The prevalence of Metabolic Syndrome (MetS) increases with aging, significantly contributing to the rising burden of non-communicable diseases (NCDs). This study aimed to investigate over-time changes in the prevalence of MetS and its components among the elderly population of Iran.

Methods: We analyzed data from the 2016 and 2021 national STEPwise approach to non-communicable disease risk factor Surveillance (STEPS) for participants aged ≥65 who completed all three survey steps (questionnaire-based assessments, physical measurements, and laboratory tests) with no missing data on MetS components. According to the STEPS protocol, individuals with severe mental disorders, physical limitations that prevented measurements, or inability to provide laboratory samples were excluded. Using survey analysis techniques and weights, we ensured the findings are nationally representative. MetS was defined using the following criteria: National Cholesterol Education Program Adult Treatment Panel III (NCEP ATPIII), International Diabetes Federation (IDF), American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI), and Joint Interim Statement (JIS). Regional IDF (RIDF) and regional JIS (RJIS) were defined by ethnicity-specific values of waist circumference.