March 10, 2011 -- Women who drink a cup or more of coffee each day may be less likely to have a stroke, compared to women who drink less coffee, according to new research in the journal Stroke.
The new findings should not be taken to mean that everyone should start drinking coffee to lower their stroke risk, as the medical literature has been somewhat mixed regarding the effects of coffee on cardiovascular risk.
Of 34,670 women aged 49 to 83, women who drank more than a cup of coffee each day had a 22% to 25% lower risk for stroke than women who drank less coffee.
Women who reported drinking anywhere from one to five or more cups of coffee a day showed similar benefits in stroke reduction. Drinking more coffee did not reduce stroke risk any further, the study showed.
Exactly what it is about coffee that may lower stroke risk is unknown. Coffee may reduce inflammation and help make the body more responsive to insulin, the study authors say. It may also be that women who don’t drink coffee were exposed to another unknown risk factor.
“Additional prospective studies on coffee consumption and stroke incidence as well as mechanistic studies investigating possible effects of coffee consumption on cardiovascular risk factors are warranted,” write study authors, who were led by Susanna C. Larsson, PhD, lead researcher in the division of nutritional epidemiology at the National Institute of Environmental Medicine of the Karolinska Institute in Stockholm, Sweden.
During 10-plus years of follow-up, there were 1,680 strokes, including 1, 310 ischemic strokes, which are caused by blocked blood flow to regions of the brain; 154 hemorrhagic strokes, which are caused by bleeding in the brain; 79 subarachnoid hemorrhages, which are caused by bleeding in the subarachnoid space of the brain, and 137 unspecified types of strokes.
Coffee drinking lowered women’s risk for total strokes and ischemic and subarachnoid hemorrhages, in particular, the study found. Coffee consumption did not affect hemorrhagic stroke risk, but this may be due to the low number of these strokes in the new study.