Objective. Men have higher lifetime risk for coronary heart disease and increased magnitude of atherosclerosis compared with age-matched women. By establishing a novel very high-resolution ultrasound technique (55 MHz), we have previously shown that the intima thickness (IT) of radial arteries, measured separately from the media thickness, increases with age in older populations and with greater wall thickness in males. It is not known when these sex differences in vascular structure occur. Moreover, girls report more psychosomatic symptoms than boys, which may influence vascular structure.
We tested the hypothesis that vascular structural phenotype of radial arteries is different between sexes already in childhood/ adolescence in terms of IT and intima media thickness (IMT). Further, we wanted to explore the natural development of vascular structure between sexes from prepuberty through puberty.
Methods. 243 healthy children (117 girls) aged 10 years and 166 adolescents (97 girls) aged 17.5 years were recruited from schools in Gothenburg. Body mass index was similar in each age group. The IT and IMT of radial arteries were assessed by the newly developed very high resolution ultrasound system (Visualsonics, Toronto, Canada) with subjects in supine position. The Beck Youth Inventories of Emotional and Social Impairment were used to assess and screen for depression, anxiety, anger, disruptive behavior and self concept in school children and adolescents. Age and sex differences were tested by ANOVA (SPSS15.0).
Results. Radial IT was similar between sexes within the respective age group, being approximately 60 and 80 µm for the younger and older subjects, respectively. Children demonstrated similar IMT of about 195 µm, while in adolescents IMT was different between sexes, being 208 and 234 µm for girls and boys, respectively (p<0.001). Radial arterial diameter increased during puberty from 1.61 to 1.86 mm and 1.68 to 2.12 mm for girls and boys, respectively (p<0.001 for both), while only the adolescent group showed a significant sex-difference. Notably, systolic blood pressure (SBP) remained unchanged during puberty for girls, increasing from 104 to 106 mmHg, while SBP increased substantially in boys from childhood to adolescence (101 to 114 mmHg, p<0.001). In girls, scores for anxiety and depression increased (anxiety: 0.64 to 0.8, p=0.034; depression: 0.54 to 0.69, p=0.018), and score for self concept decreased (2.39 to 1.98, p<0.001) with age. In boys, score for self concept decreased through puberty (2.4 to 2.17, p=0.016).
Conclusion. Radial arterial vasculature develops differently between sexes through puberty, inasmuch that both IT and IMT were elevated in boys vs girls, perhaps related to the more augmented SBP in the former. Further, it is interesting to note that radial vascular structural development in girls from 10 to 18 years of age does not seem to be linked to the increased magnitude of psychosomatic symptoms, i.e. increased scores for depression and anxiety. The increased radial IMT in young boys may constitute an initial first step in the atherogenic process, which speculatively, could be related to the earlier onset of cardiovascular events in men compared to women.