Background: Job strain (high demands and low decision latitude) and the DD genotype of an I/D polymorphism in the adrenergic alpha2B-receptor have been associated with hypertension, respectively. We hypothesized that the I/D polymorphism interacts with external stress, such as job strain, in the development of hypertension.
Methods: A sample of 3045 employed men and women from the population cohort of Malmö Diet and Cancer Study, n = 28 098, with baseline data regarding work characteristics and cardiovascular risk factors, were genotyped for the adrenergic alpha2B-receptor I/D polymorphism. This was possible in 1302 men and 1662 women, and these individuals formed the study group.
Results: The age-adjusted systolic blood pressure (SBP) for men with the DD polymorphism and job strain (n = 26) was 147.0 +/- 3.4 mmHg, whereas for men with the DD polymorphism but without job strain (n = 184), the SBP was 138.2 +/- 1.4 mmHg (P = 0.018). Similar findings were made regarding diastolic blood pressures (DBP) in men. Job strain and the I/D polymorphism in the adrenergic alpha2B-receptor gene significantly interacted in men [P = 0.008 for SBP, P = 0.03 for DBP, adjusted for age, body mass index, occupational status and nationality (Model 1)]. Increasing latitude score was inversely correlated with SBP (beta -0.17, P = 0.03, Model 1) in DD men, but not in men with the I-allele; interaction significance for genotype x latitude score, P = 0.02 for SBP (Model 1). In women, there were no significant interactions between genotype and work characteristics (P = 0.32 for SBP, and P = 0.60 for DBP).
Conclusion: For the first time, a significant interaction between a genetic factor and work environment, resulting in elevated blood pressures, has been described.