Blood pressure and puberty

Influence of puberty on relationships between body composition and blood pressure: a cross-sectional study

BACKGROUND

Fat mass (FM) and fat-free mass (FFM) are positively associated with blood pressure (BP) in youth. Yet, how puberty, independent of age, affects these relationships remains unclear. Given puberty may be a crucial period for cardiometabolic health, we examined how pubertal development moderates the associations of FM/FFM with BP.

METHODS

Pubertal development, resting BP, and body composition were assessed in a convenience sample of youth (5.5-17 years). General linear models were conducted to assess if pubertal development moderated the relationships between FM/FFM and systolic/diastolic BP standardized for age, sex, and height (SBPz/DBPz).

RESULTS

Among participants (N = 1405; age: M = 13.3 ± 2.9 years; 65.4% female; 53.2% racial/ethnic minority), FM/FFM were positively associated with SBPz and DBPz (ps ≤ 0.02). Pubertal development moderated the associations between FFM and BPz (ps ≤ 0.01), but not FM (ps > 0.43). For early/mid and late pubertal participants, there were positive associations between FFM and BP (DBPz: βs = 0.10-0.18, ps ≤ 0.01; SBPz: βs = 0.33-0.43, ps < 0.001); however, these relationships were attenuated, especially for prepubertal DBPz (DBPz: β = 0.01, p = 0.91; SBPz: β = 0.24, p = 0.001).

CONCLUSIONS

Puberty moderated the relationships between FFM and SBPz/DBPz in analyses that separately modeled the contributions of age and sex. These data suggest that the FFM-DBPz association may potentially be impacted by increasing sex hormone concentrations during puberty.

IMPACT

Fat mass (FM) and blood pressure (BP) were positively associated throughout puberty. Fat-free mass (FFM) and BP were positively associated throughout puberty; however, puberty moderated the FFM-BP relationship, such that there was a positive relationship in early/mid and late puberty, but the relationship was attenuated for prepubertal children. These findings contribute further insight into physiological and cardiometabolic changes occurring during puberty. Changes in hormone concentrations may explain the impact puberty has on the FFM-BP relationship. Understanding predictors of BP are important as childhood BP is associated with future cardiometabolic outcomes.

Epidemiological studies on noise and blood pressure in children: Observations and suggestions

OBJECTIVE

The goal of this review was to investigate methodological differences in studies on the effects of aircraft or road-traffic noise on blood pressure (BP) of urban children, emphasizing the similarities and differences in blood pressure measurements.

METHODS

A literature search has identified eight peer-reviewed studies, four conference proceedings and one PhD thesis on the effects of aircraft or road-traffic noise on children's blood pressure published in English in the last 30 years. Most of the studies were cross-sectional, and four studies were longitudinal, with follow-up period from one to three years. The studies were analyzed according to the following methodological issues: study design, children's characteristics, noise exposure assessment and blood pressure measurements. The effects of noise on systolic and diastolic pressure were presented in detail.

RESULTS

Studies on aircraft noise had more uniform methodology, indicating a slight tendency towards a positive relationship between aircraft noise exposure and BP in children. The studies on road-traffic noise were methodologically diverse, but compared to aircraft noise studies they showed a more uniform trend in the direction of a positive relationship with systolic BP. The time, place and number of BP measurements, as well as the devices and cuff sizes varied among the studies. Children's age, gender, body composition and ethnicity, and socio-economic status remain the greatest source of diversity in BP values.

CONCLUSIONS

The reviewed studies were methodologically diverse concerning noise exposure assessment, BP measurement, study design and control for confounders. In spite of this, they indicate a tendency toward positive association between noise exposure and children's blood pressure. We recommended strategies that might help researchers adopt similar procedures when measuring BP in future field studies.

Serum total cholesterol, HDL cholesterol and blood pressure levels in 13-year-old children in Eastern Finland. The North Karelia Youth Project

North Karelia Youth Project is a community and school-based intervention study of 13-year-old schoolchildren in Eastern Finland. This paper deals with serum total cholesterol, HDL cholesterol and blood pressure levels with some important background variables in the baseline survey in 1978. A total of 966 children were studied. A high mean serum serum cholesterol level (5.1 mmol/l) among both boys and girls was an outstanding finding. The cholesterol level was higher in the rural than urban areas. Different diet can explain this difference. Mean blood pressure was 117/67 mmHg among girls and 117/63 among boys. The high risk factor levels at this age support strongly the idea that the prevention of cardiovascular diseases should be started already in childhood.

