Anger suppression and adiposity modulate association between ADRB2 haplotype and cardiovascular stress reactivity

The purpose of this study was to examine how variation in the beta-2 adrenergic receptor gene (ADRB2), in combination with the moderating influences of race, body mass index (BMI), and anger expression style (anger-in, anger-out), affects blood pressure (BP) at rest and in response to acute laboratory stress.

Four hundred fifty adolescents (mean age = 18.5 +/- 2.7 years; 228 [124 males] whites and 222 [110 males] blacks completed two stressors (video game challenge, forehead cold pressor). Hemodynamic measures were taken before, during, and after each stressor. Stressors were separated by a 20-minute rest period.

Frequency of detrimental haplotype (Gly16/Glu27) carrier status was greater among whites than blacks (p < .05). A significant three-way interaction among haplotype, BMI, and race for resting systolic blood pressure (SBP) found the highest BP level to be among high BMI carriers, but only for whites. A separate three-way interaction was found to be significant for haplotype, anger-in and race such that high anger-in carriers showed the highest level of resting SBP (p < .05) and total peripheral resistance (TPR) (p < .05) and the greatest TPR reactivity to the cold pressor task (p < .01). Post hoc analyses revealed these interactions with anger-in were only present among blacks. No significant interactions with anger-out for either ethnic group were observed.

This study demonstrates modulating influences of BMI and anger expression styles on ADRB2 gene associations with hemodynamic function at rest and in response to laboratory stress. These findings support the hypothesis that consideration of gene-environment interactions may better characterize the role of ADRB2 variation in the development of stress-induced essential hypertension.