Lp-PLA2 mass and activity shows racial variation
MedWire News: The mass and activity level of lipoprotein-associated phospholipase A2 (Lp-PLA2) varies according to race, say researchers who add that the finding may need to be considered when assessing cardiovascular (CV) risk.
"Lp-PLA2 is viewed as a novel coronary heart disease (CHD) risk marker that could be used to risk stratify individuals when considering primary prevention strategies, such as initiating statin therapy or setting lipid treatment goals," write Keane Lee (Stanford University School of Medicine, California, USA) and colleagues in the journal BMC Cardiovascular Disorders.
The team adds that other research groups have suggested using a single threshold for Lp-PLA2 mass, regardless of gender and race, for categorizing risk.
However, "the results from this study confirm that Lp-PLA2 mass and activity levels vary significantly between Whites and non-Whites, independent of known biological and lifestyle factors," which could affect the performance of Lp-PLA2 as a prognostic risk marker, add Lee et al.
For the present study, they recruited 714 older (mean age 66 years) adults who were free from clinical CHD and not taking dyslipidemia medication at study inclusion. The team evaluated the association between race and Lp-PLA2 mass and activity in these individuals, after adjusting for various biologic, lifestyle, demographic, and genetic factors.
Mean Lp-PLA2 mass and activity levels were highest among Whites (n=540; 233 ng/ml and 134 nmol/ml-min, respectively), followed by Hispanics (n=62; 221 ng/ml and 124 nmol/ml-min), and then Asians (n=52; 202 ng/ml and 124 mmol/ml-min). African-Americans had the lowest Lp-PLA2 mass and activity levels, at 198 ng/ml and 108 nmol/ml-min, respectively.
The observed differences were not affected by covariates such as age, gender, diabetes, hypertension, body mass index, lipid measurements, C-reactive protein, smoking status, physical activity, diet, income, and three single nucleotide polymorphisms known to be associated with Lp-PLA2 activity levels.
"These findings suggest that differences in Lp-PLA2 mass and activity levels between Whites and non-Whites may be due to other genetic factors or perhaps to unmeasured lifestyle factors," comment Lee et al.
They remark that using the same Lp-PLA2 threshold in Whites and African Americans may underestimate risk in African Americans.
The team concludes, therefore, that "before incorporating information on Lp-PLA2 mass and activity levels in assessing CV risk for individual patients, additional larger, multi-racial prospective studies are needed to delineate the specific risk associated with different Lp-PLA2 levels within individual racial groups."
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By Nikki Withers