Trajectory of systolic blood pressure in children and adolescents

PURPOSE

Rapid height and weight changes during childhood contribute markedly to blood-pressure change during children's physical growth. This article evaluates the differences in systolic blood pressure (SBP) growth or changes between four gender-ethnic groups: African American males (AM), Caucasian males (CM), African American females (AF), and Caucasian females (CF).

METHODS

Subjects 6-9 years old at entry (n = 1302) were followed for 12 years. The repeated-measure data of SBP were analyzed using the Gompertz growth model with random coefficients.

RESULTS

Mean SBP (mmHg) at age 6 years was lowest in African American girls (82.23 +/- 0.76) and highest in Caucasian boys (102.83 +/- 0.5). And for both ethnic groups, girls had lower levels at which SBP growth stopped. The peak growth ages (years) also differed by group: 9.30 +/- 0.73, 9.91 +/- 0.28, 10.00 +/- 0.82, and 10.60 +/- 0.22 for African American girls, African American boys, Caucasian girls and Caucasian boys, respectively.

CONCLUSION

SBP growth differed among gender-ethnic groups with respect to mean SBP level at age 6, the level at which SBP growth stops and the mean age at which SBP growth rate was at its peak.

Adolescence as possible critical temporal window for blood pressure short term monitoring in boys and girls

Adolescence is a critical temporal window for the development of obesity in adult age. We studied this period for short-term monitoring of blood pressure in both genders. Weight, height, body mass index (BMI), systolic and diastolic blood pressure (SBP, DBP) were recorded in 937 adolescents, 474 boys and 463 girls aged 12 years, and again 2 years later in the same subjects. Boys with BP values > or = 95th percentile at both ages (no. = 8) showed at 12 years weight (kg 61.4) height (cm 159.5) and BMI (23.5), and also at 14 years (77.0, 172.4, 25.6) values consistently higher than boys with high BP values at either ages taken singularly (no. = 32 + 32) (mean 49.2, 154.4, 21.5, respectively, at 12 years, and 62.1, 167.0, 22.2 at 14 years). These 64 boys, had values higher than boys with BP always below the 95th percentile (no. = 402) (45.5, 151.4, 19.7 at 12 years, and 56.9, 164.6, 20.9 at 14 years). This was confirmed for weight and BMI in girls. Stepwise logistic regression revealed that weight at 12 years and high BP values at 12 years were predictive independent risk factors for hypertension at 14 years. Odds ratio indicated that increment of body weight unit (1 kg) at 12 years predicted an average increase of 4% of risk for high BP values at 14 years, while high BP values at 12 years was predictive for a 2.19 times risk for high BP values at 14 years. Body weight, BMI and BP at 12 years of age may give useful indications for the prevision (and possible prevention) of hypertension and overweight at 14 years of age.

Body size, fat distribution, menarcheal age and blood pressure in 14-year-old girls

BACKGROUND

The relationships between body size and fatness and blood pressure are generally acknowledged. The majority of the few studies that have examined the effect of fat distribution and maturation rate on blood pressure have used secondary sex characteristics as the measure of maturity. The aim of the present study is to examine the associations between blood pressure and relative weight, fat distribution, recalled menarcheal age and occurrence of menstruation (yes/no) in a sample comprising of 1149 14-year-old girls.

METHODS

Systolic and diastolic blood pressure (DBP), height, weight and body circumferences were measured using standard protocols. Fatness was expressed as body mass index (BMI, kg/m2), whereas fat distribution was estimated by using waist-to-hip ratio. The girls' maturity status was assessed from exact recalled date of menarche. One-way analysis of covariance and multiple linear regression analyses were used to determine the strength of association among systolic blood pressure (SBP), DBP and BMI, menarcheal age and indices of fat distribution.

RESULTS AND CONCLUSION

Height and BMI are significantly associated with SBP. Relative weight is the most important factor related to SBP independently of chronological age and maturity status. Height and age at menarche are significantly associated with DBP. Height of 14-year-old girls shows the same strength of association with SBP and DBP, whereas maturity status negatively correlates with DBP. Fat distribution shows no effect on the level of DBP in girls.

Blood pressure at age 3-24 years in a rural community in Anhui, China

PURPOSE

This community-based study in Anhui, China examined the sex-specific pattern of blood pressure (BP) and its major determinants between age 3 and 24 years.

METHODS

BP, height, weight, and related covariates were obtained from all eligible subjects by consistent methods. A generalized additive model was used to explore independent relations between BP and covariates. The sample for analyses included a total of 14,277 subjects (7244 males and 7033 females).

