A prospective study of HDL-C and cholesteryl ester transfer protein gene mutations and the risk of coronary heart disease in the elderly

High density lipoprotein cholesterol (HDL-C) levels are inversely associated with the incidence of coronary heart disease (CHD) in middle-aged individuals; in the elderly, the association is less clear. Genetic factors, including variations in the cholesteryl ester transfer protein (CETP) gene, play a role in determining HDL-C levels. Controversy remains about whether CETP deficiency and the resultant rise in HDL-C are antiatherogenic, or whether CETP has the opposite effect due to its role in reverse cholesterol transport. In a seven-year follow-up of 2,340 men aged 71–93 in the Honolulu Heart Program, the age-adjusted CHD incidence rates were significantly lower in men with high versus low HDL-C levels. After adjustment for age, hypertension, smoking, and total cholesterol, the relative risk of CHD for those with HDL-C levels ≥60 mg/dl, compared with those with HDL-C levels <40 mg/dl, was 0.6. Men with a CETP mutation had the lowest rates of CHD, although this was not statistically significant.These data indicate that HDL-C remains an important risk factor for CHD in the elderly. Whether a CETP mutation offers additional protection against CHD warrants further investigation. High density lipoprotein cholesterol (HDL-C) levels are inversely associated with the incidence of coronary heart disease (CHD) in middle-aged individuals; in the elderly, the association is less clear. Genetic factors, including variations in the cholesteryl ester transfer protein (CETP) gene, play a role in determining HDL-C levels. Controversy remains about whether CETP deficiency and the resultant rise in HDL-C are antiatherogenic, or whether CETP has the opposite effect due to its role in reverse cholesterol transport. In a seven-year follow-up of 2,340 men aged 71–93 in the Honolulu Heart Program, the age-adjusted CHD incidence rates were significantly lower in men with high versus low HDL-C levels. After adjustment for age, hypertension, smoking, and total cholesterol, the relative risk of CHD for those with HDL-C levels ≥60 mg/dl, compared with those with HDL-C levels <40 mg/dl, was 0.6. Men with a CETP mutation had the lowest rates of CHD, although this was not statistically significant. These data indicate that HDL-C remains an important risk factor for CHD in the elderly. Whether a CETP mutation offers additional protection against CHD warrants further investigation. High density lipoprotein cholesterol (HDL-C) blood levels have been inversely associated with the incidence of coronary heart disease (CHD) in middle-aged and, to a lesser extent, in elderly individuals (1Castelli W.P. Doyle J.T. Gordon T. Hames C.G. Hjortland M.C. Hulley S.B. Kagan A. Zukel W.J. HDL cholesterol and other lipids in coronary heart disease. The cooperative lipoprotein phenotyping study.Circulation. 1977; 55: 767-772Google Scholar, 2Abbott R.D. Wilson P.W. Kannel W.B. Castelli W.P. High density lipoprotein cholesterol, total cholesterol screening, and myocardial infarction. The Framingham Study.Arteriosclerosis. 1988; 8: 207-211Google Scholar, 3Gordon D.J. Rifkind B.M. High-density lipoprotein—the clinical implications of recent studies.N. Engl. J. Med. 1989; 321: 1311-1316Google Scholar, 4Stampfer M.J. Sacks F.M. Salvini S. Willett W.C. Hennekens C.H. A prospective study of cholesterol, apolipoproteins, and the risk of myocardial infarction.N. Engl. J. Med. 1991; 325: 373-381Google Scholar, 5Pekkanen J. Linn S. Heiss G. Suchindran C.M. Leon A. Rifkind B.M. Tyroler H.A. Ten-year mortality from cardiovascular disease in relation to cholesterol level among men with and without preexisting cardiovascular disease.N. Engl. J. Med. 1990; 322: 1700-1707Google Scholar, 6Assmann G. Schulte H. von Eckardstein A. Huang Y. High-density lipoprotein cholesterol as a predictor of coronary heart disease risk. The PROCAM experience and pathophysiological implications for reverse cholesterol transport.Atherosclerosis. 1996; 124: S11-S20Google Scholar, 7Kitamura A. Iso H. Naito Y. Iida M. Konishi M. Folsom A.R. Sato S. Kiyama M. Nakamura M. Sankai T. High-density lipoprotein cholesterol and premature coronary heart disease in urban Japanese men.Circulation. 