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The Impact of High Density Lipoprotein Cholesterol on Five-Year Mortality in Older Adults

by Millman, Lisa Margaret

Abstract (Summary)
The National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (ATP III) guidelines have defined a high density lipoprotein cholesterol (HDL-C) of <50 mg/dL in women and <40 mg/dL in men as a risk factor for cardiovascular disease. Our research aim was to examine the relationship between untreated HDL-C levels below this recommended level on five year cardiovascular, stroke, and all-cause mortality in adults over 71 years of age. The Established Populations for Epidemiologic Studies of the Elderly (EPESE) is a prospective cohort study of community dwelling adults over 65 years of age in East Boston, MA; Iowa and Washington Counties, IA; New Haven, CT; and Durham, NC. The National Institutes of Aging (NIA) started EPESE to study health, social, psychological, and economic aspects of older adults lives through extensive annual interviews. The EPESE dataset is further enriched by serum measures including low-density lipoprotein cholesterol (LDL-C), HDL-C, total cholesterol, triglycerides, glucose, BUN and creatinine, which were obtained at the sixth annual follow-up interview. Our primary outcome was all-cause mortality with secondary mortality outcomes of acute myocardial infarction (AMI), coronary artery disease (CAD) not AMI, and congestive heart failure (CHF). The mean age of our cohort was 78.7 years with the majority being female (63.86%), white (88.15%), and married (52.80%). Just over half (52.07%) of our cohort met the criteria for low HDL-C as defined by ATP III. Chi square and Fisher exact test were used to compare demographics (age, gender, race, marital status, education), clinical variables (history of MI, cancer, diabetes, angina, smoking, alcohol use), and functional variables (activities of daily living, gross mobility, cognitive status) at baseline and five year follow-up. Cox proportional hazard models were created using a step-wise approach to assess the impact of low HDL-C on mortality. Low HDL-C was not significantly associated with crude all-cause (P= .413), AMI (P= .473), CHF (P= .259), and stroke (P= .345) mortality. HDL-C was significantly associated with unadjusted CAD (P= .033) mortality. However, after adjustment for demographics, clinical, and functional variables as well as the other blood values all outlined above, HDL-C was not associated with five year all-cause, AMI, CAD, CHF or stroke mortality with adjusted hazard ratios of (HR=1.03, 95% CI 0.90-1.18), (HR=1.09, 95% CI 0.70-1.71), (HR=1.33, 95% CI 0.91-1.92), (HR=1.07, 95% CI 0.63-1.81) and (HR=0.80, 95% CI 0.51-1.27) respectively. In older community dwelling adults enrolled in EPESE, low HDL-C levels as stratified by current recommended guidelines (<50 mg/dL in women and <40 mg/dL in men) were not associated with increased risk of five-year cardiovascular, stroke or all-cause mortality. HDL-C alone may have minimal effect on future longevity in older adults due to competing risk and co-morbid conditions. Further studies are required to determine whether the movement toward more aggressive lipid profile interventions specifically to raise HDL-C in older adults would prove beneficial in this growing segment of our population.
Bibliographical Information:

Advisor:Joanne Foody

School:Yale University

School Location:USA - Connecticut

Source Type:Master's Thesis

Keywords:lipoproteins hdl high density lipoprotein cholesterol c risk factors cardiovascular diseases mortality intervention studies

ISBN:

Date of Publication:11/15/2006

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