Increased risk of stroke with increased nonfasting triglyceride levels


Increased risk of stroke with increased nonfasting triglyceride levels

In addition to being associated with increased risk of heart attack, elevated nonfasting levels of triglycerides appear to be associated with increased risk of ischemic stroke, according to a study released on November 12, 2008 in JAMA.

Elevated levels of nonfasting triglycerides indicate that remnant lipoproteins, which remain after metabolism and storage, are present. Previously, it has been shows that elevated levels of these substances are associated with an increased risk of ischemic heart disease. The authors of the study thus propose: "It is therefore possible that nonfasting triglyceride levels are also associated with increased risk of ischemic stroke." The continue, describing a major aspect of these previous studies: "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."

To investigate the effects of nonfasting triglyceride levels on ischemic stroke risk, Jacob J. Freiberg, M.D., of Copenhagen University Hospitals, Denmark, and colleagues examined the Copenhagen City Heart Study, a cohor study based on a Danish population beginning in 1976 with follow-up through July 2007. The study included 13,956 men and women between the ages of 20 and 93 years. At the start of the study and in further follow-up visits, participant nonfasting triglyceride levels were measured and stroke incidence was noted.

Ischemic stroke was developed in 11% (1,529 subjects) of the participants. When comparing with increasing levels of nonfasting triglycerides, the cumulative incidence of ischemic stroke increased. In particular, in comparison with men with nonfasting levels of triglycerides less than 89 mg/dL:

  • Men with levels between 89 and 176 mg/dL had a 30% increased risk of ischemic stroke;
  • Men with levels between 177 and 265 mg/dL had a 60% increased risk;
  • Men with levels between 266 and 353 mg/dL had a 50% higher risk;
  • Men with levels between 354 and 442 mg/dL had a 120% increased risk;
  • Men with levels greater than 443 mg/dL had a 15% increased risk.

Analogously, for women, in comparison with women with nonfasting triglyceride levels less than 89 mg/dL:

  • Women with levels between 89 and 176 mg/dL had a 30% increased risk of ischemic stroke;
  • Women with levels between 177 and 265 mg/dL had a 100% increased risk;
  • Women with levels between 266 and 353 mg/dL had a 40% higher risk;
  • Women with levels between 354 and 442 mg/dL had a 150% increased risk;
  • Women with levels greater than 443 mg/dL had a 280% increased risk.

The absolute risk of ischemic stroke within ten years varied with age and gender, ranging in men from 2.6% in those younger than 55 years with nonfasting triglyceride levels of less than 89 mg/dL, to 16.7% in men age 55 years or older with nonfasting triglyceride levels greater than or equal to 443 mg/dL. The corresponding range in women was 1.9% to 12.2% respectively.

In men with history of ischemic stroke, nonfasting triglyceride levels were approximately 191 mg/dL in comparison with controls which 148 mg/dL. In women with history of ischemic stroke, these values were approximately 167 mg/dL in comparison to 127 mg/dL.

The authors note the novel results they obtained by using the methods they did, including higher statistical power: "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...", they say. "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." They conclude.

Nonfasting Triglycerides and Risk of Ischemic Stroke in the General Population

Jacob J. Freiberg, MD; Anne Tybjærg-Hansen, MD, DMSc; Jan Skov Jensen, MD, DMSc; Børge G. Nordestgaard, MD, DMSc

JAMA. 2008;300(18):2142-2152.

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