1994; 89: 2533-2539Google Scholar, 8Corti M.C. Guralnik J.M. Salive M.E. Harris T. Field T.S. Wallace R.B. Berkman L.F. Seeman T.E. Glynn R.J. Hennekens C.H. HDL cholesterol predicts coronary heart disease mortality in older persons.JAMA. 1995; 274: 539-544Google Scholar, 9Zimetbaum P. Frishman W.H. Ooi W.L. Derman M.P. Aronson M. Gidez L.I. Eder H.A. Plasma lipids and lipoproteins and the incidence of cardiovascular disease in the very elderly. The Bronx Aging Study.Arterioscler. Thromb. 1992; 12: 416-423Google Scholar). Reports from the Honolulu Heart Program (HHP) were among the first to describe the inverse relationship of “α” cholesterol (HDL-C) with CHD (10Rhoads G.G. Gulbrandsen C.L. Kagan A. Serum lipoproteins and coronary heart disease in a population study of Hawaii Japanese men.N. Engl. J. Med. 1976; 294: 293-298Google Scholar). This inverse HDL-C to CHD relationship in the Honolulu Japanese-American sample has also appeared in four other cohorts (Albany, Framingham, Evans County, and San Francisco) in the Cooperative Lipoprotein Phenotyping Study (1Castelli W.P. Doyle J.T. Gordon T. Hames C.G. Hjortland M.C. Hulley S.B. Kagan A. Zukel W.J. HDL cholesterol and other lipids in coronary heart disease. The cooperative lipoprotein phenotyping study.Circulation. 1977; 55: 767-772Google Scholar). The relationships of HDL-C to cardiovascular events in older individuals have been far less consistent than the strong relationships seen in middle-aged individuals. There have been few studies in elderly minority populations. Most studies in older individuals have been case control studies. In addition, few have been able to reliably exclude prevalent atherosclerotic disease. The mechanistic relationships of the association between HDL-C and CHD remain poorly understood. A number of antiatherogenic properties of HDL-C have been suggested as possible explanations for the association between HDL-C and CHD (11Lusis A.J. Atherosclerosis.Nature. 2000; 407: 233-241Google Scholar, 12Tall A.R. Plasma high density lipoproteins. Metabolism and relationship to atherogenesis.J. Clin. Invest. 1990; 86: 379-384Google Scholar). Genetic factors, including variations in the cholesteryl ester transfer protein (CETP) gene, are thought to play a major role in the determination HDL-C levels. CETP mediates the transfer of cholesteryl esters from HDL-C and low density lipoprotein cholesterol (LDL-C) into triglyceride (TG)-rich lipoproteins (11Lusis A.J. Atherosclerosis.Nature. 2000; 407: 233-241Google Scholar). Controversy remains about whether CETP deficiency and the resultant rise in HDL-C is antiatherogenic, or whether CETP has the opposite effect due to its role in reverse cholesterol transport. This determination has become important because of the development of pharmaceutical compounds that can alter CETP levels in the body. We have previously shown in elderly Japanese-American men of the HHP that the prevalence of CETP mutations is high and often associated with elevated concentrations of HDL-C (13Zhong S. Sharp D.S. Grove J.S. Bruce C. Yano K. Curb J.D. Tall A.R. Increased coronary heart disease in Japanese-American men with mutation in the cholesteryl ester transfer protein gene despite increased HDL levels.J. Clin. Invest. 1996; 97: 2917-2923Google Scholar). The continued follow-up of the now elderly HHP cohort, and the careful classification of cardiovascular events in this cohort, provide an opportunity to further examine the relationship of HDL-C and CETP mutations to incident CHD. The HHP is a long-term, prospective study of heart disease, stroke, and other diseases in a sample of 8,006 Japanese-American men, aged 45 to 68 years at the time of study enrollment in 1965–1968. Kuakini Medical Center’s Institutional Review Board approved the project. Follow-up in this report began at physical examinations given from 1991–1993 to 3,741 surviving HHP subjects. Men with a history of CHD at this examination, and those who reported being on lipid lowering medications, were excluded from these analyses. Prevalent cases