Coronary atherosclerosis in indigenous South American Tsimane: a cross-sectional cohort study.
BACKGROUND: Conventional coronary artery disease risk factors might potentially explain at least 90% of the attributable risk of coronary artery disease. To better understand the association between the pre-industrial lifestyle and low prevalence of coronary artery disease risk factors, we examined the Tsimane, a Bolivian population living a subsistence lifestyle of hunting, gathering, fishing, and farming with few cardiovascular risk factors, but high infectious inflammatory burden. METHODS: We did a cross-sectional cohort study including all individuals who self-identified as Tsimane and who were aged 40 years or older. Coronary atherosclerosis was assessed by coronary artery calcium (CAC) scoring done with non-contrast CT in Tsimane adults. We assessed the difference between the Tsimane and 6814 participants from the Multi-Ethnic Study of Atherosclerosis (MESA). CAC scores higher than 100 were considered representative of significant atherosclerotic disease. Tsimane blood lipid and inflammatory biomarkers were obtained at the time of scanning, and in some patients, longitudinally. FINDINGS: Between July 2, 2014, and Sept 10, 2015, 705 individuals, who had data available for analysis, were included in this study. 596 (85%) of 705 Tsimane had no CAC, 89 (13%) had CAC scores of 1-100, and 20 (3%) had CAC scores higher than 100. For individuals older than age 75 years, 31 (65%) Tsimane presented with a CAC score of 0, and only four (8%) had CAC scores of 100 or more, a five-fold lower prevalence than industrialised populations (p≤0·0001 for all age categories of MESA). Mean LDL and HDL cholesterol concentrations were 2·35 mmol/L (91 mg/dL) and 1·0 mmol/L (39·5 mg/dL), respectively; obesity, hypertension, high blood sugar, and regular cigarette smoking were rare. High-sensitivity C-reactive protein was elevated beyond the clinical cutoff of 3·0 mg/dL in 360 (51%) Tsimane participants. INTERPRETATION: Despite a high infectious inflammatory burden, the Tsimane, a forager-horticulturalist population of the Bolivian Amazon with few coronary artery disease risk factors, have the lowest reported levels of coronary artery disease of any population recorded to date. These findings suggest that coronary atherosclerosis can be avoided in most people by achieving a lifetime with very low LDL, low blood pressure, low glucose, normal body-mass index, no smoking, and plenty of physical activity. The relative contributions of each are still to be determined. FUNDING: National Institute on Aging, National Institutes of Health; St Luke's Hospital of Kansas City; and Paleocardiology Foundation.
Department of Anthropology, University of New Mexico, Albuquerque, NM, USA. Electronic address: hkaplan@unm.edu. Saint Luke's Mid America Heart Institute, University of Missouri-Kansas City, Kansas City, MO, USA. School of Human Evolution and Social Change, and Center for Evolution and Medicine, Arizona State University, Tempe, AZ, USA. Ascension Healthcare, Milwaukee, WI, USA. Al Azhar University, Cairo, Egypt. Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany. National Museum of Natural History, Smithsonian Institution, Washington, DC, USA; Dartmouth College, Hanover, NH, USA. Newport Diagnostic Center, Newport Beach, CA, USA. South Coast Radiological Medical Group, Laguna Hills, CA, USA. Institute for Advanced Study in Toulouse, Toulouse, France; Department of Anthropology, University of New Mexico, Albuquerque, NM, USA. Department of Medicine, Universidad de San Simón, Cochabamba, Bolivia. University of California, Irvine School of Medicine, Irvine, CA, USA; Miller Women's and Children's Hospital Long Beach, CA, USA. Renown Institute for Heart and Vascular Health, Reno, NV, USA; University of Nevada, Reno, NV, USA. Laboratorio de Paleopatologia, Catedra Pedro Weiss, Universidad Peruana Cayetano Heredia, Lima, Peru. Department of Bioengineering, University of Washington, Seattle WA, USA. Department of Anthropology University of California Santa Barbara, Santa Barbara, CA, USA. Weill Cornell Medical College and the NewYork-Presbyterian Hospital, NY, USA. Icahn School of Medicine at Mount Sinai, New York, NY, USA. University of Southern California Leonard Davis School of Gerontology, Los Angeles, CA, USA; Dornsife College, University of Southern California, Los Angeles, CA, USA. Department of Anthropology University of California Santa Barbara, Santa Barbara, CA, USA; Long Beach Memorial, Long Beach, CA, USA. University of California Irvine, Orange, CA, USA.
