Secular changes in blood pressure in childhood, adolescence and young adulthood: systematic review of trends from 1948 to 1998

Prevalence of Hypertension among Children and Adolescents in India: A Systematic Review and Meta-Analysis

OBJECTIVE

To conduct a systematic review to provide pooled estimates of the prevalence of hypertension among children aged less than 18 y in India.

METHODS

Three electronic databases (PubMed, EMBASE, and Web of Science) were searched from inception to August 2020 by using terms related to hypertension, children, prevalence, and India. Studies reporting the prevalence of hypertension, defined based on at least three measurements, were included. Two investigators independently performed the literature search, study selection, and data extraction for this review. Random effect meta-analysis was used to provide pooled estimates of hypertension.

RESULTS

A total of 64 studies were included in this systematic review. The pooled prevalence was 7% (95% CI: 6%-8%) for hypertension, 4% (95% CI: 3%-4.1%) for sustained hypertension and 10% (95% CI: 8%-13%) for prehypertension. While there was no significant difference in hypertension across five different regions of the country, an upward rising trend was observed after the year 2005. Urban children had a higher prevalence of hypertension as compared to their rural counterparts. Children with obesity had a significantly high prevalence of hypertension (29%) than normal-weight children (7%).

CONCLUSION

In this review, it was observed that considerable proportions (7%) of school going children are hypertensive in India. Prevalence was higher in urban and overweight children. This study highlights that hypertension is a public health problem in India; hence, there is a need to implement public health measures to prevent hypertension.

Blood pressure and resting heart rate in 3-17-year-olds in Germany in 2003-2006 and 2014-2017

To track blood pressure (BP) and resting heart rate (RHR) in children and adolescents is important due to its associations with cardiovascular outcomes in the adulthood. Therefore, the aim of this study was to examine BP and RHR over a decade among children and adolescents living in Germany using national examination data. Cross-sectional data from 3- to 17-year-old national survey participants (KiGGS 2003–06, n = 14,701; KiGGS 2014–17, n = 3509) including standardized oscillometric BP and RHR were used for age- and sex-standardized analysis. Measurement protocols were identical with the exception of the cuff selection rule, which was accounted for in the analyses. Different BP and RHR trends were observed according to age-groups. In 3- to 6-year-olds adjusted mean SBP and DBP were significantly higher in 2014–2017 compared to 2003–2006 (+2.4 and +1.9 mm Hg, respectively), while RHR was statistically significantly lower by −3.8 bpm. No significant changes in BP or in RHR were observed in 7- to 10-year-olds over time. In 11- to 13-year-olds as well as in 14- to 17-year-olds lower BP has been observed (SBP −2.4 and −3.2 mm Hg, respectively, and DBP −1.8 and −1.7 mm Hg), while RHR was significantly higher (+2.7 and +3.7 bpm). BP trends did not parallel RHR trends. The downward BP trend in adolescents seemed to follow decreasing adult BP trends in middle and high-income countries. The increase in BP in younger children needs confirmation from other studies as well as further investigation. In school-aged children and adolescents, the increased RHR trend may indicate decreased physical fitness.

Global epidemiology, health burden and effective interventions for elevated blood pressure and hypertension

High blood pressure is one of the most important risk factors for ischaemic heart disease, stroke, other cardiovascular diseases, chronic kidney disease and dementia. Mean blood pressure and the prevalence of raised blood pressure have declined substantially in high-income regions since at least the 1970s. By contrast, blood pressure has risen in East, South and Southeast Asia, Oceania and sub-Saharan Africa. Given these trends, the prevalence of hypertension is now higher in low-income and middle-income countries than in high-income countries. In 2015, an estimated 8.5 million deaths were attributable to systolic blood pressure >115 mmHg, 88% of which were in low-income and middle-income countries. Measures such as increasing the availability and affordability of fresh fruits and vegetables, lowering the sodium content of packaged and prepared food and staples such as bread, and improving the availability of dietary salt substitutes can help lower blood pressure in the entire population. The use and effectiveness of hypertension treatment vary substantially across countries. Factors influencing this variation include a country's financial resources, the extent of health insurance and health facilities, how frequently people interact with physicians and non-physician health personnel, whether a clear and widely adopted clinical guideline exists and the availability of medicines. Scaling up treatment coverage and improving its community effectiveness can substantially reduce the health burden of hypertension.

Age-period-cohort projection of trends in blood pressure and body mass index in children and adolescents in Hong Kong

Background

Blood pressure (BP) and body mass index (BMI) trends during childhood and adolescence are complex, making context-specific projections necessary to inform prevention and presage changes.

