Influence of blood pressure level and age on within-visit blood pressure variability in children and adolescents

Geneenvironment interaction between phthalate exposure and pubertal genetic polymorphisms on blood pressure variability in children: Exploring the moderating effects of lifestyle behaviours

Phthalates (PAEs) are synthetic compounds extensively employed in consumer products. Blood pressure (BP) in children can vary, the degree of visit-to-visit BP variability (VVV) is at least partially independent of BP. The interactions between PAEs exposure, pubertal-related genetic susceptibility and lifestyles on childhood VVV are not investigated. This study utilized data from a cohort collected from Oct 2017-2020 in Xiamen, China. Seven urine PAE metabolites were measured. The long-term VVV was characterized employing the standard deviation (SD) and average real variability. We constructed a genetic risk score (GRS) of pubertal-related genes and healthy lifestyle scores. Exposed to high levels of mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP) (OR=1.43, 95 %CI=1.07, 1.92) and mono-2-ethyl-5-oxohexyl phthalate (OR=1.36, 95 % CI=1.01, 1.83) was related to increased SBP-SD, and the OR for high SBP-SD related to high GRS was 1.38 (95 % CI=1.02, 1.85). Compared to participants who had low GRS and low MEHHP exposure, participants exhibiting high GRS and MEHHP levels were more likely to experience high SBP-SD (OR=2.00, P<0.05). Individuals exhibiting low GRS, low MEHHP levels, and adhering to healthy lifestyles were associated with the least probability of experiencing high SBP-SD (OR=0.31, P<0.05). Increased PAEs exposure could elevate childhood systolic VVV, and exacerbated the adverse impact of pubertal-related genetic susceptibility on the high VVV of SBP; however, healthy lifestyles might alleviate these adverse effects. Promoting healthy lifestyles and reducing PAEs exposure for preventing elevated BP variability among children is important, especially for individuals with greater genetic susceptibility to early pubertal onset. ENVIRONMENTAL IMPLICATION: Blood pressure (BP) in children can vary, as a noninvasive, inexpensive and applicable method, the extent of visit-to-visit variability (VVV) is at least partially independent of BP. The interactions between phthalates (PAEs) exposure, variants of puberty-related genes and lifestyles on VVV are not investigated. Increased childhood systolic VVV might be associated with PAEs exposure, with the associations more pronounced combined with pubertal genetic susceptibility. Yet, healthy habits could partly eliminate such adverse effects. Our study underscores the importance of advocating for healthy lifestyles and reducing exposure to PAEs, especially among individuals with high genetic susceptibility to early puberty onset.

Impact of within-visit systolic blood pressure change patterns on blood pressure classification: the Cardiovascular Risk in Young Finns Study

AIMS

Most international guidelines recommend that repeat blood pressure (BP) readings are required for BP classification. Two international guidelines diverge from this by recommending that no further BP measurements are required if the first clinic BP is below a hypertension threshold. The extent to which within-visit BP variability patterns change over time, and whether this could impact BP classification is unknown. We sought to examine this.

METHODS AND RESULTS

Data were from the Cardiovascular Risk in Young Finns Study, a prospective cohort study. Up to 2799 participants were followed from childhood (9-15 years) to adulthood (18-49 years) over up to six visits. Patterns of within-visit systolic BP (SBP) variability were defined as no-change, decrease, increase between consecutive readings (with 5 mmHg change thresholds). Classification of SBP (normal, high-normal, hypertension) using the first reading was compared with repeat readings. On average, SBP decreased with subsequent measures, but with major individual variability (no-change: 56.9-62.7%; decrease: 24.1-31.6%; increase: 11.5-16.8%). Patterns of SBP variability were broadly similar from childhood to adulthood, with the highest prevalence of an increase among participants categorized with normal SBP (12.6-20.3%). The highest prevalence of SBP reclassification occurred among participants with hypertension (28.9-45.3% reclassified as normal or high-normal). The prevalence of reclassification increased with the magnitude of change between readings.

CONCLUSION

There is a major individual variation of within-visit SBP change in childhood and adulthood and can influence BP classification. This highlights the importance of consistency among guidelines recommending that repeat BP measurements are needed for BP classification.

Within-visit SBP variability from childhood to adulthood and markers of cardiovascular end-organ damage in mid-life

BACKGROUND

Within-visit SBP variability is associated with age and SBP, but its long-term clinical significance is unknown. We examined the association between child, adult, and life-time within-visit SBP variability with markers of end-organ damage using data from a 31-year longitudinal study.

