PHILADELPHIA, June 23—By the time they reach their teen years, those with type 1 diabetes already have significantly more risk of atherosclerosis—or plaque buildup in their arteries—than their peers, according to a study released this weekend by researchers at the Keck School of Medicine of the University of Southern California and Childrens Hospital Los Angeles. Researchers presented the pilot study at the American Diabetes Association’s 61st Annual Scientific Sessions.
Atherosclerosis is a critical health issue in the United States, accounting for more than 1.5 million heart attacks and 600,000 strokes every year. And it’s particularly important for people with diabetes, who are especially susceptible to cardiovascular problems. The team of researchers sought to determine whether teen-agers and young adults with type 1 diabetes faced increased risk of atherosclerosis, and if so, which factors seemed to put them more at risk. They compared 57 adolescents between ages 12 and 21 with insulin-dependent diabetes to a group of age- and gender-matched young adults without diabetes, running blood tests and measuring the thickness of their neck arteries through ultrasound. Researchers found that the intima-media thickness (IMT)—a measure of the innermost layer of the artery wall—was significantly greater in the teens with diabetes.
They also found that those with greater IMT tended to have high levels of certain lipids in the blood: apolipoprotein B (apoB), a structural component of cholesterol; low-density lipoprotein (or LDL, the so-called "bad" cholesterol); and lipoprotein a (or Lp a, a sort of fat cousin to LDL).
They also had higher-than-average levels of homocysteine, an amino acid suspected of contributing to atherosclerosis. Those with greater IMT also were more likely to be male. Factors not found related to IMT were body mass index, duration of diabetes, family history, exposure to tobacco smoke or HbA1c (long-term blood glucose levels), although researchers say such findings must be confirmed in a larger study.
Researchers suggest that physicians look closely at levels of substances in the blood such as LDL in those with insulin-dependent diabetes, even at an early age. (Physicians frequently suggest that adults with similar characteristics—such as those with high LDL levels—increase exercise, change their diet, and if necessary, take lipid-lowering medications.)
"The increased lipid levels in adolescents and young adults with diabetes, and the possible association with atherosclerosis, suggests that abnormal lipid levels may warrant intervention," says Jody Krantz, M.D., fellow in the division of endocrinology at Childrens Hospital Los Angeles.
J.S. Krantz, F.R. Kaufman, H. Hodis, C. Liu, M. Halvorson. "Increased Atherosclerosis, Measured by Carotid Artery IMT (CCA IMT), in 12-21 Year Olds with Type 1 Diabetes" American Diabetes Association 61st Annual Scientific Sessions, June 22-26, 2001. Poster Session 637-P.