Abstract
BACKGROUND: Genetic determinants of blood pressure (BP) responses to the cold pressor test (CPT), a phenotype associated with risk of hypertension and cardiovascular disease has not been well studied. METHODS: We examined the heritability of BP response to CPT in 1,994 subjects from 627 families in rural north China. BP was measured before and at 0, 1, 2, and 4 min after the participants immersed their hand in ice water for 1 min. Heritabilities of baseline BP and responses at 0 min, maximum response, and area-under-the-curve (AUC) during CPT were computed using a variance components method. Additionally, bivariate heritabilities were calculated to test the existence of shared genetic determinants between baseline BP and responses to CPT. RESULTS: Heritabilities of baseline BP and responses to CPT were estimated from 14 to 35%, which all significantly differed from 0 (P < or = 0.002). Genetic correlations (s.e.) due to the same genes between baseline BP and responses to CPT ranged from -0.07 (0.14) to 0.21 (0.15), which were not significantly different from 0. Genetic correlations between reactivity and recovery were 0.67 (0.10) and 0.59 (0.10) for systolic (SBP) and diastolic BP (DBP), respectively, which were significantly different from 0. CONCLUSIONS: We concluded that (i) baseline BP and BP responses to CPT had strong genetic determinants; (ii) baseline BP and BP response to CPT did not share the same genetic components; and (iii) BP reactivity and recovery shared the same genetic components. These findings may lead to a better understanding of the genetic mechanism of BP responses to CPT.