Abstract
Background:
The relationship between metabolic syndrome (MetS) and Alzheimer disease (AD) has gained increasing attention in recent years, reflecting the growing recognition of metabolic factors in neurodegenerative conditions. The present study aims to estimate the prevalence of MetS in patients with AD.
Methods:
A systematic review and meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A comprehensive literature search of PubMed, Scopus, and Web of Science was performed. Observational studies reporting the prevalence of MetS among patients with AD and/or providing comparative data with control groups were included. Pooled prevalence and odds ratios with 95% confidence intervals (CIs) were calculated using a random-effects model, and heterogeneity was assessed using the
I
2
statistic. Subgroup and meta-regression analyses were also performed.
Results:
Nine studies were included. The pooled prevalence of MetS among patients with AD was 46.7% (95% CI: 28.0%–65.8%;
I
2
= 97.11%). In subgroup analysis by continent, the prevalence was 26.1% (95% CI: 11.1%–44.4%) in Asia (
I
2
= 84.42%) and 52.8% (95% CI: 25.2%–79.5%) in Europe (
I
2
= 97.05%), while the estimate from North America was 72.2% (95% CI: 62.5%–81.0%) based on a single study. The comparative analysis showed an odds ratio of 1.64 (95% CI: 0.75–3.57), with no statistically significant association between AD and MetS. Meta-regression identified glucose as significantly associated with MetS prevalence (β = 0.022;
P
= .021).
Conclusion:
MetS was frequently observed among patients with AD; however, the pooled prevalence estimate should be interpreted cautiously because of substantial between-study heterogeneity. The comparative analysis did not demonstrate a statistically significant association between AD and MetS. Further studies using standardized definitions and more homogeneous populations are needed to clarify this relationship and the sources of heterogeneity.