The ages of the participants were between 25 and 64 years old. Also required was that they had no history of hypertension drug use and no history of stroke or heart disease.
The results of the study were inconclusive leaving it an open question as to how much coffee drinking affects hypertension.
During the course of the study, 2500 participants, or approximately 10%, began taking some type of anti hypertension drug. Previous studies have shown that roughly 19% of non-coffee drinkers developed high blood pressure during the time period of the study. What's unknown is how many of the participants developed high blood pressure (blood pressure chart) but are either unaware of it or not taking medication for it.
Part of the questionnaire that participants were asked to complete focused on how many cups of coffee they drink daily. The more cups of coffee a participant drank, the greater the chances are that he or she would end up in the group taking anti hypertension drugs. So although there does seem to be some slight causation link between coffee drinking and high blood pressure, the risk seems to be small, and many questions still remain.
For example, coffee drinkers tend to drink alcohol more than non coffee drinkers. Though the occasional drink may be good for relieving stress and may even reduce diastolic blood pressure, studies have consistently shown that alcohol when consumed in excess increases blood pressure. We also know that over time, excess drinking can damage the heart. The study did not control for alcohol consumption.
Coffee drinkers also, as a rule, smoke cigarettes more than non smokers. Smoking tends to harden the blood arteries and constrict blood flow. The heart has to pump harder to force the blood through the narrow arteries and blood pressure rises as a result. In addition, studies have also demonstrated that discontinuing tobacco smoking will likely lead to a decrease in blood pressure. The study did not control for smoking.
Other lifestyle factors that come into play are eating habits, gender, weight, exercise, and salt intake. Diet, as we know, has a great impact on whether a person develops hypertension. Is a person who drinks coffee more likely to also have bad eating habits which can lead to high blood pressure?
Exercise is very beneficial to the heart and arterial system. Is a coffee drinker more likely to be sedentary than a non coffee drinker?
For years now, it seems as though every bit of food we put into our bodies is somehow harmful to us. Fish is good for the heart but are we willing to risk ingesting too much mercury. A vegetarian diet is good for health, but are we willing to risk bone loss? Fruits have loads of healthy antioxidants, but will the sugar content in them rot our teeth?
But there is one piece of good news from the study. It seems as though coffee drinking actually lowers the risk of getting type 2 diabetes. At this point, we'll take all the good news we can get.