Gender differences in serum angiotensin-converting enzyme activity and blood pressure in children: an observational study.

BACKGROUND Angiotensin-converting enzyme (ACE) is a key enzyme of the renin-angiotensin system that plays an important role in regulating blood pressure. ACE enzyme activity and its relationships with blood pressure (BP) during childhood and adolescence have not yet been clearly established. OBJECTIVE To determine serum ACE (S-ACE) levels and BP changes in school children between 8 and 18 years of age and how S-ACE and BP in males and females might differ, as well as to determine S-ACE and BP relationships. METHODS Blood pressure, height, weight, body mass index (BMI), and S-ACE were measured in 501 children. RESULT Mean S-ACE values were higher in boys (143.7+/-57.1) than in girls (130.2 +/- 54.9) (p = 0.004). S-ACE values decreased in girls and increased in boys with age, and values for girls were lower than for age-matched boys after onset of puberty. Age was a strong determinant of BP levels in both genders. We found a relationship between ACE and systolic blood pressure (SBP) and diastolic blood pressure (DBP) in girls (SBP r= -0.20 p<0.001 DBP r=0.12 p<0.03). BMI had greater correlation with SBP and DBP in girls (r=0.37, and 0.31, respectively; p < 0.001) than in boys (r=0.26, and 0.25 respectively; p<0.001). CONCLUSION These results indicate that gender differences in serum ACE activity exist in the children from this study. This activity was lower and decreased with age in girls, while BP increased. Because sexual dimorphism in BP emerges in puberty, our findings suggest that gonadal hormones might affect S-ACE activity and BP. These results may have important therapeutic implications.