An observational study in Type 2 Diabetes Mellitus and Cognitive Impairment, sponsored by The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School. Recruiting at 1 site in China. Open to participants aged 40 Years to 75 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2022-10-26.
Sponsored by The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School · Observational
This is a cross-sectional and longitudinal study to establish diagnostic models based on olfactory function assessments and odor-induced brain activation for cognitive impairment in patients with type 2 diabetes mellitus.
Patients with diabetes have increased risks of cognitive impairment and dementia, which affecting the quality of life and diabetes management. Therefore, it is an urgent challenge to identify non-invasive biomarkers for early diagnosis and prognosis of the cognitive decline in patients with diabetes. Previous research has shown that both olfactory dysfunction and decreased odor-induced brain activation are present before clinically measurable cognitive decrements in type 2 diabetes. This is a cross-sectional and longitudinal study to establish diagnostic models based on olfactory function assessments and odor-induced brain activation for cognitive impairment in patients with type 2 diabetes mellitus. The investigators will recruit 200 patients with type 2 diabetes in the outpatient and inpatient departments. Health controls will be recruited from the community. At the baseline, clinical information collection, 100g-steamed bread meal test, biochemical measurement, cognitive assessments, olfactory test and functional magnetic resonance imaging(fMRI) scan will be conducted for all participants. Study duration was 3 years with a follow-up every 18 months. In the longitudinal study, all of the assessments will be repeated to evaluate changes of observational parameters.
10,925 studies on the registry are indexed under Diabetes Mellitus; 1,319 are open to participants now.
This study's planned enrollment of 200 is below the median of 233 across 2,220 observational studies indexed under Diabetes Mellitus.
Browse Diabetes Mellitus studies →The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School is the lead sponsor of 242 studies on the registry; 144 are open to participants now.
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T2DM patients will be recruited from the outpatient and inpatient units of the endocrinology department of the investigator's hospital. Healthy control will be recruited in the community.
Exclusion Criteria:
These patients must have a definite diagnosis of type 2 diabetes mellitus (T2DM) according to the American Diabetes Association (ADA) standards. Some of these patients have symptoms of cognitive impairment, while others have normal cognition. All T2DM patients will undergo physical exam, cognitive and olfactory test as well as structural and brain functional MRI at baseline and follow-up time points.
Behavioral: Cognitive assessments · Other: Olfactory function measurements · Other: Functional magnetic resonance imaging
These participants have normal glucose tolerance and normal cognition. All HC subjects will undergo physical exam, cognitive and olfactory test as well as structural and brain functional MRI at baseline and follow-up time points.
Behavioral: Cognitive assessments · Other: Olfactory function measurements · Other: Functional magnetic resonance imaging
Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Rey Auditory Verbal Learning Test (RAVLT), Boston Naming Test (BNT), Digit Span Test (DST), Trail Making Test (TMT).
Olfactory Threshold, Odor Identification Score, Odor Memory Score.
resting-state fMRI, odor-induced fMRI.
Also known as: fMRI
Baseline cognitive performance
The Montreal Cognitive Assessment (MoCA) score, ranges from 0 to 30, and higher scores mean better cognition.
Time frame: Day 1 of entry study
Baseline olfactory threshold
Olfactory threshold test: score range 1-13.5, which is determined based on a series of binary dilutions of the N-butanol solution in light mineral oil. The higher the score is, the more sensitive the participant is in detecting an odor. Scores of 8-10 were considered normal olfactory sensitivity, whereas scores of 1-3 signified olfactory dysfunction or anosmia, and scores of ≥10 indicate better olfactory sensitivity.
Time frame: Day 1 of entry study
Baseline olfactory memory
Olfactory memory test: Part A: Participants are shown 4 pictures for each odor (10 odors in total), then they need to select what they sniffed. Have a 10-minute break. Part B: Participants sniff 20 different odors, 10 of which are the same odors as in Part A. They need to select the picture and figure out whether the odor is old or new.
Time frame: Day 1 of entry study
Baseline odor-induced brain fMRI activation
Each participant underwent a series of task fMRI scans to measure temporal brain response to four increasing concentrations of lavender odors (0.032%, 0.10%, 0.32%, and 1.0) diluted in 1,2-propanediol (Sigma-Aldrich, St. Louis, MO). The visual cues of "+" and "smell" were used for baseline and odor stimulation, respectively. Each concentration was assessed three times, with fresh air and scent occurring alternately. Participants were instructed to press a button once they smelled the lavender scent. A general linear model was used to estimate odor-induced brain activation. Contrasts between "fresh air \> rest" and "scent \> rest" for each participant were made to get odor-induced brain activation value. Bilateral parahippocampus, amygdala, piriform cortex, insula, orbitofrontal cortex, entorhinal cortex, and hippocampus were extracted and merged as olfactory regions of interest (ROIs) for further analyses.
Time frame: Within 1 week after cognitive assessments
Longitudinal changes of cognitive performance
Compare the change of MoCA score from baseline to each follow-up time points (18 months' follow-up, 36 months' follow-up). The Montreal Cognitive Assessment (MoCA) score, ranges from 0 to 30, and higher scores mean better cognition.
Time frame: From baseline to 18 months' follow-up and 36 months' follow-up
Longitudinal changes of olfactory threshold
Compare the change of olfactory threshold tests score from baseline to each follow-up time points (18 months' follow-up, 36 months' follow-up). Olfactory threshold test: score range 1-13.5, which is determined based on a series of binary dilutions of the N-butanol solution in light mineral oil. The higher the score is, the more sensitive the participant is in detecting an odor. Scores of 8-10 were considered normal olfactory sensitivity, whereas scores of 1-3 signified olfactory dysfunction or anosmia, and scores of ≥10 indicate better olfactory sensitivity.
Time frame: From baseline to 18 months' follow-up and 36 months' follow-up
Longitudinal changes of olfactory memory
Compare the change of olfactory memory tests score from baseline to each follow-up time points (18 months' follow-up, 36 months' follow-up). Olfactory memory test: Part A: Participants are shown 4 pictures for each odor (10 odors in total), then they need to select what they sniffed. Have a 10-minute break. Part B: Participants sniff 20 different odors, 10 of which are the same odors as in Part A. They need to select the picture and figure out whether the odor is old or new.
Time frame: From baseline to 18 months' follow-up and 36 months' follow-up
Longitudinal changes of odor-induced brain fMRI activation
Compare the change of odor-induced brain activation beta value from baseline to each follow-up time points (18 months' follow-up, 36 months' follow-up)
Time frame: From baseline to 18 months' follow-up and 36 months' follow-up
Baseline brain structural MRI scan
Cortical morphology
Time frame: Within 1 week after cognitive assessments
Baseline brain functional MRI scan
Large-scale network functional connectivity
Time frame: Within 1 week after cognitive assessments
Longitudinal changes of brain structural MRI scan
Compare the change of cortical morphology from baseline to each follow-up time points (18 months' follow-up, 36 months' follow-up)
Time frame: From baseline to 18 months' follow-up and 36 months' follow-up
Longitudinal changes of functional MRI scan
Compare the change of large-scale network functional connectivity from baseline to each follow-up time points (18 months' follow-up, 36 months' follow-up)
Time frame: From baseline to 18 months' follow-up and 36 months' follow-up
Plan to share: Yes — IPD sharing will be made during the 12 months after the end of study, and the original data can be obtained from the PI if necessary.
Supporting information: Study protocol, Sap, Analytic code
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The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School