METHODS

Within-visit SBP variability was calculated as the standard deviation of three sitting SBP readings among up to 3010 participants aged 6-18 years (childhood) who were re-measured up to seven times to mid-adulthood. Markers of cardiovascular end-organ damage in adulthood were carotid intima--media thickness, brachial flow-mediated dilatation, carotid distensibility, pulse wave velocity, left ventricular mass index, carotid plaque, and coronary artery calcification.

RESULTS

The mean (standard deviation) cumulative within-visit SBP variability was 2.7 (1.5) mmHg in childhood, 3.9 (1.9) mmHg in adulthood and 3.7 (1.5) mmHg across the observed life-time. Childhood within-visit SBP variability was not correlated with its subsequent values measured from 3 to 31 years later. With adjustment for age, sex, cumulative SBP, BMI and serum lipids, neither child, adult, or life-time cumulative within-visit SBP variability associated with markers of cardiovascular end-organ damage. However, higher child, adult, and life-time cumulative SBP significantly associated with higher carotid intima--media thickness, higher pulse wave velocity, lower brachial flow-mediated dilatation, lower carotid distensibility in adulthood.

CONCLUSION

Within-visit SBP variability from childhood to adulthood does not provide additional predictive utility over SBP over the same period of the life course.

Relation between Blood Pressure Variability within a Single Visit and Stroke

Blood pressure variability (BPV) has been identified as an important risk factor for cardiovascular events. The white coat effect (WCE), which is measured as the first systolic blood pressure (SBP) measurement minus the mean of the second and third measurements, is a BPV indicator within a single visit. In total, 2,972 participants who had three measurements of BP within a single visit were included. The participants were divided into three groups based on their WCE percentiles: Group 1 (WCE_2.5-97.5, 2.5–97.5th percentiles of WCE), Group 2 (WCE_2.5, 0–2.4th percentiles of WCE), and Group 3 (WCE_97.5, 97.6–100th percentiles of WCE). A multiple logistic regression model was used to analyze the relationship between WCE and stroke after adjusting for cardiovascular disease risk factors. Compared with the WCE_2.5-97.5 group, the OR for stroke in the WCE_2.5 group was 2.78 (95% CI: 1.22, 6.36, p=0.015). After adjusting for cardiovascular factors, OR increased to 3.12 (95% CI: 1.22, 7.96, p=0.017). The OR of WCE for stroke was 0.93 (95%CI: 0.87, 0.99, p=0.036). BPV within a single visit is associated with stroke. The value and direction of the change may be important as well.

Utility of blood pressure measurements at an initial screening visit to identify Chinese children and adolescents with hypertension

The performance of different BP readings and their combinations at a visit to identify children and adolescents with pediatric hypertension remains controversial. We aimed to assess the utility of different blood pressure (BP) readings and their combinations obtained at the initial screening visit for identifying Chinese children and adolescents with hypertension. Participants were 7831 children and adolescents aged 6‐17 years measured as part of a cross‐sectional survey conducted in Jinan, China between September 2012 and November 2014. BP was measured three times at up to three visits. Elevated BP at the initial visit was defined as systolic BP and/or diastolic BP ≥ age‐ and sex‐specific 95th percentiles using the Chinese BP references for children and adolescents based on different BP readings and their combinations. Participants with elevated BP using (BP2+BP3)/2 across three visits were defined as having hypertension. Of the different readings or combinations examined, the mean of the last two readings at the initial visit had the best predictive utility for children and adolescents with hypertension (sensitivity: 100.0%; specificity: 86.9%; positive predictive value: 27.6%; negative predictive value: 100.0%). This was also reflected in the area under the curve being highest for the mean of the last two readings (0.93, 95% confidence interval: 0.93‐0.94) compared with any of the other readings or combinations (BP1, BP2, BP3, [BP1+BP2]/2, [BP1+BP3]/2, and [BP1+BP2+BP3]/3; all p < .001). Taking three measurements of BP and using the average of the last two readings at a screening visit may be optimal for the identification of hypertension in youth.

