 2024.10 – 2025.3: study protocol was optimized and various preparations such as 
the investigator's manual and patient's diary were completed; Subjects were screened 
into the group; Subjects were instructed to take medications and were followed up 
②2025.4 – 2025.9: subjects were screened into the group; Subjects were instructed to 
take medications and were followed up 
③2025.10 – 2026.3: subjects were screened into the group; Subjects were instructed 
to take medications and were followed up 
④ 2026.4 – 2026.9: All data were entered, statistically analyzed, articles were written, 
and the final questions were completed.  
十七、 
Safety Visit 
A safety visit was conducted one week after the study and any adverse events were 
reported. 
十八、 
Handling of subject information and biological samples 
To ensure evaluation and supervision by the Research Coordination Center of 
Endocrinology Department, Huadong Hospital, Fudan University, the researchers 
should agree to keep all research materials (including original records, informed 
consent network authorization of all patients, and all CRF), and assign a special 
counter to lock and store them. Shelf life 15 years. All materials for this clinical study 
were owned by the project collaboration group organized by Huadong Hospital,  
Fudan University. 
The samples of the subjects were tested in the test center, and the biological 
samples were stored in the -80℃ refrigerator for a period of 5 years. After the 
expiration of the storage period, the biological samples were destroyed in accordance 

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with the Shanghai Measures for the Administration of Medical Waste and other laws 
and regulations, and were recorded and retained. 
十九、 
Data and copyright 
1. Data management 
1) fill in and transfer of case report form 
The case report form was completed by the investigator and must be completed for 
each enrolled case. The completed case report forms were entered and managed by 
the data administrator. 
2) data entry and modification 
For questions existing in the case report form, the data administrator will 
generate a question answer form and send the questions to the investigator, who 
should answer and return the questions as soon as possible. The data administrator 
will modify, confirm and enter the data according to the investigator's answers, and 
then send the questions again if necessary. 
3) data lock 
After reviewing and confirming the correctness of the established database, the 
project principal, main researcher and statistical analyst locked the data. The locked 
data file is not changed. Problems found after data lock-in were corrected in the 
statistical analysis procedure after validation. 
4) data processing 
After all the study data were entered and locked, the database was submitted to 
the statistical analyst for statistical analysis according to the requirements of the 
statistical plan. After the statistical analysis was completed, the general and sub-
reports for statistical analysis were written by the statistical analysts and submitted to 
the principal investigator of the trial for writing the study report. 
5) Data confidentiality 
All subject information used in this study must be kept strictly confidential, and 
information about subjects who participated in the study and who were enrolled in the 
study must be kept confidential. Subject information and study data will be identified 
by study number. Information that identifies him or her will not be disclosed to 
members outside the study group unless subject approval is obtained. Subject identity 
was to be kept confidential by all study members. The subject's profile will be 

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maintained in a locked cabinet for access by the investigator only. To ensure that the 
study was conducted as required, members of the ethics committee were provided 
with access to subject profiles at the study unit as necessary. No personal information 
will be disclosed for the subject when the results of this study are published. 
All study members should keep the study data confidential. They should not 
inform the members other than the research group of the study data without the 
permission of the main investigator, and should not transfer the study data to external 
units without the permission of the hospital. 
6) Quality control 
The lead investigator organized training to ensure that the study was conducted 
in a standardized manner, that the case report forms were completed, and that other 
reports complied with GCP principles and the study protocol. All data and 
information must be verifiable, and all observations and findings should be verifiable 
in order to assure the reliability of the study data. Quality control will be applied at 
each stage of the study to assure reliability of all data and accuracy of study 
procedures. The lead investigator should ensure that the investigator followed the 
protocol, confirmed the accuracy of the data, and documented the completeness of the 
report, and obtained informed consent from all subjects prior to study initiation. Any 
deviations or deviations from the protocol should be reported to the ethics committee 
in a timely manner. When necessary, the research group will designate standard 
operating procedures and carry out quality control procedures at each link of the 
implementation of research and data processing to ensure the specification and 
reliability of research implementation and data operation. 
2. 
Copyright 
Authors of published articles must conform to the following guidelines for authors 
issued by the editorial board of international medical journals: 
1) The author must make a substantial contribution to the conception and design of 
the test, the acquisition of data, or the analysis of data, and the interpretation of the 
results; 
2) The author must draft and publish the article in person or contribute to important 
revisions to the original (data analysis, interpretation, or other important intellectual 
content) that have been approved by other authors during the review process; 
3) The author must provide an approval of the final draft of the article before it is 
submitted to the publication for publication. 

