Differences in Lp[a] concentrations and apo[a] polymorphs between black and white Americans

Area of Science:

• Biochemistry and Molecular Biology
• Human Genetics and Population Studies
• Cardiovascular Disease Risk Factors

Background:

• Lipoprotein(a) [Lp(a)] is an independent risk factor for atherosclerotic cardiovascular diseases.
• Lp(a) levels and its apolipoprotein(a) [apo(a)] size isoforms exhibit population-specific variations.
• Understanding racial differences in Lp(a) is crucial for assessing cardiovascular risk stratification.

Purpose of the Study:

• To investigate and compare Lp(a) concentrations and apo(a) size isoform distributions between Black and White populations.
• To determine the relationship between apo(a) size and Lp(a) levels across different racial groups.
• To identify potential racial disparities in Lp(a) as a cardiovascular risk marker.

Main Methods:

• Plasma Lp(a) concentrations were measured using an ELISA method insensitive to apo(a) size.
• Apo(a) size isoforms were determined by high-resolution agarose gel electrophoresis.
• Allele frequencies were estimated using maximum likelihood methods in a cohort of 3959 individuals from four U.S. communities.

Main Results:

• Significant differences in apo(a) allele frequencies and phenotype distributions were observed between Black and White participants (P < 0.0001).
• Black individuals showed higher Lp(a) concentrations (mean 94 nmol/L) compared to White individuals (mean 48 nmol/L).
• The relationship between apo(a) size and Lp(a) concentration varied significantly by race, especially in intermediate isoform ranges (K4(20)-K4(30)).

Conclusions:

• Black and White populations exhibit significant differences in Lp(a) concentrations and apo(a) allele frequencies.
• Racial disparities exist in the association between apo(a) size isoforms and Lp(a) levels.
• These findings underscore the importance of considering race in the interpretation of Lp(a) levels for cardiovascular risk assessment.