Predictive Model for Ambulatory Hypertension Based on Office Blood Pressure in Obese Children

Background: The epidemic of obesity, along with hypertension (HT) and cardiovascular disease, is a growing contributor to global disease burden. It is postulated that obese children are predisposed to hypertension and subsequent cardiovascular disease in adulthood. Early detection and management of hypertension in these children can significantly modify the course of the disease. However, there is a paucity of studies for the characterization of blood pressure in obese children through ambulatory blood pressure monitoring (ABPM), especially in the developing world. This study aims to characterize ambulatory blood pressure in obese children and to explore feasibility of using office BP that will predict ambulatory hypertension. Methods:In the present study, 55 children with a body mass index (BMI) in the ≥95th percentile for age and sex were enrolled in a tertiary care hospital and underwent 24 h of ABPM and detailed biochemical investigations. Results:Ambulatory hypertension was recorded in 14/55 (25.5%; white coat hypertension in 17/29 (58.6%) and masked hypertension in 2/26 (7.69%). For office SBP percentile the area under curve (AUC) was 0.773 (95% CI: 0.619-0.926, p = 0.005) and for office DBP percentile the AUC was 0.802 (95% CI: 0.638-0.966, p = 0.002). The estimated cut offs (Youden's index) for office blood pressure which predicts ambulatory hypertension in obese children were the 93rd percentile for systolic BP (sensitivity-67% and specificity-78%) and the 88th percentile for diastolic BP (sensitivity-83% and specificity-62%). Conclusion:Ambulatory blood pressure abnormalities are highly prevalent among children with obesity. Office blood pressure did not accurately predict ambulatory hypertension. More than half of the children labeled as "hypertension" on office blood pressure measurement in the study were diagnosed to have white coat hypertension (WCH), thus emphasizing the role of ABPM for evaluation of WCH before the child is subjected to detailed investigations or started on pharmacotherapy.

Performance of blood pressure measurements at an initial screening visit for the diagnosis of hypertension in children

Hypertension in children is defined as sustained elevated blood pressure (BP) over several visits. For the screening of hypertension, it is standard to obtain several BP readings at the initial visit. There is however no recommendation on the minimum number of readings needed. We evaluated the performance of BP readings obtained at one initial screening visit to predict the diagnosis of hypertension in children. In a school-based study conducted in Switzerland, BP was measured three times on up to three visits in 5207 children. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of elevated BP at the initial screening visit for the identification of hypertension were estimated using the 1st, 2nd, and 3rd BP readings (R1, R2, R3), as well as (R1 + R2)/2 and (R1 + R2 + R3)/3). These performance indices were compared with the reference method (R2 + R3)/2. The ability of BP readings to discriminate children with and without hypertension was evaluated with receiver operating characteristic curve analysis. The prevalence of systolic/diastolic hypertension was 2.2%. The greatest performance to identify children with hypertension was obtained with R2 (sensitivity: 97%; specificity: 88%; PPV: 15%; NPV: 100%) and the reference method, (R2 + R3)/2 (sensitivity: 100%; specificity: 90%; PPV: 18%; NPV: 100%). The ability to discriminate using R1, R2, (R1 + R2)/2, and (R2 + R3)/2 for the identification of hypertension was strong (AUC: 0.89, 0.93, 0.92, and 0.95, respectively). Obtaining two BP readings and using only the second one at a screening visit may be sufficient as initial step for the identification of hypertension in children.

The population-based prevalence of hypertension and correlates of blood pressure among Australian children

OBJECTIVE

Hypertension is increasingly recognized as a disease spanning the entire life course. Continued efforts to refine the diagnosis and management of hypertension in children are highlighted by the recent American Academy of Pediatrics (AAP) guidelines, which include lower threshold values than the previous reference standard (Fourth Report). We aimed to determine the population-based prevalence of children exceeding thresholds for hypertension using these two guidelines. We also sought to identify the correlates of blood pressure (BP) among Australian children.

METHODS

Cross-sectional data from the Growing Up in Australia: Longitudinal Survey of Australian Children were analyzed. Blood pressure was measured in 7139 Australian children aged 10-12 years and sampled using population-based methodology. The association between BP and explanatory variables linked to BP in other populations was examined using multiple linear regression with fractional polynomial terms for continuous, non-linear relationships.

RESULTS

The threshold for hypertension was exceeded in 3.1% and 5.4%, and prehypertension in 3.0% and 3.7% of children, using the Fourth Report and AAP guidelines respectively. Children at the threshold for obesity had a 9.1 mmHg higher adjusted BP than those on the 50th centile for body mass index (BMI) (95% CI 8.4 to 9.9). BMI had a non-linear relationship with BP, and the magnitude of association between BMI and BP increased with BMI. Socioeconomic status, hypertension during pregnancy, birth weight, and sports participation were also independently associated with BP.

CONCLUSIONS

Using the AAP guidelines is likely to substantially increase the population prevalence of hypertension. The association between BMI and BP was strongest and non-linear for obese children, who should be the focus of interventional trials.