Between the 1980s and 1990s, blood pressure in the population dropped in about 21 countries, but now thanks to medicine. Scientists from the World Health Organization who conducted the study said they do not know what caused this small, but significant decline, but they think that more fruit and vegetables and less salt could be one of the explanations. Professor Hugh Tunstall-Pedoe, of the Ninewells Hospital in Dundee, Scotland, stated: "Blood pressure is changing in the population independent of medication. Whatever is moving, the blood pressure must be more powerful than medication." The scientists ruled out medicines because the study was also conducted on people who did not take drugs for lowering the blood pressure. "Blood pressure has got more dimensions than popping pills and people need to be aware of that," he added. Also, "people are not eating the same things they were 20 or 30 years ago. Some factors in the diet may be relevant to blood pressure. People actually may have been doing some things right." The study involved 100,000 people in 21 countries and wanted to see if lower blood pressure was due to better drugs or people leading more healthy lifestyles. High blood pressure is an important risk factor for cardiovascular disease, which killed 16.7 million people worldwide, 29.2% of global deaths. Tunstall-Pedoe also said: "The three Finnish populations, for example, had much higher levels than those in southern Europe," pointing out the differences between people from different countries.