Regular consumption of coffee has been linked with many benefits such as a decreased risk of diabetes mellitus type 2, Parkinson's Disease, dementia, stroke, various cancers, and heart arrhythmias. Coffee is also known to be a powerful antioxidant.
Despite the benefits garnered by drinking coffee, there has also been concern that it may increase the risk of high blood pressure, a condition linked with many negative outcomes including stroke, heart attack, and death. Two previous meta-analyses of coffee drinking demonstrated a slight increase in the risk of high blood pressure. However, these studies were of a short duration, lasting 85 days or less.
The new study, published in the American Journal of Clinical Nutrition included 172,567 patients with a minimum follow-up of over 6 years. The researchers found that compared to drinking less than one cup of coffee daily, the relative risk of high blood pressure when drinking 1 to 3 cups of coffee was 1.09; that for drinking 3 to 5 cups of coffee was 1.07; that for drinking 5 or more cups of coffee daily was 1.08.
The researchers concluded that habitually drinking coffee was not associated with an increased risk of high blood pressure although there was a slight increase in risk with moderate coffee consumption (3 to 5 cups daily).
You can read the abstract of this study at http://www.ajcn.org/content/early/2011/03/30/ajcn.110.004044.abstract.