Dose-Dependent Inverse Relationship Between Alcohol Consumption and Serum Lp(a) Levels in Black African Males

Abstract

Abstract-Serum or plasma levels of Lp(a) vary widely between individuals and are higher in Africans and their descendants compared with white persons. In whites, high serum levels of Lp(a) are associated with the premature development of atherosclerosis. In both ethnic groups, serum Lp(a) levels are highly genetically determined and only a few environmental or physiological factors, like testosterone or estrogen, have been shown to lower serum Lp(a) levels. In whites, alcohol consumption is associated with lower serum Lp(a) levels. However, the mechanism underlying this association and whether it holds true for blacks is not known. To address these questions, we analyzed serum Lp(a) levels in 333 middle-aged males of African descent from the Seychelles Islands (Indian Ocean). In addition, we analyzed the size of the apo(a) isoforms and the serum levels of albumin and sex hormones in a subset of 279 subjects. Serum Lp(a) levels were similar in teetotalers (median, 32.5 mg/dL; nϭ42) and occasional drinkers (median, 34.1 mg/dL; nϭ112). In contrast, individuals consuming 10 to 80 g of ethanol/d (nϭ83) and heavy drinkers (Ͼ80 g of ethanol/d, nϭ96) had a 9% and 32% lower median Lp(a) level than teetotalers, respectively (Pϭ0.01). The size distribution of the apo(a) isoforms and the mean serum levels of albumin, estradiol, and luteinizing hormone were similar in teetotalers and occasional drinkers compared with moderate and heavy drinkers. These latter 2 groups had lower serum levels of testosterone and sex hormone-binding globulin. These data indicate that alcohol intake is associated in a dosedependent manner with lower serum Lp(a) levels in males of African descent and that this association is not related to the size of the apo(a) isoforms, to the synthetic function of the liver, or to sex hormone biochemical status.

Anestesia na população negra

“…Modificações neurohumorais provocadas pela seleção natural durante o transporte desumano nos navios negreiros asseguraram a sobrevivência apenas dos negros capazes de reter sódio e água em função dos baixos níveis de renina e do sistema calicreína-bradicinina, facilitando a ação da vasopressina. No negro americano hipertenso, há menor atividade anti-hipertensiva do captopril, losartan ou metroprolol (redutores de renina), inclusive os IECA provocam maior aparecimento de efeitos colaterais, como tosse e angioedema intenso 16 . Algumas doenças degenerativas, carenciais e infecto-contagiosas são ainda mais freqüentes na raça negra do ponto de vista estatístico (Quadro I).…”

“…Baixa densitometria óssea e maior incidência de osteoporose (fenótipo) no preto idoso pode estar relacionado com a melanina, dificultando a captação da radiação solar, menor ingesta de vitamina D e disfunção paratireoidiana, como também com a redução na ingesta de cálcio pela alta intolerância ao leite e derivados 1-3 . Elevação plasmática da lipoproteína (a) favorece o aparecimento de aterosclerose e inibe a atividade do plasminogênio, o que facilita o aparecimento de trombose central ou periférica, sobretudo nos negros idosos, obesos, diabéti-cos e aqueles com baixos níveis de renina 16 .…”

“…Também na dor crônica, o paciente preto sofre mais do que o branco, embora demore na procura da ajuda médica 56,57 . A deficiência da desidrogenase torna o negro mais sensível ao etanol 16 . Também o negro mostra dificuldade em largar o vício do cigarro: há aumento na atividade da nicotina pela demora em se eliminar seu metabólito ativo: conitina 58 .…”

“…Neurohumoral changes caused by natural selection during inhuman transportation in slave ships have assured the survival only of blacks able to retain sodium and water as a function of low renin and kallikrein-bradykinin levels. In hypertensive American blacks, the lower anti-hypertensive activity of captopril, losartan or metroprolol (renin reducers), including ACE inhibitors, leads to more side-effects such as intensive cough and angioedema 16 . Some degenerative, poverty-related and infectious-contagious diseases are statistically more common among blacks (Chart I).…”

“…Low bone densitometry and higher incidence of osteoporosis (fenotype) in elderly blacks may be related to melanin impairing sun radiation uptake, to less vitamin D ingestion and to parathyroid dysfunction, as well as decreased calcium ingestion due to high intolerance to milk and dairy products 1-3 . Lisoprotein (a) plasma increase favors the appearance of arteriosclerosis and inhibits plasminogen activity thus helping the appearance of central or peripheral thrombosis, especially in elderly, obese and diabetic blacks, and those with low renin levels 16 .…”