Mild cognitive impairment

The prevalence of mild cognitive impairment in type 2 diabetes mellitus patients: a systematic review and meta-analysis

AIMS

Mild Cognitive impairment (MCI) is common in type 2 diabetes mellitus (T2DM) patients. The impaired cognitive function had harmful effect on patients' diabetic conditions. This study aimed to estimate the prevalence of MCI in T2DM (T2DM-MCI) patients by conducting a systematic review and meta-analysis of observational studies.

METHODS

We carried out a literature search until June 1, 2020, for all observational studies in the following databases: Medline (PubMed), Web of Science, and Embase. Two independent reviewers initially screened the eligible articles. Then, a meta-analysis (random effects model) was conducted to estimate the prevalence of MCI in people with T2DM with STATA 16.

RESULTS

A total of 1808 articles were first considered after reading title and abstract, 12 of which remained after reviewing the full text. The combined prevalence of MCI in T2DM patients was estimated to be 45.0% (95% CI=36.0, 54.0). There was no significant heterogeneity through meta-regression and sensitivity analysis. Overall, Europe (n=2, r=36.6%, 95% CI=26.3, 46.9, I²=82.3%) had a lower prevalence than Asia (n=10, r=46.4%, 95% CI=36.2, 56.6, I²=98%). The overall prevalence in female patients (n=14, r=46.9%, 95% CI=34, 59.8, I²=98.3%) was higher than that in male patients (n=14, r=38.8%, 95% CI=27, 50.7, I²=98%). Subgroup analysis based on age demonstrated a lower prevalence in patients older than 60 years (n=9, r=44.3%, 95% CI=33.1, 55.6, I²=98.3%) than patients younger than 60 years (n=3, r=46.4%, 95% CI=33.3, 59.5, I²=91.2%).

CONCLUSION

Our results demonstrate that the pooled estimated prevalence of mild cognitive impairment in type 2 diabetes mellitus patients is high worldwide, especially in China Asia. Primary care clinicians should pay more attention to the cognitive function of T2DM patients, as mild cognitive impairment is one of the risk factors for Alzheimer's disease.

The modulation effect of non-invasive brain stimulation on cognitive function in patients with mild cognitive impairment: a systematic review and meta-analysis of randomized controlled trials

Background

To prevent and control dementia, many scholars have focused on the transition stage between normal ageing and dementia, mild cognitive impairment (MCI) which is a key interventional target for dementia. Studies have shown that non-invasive brain stimulation (NIBS) is beneficial to improve cognitive function of MCI patients. However, whether NIBS is conducive to the protection of cognitive ability in MCI patients remains unknown due to limited evidence. The aim of the study was to systematically evaluate the modulation effect of NIBS on cognitive function (global cognitive ability and specific domains of cognition) in patients with MCI.

Results

A total of 11 RCTs comprising a total of 367 MCI participants. Meta-analysis showed that NIBS can significantly improve global cognition (n = 271, SMD = 0.94, 95% CI 0.47–1.41, p < 0.0001) and verbal fluency (n = 72, MD = 2.03, 95% CI 0.17–3.88, p = 0.03). However, there was no significant improvement in other domains of cognition.

Conclusions

NIBS has a positive effect on improving global cognitive function and verbal fluency. At the same time, it has a small positive effect on improving executive function. However, these findings should be interpreted carefully due to the limitations of the study.

Electronic supplementary material

The online version of this article (10.1186/s12868-018-0484-2) contains supplementary material, which is available to authorized users.

Mild cognitive impairment predicts institutionalization among older men: a population-based cohort study

Background

There is a lack of evidence on the contribution of mild cognitive impairment (MCI) to institutionalization in older adults. This study aimed to evaluate a range of risk factors including MCI of institutionalization in older men.

Methods

Men aged ≥70 years (n = 1705), participating in the Concord Health and Ageing in Men Project, Sydney, Australia were studied. Participants completed self-reported questionnaires and underwent comprehensive clinical assessments during 2005–2007. Institutionalization was defined as entry into a nursing home facility or hostel at any time over an average of 5 years of follow-up. Cox regression analysis was conducted to generate hazard ratios (HR) with 95% confidence intervals (CI).

Results

A total of 125 (7.3%) participants were institutionalized. Piecewise Cox proportional models were generated and divided at 3.4 years (1250 days) of follow-up due to violation of the proportional hazards assumption for the association between MCI and institutionalization (χ² = 6.44, p = 0.01). Dementia, disability in Activities of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL), poor grip strength, few social interactions, being a Non-English speaking immigrant and age were predictive of institutionalization during both time periods, whereas MCI (HR = 4.39, 95%CI 2.17–8.87) only predicted institutionalization in the period beyond 3.4 years of follow-up. Being married (HR = 0.42, 95%CI: 0.24–0.72) was protective only during the period after 3.4 years of follow-up.

Discussion

In this study, the strongest predictors of institutionalization were dementia, MCI, ADL and IADL disability. MCI was not a predictor of early institutionalization but became a significant predictor beyond 3.4 years of follow-up.