Genetic influences on blood pressure with the cold-pressor test: a twin study

Abstract

To determine the genetic and environmental contributions to resting blood pressure, the level of blood pressure during the cold-pressor test and the increase in blood pressure with the cold-pressor test in an adult cohort of normotensive twins. Ninety-one monozygotic and 41 dizygotic normal twin pairs were recruited by advertisement. The mean age was 34 ±14 years (mean ± SD). Systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate were measured continuously at the finger (using a Finapres device) and verified at the upper arm oscillometrically (using a Dinamap device) every minute. The cold-pressor test was conducted by immersing the nondominant hand into cold (Results Heritability estimates of additive genetic effects were statistically significant for SBP and DBP but not for heart rate during rest and during the cold-pressor test. Furthermore, the path analysis indicated shared as well as specific genetic components both for the blood pressure level at rest and for that during the cold-pressor test. However, the genetic influences on the blood pressure level at rest and on the increase in blood pressure during the cold-pressor test (the blood pressure level during the cold-pressor test minus that during rest) were entirely independent of one another. A significant genetic covariation exists for SBP and DBP during rest and during the cold-pressor test, as well as a significant genetic variation that is specific to the cold-pressor stress condition. These findings suggest that different genes or sets of genes contribute to blood pressure regulation during rest and to blood pressure reactivity to cold-pressor stress.