of stroke and cancer were also excluded. In this report, up to 7 years of follow-up data are available to examine the relationship between HDL-C and CHD. Based on a comprehensive system of follow-up, cases of CHD were identified by continuous surveillance of hospital discharge records, obituary notices, and death certificates. Using a standardized protocol and case definition criteria, a physician committee classified suspected endpoints. For this report, subjects were followed for the first occurrence of CHD. Here, CHD is defined to include unequivocal findings of a nonfatal myocardial infarction (MI), coronary death, and sudden death within an hour that could not be attributed to another cause. Risk factor measurements included body mass index (BMI) (kg/m2), physical activity index, alcohol consumption, hypertension, serum cholesterol, smoking habits, serum glucose levels, and TG levels. A diagnosis of hypertension was made when either a systolic or diastolic blood pressure was ≥160 and 95 mm Hg, respectively, or when a subject was receiving medication for high blood pressure. Assessment of physical activity was based on the use of the physical activity index, a common measure used to quantify overall metabolic output in a typical 24-h period and known to be inversely associated with the risk of cardiovascular disease (CVD) (14Abbott R.D. Rodriguez B.L. Burchfiel C.M. Curb J.D. Physical activity in older middle-aged men and reduced risk of stroke: the Honolulu Heart Program.Am. J. Epidemiol. 1994; 139: 881-893Google Scholar). The methods and procedures utilized in the HHP are documented in detail elsewhere (15Kagan A. Harris B.R. Winkelstein Jr., W. Johnson K.G. Kato H. Syme S.L. Rhoads G.G. Gay M.L. Nichaman M.Z. Hamilton H.B. Tillotson J. Epidemiologic studies of coronary heart disease and stroke in Japanese men living in Japan, Hawaii and California: demographic, physical, dietary and biochemical characteristics.J. Chronic Dis. 1974; 27: 345-364Google Scholar, 16Worth R.M. Kagan A. Ascertainment of men of Japanese ancestry in Hawaii through World War II Selective Service registration.J. Chronic Dis. 1970; 23: 389-397Google Scholar). Blood was centrifuged within 30 min of collection at 3,000 g for 10 min at 4°C, and the plasma was frozen at −70°C for up to 2 months. Samples were then shipped on dry ice to the University of Vermont, where HDL-C was separated by precipitation with dextran sulfate and magnesium chloride (17Fried L.P. Borhani N.O. Enright P. Furberg C.D. Gardin J.M. Kronmal R.A. Kuller L.H. Manolio T.A. Mittelmark M.B. Newman A. The Cardiovascular Health Study: design and rationale.Ann. Epidemiol. 1991; 1: 263-276Google Scholar). DNA was obtained from white blood cells separated from plasma samples procured at the examination, and genotyping was carried out for intron 14 and exon 15 mutations in the CETP gene. For this report, a CETP mutation is defined as the presence of either an intron 14 or an exon 15 mutation. The percent of men who fell within a range of HDL-C and who had a CETP mutation, were calculated within age-specific strata for ages that were observed at the time of study enrollment. Age-adjusted risk factors across the ranges of HDL-C levels and according to CETP status were estimated from analysis of covariance models (18Lane P.W. Nelder J.A. Analysis of covariance and standardization as instances of prediction.Biometrics. 1982; 38: 613-621Google Scholar). Similar procedures were used to assess changing levels of HDL-C and the percent of men with a CETP mutation as they might occur with age (a test for trend). Age-adjusted tests further examined trends in risk factor changes across levels of HDL-C. Crude and age-adjusted incidence rates of CHD in person-years were estimated according to ranges of HDL-C concentrations and by CETP mutation status based on the 7 years of follow-up data that were available for the 2,340 men without prevalent disease, who were examined from to (18Lane P.W. Nelder J.A. Analysis of covariance and standardization as instances of prediction.Biometrics. 