Effect of long-term beta-carotene and vitamin A on serum cholesterol and triglyceride levels among participants in the Carotene and Retinol Efficacy Trial (CARET)

Atherosclerosis. 1999 Apr;143(2):427-34. doi: 10.1016/s0021-9150(98)00303-7.

Abstract

Objective: The Carotene and Retinol Efficacy Lung Cancer Chemoprevention Trial (CARET) ended prematurely due to the unexpected findings that the active treatment group on the combination of 30 mg beta-carotene and 25,000 IU retinyl palmitate had a 46% increased lung cancer mortality and a 26% increased cardiovascular mortality compared with placebo. This study was designed when the CARET intervention was halted to evaluate the effects of long-term supplementation with beta-carotene and retinol on serum triglyceride and cholesterol levels, in an attempt to explore possible explanations for the CARET result.

Methods: Serum triglyceride levels, and total, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) cholesterol levels were determined in a subgroup of 52 CARET participants. Baseline and mid-trial levels were available on 23 participants on placebo and 29 on active treatment who were then serially followed for 10 months after trial termination.

Results: Triglyceride, and total, HDL and LDL cholesterol levels were similar in the two groups at baseline. After a mean of 5 years on the intervention there was a small nonsignificant increase in serum triglyceride levels in the active group, but no difference in total, HDL, or LDL cholesterol levels. After stopping the intervention there was a decrease in triglyceride levels in the active intervention group, and no change in the other parameters.

Conclusion: Based on a small convenience sample, CARET participants in the active treatment arm had a small nonsignificant increase in serum triglyceride levels while on the intervention, and a decrease in serum triglyceride levels after the intervention was discontinued. No significant changes in total or HDL cholesterol were noted. These results argue against a major contribution of treatment-induced changes in serum lipid and lipoprotein levels to the increased cardiovascular mortality in the active treatment group.

Publication types

  • Clinical Trial
  • Controlled Clinical Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Antioxidants / administration & dosage*
  • Arteriosclerosis / prevention & control
  • Cholesterol / blood*
  • Drug Administration Schedule
  • Female
  • Follow-Up Studies
  • Humans
  • Lipoproteins, HDL / blood*
  • Lipoproteins, HDL / drug effects
  • Male
  • Middle Aged
  • Reference Values
  • Sampling Studies
  • Time Factors
  • Triglycerides / blood*
  • Vitamin A / administration & dosage*
  • beta Carotene / administration & dosage*

Substances

  • Antioxidants
  • Lipoproteins, HDL
  • Triglycerides
  • beta Carotene
  • Vitamin A
  • Cholesterol