Assessing secular trends in blood pressure in children and adolescents

Divergent secular trends in blood pressure and body mass index in children and adolescents in Hong Kong

Secular trends in blood pressure (BP) and body mass index (BMI) during childhood and adolescence are sentinels for the future population cardiovascular disease burden. We examined trends in BP z-score (ages 9-18 years from 1999 to 2014) and BMI z-score (ages 6-18 years from 1996 to 2014) in Hong Kong, China. Overall, BP z-score fell, systolic BP from 0.08 to -0.01 in girls and from 0.31 to 0.25 in boys. However, the trends were not consistent, for both sexes, systolic BP z-score was stable from 1999, decreased slightly from 2002 to 2005 and increased slightly to 2014, diastolic BP z-score decreased slightly from 1999 to 2004 and then remained stable to 2014. In contrast, BMI z-score rose from -0.15 to -0.01 in girls and from 0.14 to 0.34 in boys, mainly during 1997 to 2010. The upper tail of the systolic (except boys) and diastolic BP distribution shifted downwards, whereas the entire BMI distribution shifted upward. BP declined slightly whereas BMI rose in Hong Kong children and adolescents during the last 20 years, with systolic BP and BMI in boys above the reference. This warrants dual action in tackling rising BMI and identifying favorable determinants of BP, particularly targeting boys.

Secular trends in blood pressure among Japanese schoolchildren: a population-based annual survey from 1994 to 2010

Background

Monitoring secular trends in blood pressure (BP) among children is important in predicting subsequent hypertension and cardiovascular disease. We investigated secular trends in BP using data from population-based annual screenings of Japanese schoolchildren.

Methods

The participants were 10 894 children (all fourth graders between 1994 and 2010 and all seventh graders between 1997 and 2010) living in the town of Ina in Saitama Prefecture, Japan. Body height, weight, and BP were measured, after which children were classified as non-overweight, overweight, or obese. Trends in variables relative to calendar year were analyzed using regression models.

Results

Systolic BP was significantly associated with calendar year among fourth- and seventh-grade boys (−0.350 and −0.434 mm Hg/year, respectively) and fourth- and seventh-grade girls (−0.513 and −0.473 mm Hg/year, respectively) (all P < 0.001), respectively, over time. Systolic BP and calendar year were significantly negatively correlated regardless of physique or sex among all fourth graders, but not among obese seventh-grade girls. In addition, diastolic BP and calendar year did not significantly correlate among seventh-grade overweight or obese boys or obese seventh-grade girls.

Conclusions

BP decreased among fourth-grade schoolchildren in Ina during the past 17 years, regardless of sex or physique. However, BP and calendar year did not significantly correlate among obese seventh graders.

Blood pressure and associated factors in a North African adolescent population. a national cross-sectional study in Tunisia

Background

In southern and eastern Mediterranean countries, changes in lifestyle and the increasing prevalence of excess weight in childhood are risk factors for high blood pressure (BP) during adolescence and adulthood. The aim of this study was to evaluate the BP status of Tunisian adolescents and to identify associated factors.

Methods

A cross-sectional study in 2005, based on a national, stratified, random cluster sample of 1294 boys and 1576 girls aged 15-19 surveyed in home visits. The socio-economic and behavioral characteristics of the adolescents were recorded. Overweight/obesity were assessed by Body Mass Index (BMI) from measured height and weight (WHO, 2007), abdominal obesity by waist circumference (WC). BP was measured twice during the same visit. Elevated BP was systolic (SBP) or diastolic blood pressure (DBP) ≥ 90th of the international reference or ≥ 120/80 mm Hg for 15-17 y., and SBP/DBP ≥ 120/80 mm Hg for 18-19 y.; hypertension was SBP/DBP ≥ 95th for 15-17 y. and ≥ 140/90 mm Hg for 18-19 y. Adjusted associations were assessed by logistic regression.

Results

The prevalence of elevated BP was 35.1%[32.9-37.4]: higher among boys (46.1% vs. 33.3%; P < 0.0001); 4.7%[3.8-5.9] of adolescents had hypertension. Associations adjusted for all covariates showed independent relationships with BMI and WC: - obesity vs. no excess weight increased elevated BP (boys OR = 2.1[1.0-4.2], girls OR = 2.3[1.3-3.9]) and hypertension (boys OR = 3.5[1.4-8.9], girls OR = 5.4[2.2-13.4]), - abdominal obesity (WC) was also associated with elevated BP in both genders (for boys: 2nd vs. 1st tertile OR = 1.7[1.3-2.3], 3rd vs.1st tertile OR = 2.8[1.9-4.2]; for girls: 2nd vs. 1st tertile OR = 1.6[1.2-2.1], 3rd vs.1st tertile OR = 2.1[1.5-3.0]) but only among boys for hypertension. Associations with other covariates were weaker: for boys, hypertension increased somewhat with sedentary lifestyle, while elevated BP was slightly more prevalent among urban girls and those not attending school.

Conclusion

Within the limits of BP measurement on one visit only, these results suggest that Tunisian adolescents of both genders are likely not spared from early elevated BP. Though further assessment is likely needed, the strong association with overweight/obesity observed suggests that interventions aimed at changing lifestyles to reduce this main risk factor may also be appropriate for the prevention of elevated BP.

Secular changes in anthropometric measurements and blood pressure in children of Crete, Greece, during 1992/93 and 2006/07

OBJECTIVES

To examine secular changes in anthropometric measurements and blood pressure (BP) in 1st-grade children in Crete, Greece, during 1992/93 and 2006/07.

METHODS

Children (aged 5.7-7.8 years) from two representative cross-sectional cohorts participated during 1992/93 (n=606) and 2006/07 (n=361). Body weight, body-mass-index (BMI), waist circumference (WC), waist-to-hip (WHpR) and waist-to-height (WHtR) ratios, BP, 20 m-shuttle-run test (20 mSRT), and moderate-to-vigorous-physical-activity (MVPA) were assessed.

RESULTS

There was a significant increase (P<0.01) in body weight (+10.2% and +6.7%), BMI (+6.9% and +4.0%), WC (+5.6% and +5.1%), WHpR (+3.0% and +3.4%), and WHtR (+4.2% and +3.8%), for boys and girls, respectively, and in the proportion of overweight/obese boys (19.4% vs. 33.7%; P<0.001) between 1992/93 and 2006/07. Both genders had decreased BP measurements in 2006/07 compared to 1992/93 (P<0.001). In both periods, BP was higher in obese compared to overweight and normal children (P<0.001), but there was no relationship between BP and physical activity (PA).

CONCLUSIONS

A substantial decrease in BP was observed in Cretan children over a 15-year period, despite a concurrent increase in obesity and anthropometric indices. This may be attributed to lifestyle and dietary changes and does not support the hypothesis that the obesity epidemic in children has resulted in proportionate increases in BP levels.