1982; 38: 613-621Google Scholar). test for an effect of HDL-C level and CETP mutation on the risk of CHD for age and the other models were used models and Scholar). HDL-C was as a continuous risk relative of CHD associated were also estimated the risk of CHD between the ranges of HDL-C levels. as a continuous a test for was for whether was a in the risk of CHD with changes in levels of HDL-C. Similar models were used to the incidence of CHD between men with and without a CETP mutation. reported were based on tests of based on the Program were used to examine the relationship of HDL-C to age and age-adjusted risk factors on and of High Blood in of the report of the Program on and of high blood cholesterol in Scholar). in are the percent of HHP men HDL-C levels fell in important and ≥60 and who were with either of the CETP by age can be of the men had HDL-C levels of ≥60 of HDL-C of ≥60 increased significantly with There was of a relationship between CETP mutations and of men within ranges of HDL-C levels and the percent prevalence of CETP mutation according to for cholesteryl ester transfer high density lipoprotein in a cholesteryl ester transfer high density lipoprotein in 2 are the age-adjusted of the study by HDL-C between HDL-C levels and physical activity index, alcohol and serum cholesterol were In the prevalence of hypertension, serum and with levels of HDL-C. HDL-C was also associated with a in the prevalence of CETP of CETP mutations was than in men with HDL-C levels ≥60 versus men with levels <40 and risk factor levels by ranges of HDL-C for activity index cholesterol smoking body mass in a body mass age-adjusted for those with and without CETP There were individuals with either mutation. were for intron were for exon and was for exon from HDL-C levels were significantly in those with a CETP mutation. In TG and glucose levels were lower in those with a mutation. with the other risk factors were not of risk factor levels by the presence and of a CETP activity index cholesterol smoking between those with versus without a CETP mutation between those with versus without a CETP mutation between those with versus without a CETP mutation between those with versus without a CETP mutation between those with versus without a CETP mutation in a the relative of CHD for age, hypertension, smoking, and total for those with HDL-C levels between to and ≥60 mg/dl, as compared with those with HDL-C levels that were lower can be the risk of CHD in men with HDL-C concentrations ≥60 was when compared with men with HDL-C levels <40 Risk of CHD significantly with HDL The age-adjusted CHD incidence rates from years for men with HDL-C levels <40 to years in men with HDL-C levels ≥60 in the age-adjusted CHD incidence years by level of HDL-C and according to the presence and the of a CETP mutation. The lower HDL-C were due to the number of events in those with a CETP mutation. the four the in the rates of CHD between the HDL-C strata in men without a CETP mutation the presence of a CETP mutation appeared when HDL-C strata were the effect of CETP on the risk of CHD to the number of individuals with a mutation is and, among this were the to an association between CETP and the risk of CHD is be that with a sample a relationship between CETP and CHD have including a possible effect between CETP and HDL-C. important of this study is that HDL-C is a risk factor for CHD in this elderly The of HDL-C as a risk factor for CHD in those has not been M.C. Guralnik J.M. Salive M.E. Harris T. Field T.S. Wallace R.B. Berkman L.F. Seeman T.E. Glynn R.J. Hennekens C.H. HDL cholesterol predicts coronary heart disease mortality in older persons.JAMA. 1995; 274: 539-544Google Scholar, 9Zimetbaum P. Frishman W.H. Ooi W.L. Derman M.P. Aronson M. Gidez L.I. Eder H.A. Plasma lipids and lipoproteins and the incidence of cardiovascular disease in the very elderly. The Bronx Aging Study.Arterioscler. Thromb. 1992; 12: 416-423Google Scholar, and lipoprotein of coronary heart disease in elderly men in the Honolulu Heart Epidemiol. 1992; Scholar, Seeman T.E. Leon Berkman L.F. of association between cholesterol and coronary heart disease mortality and and mortality in older than 1994; Scholar, predicts death from coronary heart disease in elderly men not The Epidemiol. 