Plasma copeptin levels and ambulatory blood pressure characteristics in healthy adults

Objective: We investigated whether copeptin – a well characterized vasopressin-related stress hormone – is associated with circadian ambulatory blood pressure (BP) variability and/or mean BP levels in young adults. Method and results: We studied a population-based sample of healthy adults aged 25–41 years. Individuals with diabetes, treated hypertension, and cardiovascular disease were excluded. Ambulatory 24-h BP monitoring was performed using validated devices. To evaluate the relationships of copeptin with mean ambulatory BP levels and BP variability during daytime and night-time, multivariable adjusted regression models were constructed. BP variability was defined as SD of all intraindividual BP values. Of the 2012 individuals included in this study, 53% were women and the median age was 37 years. Median plasma copeptin levels were 3.9 (interquartile range 2.7, 5.8) in men and 2.3 pmol/l (interquartile range 1.6, 3.6) in women (P < 0.0001). In multivariable linear regression models, log-transformed copeptin was significantly associated with systolic and diastolic night-time BP levels among men [β = 1.9, 95% confidence interval (CI) 0.6, 3.1, P = 0.003; and β = 1.4, 95% CI 0.6, 2.3, P = 0.001, respectively], but not among women. In addition, copeptin was strongly associated with an increased systolic and diastolic daytime (β = 0.5, 95% CI 0.2, 0.7, P = 0.001; β = 0.5, 95% CI 0.3, 0.8, P < 0.0001, respectively) and night-time BP variability (β = 0.6, 95% CI 0.3, 0.9, P = 0.0002; β = 0.4, 95% CI 0.2, 0.7, P = 0.002, respectively). Conclusion: In this large population-based study of young and healthy adults, plasma levels of copeptin were significantly associated with an increased BP variability in both sexes and an elevated night-time BP among men.