ABSTRACT
<p><b>BACKGROUND</b>This study was designed to evaluate the relationship between high-density lipoprotein cholesterol (HDL-C) level and acute myocardial infarction (AMI) and coronary heart disease (CHD) death and to explore the protective effect of HDL against CHD in the elderly Chinese.</p><p><b>METHODS</b>Started from 1986, 1211 retirees (92% males) were enrolled consecutively and studied prospectively. The average starting age was 70 +/- 9 years, and that at the end of the study was 80 +/- 9 years. During the follow-up study, all the participants received yearly physical examination and blood chemistry survey from 1986 - 2000. The average duration of the follow up study was 11.2 years. The end point of this study was either attacks of AMI or death due to CHD and other causes. CHD risk factors were screened by logistic regression analysis. According to their HDL-C levels, cases were divided into low (< 1.03 mmol/L), medium (or normal, 1.03 - 1.56 mmol/L) and high (> 1.56 mmol/L) level groups, the differences in incidence of AMI and CHD death in each group were analyzed.</p><p><b>RESULTS</b>The cumulative attacks of acute coronary syndrome (mostly AMI) were 214 cases, including 89 cases of coronary death and 308 death caused by other diseases during the follow up study. AMI occurrence and CHD death in normal HDL-C group were lower than those in the low HDL-C group by 40% and 53%; and those in the high HDL-C group were lower than in the normal group by 56% and 50%, respectively. Statistical analysis on normal lipid cases (411 cases, total cholesterol < 5.17 mmol/L, triglyceride < 1.69 mmol/L) revealed that the cases at low HDL-C level had similar rates of AMI events and CHD mortality as those of the entire group (including hyperlipidemia); however, AMI attacks and CHD deaths decreased significantly at the normal and high HDL-C levels. The results demonstrated that the protective effect of HDL against coronary artery disease is more prominent in people with low lipid level.</p><p><b>CONCLUSION</b>Low HDL is an important independent risk factor for AMI attacks and CHD death in the elderly; high HDL has significant protective effect against coronary artery disease.</p>
Subject(s)
Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Cholesterol, HDL , Blood , Cholesterol, LDL , Blood , Coronary Disease , Blood , Myocardial Infarction , Risk FactorsABSTRACT
<p><b>BACKGROUND</b>It is still controversial whether or not the correlation between lipid abnormality and coronary heart disease (CHD) becomes weaker in the elderly, and whether patients above 80 years old still benefit from lipid management for the secondary prevention of CHD. The purpose of this study is to assess the correlation between hyperlipidemia and the risk of CHD events in the elderly, and to determine if it is appropriate to use lipid-lowering drugs in those aged above 80, as prescribed by the recommended guidelines for lipid management.</p><p><b>METHODS</b>One thousand two hundred and eleven retirees, mainly males (92%), aged 70 +/- 9 years, were enrolled in this study. Lifestyle habits and medical history were recorded via questionnaires. During the period 1986 - 2000, all subjects participated in an annual physical examination with a blood chemistry survey. The mean follow-up period was 11.2 years. Subjects with incidental illnesses, especially cardiovascular diseases, were diagnosed or treated promptly. Serum lipid parameters, including total cholesterol (TC), low and high-density lipoprotein cholesterol (LDL-C and HDL-C) and triglyceride (TG) levels were analyzed according to standardization of lipid and lipoprotein measurements. The association between lipid levels and the prevalence of acute myocardial infarction (AMI) or coronary death was analyzed statistically.</p><p><b>RESULTS</b>Lipid abnormalities occurred in 2/3 of the 1211 subjects. The most common lipid disorder was high TC and high LDL-C, which was much more prevalent than high TG. Among the subjects, 51.6% had TC levels above 5.2 mmol/L. Mean TC and LDL-C reached peak levels in the 65 - 74 age group without significant decrease until ages over 90. The cumulative total number of deaths due to various causes was 397 in the 15-year follow-up period, with the mortality rate in the high lipid group slightly lower than that in the normal lipid group (30.6% vs 35.3%), although the difference was not significant (P = 0.1931). However, there were more cases of coronary death in the high lipid group than in the normal lipid group (7.9% vs 4.6%, P = 0.0045). When examining AMI survivors, more AMI cases were found in the high lipid group than in the low lipid group (20.9% vs 11.4%, P < 0.0001). The cumulative number of coronary deaths was 89 (with 88 cases above age 70), and the total number of CHD cases was 214 (17.7% of the whole group). Logistic regression analysis reveals that age, hypertension, LDL-C, and HDL-C are important risk factors for CHD. Lifestyle changes were common, but only 45% of the hyperlipidemic cases received drug treatment. Statins were commonly used only in recent years.</p><p><b>CONCLUSION</b>The above results show that high TC and LDL-C levels are correlated with a high CHD risk even in people over 80. For elderly patients with clinical CHD and an aggregation of CHD risk factors, cholesterol-lowering therapy might be considered if the general health of the patient makes this permissible.</p>