1992; Scholar). In low levels of HDL-C have been and associated with an increased risk of coronary disease in studies middle-aged cohorts (1Castelli W.P. Doyle J.T. Gordon T. Hames C.G. Hjortland M.C. Hulley S.B. Kagan A. Zukel W.J. HDL cholesterol and other lipids in coronary heart disease. The cooperative lipoprotein phenotyping study.Circulation. 1977; 55: 767-772Google Scholar, 2Abbott R.D. Wilson P.W. Kannel W.B. Castelli W.P. High density lipoprotein cholesterol, total cholesterol screening, and myocardial infarction. The Framingham Study.Arteriosclerosis. 1988; 8: 207-211Google Scholar, 3Gordon D.J. Rifkind B.M. High-density lipoprotein—the clinical implications of recent studies.N. Engl. J. Med. 1989; 321: 1311-1316Google Scholar, 4Stampfer M.J. Sacks F.M. Salvini S. Willett W.C. Hennekens C.H. A prospective study of cholesterol, apolipoproteins, and the risk of myocardial infarction.N. Engl. J. Med. 1991; 325: 373-381Google Scholar, 5Pekkanen J. Linn S. Heiss G. Suchindran C.M. Leon A. Rifkind B.M. Tyroler H.A. Ten-year mortality from cardiovascular disease in relation to cholesterol level among men with and without preexisting cardiovascular disease.N. Engl. J. Med. 1990; 322: 1700-1707Google Scholar, 6Assmann G. Schulte H. von Eckardstein A. Huang Y. High-density lipoprotein cholesterol as a predictor of coronary heart disease risk. The PROCAM experience and pathophysiological implications for reverse cholesterol transport.Atherosclerosis. 1996; 124: S11-S20Google Scholar, 7Kitamura A. Iso H. Naito Y. Iida M. Konishi M. Folsom A.R. Sato S. Kiyama M. Nakamura M. Sankai T. High-density lipoprotein cholesterol and premature coronary heart disease in urban Japanese men.Circulation. 1994; 89: 2533-2539Google Scholar). For the Framingham Heart Study that men aged years to years with HDL-C levels in the had a to of compared to men with HDL-C levels. were in R.D. Wilson P.W. Kannel W.B. Castelli W.P. High density lipoprotein cholesterol, total cholesterol screening, and myocardial infarction. The Framingham Study.Arteriosclerosis. 1988; 8: 207-211Google Scholar). from four studies that a in HDL-C was associated with a to in the risk of coronary disease in middle-aged individuals D.J. Rifkind B.M. High-density lipoprotein—the clinical implications of recent studies.N. Engl. J. Med. 1989; 321: 1311-1316Google Scholar). The relationship between HDL-C and CHD is not to In middle-aged men in Japan, the incidence of CHD and for other risk factors, was in the lowest of HDL-C than in the A. Iso H. Naito Y. Iida M. Konishi M. Folsom A.R. Sato S. Kiyama M. Nakamura M. Sankai T. High-density lipoprotein cholesterol and premature coronary heart disease in urban Japanese men.Circulation. 1994; 89: 2533-2539Google Scholar). In elderly the relationship between HDL-C and CHD In a sample of men and years of age from HDL-C was not associated with CHD mortality or from Seeman T.E. Leon Berkman L.F. of association between cholesterol and coronary heart disease mortality and and mortality in older than 1994; Scholar). In a follow-up of a population from and that low HDL-C CHD mortality and the occurrence of CHD events M.C. Guralnik J.M. Salive M.E. Harris T. Field T.S. Wallace R.B. Berkman L.F. Seeman T.E. Glynn R.J. Hennekens C.H. HDL cholesterol predicts coronary heart disease mortality in older persons.JAMA. 1995; 274: 539-544Google Scholar). studies also to the protocol and with case based on death certificates. the to and of methods for and events were not of the study was to provide prospective on the relationship between CETP gene mutations and CHD. not statistically the risk of CHD is lower in the presence versus the of a CETP mutation, for those individuals with HDL-C levels ≥60 This findings are to an prevalence study reported by Y. T. A. M. Iso H. Y. Y. H. Iida M. J. H. Y. A low prevalence of coronary heart disease among subjects with increased lipoprotein cholesterol levels, including those with plasma cholesteryl ester transfer protein Med. 27: in subjects with CETP mutations and HDL-C levels were to have very CHD. findings not an of a of CHD in subjects with a CETP gene mutation and HDL-C levels from to (13Zhong S. Sharp D.S. Grove J.S. Bruce C. Yano K. Curb J.D. Tall A.R. Increased coronary heart disease in Japanese-American men with mutation in the cholesteryl ester transfer protein gene despite increased HDL levels.J. Clin. Invest. 