Objective

This study aimed to project BP and BMI in Hong Kong Chinese children and adolescents from 2015 to 2024 based on trends in BP and BMI observed from 1996/99 to 2014.

Methods

We decomposed recent trends into sex-specific contributions of age, period and cohort using age-period-cohort linear regression with Bayesian inference and autoregressive priors based on BP in children and adolescents aged 9–18 years from 1999 to 2014 and BMI in those aged 6–18 years from 1996 to 2014. We then used the resultant models to project BP and BMI from 2015 to 2024.

Results

During the study period, systolic BP decreased from 1999 to 2004/5 before gradually increasing to 2014 during childhood (for boys: from 104.6 to 101.9 and then to 103.4 mmHg) and during adolescence. Similar patterns were observed for diastolic BP. BMI generally increased from 1996 to 2009 before falling to 2014 during childhood (e.g. for boys: from 17.2 to 18.0 and then to 17.1 kg/m²). From 2015 onwards, systolic BP was projected to increase in girls, but remain stable in boys. For both sexes, diastolic BP was projected to increase, whereas BMI was projected to decrease to 2024.

Conclusions

In this economically developed Chinese setting, future trends in BP and BMI in children and adolescents are predicted to be divergent, consistent with prior discordant trends in BP and BMI.

Global Prevalence of Hypertension in Children: A Systematic Review and Meta-analysis

IMPORTANCE

Reliable estimates of the prevalence of childhood hypertension serve as the basis for adequate prevention and treatment. However, the prevalence of childhood hypertension has rarely been synthesized at the global level.

OBJECTIVE

To conduct a systematic review and meta-analysis to assess the prevalence of hypertension in the general pediatric population.

DATA SOURCES

PubMed, MEDLINE, Embase, Global Health, and Global Health Library were searched from inception until June 2018, using search terms related to hypertension (hypertension OR high blood pressure OR elevated blood pressure), children (children OR adolescents), and prevalence (prevalence OR epidemiology).

STUDY SELECTION

Studies that were conducted in the general pediatric population and quantified the prevalence of childhood hypertension were eligible. Included studies had blood pressure measurements from at least 3 separate occasions.

DATA EXTRACTION AND SYNTHESIS

Two authors independently extracted data. Random-effects meta-analysis was used to derive the pooled prevalence. Variations in the prevalence estimates in different subgroups, including age group, sex, setting, device, investigation period, BMI group, World Health Organization region and World Bank region, were examined by subgroup meta-analysis. Meta-regression was used to establish the age-specific prevalence of childhood hypertension and to assess its secular trend.

MAIN OUTCOMES AND MEASURES

Prevalence of childhood hypertension overall and by subgroup.

RESULTS

A total of 47 articles were included in the meta-analysis. The pooled prevalence was 4.00% (95% CI, 3.29%-4.78%) for hypertension, 9.67% (95% CI, 7.26%-12.38%) for prehypertension, 4.00% (95% CI, 2.10%-6.48%) for stage 1 hypertension, and 0.95% (95% CI, 0.48%-1.57%) for stage 2 hypertension in children 19 years and younger. In subgroup meta-analyses, the prevalence of childhood hypertension was higher when measured by aneroid sphygmomanometer (7.23% vs 4.59% by mercury sphygmomanometer vs 2.94% by oscillometric sphygmomanometer) and among overweight and obese children (15.27% and 4.99% vs 1.90% among normal-weight children). A trend of increasing prevalence of childhood hypertension was observed during the past 2 decades, with a relative increasing rate of 75% to 79% from 2000 to 2015. In 2015, the prevalence of hypertension ranged from 4.32% (95% CI, 2.79%-6.63%) among children aged 6 years to 3.28% (95% CI, 2.25%-4.77%) among those aged 19 years and peaked at 7.89% (95% CI, 5.75%-10.75%) among those aged 14 years.

CONCLUSIONS AND RELEVANCE

This study provides a global estimation of childhood hypertension prevalence based on blood pressure measurements in at least 3 separate visits. More high-quality epidemiologic investigations on childhood hypertension are still needed.

Contributions of mean and shape of blood pressure distribution to worldwide trends and variations in raised blood pressure: a pooled analysis of 1018 population-based measurement studies with 88.6 million participants

BACKGROUND

Change in the prevalence of raised blood pressure could be due to both shifts in the entire distribution of blood pressure (representing the combined effects of public health interventions and secular trends) and changes in its high-blood-pressure tail (representing successful clinical interventions to control blood pressure in the hypertensive population). Our aim was to quantify the contributions of these two phenomena to the worldwide trends in the prevalence of raised blood pressure.

