Feeling of loneliness and determinants of health as correlates of cardiometabolic syndrome: a population-based US study

Loneliness is an emerging social health factor that has been linked to cardiovascular outcomes and early mortality. Cardiometabolic syndrome is characterized by a combination of metabolic disturbances, including impaired glucose regulation alongside abdominal obesity, hypertension, and dyslipidemia, and is associated with an increased risk of cardiovascular and metabolic diseases. While prior research has linked loneliness to individual CMS components, some studies have also examined its association with metabolic syndrome as a cluster; however, this association has not been extensively examined in large, weighted samples of U.S. adults spanning a wide age range. Moreover, the biological, social, and behavioral factors associated with both loneliness and CMS have not been examined together. Therefore, this study investigated whether loneliness is associated with CMS, while examining biological, social, and behavioral factors associated with both conditions. We conducted a secondary analysis of 160,223 adults across 24 U.S. states using data from the 2023 Behavioral Risk Factor Surveillance System (BRFSS). The main exposure was self-reported loneliness, and the outcome was cardiometabolic syndrome (CMS), operationally defined in our study as the presence of self-reported type 2 diabetes plus at least two of the following: hypertension, obesity (BMI ≥ 30.0 kg/m²), or self-reported high cholesterol, based on the available BRFSS data. Additional predictors included biological, social, and behavioral factors. Survey-weighted chi-square tests and survey-weighted logistic regression models were used to examine associations between loneliness, CMS, and other study variables. An additional analysis examined the association between loneliness and CMS after adjustment for depression. Among respondents, 7.55% ( n = 14,362) had CMS and 3.02% ( n = 2,725) reported always feeling lonely. In the fully adjusted model ( N = 84,939), always feeling lonely was associated with higher odds of CMS (aOR = 1.61, 95% CI: 1.09–2.36; p = 0.015). Male sex, older age, Black race, lower education and income, former smoking, and physical inactivity were also associated with higher odds of CMS. Adjustment for depression attenuated the loneliness-CMS association, which remained significant when income was excluded ( N = 100,238 ); (aOR = 1.44, 95% CI: 1.03–2.01; p = 0.031), but not in the fully adjusted model ( N = 84,659); (aOR = 1.41, 95% CI: 0.96–2.07; p = 0.079). Loneliness was associated with cardiometabolic syndrome, although the association was attenuated after accounting for depression, suggesting potential overlap among psychosocial factors. Longitudinal studies are needed to clarify temporality and determine whether addressing loneliness may influence cardiometabolic health.