RESULTS

Systolic blood pressure (SBP) increased linearly with age to an apparent plateau around the age of 15 years in girls and 20 years in boys. Diastolic blood pressure (DBP) essentially paralleled SBP. Until the age of 10, both SBP and DBP were similar in boys and girls; thereafter, values for boys surpassed those for girls with an average difference of 9 mmHg and 4 mmHg for SBP and DBP, respectively, at 20 years of age. This sex difference appeared to persist into early adulthood. The independent relation between BP and each of the three major determinants (age, height, and weight) was nonlinear over the age range studied. Sex-specific regression models with linear terms for age, height and weight were developed for each of four age groups (3-9, 10-14, 15-19, 20-24 years). The 5th, 10th, 90th, and 95th percentiles based on the percentage of predicted values can serve as the cutoffs for low, normal-low, normal-high, and high BP. The predicted values were derived from the above regression models that take into account an individual's sex, age, height, and weight.

CONCLUSIONS

This analysis provided important basis for classification of hypertension status and subsequent investigation of environmental risk factors in this population.

Blood pressure and self-assessment of female sexual maturation

The relationship of sexual maturation to blood pressure was investigated in a sample (n = 361) of white, non-Hispanic females, aged 7-18 years. Sexual maturation was determined by self-assessment. Systolic and fourth- and fifth-phase diastolic blood pressures increased significantly with increasing maturation. Body mass index, breast development, and pubic hair growth explained 29% of the systolic blood pressure variance and 23% of the fourth- and fifth-phase diastolic blood pressure variances. The interpretation of a child's or adolescent's blood pressure should take into account his or her stage of sexual maturation and body size. A consideration of growth and maturation may contribute to studies of the natural history of blood pressure.

Blood pressure and body size in precocious puberty

Blood pressure increases with age in normal children. This increase appears to be related to body size. To assess the role of body size as a determinant of blood pressure in precocious puberty, we compared the blood pressure of 81 children with precocious puberty with the blood pressure standards for normal children from the NHLBI Task Force on Blood Pressure Control in Children. Children with precocious puberty had significantly increased blood pressure for chronologic age (p less than 0.05) but generally appropriate blood pressure for height age or weight age. These data are consistent with the hypothesis that increased body size causes the increased blood pressure for chronologic age in children with precocious puberty. Physicians who evaluate such children should assess whether blood pressure is appropriate for height age rather than chronologic age.

Determinants of blood pressure in 7th grade Jerusalem school children

The determinants of blood pressure level were analyzed in a group of 1154 Jerusalem school children aged 12. After controlling for age, significant differences in blood pressure measurements were found between three groups: boys, pre-menarche girls and post-menarche girls. A comparison of the means of selected biological variables showed that girls who have reached menarche have levels of systolic blood pressure, weight, height and Quetelet's index higher than boys and pre-menarche girls. However, levels of triceps skinfold thickness and pulse rate were similar in the two groups of girls and higher than in boys. Using multiple regression analysis, we found that much of the variance (boys 29%, post-menarche girls 21% and pre-menarche girls 15%) of systolic blood pressure could be explained by a combination of biological variables (Quetelet, pulse rate, triceps skinfold thickness and height) while these variables explained a much smaller proportion (boys 12%, post-menarche girls 17% and pre-menarche 9%) of diastolic blood pressure variance. The predictive power of systolic blood pressure by the measured biological variables was higher in boys than in girls. However, diastolic blood pressure was better predicted by the biological variables in the group of girls with menarche than in other groups. Elevated blood pressure was observed in 3.2% of the examined children. High values for Quetelet's index were observed in 6.4%. The prevalence of elevated measurements of blood pressure and Quetelet's index were significantly higher in girls with menarche. Among children aged 12, the association between sociodemographic characteristics and blood pressure level was weak, as measured in multiple regression analysis.

Determination of blood pressure in children

The present paper reviews the epidemiologic patterns of blood pressure in children by demographic variables such as age, race, sex, education and social class. Other possible determinants for high blood pressure in both adults and children are also discussed, including obesity and salt intake. Special attention is given to the phenomenon of tracking and to genetic influences in blood pressure, the latter discussed in the context of the strengths and limitations of twin and familial aggregation studies.

Factors related to tracking of blood pressure in children. U.S. National Center for Health Statistics Health Examination Surveys Cycles II and III

In this paper we examine the relationship of growth, obesity, and the degree of sexual and bone maturation to blood pressure in a U.S. national probability sample of 2165 children examined by the U.S. National Center for Health Statistics on two occasions, approximately 4 years apart. Subjects who maintained, increased, or decreased their peer rank order of blood pressure are described. Children who maintained their blood pressure in the upper quintile were taller, heavier, more obese, had greater bone age, greater numbers of permanent teeth, and were more sexually mature than their peers, while those maintaining their blood pressure in the lowest quintile of blood pressure were shorter, lighter, less obese, had lesser bone age, fewer permanent teeth, and were less sexually mature. Subjects whose blood pressures were initially in the lowest four quintiles and then rose to the top quintile were also taller, heavier, more obese, and had greater bone age, while those with blood pressures falling to the lowest quintile from the upper four quintiles were shorter, lighter, less obese, and had lesser bone age. Thus, the level at which blood pressure tracks during childhood is related to growth, obesity, and to the degree of maturation acquired. In addition, children whose blood pressures are rising or falling in relation to their peers have body growth and maturation characteristics similar to those who maintain their rank order high or low respectively.

