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


METHODS
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 non-dominant hand into cold (< 4 degrees C) water for 2 min. Statistical analysis was performed by using the SPSS program; parameters of the quantitative genetic models were estimated by path-analysis techniques using the LISREL 8 program.


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.


CONCLUSIONS
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.
Franz Volhard Clinic, Virchow Klinikum, Humboldt University of Berlin, Germany.
A
A
Busjahn
H D
HD
Faulhaber
R J
RJ
Viken
R J
RJ
Rose
F C
FC
Luft
D000328:Adult; D001794:Blood Pressure / Q000235:genetics*; D003080:Cold Temperature; D006339:Heart Rate; D006801:Humans; D008875:Middle Aged; D012146:Rest; D013312:Stress, Physiological / Q000503:physiopathology; D014429:Twins, Dizygotic / Q000235:genetics*; D014430:Twins, Monozygotic / Q000235:genetics*