The scientific consensus that blood pressure rises naturally with age has been upended by a new study of remote tribal groups in the Venezuelan rainforest, which found that hypertension could be a result of a Western lifestyle. Researchers contacted two groups in the depths of the Amazon, reports ScienceDaily.com. The first, the Yanomami, have almost no contact with the Western world: They are hunter-gatherers who eat a lot of fruit and fiber and little fat or salt. The second tribe, the Yekwana, have greater exposure to the Western world through their contact with missionaries, doctors, and miners, and eat more processed food and salt. Researchers took the blood pressure of dozens of members of both tribes, ages 1 to 60. In the Yekwana, blood pressure increased with age, albeit at a lower rate than in the U.S. and other Western societies. But in the isolated Yanomami tribe, blood pressure levels were roughly the same for all ages. The researchers note that their study was small and included only 11 Yekwana members over age 40, and didn’t reveal exactly which lifestyle and diet differences might be behind the disparity. But lead author Noel Mueller, from Johns Hopkins University, says the findings are significant. “The idea that blood pressure rises with age as part of a natural phenomenon,” he says, “is increasingly being dispelled.”