Pediatric blood pressure: ethnic comparisons in a primary care center

This study reviews the blood pressure (BP) determinations previously recorded in a primary care center serving a low socioeconomic population and compares the systolic blood pressure (SBP) and diastolic blood pressure (DBP) distributions within the clinic population among the three major ethnic groups represented, and also between this clinic population and a recently reported standard population (Task Force for Blood Pressure Control in Children, NHLBI). The study group consisted of 2810 children 3-17 years of age, of whom 49.2% were of Spanish surname, 23.4% black, and 27.4% white. As a standard clinic procedure, BP readings were obtained from the right arm with the subject seated. Comparisons of the average SBP by 3-year age groups, by sex, within the clinic population showed that blacks had higher SBPs than children with Spanish surnames or whites in all of the five male subgroups and in four of the five female subgroups. Black males had higher DBPs than Spanish or whites in four of the five subgroups; black females had higher DBPs in three of the five subgroups. In comparison with the standard population, the overall 95th percentile values for both SBP and DBP were lower. The prevalence of readings above the 95th percentile values reported for the standard population over all age groups was as follows: SBP, 1.53%; DBP, 1.60%; and both SBP and DBP, 0.57%. Proportionately, elevated readings were most common among blacks and least common among whites. However, these differences between ethnic groups could be accounted for statistically, to a great extent, by adjusting for height and weight, since blacks were the tallest and heaviest of the three groups. These results suggest that, even in childhood, blacks presenting at a primary care center have higher BPs than Spanish or whites, but that this differences is largely related to body size.

Blood pressure, growth and maturation from childhood through adolescence. Mixed longitudinal analyses of the Philadelphia Blood Pressure Project

This paper presents data on the extent to which blood pressure (BP) and growth status at 7 years of age are associated with BP, growth, and maturity status during adolescence. Two samples of black adolescents, namely, a representative sample (n = 562) stratified by sex and age (11 to 15 years) and a sample (n = 256) with supine BP over one standard deviation above the mean at 7 years of age (High BP7), were selected from the Philadelphia Collaborative Perinatal Project (CPP) population and followed longitudinally for 3 years. When the subjects reached adolescence we again measured supine blood pressure, height, weight, and skeletal maturity. Analyses of the data collected at 7 years of age by the CPP indicated that weight and height are highly significantly associated with systolic blood pressure (SBP) and diastolic blood pressure (DBP) respectively. Accordingly, the SBP, DBP, weights, and heights of the representative sample at age 7 were divided into percentile groupings (< 15%, 15%-85%, > 85%). Using mixed longitudinal analyses during adolescence, we found that mean SBP tracked in males through age 15 and in females through age 13 based on the percentile groupings of SBP, height, and weight. Moreover, the weight percentile groupings provided the best discrimination of SBP at these ages. Skeletal age also tracked throughout early adolescence using these percentile groupings of 7-year heights and weights. In females only, diastolic phase 4 (DBP4) during adolescence was significantly associated with 7-year height percentile groupings. In comparing the representative and the High BP7 samples at each chronological age for BP, height, weight, and skeletal age at adolescence (ages 12 to 17 years), it was found that the High BP7 sample was, on the average, taller and heavier at age 7 and throughout early adolescence. At age 17 in males, however, there were no significant differences in BP, growth, or maturity status. In females, SBP of the High BP7 sample remained significantly higher, and there was a tendency for them to remain heavier through age 17. Hence BP variation is so closely associated with growth and maturation that these factors must be taken into account when assessing BP in childhood and adolescence.

High blood pressure in children: problems and guidelines for evaluation and treatment

Evidence is presented from studies of the authors and of other investigators that primary hypertension is more common in children than was previously thought. Ninety-five percent of 131 asymptomatic children with incidental hypertension were considered to have primary hypertension after investigation for possible causes. The definition of hypertension was based on normal ranges of blood pressure for each age and sex. However, the definition of juvenile hypertension is still unsettled as is the question of treatment. Investigation of the effect of prolonged antihypertensive therapy on growth and development is needed. Primary hypertension in the young makes possible the study of the disease at its inception.