Social connections influence cardiovascular and metabolic outcomes, but more research is needed to examine whether different aspects of social connections relate differently to physical, physiological, and biological markers of cardiometabolic health. This study examined associations between structural, functional, and quality aspects of social connections and key anthropometric and cardiometabolic markers. Using data from Understanding Society, linear regression analyses adjusted for identified confounders explored associations between living with others (structural), social support (functional), and relationship strain (quality) with anthropometric (BMI, waist circumference; n=16,284), cardiovascular (pulse rate, systolic blood pressure (BP), diastolic BP; n=13,902), and metabolic markers (triglycerides, total cholesterol, glycated haemoglobin (HbA1c); n=10,070). Living with others was associated with higher BMI (B=0.638, 95%CI=0.365 to 0.911) and waist circumference (B = 1.597, 95%CI = 0.928 to 2.265), while greater social support and lower relationship strain showed the reverse association. Living with others, greater social support, and lower relationship strain were all associated with lower pulse rate, although just social support and low relationship strain were associated with lower diastolic BP and none of the three exposures with lower systolic BP. Greater social support and lower relationship strain (but not living with others) were associated with lower total cholesterol (B = -0.019, 95%CI = -0.033 to -0.005; B = -0.022, 95%CI = -0.039 to -0.006), triglycerides (B = -0.012, 95%CI = -0.018 to -0.005; B = -0.014, 95% CI = -0.022 to -0.006), and HbA1c levels (B = -0.003, 95%CI = -0.005 to -0.001; B = -0.006, 95% CI = -0.008 to -0.003). There was some suggestion of moderation by sex, although this was modest. These findings enhance understanding of the nuanced relationship between structural, functional, and quality aspects of social connections and health.