METHODS

We pooled 1018 population-based studies with blood pressure measurements on 88.6 million participants from 1985 to 2016. We first calculated mean systolic blood pressure (SBP), mean diastolic blood pressure (DBP) and prevalence of raised blood pressure by sex and 10-year age group from 20-29 years to 70-79 years in each study, taking into account complex survey design and survey sample weights, where relevant. We used a linear mixed effect model to quantify the association between (probit-transformed) prevalence of raised blood pressure and age-group- and sex-specific mean blood pressure. We calculated the contributions of change in mean SBP and DBP, and of change in the prevalence-mean association, to the change in prevalence of raised blood pressure.

RESULTS

In 2005-16, at the same level of population mean SBP and DBP, men and women in South Asia and in Central Asia, the Middle East and North Africa would have the highest prevalence of raised blood pressure, and men and women in the high-income Asia Pacific and high-income Western regions would have the lowest. In most region-sex-age groups where the prevalence of raised blood pressure declined, one half or more of the decline was due to the decline in mean blood pressure. Where prevalence of raised blood pressure has increased, the change was entirely driven by increasing mean blood pressure, offset partly by the change in the prevalence-mean association.

CONCLUSIONS

Change in mean blood pressure is the main driver of the worldwide change in the prevalence of raised blood pressure, but change in the high-blood-pressure tail of the distribution has also contributed to the change in prevalence, especially in older age groups.

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.

Worldwide trends in blood pressure from 1975 to 2015: a pooled analysis of 1479 population-based measurement studies with 19·1 million participants

BACKGROUND

Raised blood pressure is an important risk factor for cardiovascular diseases and chronic kidney disease. We estimated worldwide trends in mean systolic and mean diastolic blood pressure, and the prevalence of, and number of people with, raised blood pressure, defined as systolic blood pressure of 140 mm Hg or higher or diastolic blood pressure of 90 mm Hg or higher.

METHODS

For this analysis, we pooled national, subnational, or community population-based studies that had measured blood pressure in adults aged 18 years and older. We used a Bayesian hierarchical model to estimate trends from 1975 to 2015 in mean systolic and mean diastolic blood pressure, and the prevalence of raised blood pressure for 200 countries. We calculated the contributions of changes in prevalence versus population growth and ageing to the increase in the number of adults with raised blood pressure.

FINDINGS

We pooled 1479 studies that had measured the blood pressures of 19·1 million adults. Global age-standardised mean systolic blood pressure in 2015 was 127·0 mm Hg (95% credible interval 125·7-128·3) in men and 122·3 mm Hg (121·0-123·6) in women; age-standardised mean diastolic blood pressure was 78·7 mm Hg (77·9-79·5) for men and 76·7 mm Hg (75·9-77·6) for women. Global age-standardised prevalence of raised blood pressure was 24·1% (21·4-27·1) in men and 20·1% (17·8-22·5) in women in 2015. Mean systolic and mean diastolic blood pressure decreased substantially from 1975 to 2015 in high-income western and Asia Pacific countries, moving these countries from having some of the highest worldwide blood pressure in 1975 to the lowest in 2015. Mean blood pressure also decreased in women in central and eastern Europe, Latin America and the Caribbean, and, more recently, central Asia, Middle East, and north Africa, but the estimated trends in these super-regions had larger uncertainty than in high-income super-regions. By contrast, mean blood pressure might have increased in east and southeast Asia, south Asia, Oceania, and sub-Saharan Africa. In 2015, central and eastern Europe, sub-Saharan Africa, and south Asia had the highest blood pressure levels. Prevalence of raised blood pressure decreased in high-income and some middle-income countries; it remained unchanged elsewhere. The number of adults with raised blood pressure increased from 594 million in 1975 to 1·13 billion in 2015, with the increase largely in low-income and middle-income countries. The global increase in the number of adults with raised blood pressure is a net effect of increase due to population growth and ageing, and decrease due to declining age-specific prevalence.

INTERPRETATION

During the past four decades, the highest worldwide blood pressure levels have shifted from high-income countries to low-income countries in south Asia and sub-Saharan Africa due to opposite trends, while blood pressure has been persistently high in central and eastern Europe.

FUNDING

Wellcome Trust.

