Ethnicity
- Circulating lipoprotein(a) (Lp(a)) levels vary more than 7-fold among populations and generally parallel the rates of heart disease, with a few exceptions.1 Eskimos, Native Americans, Hispanics, Chinese, and French populations have low rates of heart disease, that is accompanied by low levels of Lp(a).1
- Blood levels of Lp(a)are similar in men and women and are skewed in the population with a tail toward the highest levels. Therefore median levels are more accurate than mean levels. 1
- Median levels are lowest in American Indians (3 mg/dl) followed by whites (12 mg/dL) and highest in blacks (39 mg/dl).2 The levels are intermediate among Chinese (11 mg/dl) and Japanese (13 mg/dl) Hispanics (19 mg/dl).3 Elevated Lp(a) levels (>25 to 30 mg/dl) are present in up to 30% of whites and 70% of blacks.4
- Blacks have the highest Lp(a) levels (2-3 fold higher than whites) and the distribution is less skewed than in whites. Nonetheless, Lp(a) confers less risk in blacks than in whites (Figure 039). This is primarily due to favorable distribution of Lp(a) isoforms with a low prevalence of the highly atherogenic small isoforms and high prevalence of relatively benign large Lp(a) isoforms.5-9 Besides blacks have an antiatherogenic lipid profile (lower LDL-C and triglyceride levels and higher HDL-C levels) which may counterbalance the atherogenic potential of Lp(a).8, 9
- Hispanics have higher Lp(a) levels than American Indians, but lower levels than whites. Besides, Hispanics with the highest percentage of American Indian heritage have even lower Lp(a) levels.10 These data underscore the importance of ethnicity and genetics in determining Lp(a) levels.1
- Japanese have Lp(a) levels similar to whites, although Chinese have lower levels than whites.11, 12 Lp(a) levels are more closely related to stroke among Chinese and Japanese ─ the predominant form of CVD in these populations.13-15
- The Asian Indians have the second highest level of Lp(a) and the levels are 3 times higher than the Chinese ─ a difference that is evident even in cord blood and parallel the wide difference in CAD rates between these 2 populations.1 High levels of Lp(a) are highly prevalent and highly correlated with malignant heart disease in young Indians.16 (see Lipoprotein(a) in Asian Indians)
- Unlike Asian Indians, blacks are somewhat protected against the dangers of Lp(a) by having a less dangerous form of it and by their high levels of HDL, which Indians typically lack.1
- However the 20 year follow up of ARIC study (266,360 person years of follow up and 2497 CVD events) has reported the CAD risk in African-Americans from elevated Lp(a) to be as strong as in whites. Strikingly Lp(a) conferred a greater risk of stroke in African-Americans than in whites.17 See Figure 111
Sources
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2. Wang W, Hu D, Lee ET, et al. Lipoprotein(a) in American Indians is Low and Not Independently Associated with Cardiovascular Disease. The Strong Heart Study. Ann Epidemiol. 2002;12(2):107-114.
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