Browsing by Autor "Wendy J. Mack"

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Brain volume, energy balance, and cardiovascular health in two nonindustrial South American populations
(National Academy of Sciences, 2023) Hillard Kaplan; Paul L. Hooper; Margaret Gatz; Wendy J. Mack; Emma Law; Helena C. Chui; M. Linda Sutherland; James D. Sutherland; Christopher J. Rowan; L. Samüel Wann
Little is known about brain aging or dementia in nonindustrialized environments that are similar to how humans lived throughout evolutionary history. This paper examines brain volume (BV) in middle and old age among two indigenous South American populations, the Tsimane and Moseten, whose lifestyles and environments diverge from those in high-income nations. With a sample of 1,165 individuals aged 40 to 94, we analyze population differences in cross-sectional rates of decline in BV with age. We also assess the relationships of BV with energy biomarkers and arterial disease and compare them against findings in industrialized contexts. The analyses test three hypotheses derived from an evolutionary model of brain health, which we call the embarrassment of riches (EOR). The model hypothesizes that food energy was positively associated with late life BV in the physically active, food-limited past, but excess body mass and adiposity are now associated with reduced BV in industrialized societies in middle and older ages. We find that the relationship of BV with both non-HDL cholesterol and body mass index is curvilinear, positive from the lowest values to 1.4 to 1.6 SDs above the mean, and negative from that value to the highest values. The more acculturated Moseten exhibit a steeper decrease in BV with age than Tsimane, but still shallower than US and European populations. Lastly, aortic arteriosclerosis is associated with lower BV. Complemented by findings from the United States and Europe, our results are consistent with the EOR model, with implications for interventions to improve brain health.
High Prevalence of Cerebrovascular Calcifications and Clinical Correlates in Indigenous Bolivian Forager‐Horticulturalists: A Population‐Based Observational Study
(Wiley, 2026) Giuseppe Barisano; Bavrina Bigjahan; Grant D. Schleifer; Maria Ashna; Wendy J. Mack; M. Linda Sutherland; James D. Sutherland; Chui Hc; Meng Law; Thomas Fischbach
Despite the physically active subsistence lifestyle and the low rates of typical cardiovascular risk factors and coronary artery disease, intracranial vascular calcifications are common in these Bolivian Amerindian people, suggesting that alternative factors may contribute to intracranial arteriosclerosis and a novel dementia phenotype.
Increases in regional brain volume across two native South American male populations
(Springer International Publishing, 2024) Nikhil N. Chaudhari; Phoebe Imms; Nahian F. Chowdhury; Margaret Gatz; Benjamin C. Trumble; Wendy J. Mack; Emma Law; M. Linda Sutherland; James D. Sutherland; Christopher J. Rowan
Prevalence of cerebrovascular calcifications in indigenous Bolivian Tsimane and Moseten
(Wiley, 2023) Giuseppe Barisano; M. Linda Sutherland; James D. Sutherland; Margaret Gatz; Wendy J. Mack; Helena C. Chui; Meng Law; Daniel Eid Rodríguez; Raúl Quispe Gutierrez; Andrei Irimia
Abstract Background Intracranial arteriosclerosis has been increasingly recognized as an etiological factor contributing to cognitive impairment. Indigenous Tsimane and Moseten, Amerindians of the Bolivian Amazon with physically‐active subsistence lifestyle, are reported to have lower prevalence of dementia (Gatz et al., Alzheimer’s Dement, In press) and coronary artery disease (Kaplan et al.,Lancet,2017) than Western populations. We assessed the prevalence of intracranial arteriosclerosis, cerebrovascular calcifications, and leukoaraiosis in these populations and investigated their relationship with brain atrophy and cognition. Method 155 participants aged ≥60 (60.6% females) underwent a non‐contrast computed tomography scan and cognitive testing. Visual rating scales were used to evaluate global cortical atrophy (GCA, simplified Pasquier), medial temporal atrophy (MTA, Scheltens), internal carotid artery (ICA) calcifications extent and morphology (Babiarz/Kockelkoren), lenticulostriate arteries (LSA) calcifications (de Brouwer), deep and periventricular leukoaraiosis (Fazekas). The maximum density (Hounsfield units) of LSA calcifications and the presence of infarcts and vertebral arteries (VA) calcifications were also evaluated. Result Virtually all participants presented vascular calcifications in ICA (99.3%), LSA (87.4%), and VA (98.5%) ( Fig.1,2 ). ICA calcification morphology was continuous in 58.7% and irregular/patchy in 40.5%, indicating medial and intimal pathology, respectively ( Fig.3 ). In 13.2% of cases, the LSA calcifications were surrounded by parenchymal calcifications in the basal ganglia ( Fig.4 ). Most cases showed no radiological sign of infarcts or leukoaraiosis. ICA calcifications correlated with age (P<.0001) while other calcification locations showed little association with age. LSA calcifications were greater in men than women (P<.01) with sex differences minimal for other calcification locations. After controlling for age and sex, ICA, LSA, basal ganglia and VA calcifications were related to greater GCA (all P<.05). LSA calcification density was significantly related to greater GCA and MTA, and to poorer visuo‐constructional ability (all P<.01). Prevalence of ICA and VA calcifications were higher compared to those reported in a population‐based European sample (79% and 16.9%, respectively; Vinke et al.,Neurobiol.Aging,2021). ( Fig.5 ) Conclusion Despite the low prevalence of dementia and coronary artery disease, cerebrovascular calcifications are commonly observed in this indigenous Bolivian population, and are associated with greater brain atrophy. Their underlying pathogenetic mechanisms remain unclear, but the high prevalence of infectious and inflammatory disorders might play a role.
Prevalence of dementia and mild cognitive impairment in indigenous Bolivian forager‐horticulturalists
(Wiley, 2022) Margaret Gatz; Wendy J. Mack; Helena C. Chui; Emma Law; Giuseppe Barisano; M. Linda Sutherland; James D. Sutherland; Daniel Eid Rodriguez; Raúl Quispe Gutierrez; Juan Copajira Adrian
The prevalence of dementia in this cohort is among the lowest in the world. Widespread intracranial medial arterial calcifications suggest a previously unrecognized, non-Alzheimer's disease (AD) dementia phenotype.