The Strong Heart Study sought to estimate cardiovascular disease mortality and morbidity among Native
Americans in relation to the general United States population. They reported that cardiovascular disease
mortality rates in the Native American populations in Arizona were similar to the US averages (Lee et al.,
1998). The prevalence of hypertension in most races (reported by American Heart Association, 2018: non-
Hispanic white, non-Hispanic black, Mexican American) has generally increased over the past few decades
(Benjamin et al., 2018). One group remains unreported or underreported—Native Americans—underscoring
the importance of research in this area. Hypertension is one of the most modifiable and controllable risk factors
for cardiovascular disease; however, the etiology of the development of hypertension may vary between
racial groups. This may modify successful prevention and treatment strategies in these groups.
Hyperinsulinemia in Native American populations has been consistently reported in the literature and is
hypothesized for the current study to precede the development of: 1) endothelial dysfunction and 2) blood
pressure (BP) dysregulation in this group. It has been demonstrated that Pima Indians regulate BP differently
than their Caucasian counterparts. Pima Indians had higher fasting insulin concentrations, despite a normal
oral glucose tolerance test. Hyperinsulinemia has also been associated with markers endothelial dysfunction.
Thus, it is possible that high insulin concentration concomitantly targets two pathways associated with the
increased risk for hypertension and cardiovascular events in this population. The Native American population is
difficult to assess in a research setting due to historical reasons. However, the Hispanic population in our
region in AZ has been reported to possess high levels of Native American ancestry (NAA) (range 7-75%) and
may serve as a surrogate population. The purpose of this study is to quantify insulin status in Hispanics of
varying proportions of NAA to determine its role in endothelial function and BP regulation. We hypothesize that
Hispanics with higher proportions of NAA will: 1) possess higher insulin concentrations than those with lower
proportions of NAA; 2) demonstrate impaired endothelial function; and 3) demonstrate greater BP reactivity to
hypertensive stimuli. This 3-yr project will assess NAA, anthropometric measurements, insulin status, blood
markers, blood vessel function, and BP responses. The team includes a Co-I with expertise in DNA admixture
analysis, a physician, an endocrinologist, a statistician, and graduate and undergraduate students. The results
will provide insight into the race-specific differences in the development of BP dysregulation and will inform
future treatment strategies. We surmise that effective treatment will need to target glucose handling early to
stop the downstream cascade leading to dysregulation.