Contributions of risk factors and medical care to cardiovascular mortality trends

Ischaemic heart disease, stroke, and other cardiovascular diseases (CVDs) lead to 17.5 million deaths worldwide per year. Taking into account population ageing, CVD death rates are decreasing steadily both in regions with reliable trend data and globally. The declines in high-income countries and some Latin American countries have been ongoing for decades without slowing. These positive trends have broadly coincided with, and benefited from, declines in smoking and physiological risk factors, such as blood pressure and serum cholesterol levels. These declines have also coincided with, and benefited from, improvements in medical care, including primary prevention, diagnosis, and treatment of acute CVDs, as well as post-hospital care, especially in the past 40 years. These variables, however, explain neither why the decline began when it did, nor the similarities and differences in the start time and rate of the decline between countries and sexes. In Russia and some other former Soviet countries, changes in volume and patterns of alcohol consumption have caused sharp rises in CVD mortality since the early 1990s. An important challenge in reaching firm conclusions about the drivers of these remarkable international trends is the paucity of time-trend data on CVD incidence, risk factors throughout the life-course, and clinical care.

Retinal microvasculature and cardiovascular health in childhood

BACKGROUND AND OBJECTIVE

Alterations in retinal microvasculature are associated with increased risk of cardiovascular disease. We examined the associations of retinal vessel caliber with cardiovascular markers in school-age children.

METHODS

Among 4007 school-age children (median age of 6.0 years), we measured cardiovascular markers and retinal vessel calibers from digitized retinal photographs.

RESULTS

Narrower retinal arteriolar caliber was associated with higher systolic and diastolic blood pressure (-0.20 SD score [SDS] [95% confidence interval (CI) -0.24 to -0.18] and -0.14 SDS [-0.17 to -0.11], respectively, per SDS increase in retinal arteriolar caliber), mean arterial pressure, and pulse pressure, but not with carotid-femoral pulse wave velocity, heart rate, cardiac output, or left ventricular mass. A wider retinal venular caliber was associated with lower systolic blood pressure, mean arterial pressure, and pulse pressure and higher carotid-femoral pulse wave velocity (carotid-femoral pulse wave velocity difference = 0.04 SDS [95% CI 0.01 to 0.07] per SDS increase in retinal venular caliber). Both narrower retinal arteriolar and venular calibers were associated with higher risk of hypertension at the age of 6 years, with the strongest association for retinal arteriolar caliber (odds ratio 1.35 [95% CI 1.21 to 1.45] per SDS decrease in arteriolar caliber). Adjustment for parental and infant sociodemographic factors did not influence the observed associations.

CONCLUSIONS

Both retinal arteriolar and venular calibers are associated with blood pressure in school-age children, whereas retinal venular caliber is associated with carotid-femoral pulse wave velocity. Microvascular adaptations in childhood might influence cardiovascular health and disease from childhood onward.

Association of serum calcium and hypertension among adolescents aged 12-17 years in the rural area of Northeast China

Calcium plays an important role in regulating body homeostasis. Several studies have reported the association between serum calcium and cardiovascular disease in adults. However, studies assessing the relationship between serum calcium and hypertension were limited, especially in subject populations of adolescents. The aim of the present study was to examine the association of serum calcium levels and blood pressure levels among adolescents in the rural area of Northeast China. A total of 2,023 students participated in this study, including 894 boys and 1,129 girls, aged from 12 to 17 years old. We measured the body weight, height, systolic blood pressure (SBP), diastolic blood pressure (DBP), and serum calcium concentrations of all eligible subjects, and the body mass index (BMI) was calculated from body weight and height. Childhood hypertension was defined as SBP and/or DBP ≥95th percentile for age and gender. According to the results of multivariable linear and logistic regression analysis, we found that higher serum calcium levels were positively associated with childhood hypertension. In comparison with serum calcium levels ≤2.37 mmol/L, the multivariable odds ratio (95 % confidence interval) of hypertension among adolescents with serum calcium levels ≥2.53 mmol/L was 1.89 (1.41-2.53; P trend < 0.001). In addition, higher serum calcium levels were also positively associated with average difference in SBP and DBP; the average differences (95 % confidence interval) were 4.22 (2.74-5.83; P trend < 0.001) and 2.23(1.00-3.46; P trend < 0.001), respectively. In conclusion, higher serum calcium concentrations were found to have an association with higher blood pressure levels and higher prevalence of hypertension in the young population.

