UC Irvine

Background

Cross-sectional analyses suggest that total and low-density lipoprotein cholesterol (LDL-c) trends that had been declining are now reversing. We examined longitudinal data from the Coronary Artery Risk Development in Young Adults (CARDIA) study to examine secular trends in total cholesterol, LDL-c, high-density lipoprotein cholesterol (HDL-c), and triglycerides over 25 years. We also assessed whether modifiable lifestyle factors (body mass index, physical activity, alcohol consumption, smoking, and lipid-lowering medications) are associated with these trends.

Methods and results

CARDIA recruited 5115 black and white men and women ages 18 to 30 years from 4 US communities in 1985-1986, and re-examined them 5, 10, 15, 20, and 25 years later. Secular trends, modeled as age-matched time trends, were estimated using repeated-measures regression stratified on race and sex. Total cholesterol and LDL-c initially decreased ≈5 to 8 mg/dL between visits before plateauing and moving toward adverse trends in all groups, except black women, by year 25. HDL-c showed an upward secular trend of 1 to 3 mg/dL between visits starting at year 15 in all groups; triglyceride trends were largely flat. Obesity and use of lipid-lowering medications, which both increased over follow-up, had strong independent, but opposite, associations with lipid trends over time. In aggregate, associations of modifiable lifestyle factors counterbalanced one another, minimally influencing secular trends.

Conclusions

Over 25 years, initially favorable trends in total cholesterol and LDL-c have leveled off and may be reversing, persisting after control for modifiable risk factors. Factors such as dietary changes over 25 years and poor adherence to medications are candidates for additional investigation.