Western lifestyle rather than natural course seems to underlie age-associated BP rise
Association of Age With Blood Pressure Across the Lifespan in Isolated Yanomami and Yekwana VillagesLiterature - Mueller NT, Noya-Alarcon O, Contreras M et al. - JAMA Cardiol. 2018;doi:10.1001/jamacardio.2018.3676
Introduction and methods
While a common notion in cardiology is that blood pressure (BP) rises with age, little evidence of an age-associated rise in BP has been found in non-Westernized hunter-gatherer adults. Studies on the association between BP and age over the entire lifespan in children of isolated communities are still lacking and there are no studies focusing on age-BP association in geographically colocated communities with different levels of Westernization. Therefore, this cross-sectional study examined the age-BP association across the lifespan in two isolated Amerindian communities, the Yanomami and the Yekwana, who live in a remote area of the Venezuelan rainforest inaccessible by land.
The Yanomami community consists of hunter-gatherer-gardeners who are among the least acculturated peoples in the world, with lowest known BP measurements. The Yekwana people live close to the Yanomami community, but have been affected by missions and an airstrip for small-engine planes, allowing delivery of medicine and aspects of Western lifestyle, including intermittent exposure to processed foods and salt.
In this study sitting BP measurements were obtained from 72 Yanomami participants and 83 Yekwana participants (aged 1-60 years) between October 2015 and February 2016.
- At baseline the two groups were not significantly different in mean age, sex distribution, or height, but weight and BMI were higher in Yekwana individuals (48.4 [14.4] vs. 41.4 [13.1] kg and 23.4 [4.4] vs. 21.2 [3.9] kg/m², respectively), compared to Yanomami participants.
- Over all ages combined, Yanomami individuals had lower mean systolic BP (95.4 [8.7] mmHg vs. 104.0 [10.6] mmHg, P<0.001) and diastolic BP (62.9 [8.5] mmHg and 66.1 [9.5] mmHg, P=0.03), compared to Yekwana participants.
- The mean age-systolic BP slope was significantly steeper for Yekwana participants (0.25 [0.08] mmHg per year, P=0.003 for the difference from 0), compared to Yanomami individuals (0.00 [0.07] mmHg per year, P=0.98 for the difference from 0), with a significant interaction (P=0.02) for community with the age-SBP relation.
- Findings for the mean age-diastolic BP slope were similar, such that in Yanomami the curve was flat (-0.02 [0.07] mmHg, P=0.77) and the Yekwana showed a positive relationship (0.18 [0.08] mmHg, P=0.02).
- The data suggest that BP curves of the communities already diverge in childhood. At age 1-20 years, the age- systolic BP slope was steeper in Yekwana individuals, compared to Yanomami individuals (mean difference 0.98 [0.39] mmHg per year, P=0.01).
This small cross-sectional study showed an age-associated rise in BP in the more Westernized Yekwana community, which began in childhood, compared to an isolated non-acculturated community, suggesting that the age-associated rise in BP is not natural, but related to exposure to Westernized influences. The rise in BP in the more Westernized Yekwana community already started in childhood, indicating the potential for lifestyle interventions in children to prevent hypertension.