Despite stable national trends over the past decade, new JAMA data reveal widening age and racial disparities in metabolic syndrome, highlighting where prevention and care efforts may need to intensify.

Study: Trends and Prevalence of the Metabolic Syndrome Among US Adults. Image Credit: VashDog / Shutterstock

In a recent study published in The Journal of the American Medical Association (JAMA), researchers examined the prevalence and trends of the metabolic syndrome among adults in the United States (US).

Metabolic syndrome refers to the presence of a cluster of cardiovascular risk factors and is associated with elevated morbidity and mortality. Disruptions in lifestyle and healthcare access during the coronavirus disease 2019 (COVID-19) pandemic may have impacted the prevalence of metabolic syndrome; however, data on recent estimates remain limited.

Study Design and Data Sources

In the present study, researchers investigated changes in the prevalence of metabolic syndrome in US adults between 2013 and August 2023. They analyzed data from the National Health and Nutrition Examination Survey (NHANES) on adults aged 20 years or older. Response rates decreased from 68.5% to 25.7% between the 2013–14 and 2021–23 cycles. Survey weights were applied to non-response, and additional analyses found no evidence of non-response bias.

Diagnostic Criteria for Metabolic Syndrome

Participants met criteria for metabolic syndrome if they had at least three of the following components: hypertriglyceridemia, hypertension, elevated fasting plasma glucose or treated diabetes, large waist circumference (greater than 88 cm in females and greater than 102 cm in males), or low levels of high-density lipoprotein (HDL) cholesterol (less than 40 mg/dL in males or less than 50 mg/dL in females). Hypertriglyceridemia was defined as triglyceride levels of 150 mg/dL or higher, and hypertension was defined as the use of antihypertensive medication or systolic or diastolic blood pressure of at least 130/85 mmHg.

Elevated fasting plasma glucose or diabetes was defined as the use of anti-diabetic medication or fasting plasma glucose levels of 100 mg/dL or higher. Ethnicity and race were self-reported. Age-standardized prevalence estimates were calculated based on the 2020 US Census. Logistic regression models with interaction terms were used to evaluate trends across survey cycles and test subgroup differences.

Overall Prevalence and Component Trends

The analytic sample included 11,570 adults. The weighted prevalence of metabolic syndrome was 38.7%. Overall prevalence increased from 35.4% to 38.5% between the 2013–14 and 2021–23 cycles, but the increase was not statistically significant. A statistically significant, non-linear trend was observed in hypertriglyceridemia, which declined from 23.7% in 2013–14 to 20% in 2017–20, then increased to 25.1% in 2021–23.

Other components of metabolic syndrome exhibited non-significant fluctuations across survey cycles.

Age, Sex, and Racial Subgroup Differences

Subgroup analyses showed a significant increase in the prevalence of metabolic syndrome among adults aged 60 years or older, rising from 50.2% in 2013–14 to 62.4% in 2021–23.

Prevalence was largely stable in younger age groups, with no significant differences by sex. Among ethnic and racial groups, a significant increase was observed in non-Hispanic Black individuals. No significant trends were identified by poverty income ratio or in other subgroups, and some fluctuations may reflect limited statistical robustness.

Interpretation, Limitations, and Public Health Implications

Approximately 4 in 10 US adults met the criteria for metabolic syndrome as of 2023. Overall prevalence did not change significantly from 2013 to 2023, and most components remained stable. A modest increase in hypertriglyceridemia may reflect obesity-related dyslipidemia, worsening dietary patterns, or disruptions in medication adherence or preventive care during the COVID-19 pandemic.

Notable demographic differences included increases among older adults and non-Hispanic Black individuals, potentially reflecting higher exposure to chronic stressors, behavioral factors, or barriers to healthcare access.

Limitations include declining survey response rates and the cross-sectional design, which precludes causal inference. Sustained efforts to improve lifestyle factors, continuity of care, and preventive management remain critical to reducing cardiovascular risk, particularly in vulnerable populations.