Low total cholesterol may increase risk for stroke, CV mortality
MedWire News: Low levels of total cholesterol are associated with higher stroke and cardiovascular (CV) mortality, study findings suggest.
"Reductions of stroke by cholesterol-lowering therapy have been documented in patients with previous stroke and those at high risk for coronary disease," explains Hisako Tsuji, from Kansai Medical University in Moriguchi, Japan.
However, "these results seem to be based on predominance of atherothrombotic stroke over other subtypes of ischemic stroke," he says.
Considering this, Tsuji studied data for 16,461 Japanese individuals who participated in an annual health examination in 1997. The Japanese population has been shown to be at a very low risk for coronary disease, and atherothrombotic stroke accounts for a low proportion of ischemic strokes among these individuals. All participants were followed up until the end of 2009, and the association between total cholesterol levels and mortality was assessed.
Individuals were divided into four groups according to their total cholesterol levels: less than 160 mg/dl (4.14 mmol/l); 160-199 mg/dl (4.14-5.15 mmol/l); 200-239 mg/dl (5.18-6.19 mmol/l); and 240 mg/dl (6.22 mmol/l) or higher.
Compared with the lowest cholesterol group, the relative risks for CV or stroke deaths were consistently and significantly lower in all other groups, even after adjustment for clinical risk factors including age, gender, smoking status, diabetes, and history of CV disease.
Specifically, individuals with total cholesterol levels of 160-199, 200-239, and ≥240 mg/dl had a 48%, 54%, and 58% lower risk for CV mortality, respectively, than those with levels below 160 mg/dl. Similarly the respective risks for total stroke mortality were 60%, 67%, and 77% lower than for individuals with total cholesterol levels below 160 mg/dl.
Tsuji concludes, therefore, that "when aggressive cholesterol-lowering therapy is performed, increases in cardioembolic stroke and atrial fibrillation should be carefully monitored."
The findings are published in the journal Archives of Internal Medicine.
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By Nikki Withers