1996; 97: 2917-2923Google Scholar). The in the and findings be by the of prevalent cases of CHD, stroke, and cancer in the CETP mutations not with age, be that the gene mutations have in older individuals. The prospective study design also other have to from the A of studies is the low number of men with a CETP mutation and, studies in subjects with CETP mutations have a possible to CHD. A number of with a CETP mutation, high and risk factors were reported to have an of coronary disease K. S. Y. S. S. T. K. S. M. disease in of cholesteryl ester transfer protein and triglyceride Thromb. 1995; Scholar). a study in a Japanese with a high prevalence of the intron 14 mutation a high of changes in subjects with very high HDL-C levels K. S. T. T. Y. M. K. Y. Genetic cholesteryl ester transfer protein deficiency is in the of by CETP gene mutation is not associated with Thromb. Scholar). These were not to CETP and the data could be by other factors as alcohol G. S. Evans A. P. the effect of a of the cholesteryl ester transfer protein gene on plasma high density lipoprotein and the risk of myocardial Clin. Invest. 1995; Scholar). on CETP gene in samples have shown with HDL-C levels and data relationships with CHD G. S. Evans A. P. the effect of a of the cholesteryl ester transfer protein gene on plasma high density lipoprotein and the risk of myocardial Clin. Invest. 1995; Scholar, A. P. cholesteryl ester transfer protein HDL cholesterol, and possible risk of heart The Heart 2000; Scholar). These to have and on plasma CETP levels. studies have also data on the relationship between CETP and on the of CETP in by have an antiatherogenic effect of CETP H. K. T. K. H. A cholesteryl ester transfer protein in 2000; Scholar, H. Y. of in lipoprotein and in the of Thromb. 1995; Scholar). In a CETP was in H. K. T. K. H. A cholesteryl ester transfer protein in 2000; Scholar). studies in CETP have shown that on on the metabolic of CETP T. A. Tall A.R. atherosclerotic in cholesteryl ester transfer protein Clin. Invest. 1995; Scholar, C.L. H. Tall A.R. A with of Scholar, C. Jr., R.A. Tall A.R. Plasma lipid transfer and reverse cholesterol Scholar). of CETP has been suggested as a for HDL-C levels in C. Jr., R.A. Tall A.R. Plasma lipid transfer and reverse cholesterol Scholar, M.L. A. C. M.E. J. H. of lipid transfer protein deficiency in a with increased 1989; and recent studies indicate that CETP can HDL-C and lower J.A. J. A. and of a cholesteryl ester transfer protein in a II study.Circulation. Scholar). is that is at with the on this might a of reverse cholesterol is that HDL-C and cholesteryl ester in the can occur by other including The HDL-C that in the of CETP have other as or S. J. High-density lipoprotein the of 1990; and with lipoproteins for on the C.L. low density lipoprotein by lipoprotein to the Scholar). properties of these have been suggested by M. S. T. K. H. K. Y. and cholesteryl lipoproteins in cholesteryl ester transfer protein (CETP) deficiency from cholesterol by 1994; Scholar, M.L. M.E. H. G. R.D. P. Jr., H.B. In of within the HDL and Scholar). In these data indicate that HDL-C remains an important risk factor for CHD in the elderly. This important relationship is seen in a prospective study with control and and and as of the risk factors have relationships with cardiovascular in the elderly, HDL-C to be an clinical for individuals in this age K. Yano K. Rodriguez B.L. Curb J.D. and mortality in elderly from the Honolulu Heart a Scholar). are not the are also of a lower of coronary events in those with a CETP mutation and a high HDL-C. the study is consistent with the that could be for CHD, data are to whether CETP mutation significantly the risk of CHD. This was by of Health and Honolulu Heart and body mass index cholesteryl ester transfer protein coronary heart disease cardiovascular disease high density lipoprotein cholesterol Honolulu Heart Program low density lipoprotein cholesterol myocardial infarction