Association of apolipoprotein B with all-cause and cardiovascular mortality among adults: Results from the National Health and Nutrition Examination Surveys

Background: Apolipoprotein B (apoB) is a crucial component that directly reflects the number of atherogenic lipoprotein particles and is closely related to atherosclerosis. However, there was an inconsistency among previous studies in its relationship with mortality. Using nationally representative data, we aimed to investigate the association of apoB with cardiovascular and all-cause mortality. Methods: We retrospectively included participants from the National Health and Nutrition Examination Survey (2007-2014), and mortality was ascertained through December 31, 2015. Hazard ratios (HRs) with 95% confidence intervals (CIs) of apoB in quartiles (Q1-Q4) for mortality risk were calculated using multivariable-adjusted Cox proportional hazards models, and restricted cubic spline regressions were performed to test dose relationships. Results: We enrolled 10,375 participants with a mean age of 46.3 years, of which 47.88% were men. During a mean followup time of 69.2 months, 533 (5.14%) and 91 (0.88%) deaths were due to all causes and cardiovascular disease, respectively. After adjusting for confounders, per SD, increment of apoB was associated with an elevated risk of cardiovascular mortality (HR, 1.13; 95% CI, 1.03-1.24). The risk of all-cause mortality was significantly reduced in the third quartile (Q3) of apoB (HR, 0.71; 95% CI, 0.56-0.91) compared with the reference quartile (Q1). Moreover, spline analyses showed that the relationship of apoB with all-cause mortality was U-shaped, and the threshold value was 108 mg/dL. Conclusions: ApoB was linearly associated with increased risk of cardiovascular mortality and non-linearly associated with all-cause mortality in a U-shaped manner, independently of other cardiovascular risk factors.