Data on prevalence of metabolic syndrome in Turkey: Systematic review, meta-analysis and meta-regression of epidemiological studies on cardiovascular risk factors

OBJECTIVE
The incidence of metabolic syndrome varies greatly in developed and developing countries. In the last 10 to 15 years, important studies have been performed examining the incidence of metabolic syndrome in Turkey. This article is a meta-analysis of the studies that investigated the incidence of metabolic syndrome this country.

METHODS
Epidemiological studies from the last 15 years that provided information about the incidence of metabolic syndrome in Turkey were screened in the Ovid Medline, the Web of Science Core Collection, and the Turkish Academic Network and Information Center (ULAKBIM) databases. In addition, web pages of the Ministry of Health, the Turkish Statistical Institute, and the associations of the related medical discipilnes were screened for appropriate studies. A bias tool that is developed by our team was used to categorize the included studies as having low- or high risk of bias. A random effects model was used in the meta-analysis. Linear and nonlinear meta-regression analyses were performed to evaluate heterogeneity and temporal variations in prevalence rates.

RESULTS
Four studies (n=34893) were identified that provided information about the status of metabolic syndrome in Turkey using the Adult Treatment Panel III definition. There was excellent interobserver agreement regarding the selection of studies and the scoring of the selected research with respect to bias. The meta-analysis revealed a prevalence of 32.9% (95% confidence interval [CI]: 30.2–35) overall, 38.3% (95% CI: 35.8–40.8) in women, and 26.8% (95% CI: 23.4–30.3) in men. Two studies (n=8568) provided data according to the International Diabetes Federation definition of metabolic syndrome. The random effects model used in the meta-analysis of these studies demonstrated a prevalence of metabolic syndrome of 43.3% (95% CI: 41.9–44.7) overall, 50.4% (95% CI: 49.0–51.9) in women, and 35.4% (95% CI: 32.5–38.5) in men.

CONCLUSION
In Turkey, the incidence of metabolic syndrome is 1 in every 4 men, and 1 in every 3 women. The rate is particularly high among women. Studies designed to prevent the development of metabolic syndrome are needed.