Rancho Bernardo Study: Lipid substudy - Rancho Bernardo Study

Description:

The effects of age, weight change, and covariates on lipid and lipoprotein levels in an elderly population.

Hypothesis:

Using a cross-sectional and a prospective longitudinal analysis, the relative contributions of age, weight change, behavior change, medication use, and disease on lipid and lipoprotein levels could be determined in older adults.

Study Design

Patients Screened: 2360
Patients Enrolled: 2344
Mean Follow Up: mean follow-up 8 years
Mean Patient Age: 50-93
Female: 56

Patient Populations:

Residence in Rancho Bernardo, a middle to upper-middle class community in southern California, ages 50-96

Exclusions:

Fasted for <12 hours before lipid measurement

Primary Endpoints:

Height, weight, BMI, waist-to-hip ratio, demographic data, personal history of current cigarette smoking, alcohol consumption (≥2 drinks per week), physical activity (≥3 times per week), medication use, physician-diagnosed myocardial infarction, diabetes mellitus, and cancer with onset during the follow-up interval

Drug/Procedures Used:

A community-based sample of men and women was studied cross-sectionally in 1984 to 1987, with follow-up of 372 men and 545 women 8 years later. Lipids and lipoproteins at baseline and follow-up visits were measured.

Principal Findings:

In the cross-sectional study, levels of total cholesterol (TC) and LDL decreased with increasing age in men (TC 5.61 vs 5.13 for age 50-59 vs age 80+, p<0.001; LDL 3.60 vs 3.17 for age 50-59 vs age 80+, p<0.001). HDL increased with increasing age in men (1.33 vs 1.46 for age 50-59 vs age 80+, p<0.003).
Among women, total cholesterol and lipoprotein levels were not associated with age before or after stratification for estrogen replacement therapy (TC 5.83 vs 5.86 for age 50-59 vs age 80+, p=NS; LDL 3.45 vs 3.55 for age 50-59 vs age 80+, p=NS; HDL 1.79 vs 1.71 for age 50-59 vs age 80+, p=NS).

In the prospective study, total, LDL, and HDL cholesterol levels decreased approximately 1% per year (p<0.001) in both men and women.

Total, LDL, and HDL levels all decreased in all age groups (50-64 years, 65-74 years, and >=75 years), in all weight change groups (>2.5 kg loss, change within 2.5 kg, and >2.5kg gain) and in all waist girth change groups.

In multiple linear regression models, change in weight was the most important independent and consistent predictor of changes in total, LDL, and HDL.

Interpretation:

Cross-sectional decrements in total and LDL cholesterol with age in men are not explained by survivor bias because they are also observed prospectively. These cross sectional results are similar to the Cardiovascular Health Study, which found that HDL levels increased with age in men but not in women. Although weight change was the most important explanatory variable, total, LDL, and HDL levels also decreased with age in those who lost or gained weight. This study did not provide causal information as to the decrease in lipid levels with age. It is hypothesized that the observed decline might reflect inflammatory responses to infections, which increase with age, or age-related reduced cholesterol absorption from the intestine.

References:

Circulation. 1997;96:37-43. Lipid study J Womens Health. 1998 Feb;7(1):49-56. Heart disease risk factors and ERT in postmenopausal women Am J Epidemiol. 1994 Nov 15;140(10):857-69. Hyperinsulinemia and fatal cardiovascular disease in the elderly

Keywords: Survivors, Follow-Up Studies, Cholesterol, LDL, Hyperlipidemias, Cross-Sectional Studies, Cholesterol, HDL, Intestines, Estrogen Replacement Therapy, Linear Models


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