A Western lifestyle may be the reason that blood pressure tends to increase with age, according to a study of remote tribal communities.
Hypertension is a major risk factor for cardiovascular disease and in many developed countries, including the UK, the chances of development increase with age. More than a quarter of adults in England have high blood pressure, with recent figures showing that the proportion rises to 58% among 65-74 year-olds.
A study of remote communities in the Venezuelan rainforest has supported the idea that hypertension is not an inherent part of aging, but is the result of a longer exposure to risks resulting from lifestyle, such as high levels of salt in the environment. diet, lack of exercise and heavy drinking.
Dr Noel Mueller, an assistant professor at Johns Hopkins University who led the research, said: "The idea that blood pressure rises with age as part of a natural phenomenon is increasingly driven by evidence, including our findings here, from which it appears that in a population that is largely free of exposure to Western influences, there is no age-related increase in blood pressure. "
In the Jama Cardiology magazine Mueller and his colleagues write how they contacted two rainforest communities. The one, the Yanomami, had very little contact with the western world. The group has a hunter-gatherer-gardener-lifestyle and does not eat much salt.
The other is the nearby Yekwana community, which has experienced certain aspects of Western life through trade facilitated by a runway, including raw materials such as processed food and salt, as well as the presence of visitors – including missionaries, medical professionals and miners.
The team took the blood pressure of 72 Yanomami people and 83 of the Yekwana community between one and 60 years. While previous research has emphasized the low blood pressure of the Yanomami, this is the first time that children have been involved in such work.
Yekwana participants showed an increase in blood pressure with age – although at a much lower level than in the US, for example. However, blood pressure in the Yanomami community remained about the same.
While infants in both communities had similar low readings, the team noted that children at Yekwana and Yanomami at the age of 10 showed significant differences in blood pressure, with the difference growing with age.
"[That] For us, it says that interventions to prevent the rise in blood pressure and high blood pressure should start early in life, where we still have the possibility to change some of the exposures that can lead to high blood pressure, "said Mueller.
However, the study is very small – only 11 Yekwana individuals over the age of 40 participated in the study – and the study did not exactly determine which lifestyle and nutritional differences might be behind the trends for age and blood pressure.
"It is unclear whether these factors fully explain the results, which may also be partly due to genetic factors," said Dr James Sheppard, an expert in hypertension at the University of Oxford who was not involved in the study. He added that another problem was that the study did not measure the blood pressure of the participants as they got older and the participants were relatively young.
Prof Bryan Williams, a specialist in hypertension at the University College Hospital in London, said: "[The study] gives us an idea of how a normal blood pressure path would be without the impact of westernization – many more people would have normal blood pressure throughout life. "
The hypertension that older people in western countries such as the United Kingdom saw, he added, was caused by stiffening of the large arteries. "This probably represents some genetic predisposition, but is strongly influenced by lifestyle, as suggested by this study.It recalls the importance of a healthy lifestyle to slow the aging of the blood vessels and slow down the rise in blood pressure with age. . "