Mark, Justin

Introduction: Apolipoprotein B (ApoB) and coronary artery calcium score (CAC) are well-established risk factors for coronary heart disease (CHD). However, the interaction between these risk factors on CHD risk has not been well-studied. We investigated the association between ApoB levels and CAC with CHD risk. Methods: We analyzed 4,649 participants from the Multiethnic Study of Atherosclerosis cohort (median follow-up 13.9 years) without baseline CHD or statin use. High ApoB was defined as ≥120 mg/dL. Participants were divided into 6 groups; group 1: CAC = 0 with normal ApoB, group 2: CAC = 0 with high ApoB, group 3: CAC 1-99 with normal ApoB, group 4: CAC 1-99 with high ApoB, group 5: CAC ≥100 with normal ApoB, group 6: CAC ≥100 with high ApoB. CHD was defined as myocardial infarction, resuscitated cardiac arrest, or CHD death. Survival analysis using Kaplan-Meier and multivariable Cox proportional hazard models were performed to assess the relationship between ApoB, CAC, and time to first CHD event. Results: In an adjusted model, high ApoB, CAC (1-99), and CAC (≥100) were independently associated with CHD (HR: 1.48; 95% CI: 1.04, 2.11; HR: 2.54; 95% CI: 1.78, 3.64; and HR: 4.41; 95% CI: 3.08, 6.31, respectively). Compared to group 1 (CAC 0 with normal ApoB), CAC 0 and high ApoB (group 2) was not associated with increased risk of CHD (HR: 1.15; 95% CI: 0.59, 2.23). However, a statistically significant greater risk of CHD was observed in those with CAC 1-99 and normal ApoB (group 3) (HR: 2.12; 95% CI: 1.37, 3.28), CAC 1-99 and high ApoB (group 4) (HR: 4.12; 95% CI: 2.42, 7.00), CAC ≥100 and normal ApoB (group 5) (HR: 4.20; 95% CI: 2.78, 6.34), CAC ≥100 and high ApoB (group 6) (HR: 5.72; 95% CI: 3.40, 9.63). Conclusions: In this analysis, ApoB and CAC are independently associated with CHD risk. Individuals with high ApoB and CAC ≥100 had the highest risk of CHD. In contrast, individuals with CAC = 0 and high ApoB had no significant increase in CHD risk compared to individuals with normal ApoB levels. These findings suggest that ApoB and CAC may be complementary tools for CHD risk stratification in the context of primary prevention.

Background: Lipoprotein(a) [Lp(a)] and metabolic syndrome (MetS) are well-established risk factors for cardiovascular disease. Recent evidence suggests that high Lp(a) levels may increase the risk of coronary heart disease (CHD) in patients with diabetes, raising the question of whether similar interactions exist between Lp(a) and metabolic syndrome. We aimed to evaluate the joint association of Lp(a) and MetS with incident CHD risk in a large, multi-ethnic, prospective cohort. Methods: We analyzed 6,664 participants from the MESA (Multiethnic Study of Atherosclerosis) cohort (median follow-up 14.0 years) without baseline CHD. MetS was defined as ≥3 of the following criteria: waist circumference ≥102 cm (men), or ≥88 cm (women), triglycerides ≥150 mg/dL or use of a fibrate medication, HDL-C <40 (men) or <50 (women) or use of a fibrate medication, SBP ≥130 mm Hg and/or DBP ≥85 mm Hg or use of antihypertensive medication, fasting glucose ≥100 mg/dL or use of antidiabetic medication (4). Elevated Lp(a) was defined as a level ≥50 mg/dL. CHD was defined as myocardial infarction, resuscitated cardiac arrest, or CHD death. Participants were divided into four groups: group 1: Normal Lp(a) without MetS, group 2: elevated Lp(a) without MetS, group 3: normal Lp(a) with MetS, group 4: elevated Lp(a) with MetS. Survival analysis using Kaplan-Meier and multivariable Cox proportional hazard models were performed to assess the relationship between Lp(a), MetS, and time to CHD. Results: In an adjusted model, log [Lp(a)] and MetS were both independently associated with CHD (HR: 1.14; 95% CI: 1.03, 1.25) and (HR: 1.75; 95% CI: 1.35, 2.27). Compared to the reference group (normal Lp(a) without MetS), those with elevated Lp(a) without MetS (group 2) did not have increased risk of CHD (HR: 1.30; 95% CI: 0.94, 1.80). However, those with normal Lp(a) with MetS (group 3) had greater risk of CHD (HR: 1.56; 95% CI: 1.18, 2.05). The highest risk for CHD were in those with elevated Lp(a) with MetS (group 4) (HR: 2.37; 95% CI: 1.66, 3.37). Conclusions: In this analysis. elevated Lp(a) and MetS independently increase CHD risk. MetS alone significantly increases risk, whereas elevated Lp(a) without MetS does not demonstrate a significant effect. However, their combination confers the highest risk, suggesting a synergistic interaction. These results emphasize the value of assessing Lp(a) in individuals with MetS to improve cardiovascular risk stratification and guide targeted prevention.