Sex-specific trajectories of systolic and diastolic blood pressure in youth

Blood Pressure Trajectories From Childhood to Youth and Arterial Stiffness in Adulthood: A 30-Year Longitudinal Follow-Up Study

Background

This study aimed to identify the subgroups of individuals sharing similar blood pressure (BP) trajectories from childhood to youth and explore the associations of these trajectories with arterial stiffness in adulthood.

Methods

A group-based trajectory model was used to identify BP trajectories among 2,082 individuals in the Hanzhong adolescent hypertension cohort by using BP values repeatedly measured at four visits from childhood (6–15 years) to youth (14–23 years). The brachial–ankle pulse wave velocity (baPWV) was examined 30 years after the baseline survey. Mixed linear regression models were used to examine the associations of these trajectories with adult baPWV.

Results

Among the 2,082 individuals, three trajectory groups of systolic BP were identified as follows: the low-level group (n = 889), medium-level group (n = 1,021), and high-level group (n = 172). The baPWV in adulthood was higher in medium-level and high-level groups compared with the low-level group (1271.4 ± 224.7 cm/s, 1366.1 ± 249.8 cm/s vs. 1190.1 ± 220.3 cm/s, all p < 0.001). After adjustment for potential confounding factors, the association between baPWV and systolic BP trajectories was statistically significant (adjusted β = 49.4 cm/s; p < 0.001 for the medium-level group and β = 107.6 cm/s; p < 0.001 for the high-level group compared with the low-level group). Similar results were obtained for the association of baPWV with the trajectories of diastolic BP and mean arterial pressure (MAP), except for pulse pressure.

Conclusion

Our investigation demonstrates different BP trajectories from childhood to youth and shows the trajectories of systolic BP, diastolic BP, and MAP are significant predictors of arterial stiffness in adulthood.

Assessment of diastolic blood pressure with the auscultatory method in children and adolescents under exercise conditions

Controversy surrounds whether to define resting diastolic blood pressure (DBP) as the onset of the fourth or fifth Korotkoff phase (K4, sound muffling, or K5, sound disappearance) in children and adolescents. Although undetectable in some children (due to sounds continuing to zero cuff pressure), K5 is currently recommended for consistency with adult practice and because K4 can be difficult to discern or undetectable. However, to our knowledge, no studies have specifically assessed the reliability of measuring DBP with K4 and K5 in children and adolescents under exercise conditions. We therefore measured DBP before and immediately after a Bruce protocol stress test in 90 children and adolescents aged 12.3 ± 3.5 years (mean ± SD) in a cardiology clinic setting. When detected, K4 and K5 were 63.5 ± 9.2 and 60.2 ± 12.6 mmHg, respectively, at rest and 59.2 ± 14.6 mmHg (p = 0.028 vs rest) and 52.9 ± 18.3 mmHg (p < 0.001), respectively, immediately post-exercise. K4 and K5 were not detected in 41% and 4% of participants at rest or in 29% and 37% post-exercise, respectively, while K5 resulted in unrealistic DBP values (<30 mmHg) in an additional 11%. Better exercise performance was associated with a more frequent absence of K5 post-exercise, and after excluding participants performing at <10th percentile for age, post-exercise K4 was absent in 23%, and plausible K5 values were not obtained in 59% (p < 0.001). Although neither K4 nor K5 alone were reliable measures of DBP immediately post-exercise, a novel hybrid approach using K4, if detected, or K5, if not, produced reasonable DBP measurements in 97% of participants.

Blood Pressure Trajectories from Childhood to Adolescence in Pediatric Hypertension

It has been known for a long time that elevated blood pressure (BP) in the young may persist and progress into adult hypertension (HTN). Multiple studies have revealed the predicted BP trajectory lines starting from childhood and related them to later cardiovascular (CV) risks in adulthood. As a small baby grows into a tall adult, BP will also naturally increase. Among early-life predictors of adult HTN, birth history, such as prematurity, and low birth weight have been popular subjects in research on pediatric HTN, because body size at birth has been reported to be inversely related to the risk of adulthood HTN. The hypothesis of HTN in prematurely born adolescents has been postulated as a physiological predisposition to postnatal excessive weight gain. Current body weight is a well-known independent predictor of HTN in children, and some studies showed that children demonstrating upward crossing of their weight percentiles while growing into adolescents have significantly increased risk for elevated BP later in life. Recently, reports focused on the adverse effect of excessive catch-up growth in this population are gradually drawing attention. Accordingly, children born prematurely or with intrauterine growth restriction who show rapid changes in their weight percentile should be under surveillance with BP monitoring. Prevention of childhood obesity, along with special care for premature infants or infants small for their gestational age, by providing healthy nutritional guidelines should be cardinal strategies for the prevention of adult HTN and CV risks later in life.