The relationship between sex, insulin sensitivity, and blood pressure reactivity in Hispanics

Claus, Leah (2022) The relationship between sex, insulin sensitivity, and blood pressure reactivity in Hispanics. Masters thesis, Northern Arizona University.

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Abstract

Hyperinsulinemia is a predictor of hypertension, a condition that increases the risk for heart disease and stroke (Gans & Donker, 1991; Kannel, 2009). Hyperinsulinemia, a precursor to type II diabetes, is particularly prevalent in the Hispanic population which also carries several genetic markers associated with the dysregulation of insulin and glucose (Mercader & Florez, 2017). Studies that quantify a relationship between insulin and hypertension often fail to account for sex and ethnicity, therefore the purpose of this study was to quantify insulin status and blood pressure (BP) reactivity within the Hispanic population to provide insight into whether a relationship between sex, insulin status, and control of BP exists. Testing was completed in 11 males (M) (age: 27 ± 8 yrs) and 15 females (F) (age: 22 ± 4 yrs). Insulin sensitivity index (ISI) was measured through a modified 75-gram oral glucose tolerance test, where blood samples were drawn for measurement of glucose and insulin at baseline and minutes 30, 60, and 120. The following anthropometric measurements were obtained: waist circumference, waist to thigh ratio, and waist to hip ratio (waist circumference, M: 80.3 ± 7.7 cm, F: 74.2 ± 6.3 cm, p<0.05; waist to thigh ratio, M: 1.68 ± 0.10, F: 1.58 ± 0.13, p<0.05; waist to hip ratio, M: 0.84 ± 0.05, F: 0.76 ± 0.04, p<0.05). Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured during the cold pressor test (CPT), mental stress test (MST), and graded exercise test (GXT). CPT was a 2-min of test where the subject placed their hand in ice water. MST consisted of a 3-min test where the subject performed verbal mathematical subtraction. GXT was performed on a stationary bicycle to peak-V ̇O_2. BP reactivity was calculated as the difference between baseline and the maximum value in SBP and DBP, expressed as a delta (Δ). Data were analyzed using ANCOVA and multiple regression modeling. There were no significant differences in ISI between males and females (8.4 ± 5.1 and 6.3 ± 3.8 comp, respectively). For CPT, no sex differences were found across all variables (ΔSBP: R2= 0.04, p= 0.81; ΔDBP: R2= 0.03, p=0.90). For MST, there were no differences between males and females across all variables (ΔSBP: R2 = 0.06, p= 0.71; ΔDBP: R2= 0.08, p= 0.61). For GXT, sex differences were present in ISI and ΔSBP relationship. Males had higher values of reactivity than females. Both groups had a positive correlation between ISI and ΔSBP (R2= 0.44, p <0.01). No sex differences were present for ΔDBP. There was a trend for increasing values of ISI correlating with greater DBP reactivity (R2= 0.26, p=0.09). When waist to thigh ratio and other measures of body composition were entered as covariates, both ISI and sex terms were significant (waist to thigh ratio: R2= 0.38, p<0.01). Our data illustrate a positive association between ISI and BP reactivity during the GXT and that sex differences exist in this relationship. Once the effects of body composition parameters were removed from the model, both ISI and sex were shown to be significant predictors of diastolic BP reactivity. This suggests body composition may also be an important indicator in the overall relationship between sex, insulin status, and control of BP in the Hispanic population.

Item Type:	Thesis (Masters)
Publisher’s Statement:	© Copyright is held by the author. Digital access to this material is made possible by the Cline Library, Northern Arizona University. Further transmission, reproduction or presentation of protected items is prohibited except with permission of the author.
Keywords:	Blood pressure provocation tests; Graded Exercise Test; Insulin Resistance; Underrepresented Community; Hispanics; Hpertension
Subjects:	R Medicine > RC Internal medicine
MeSH Subjects:	C Diseases > C14 Cardiovascular Diseases
NAU Depositing Author Academic Status:	Student
Department/Unit:	Graduate College > Theses and Dissertations College of the Environment, Forestry, and Natural Sciences > Biological Sciences
Date Deposited:	08 Jun 2023 17:09
Last Modified:	08 Jun 2023 17:09
URI:	https://openknowledge.nau.edu/id/eprint/5992

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