第21页共23页 
All contributors who do not meet the above criteria for authorship will be listed in the 
acknowledgement column of the publication, if permitted by the journal, in 
accordance with the guidelines for acknowledgements issued by the editorial board of 
the International Journal of Medicine. 
二十、 
References 
[1] Arvanitakis Z, Shah RC, Bennett DA. Diagnosis and Management of Dementia: 
Review. JAMA， 2019，322(16):1589-1599. 
[2] Ren Rujing, Yin Peng, Wang Zhihui, etc.China Alzheimer's Disease Report 2021. 
Theory and practice of diagnostics, 2021, 20(4):317-337. 
[3] Balasubramanian P, Kiss T, Tarantini S et al. Obesity-induced cognitive 
impairment in older adults: a microvascular perspective. Am J Physiol Heart Circ 
Physiol, 2021, 320(2):H740-H761. 
[4] Sanford AM. Mild Cognitive Impairment. Clin Geriatr Med, 2017, 33(3):325-337. 
[5] Morley JE. An Overview of Cognitive Impairment. Clin Geriatr Med, 2018, 
34(4):505-513. 
[6] Anderson ND. State of the science on mild cognitive impairment (MCI). CNS 
Spectr, 2019, 24(1):78-87. 
[7] Kellar D, Craft S. Brain insulin resistance in Alzheimer's disease and related 
disorders: mechanisms and therapeutic approaches. Lancet Neurol, 2020,19(9):758-
766. 
[8] Tan SN, Tan C. Vortioxetine improves cognition in mild cognitive impairment. Int 
Clin Psychopharmacol, 2021, 36(6):279-287. 
[9] Canu E, Sarasso E, Filippi M et al. Effects of pharmacological and 
nonpharmacological treatments on brain functional magnetic resonance imaging in 
Alzheimer's disease and mild cognitive impairment: a critical review. Alzheimers Res 
Ther, 2018, 10(1):21. 
[10] Xu J, Ni B, Ma C et al. Docosahexaenoic acid enhances hippocampal insulin 
sensitivity to promote cognitive function of aged rats on a high-fat diet. J Adv Res, 
2023, 45:31-42. 
[11] Nikbakhtzadeh M, Shaerzadeh F, Ashabi G. Highlighting the Protective or 
Degenerative Role of AMPK Activators in Dementia Experimental Models. CNS 
Neurol Disord Drug Targets, 2021, 20(9):786-801. 

第22页共23页 
[12] Ford RJ, Fullerton MD, Pinkosky SL et al. Metformin and salicylate 
synergistically activate liver AMPK, inhibit lipogenesis and improve insulin 
sensitivity. Biochem J, 2015, 468(1):125-32. 
[13] Li LX, Liu MY, Jiang X et al. Metformin inhibits Aβ25-35 -induced apoptotic 
cell death in SH-SY5Y cells. Basic Clin Pharmacol Toxicol, 2019, 125(5):439-449. 
[14] Obafemi TO, Olasehinde OR, Olaoye OA et al. Metformin/Donepezil 
combination modulates brain antioxidant status and hippocampal endoplasmic 
reticulum stress in type 2 diabetic rats. J Diabetes Metab Disord, 2020, 19(1):499-510. 
[15] Sun M, Chen WM, Wu SY et al. Metformin in elderly type 2 diabetes mellitus: 
dose-dependent dementia risk reduction. Brain, 2024, 147(4):1474-1482. 
[16] Tang H, Guo J, Shaaban CE et al. Heterogeneous treatment effects of metformin 
on risk of dementia in patients with type 2 diabetes: A longitudinal observational 
study.Alzheimers Dement, 2024,20(2):975-985. 
[17] Imfeld P, Bodmer M, Jick SS et al. Metformin, other antidiabetic drugs, and risk 
of Alzheimer's disease: a population-based case-control study. J Am Geriatr Soc, 
2012, 60(5):916-21. 
[18] Koenig AM, Mechanic-Hamilton D, Xie SX, et al. Effects of the Insulin 
Sensitizer Metformin in Alzheimer Disease: Pilot Data From a Randomized Placebo-
controlled Crossover Study. Alzheimer Dis Assoc Disord, 2017, 31(2):107-113. 
二十一、 Appendix 
MoCA scale assessment (v0, v7) 
 
 

第23页共23页 
VISUOSPATIAL / EXECUTIVE 
Copy 
Draw CLOCK (Ten past eleven) 
POINTS 
cube 
 
[ 
] 
[ 
] 
( 3 points ) 
   / 5 
NAMING 
   / 3 
 
[ ] 
[ ] 
[ ] 
MEMORY 
Read list of words, subject must 
FACE 
VELVET 
CHURCH 
DAISY 
RED 
NO 
POINTS 
repeat them. Do 2 trials, even if 1st trial is suc-
cessful. Do a recall after 5 minutes. 
1ST TRIAL 
2ND TRI-
AL
ATTENTION 
Read list of digits (1 digit/ sec). 
Subject has to repeat them in the forward order. [  ]  2 1 8 5 4 
   / 2 
Subject has to repeat them in the backward order. [  ]  7 4 2 
Read out the following numbers. Each time the number is 1, the patient knocks 1 on the table. No score is given if the error number is greater than
or equal to 2. 
[]52139411806215194511141905112 
   / 1 
Serial 7 subtraction starting at 100. 
[ ]  93 
[ ] 86 
[ ]  79 
[ ]  72 
[ ] 65 
4 or 5 correct subtractions: 3 pts, 
2 or 3 correct: 2 pts, 
0 or 1 correct: 0 
   / 3 
LANGUAGE 
Repeat: I only know that Zhangliang is the one to help today. [ ] 
   / 2 
The cat always hid under the couch when dogs were in the room. 
[ ] 
Fluency: Name maximum number of animal names in one minute. 
[ 
]  
 (N ≥ 11 words) 
   / 1 
ABSTRACTION 
Similarity between e.g. banana - orange = fruit [  ] train - bicycle 
[  ] watch - ruler 
   / 2 
DELAYED RECALL 
Has to recall words 
WITH NO CUE 
FACE 
[ ] 
VELVET 
[ ] 
CHURCH 
[ ] 
DAISY 
[ ] 
RED 
[ ] 
Points for 
UNCUED 
recall only 
   / 5 
 
Category cue 
Multiple choice cue 
ORIENTATION 
[  ] Date 
[  ] Month 
[  ] Year 
[  ] Day 
[  ] Place 
[  ] City 
   / 6 
TOTAL 
                                        / 30