MRI brain findings in patients with depression and type 2 diabetes – a scoping review

Figures & data

Figure 1: Flow diagram showing how articles were obtained for the study

Table 1: Articles included in the scoping review

Article no.	Author	Year of publication	Country	No. of participants	Mean age in years (SD)	On DM treatment	On antidepressants	Comorbidities	Gender	Type of study	Associations found relevant in this scoping review
1	Bands et al.^Citation23	2007	Netherlands	174	65.9 (5.7)	Yes	Not recorded	Vascular comorbidities and mood disorders included but other neurological and psychiatric conditions excluded	49.4% male	Cross-sectional	Patients with T2DM had higher Beck Depression Inventory and ‘worse MRI ratings than controls’
2	Ajilore et al.^Citation24	2007	USA	65	56.6 (10.2)	Yes	Free of antidepressants > 2 weeks	Patients were excluded if they had other pre-determined comorbidities	26.2% male	Not stated	Myo-inositol concentrations were decreased in depressed diabetic patients in the frontal white matter
3	R Kumar et al.^Citation25	2008	Australia	478	60–64*	Yes	Not recorded	Not excluded	51.8% male	Cross-sectional	DM has increased brain atrophy and larger CSF volumes in 60–64-year-old patients, independent of depression
4	A Kumar et al.^Citation26	2008	USA	77	55.5 (9.6)	Yes	Free of antidepressants > 2 weeks	Other medical/ neurological and psychiatric conditions excluded	Not stated	Cross-sectional	PLWD had smaller total brain grey matter volumes regardless of whether they had depression, compared with controls
5	McIntyre et al.^Citation21	2010	Various countries	4858	Varied between studies	Varied between studies	Varied between studies	Varied between studies	Not stated	Summary article	‘The pattern of volumetric and neurocognitive deficits in diabetic populations are highly similar to that reported in populations of individuals with major depressive disorder’
6	Ajilore et al.^Citation27	2010	USA	72	55.5 (9.7)	Yes	Free of antidepressants > 2 weeks	Excluded unstable medical patients and neurological conditions	26.4% male	Not stated	DM and depression are associated with cortical grey matter thinning in the medial prefrontal area
7	Cui et al.^Citation28	2014	Israel	69	65.5 (8.7)	Yes	Not mentioned	No exclusion criteria	49.3% male	Cross-sectional	T2DM was associated with greater variability, more depression and less grey matter in the limbic and temporal-parietal lobes (e.g. cingulum, insular, hippocampus)
8	Hsu et al.^Citation29	2016	USA	604	57.7 (9.3)	Yes	Not mentioned	No exclusion criteria	40.1% male	Not stated	In T2DM, adiposity is inversely associated with brain volumes and positively associated with depression in European Americans
9	Jansen et al.^Citation30	2016	Netherlands	80	61.1 (9.5)	Yes	Not mentioned	Non-dementia patients	56.3% male	Cross-sectional	The effect of T2DM on cerebral blood flow (CBF) is small (independent of cerebral atrophy) Subcortical CBF is positively associated with depression
10	Zhang et el.^Citation31	2019	China	56	53.8 (8.1)	Not stated	Not mentioned	Other psychiatric and vascular conditions excluded	60.1% male	Cross-sectional	Increased depression and abnormal spontaneous activities in regions of the brain were found in patients with T2DM with neuropathy
11	Roy et al.^Citation32	2020	USA	122	56.8 (7.1)	Yes	Not mentioned	Other medical, psychiatric and neurological conditions were excluded	50.0% male	Not recorded	Decreased grey matter volumes (in prefrontal, hippocampus, amygdala, insular, cingulate, cerebellum, caudate, basal forebrain, and thalamus areas) were seen in DM Decreased grey matter was significantly associated with depression
12	Rensma et al.^Citation33	2020	Iceland	2135	74.5 (4.6)	Not stated	On treatment	Patients with dementia were excluded	41.7% male	Longitudinal	T2DM is associated with increased depressive symptoms and cerebral small vessel disease

*Age range, not standard deviation.

Table 2: Summary of countries and number of articles published.

No.	Country	Number of studies
1	USA	5
2	Netherlands	2
3	China	1
4	Iceland	1
5	Australia	1
6	Israel	1

Brands AMA, Manschot S, Van den Berg E, et al. A detailed profile of cognitive dysfunction and its relation to psychological distress in patients with type 2 diabetes mellitus. J Int Neuropsycholo Soc. 2009: 288–297. https://doi.org/10.1017/s1355617707070312.

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Ajilore O, Haroon E, Kumaran S, et al. Measurement of brain metabolites in patients with type 2 diabetes and major depression using proton magnetic resonance spectroscopy. Neuropsychopharm. 2007;32:1224–1231. https://doi.org/10.1038/sj.npp.1301248.

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Kumar R, Anstey KJ, Wen W. Association of type 2 diabetes with depression, brain atrophy, and reduced fine motor speed in a 60- to 64-year-Old community sample. Am J Geriatr Psych. 2008;16:12. https://doi.org/10.1097/jgp.0b013e31818b40fc.

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Kumar A, Haroon E, Darwin C, et al. Gray matter prefrontal changes in type 2 diabetes detected using MRI. J Mag Res Imag. 2008;27:14. https://doi.org/10.1002/jmri.21224.

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McIntyre RS, Kenna H, Nguyen HT. Brain volume abnormalities and neurocognitive deficits in diabetes mellitus: points of pathophysiological commonality with mood disorders? Adv Ther. 2010;27(2):63–80. https://doi.org/10.1007/s12325-010-0011–z.

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Ajilore O, Narr K, Rosenthal J, et al. Regional cortical gray matter thickness differences associated with type 2 diabetes and major depression. Psych Res. 2010;184:63–70. https://doi.org/10.1016/j.pscychresns.2010.07.003.

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Cui X, Abduljalil A, Manor BD, et al. Multi-Scale glycemic variability: A link to gray matter atrophy and cognitive decline in type 2 diabetes. PLoS ONE. 2014;9(1):e86284. https://doi.org/10.1371/journal.pone.0086284.

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Hsu F, Yuan M, Bowden DW. Adiposity is inversely associated with hippocampal volume in African Americans and European Americans with diabetes. J Diabetes Compli. 2016;30(8):1506–1512. https://doi.org/10.1016/j.jdiacomp.2016.08.012.

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Jansen JFA, Van Bussel FCG, van de Haar H, et al. Cerebral blood flow, blood supply, and cognition in type 2 diabetes mellitus. Sci Rep. 2016;6:160003. https://doi.org/10.1038/s41598-016-0003-6.

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Zhang Q, Zhang P, Yan R, et al. A single-blinded trial using resting-state functional magnetic resonance imaging of brain activityin patients with type 2 diabetes and painful neuropathy. Diabetes Ther. 2019;10:135–147. https://doi.org/10.1007/s13300-018-0534-x.

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Roy B, Ehlert L, Muller R, et al. Regional brain gray matter changes in patients with type 2 diabetes mellitus. Sci Rep. 2020;10:9925. https://doi.org/10.1038/s41598-020-67022-5.

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Rensma SP, Sloten TT, Ding J. Type 2 diabetes, change in depressive symptoms over time and cerebral small vessel disease: longitudinal data of the AGES-Reykjavik study. Diabetes Care. 2020;43:1781–1787. https://doi.org/10.2337/dc19-2437.

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