"White coat hypertension" in adolescents: Increased values of urinary cortisol and endothelin

Objective: To investigate whether "white coat hypertension" (WCH) in adoles cents is an innocent phenomenon or is associated with early changes of the vascular system and/or increased stress response, reflected in the urinary endothelin and cortisol values, respectively. Study design: The study group included 36 subjects, 14 with WCH (8 males an d 6 females) aged 12.9 +/- 3 years and 22 normotensive control subjects (12 males and 10 females) aged 13 +/- 3.5 years. WCH was defined as systolic a nd/or diastolic blood pressure (BP) greater than or equal to 95th percentil e for age, sex, and height and with reported normal BP measurements at home . Urinary endothelin (UET1), urinary free cortisol (UFC), and plasma renin levels were determined by radioimmunoassay; and urinary albumin levels were determined by nephelometry. For statistical analysis, the Mann Whitney U t est, Spearman correlation coefficient, and multivariate analysis of varianc e/multivariate analysis of covariance were used, as applicable. Results: The 24-hour values of UET1 and UFC were greater in male subjects w ith WCH than in male control subjects (P = .02), whereas no such difference was found in female subjects. The difference in UFC values in male subject s was accounted for by the day values. In subjects with WCH, and not in con trol subjects, a positive correlation of UET1 to UFC (r = 0.59, P = .027), diastolic BP (r = 0.55, P = .04), and mean BP (r = 0.65, P = .012) was dete cted. Conclusions: Our data indicate that WCH in adolescence may not be an innoce nt phenomenon and may represent a prelude to permanent idiopathic hypertens ion of adulthood.