Elevated nonfasting triglyceride levels, previously associated with an increased risk for heart attack, also appear to be associated with an increased risk for ischemic stroke, according to a new study.
Recent studies found a strong association between elevated levels of nonfasting triglycerides, which indicate the presence of remnant (a small portion that remains) lipoproteins, and increased risk of ischemic heart disease. "It is therefore possible that nonfasting triglyceride levels are also associated with increased risk of ischemic stroke," the authors write. "Triglyceride levels are usually measured after an 8- to 12-hour fast, thus excluding most remnant lipoproteins; however, except for a few hours before breakfast, most individuals are in the nonfasting state most of the time. Therefore, by mainly studying fasting rather than nonfasting triglyceride levels, several previous studies may have missed an association between triglycerides and ischemic stroke."
Jacob J. Freiberg, M.D., of Copenhagen University Hospitals, Denmark, and colleagues conducted a study to determine if increased levels of nonfasting triglycerides are associated with risk of ischemic stroke. The Copenhagen City Heart Study, a Danish population–based study initiated in 1976 with follow-up through July 2007, included 13,956 men and women age 20 through 93 years. Participants had their nonfasting triglyceride levels measured at the beginning of the study and at follow-up examinations.
Of the 13,956 participants in the study, 1,529 developed ischemic stroke. The researchers found that the cumulative incidence of ischemic stroke increased with increasing levels of nonfasting triglycerides. Men with elevated nonfasting triglyceride levels of 89 through 176 mg/dL had a 30 percent higher risk for ischemic stroke; for levels 177 through 265 mg/dL, there was a 60 percent increased risk; for 266 through 353 mg/dL, a 50 percent higher risk; for 354 through 442 mg/dL, a 2.2 times elevated risk; and for 443 mg/dL or greater, the risk of ischemic stroke was 2.5 times greater compared to men with nonfasting levels less than 89 mg/dL.
Corresponding values for women were a 30 percent increased risk of ischemic stroke for nonfasting triglyceride levels of 89 through 176 mg/dL; twice the risk for levels 177 through 265 mg/dL; a 40 percent higher risk for levels of 266 through 353 mg/dL; 2.5 times the risk for 354 through 442 mg/dL; and 3.8 times the risk for ischemic stroke for women with nonfasting triglyceride levels of 443 mg/dL or greater compared to women with nonfasting triglyceride levels less than 89 mg/dL.
Absolute 10-year risk of ischemic stroke ranged from 2.6 percent in men younger than 55 years with nonfasting triglyceride levels of less than 89 mg/dL to 16.7 percent in men age 55 years or older with levels of 443 mg/dL or greater. These values in women were 1.9 percent and 12.2 percent, respectively. Men with a previous ischemic stroke vs. controls had nonfasting triglyceride levels of 191 mg/dL vs. 148 mg/dL; for women, these values were 167 mg/dL vs. 127 mg/dL.
"By using levels of nonfasting rather than fasting triglycerides and by having more statistical power than any previous study, we detected a previously unnoticed association between linear increases in levels of nonfasting triglycerides and stepwise increases in risk of ischemic stroke …", the authors write. "Even the most recent European and North American guidelines on stroke prevention do not recognize elevated triglyceride levels as a risk factor for stroke."
"Our results, together with those from 2 previous studies, suggest that elevated levels of nonfasting triglycerides and remnant lipoprotein cholesterol could be considered together with elevated levels of low-density lipoprotein cholesterol for prediction of cardiovascular risk. However, these findings require replication in other populations."
- Jacob J. Freiberg; Anne Tybjaerg-Hansen; Jan Skov Jensen; Borge G. Nordestgaard. Nonfasting Triglycerides and Risk of Ischemic Stroke in the General Population. JAMA, 2008; 300(18):2142-2152 [link]
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