Hypertension in children and adolescents: epidemiology and pathogenesis

High blood pressure is one among the leading contributors to burden of disease globally. Approximately 54 % of stroke and 47 % of ischemic heart disease events worldwide were attributable to high blood pressure in the year 2001. There is deficiency of data on the long-term outcome of hypertension in children. In spite of this, there is sufficient evidence to suspect that the health risks of hypertension in pediatric patients are substantial. Hypertension in childhood is known to result in hypertension in young adulthood. The epidemiology of hypertension in children is well represented from various studies conducted across continents. Factors like methodological issues in measurement, socio demographic differences, adiposity levels and ethnicity appear to influence the distribution of blood pressure as well as prevalence of hypertension in children. The etio-pathogenesis of essential (primary) hypertension is multi-factorial in origin. Obesity, insulin resistance, activation of sympathetic nervous system, alterations in sodium homeostasis, renin-angiotensin system changes, changes in vascular smooth muscle structure and reactivity, high serum uric acid levels, genetic factors and fetal programming have been reported to contribute to this disorder. The causes of secondary hypertension vary with age. Renal disorders and coarctation of the aorta are the most common causes of hypertension in children up to age 6 y. In older children, renal parenchymal disease remains the most frequent cause of increased blood pressure. Other causes of hypertension in children are relatively rare and include systemic arteritis and certain tumours, endocrine dysfunction, and neurologic disorders.

Association between adiposity and blood pressure levels between the ages of 6 and 16 years. Analysis in a student population from Madrid, Spain

INTRODUCTION AND OBJECTIVES

The increase in the incidence of hypertension in children can be attributed to the rising prevalence of obesity. The objective is to analyze the impact of overweight and the degree or distribution of adiposity on blood pressure levels in a population of Spanish schoolchildren.

METHODS

A cross-sectional study was carried out in 1511 schoolchildren between 6 years and 16 years of age. We measured weight, height, waist circumference, subcutaneous skinfolds, and blood pressure. Nutritional categories were established on the basis of body mass index, waist-to-height ratio, and percent body fat. According to the National High Blood Pressure Education Program Working Group, subjects whose blood pressure was above the 90th percentile of the standard normal distribution were considered to have high blood pressure.

RESULTS

In all, 3.17% of the boys and 3.05% of the girls had high blood pressure. According to odds ratio analysis, the risk of high blood pressure increased in individuals with a body mass index indicative of obesity (7.87-fold in boys, 12.32-fold in girls), with a percent body fat>97th percentile (6.98-fold in boys, 18.51-fold in girls), or with a waist-to-height ratio ≥0.5 (10.56-fold in boys, 7.82-fold in girls).

CONCLUSIONS

Overweight and obesity increase the risk of high blood pressure in children between 6 years and 16 years of age, although the risk level varies depending on the amount and distribution of adipose tissue. Anthropometric indicators of relative adiposity and fat distribution are especially useful in the identification of children and adolescents with high blood pressure.

Secular trends in BMI and blood pressure among children and adolescents: the Bogalusa Heart Study

OBJECTIVE

The prevalence of obesity among children and adolescents increased by almost threefold from the 1970s to 2000. We examined whether these secular changes in BMI were accompanied by increases in blood pressure levels.

METHODS

A total of 24,092 examinations were conducted among 11,478 children and adolescents (aged 5-17 years) from 1974 to 1993 in the Bogalusa Heart Study (Louisiana).

RESULTS

The prevalence of obesity increased from 6% to 17% during this period. In contrast, only small changes were observed in levels of systolic blood pressure (SBP) and diastolic blood pressure (DBP), and neither mean nor high (based on the 90th percentile from the Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents) levels increased over the 20-year period. Within each race-gender group, mean levels of SBP did not change, whereas mean levels of DBP decreased by 2 mm Hg (P < .001 for trend). Levels of BMI were positively associated with levels of SBP and DBP within each of the 7 examinations, and controlling for BMI (along with other covariates) indicated that only ~60% as many children as expected had high levels of blood pressure in 1993.

CONCLUSIONS

Our finding that levels of DBP and SBP among children in this large sample did not increase despite the increases that were seen in obesity indicates that changes in blood pressure levels in a population do not necessarily parallel changes in obesity. Additional study of the potential characteristics that have ameliorated the expected increase in high blood pressure could lead to further reductions in risk.

Re-examining heritability: genetics, life history and plasticity

Human life-history traits (growth, maturation, nutritional status) are increasingly associated with risk of chronic degenerative disease. Twin studies suggest high heritability of such traits; however, although sophisticated approaches have identified genetic variation underlying a proportion of this heritability, studies also increasingly demonstrate significant plasticity, and many life-history traits are able to change by one standard deviation (SD) over 3-6 generations. Developments in our understanding of the contributions of genetics and plasticity to human life history are likely to improve understanding of the growing burden of chronic diseases. We argue that a life-history approach to understanding variation in the human phenotype must integrate these two risk components, and highlight the important contribution of plasticity to changes in disease prevalence.

Is infant weight associated with childhood blood pressure? Analysis of the Promotion of Breastfeeding Intervention Trial (PROBIT) cohort

BACKGROUND

Weight gain during infancy may programme later health outcomes, but examination of this hypothesis requires appropriate lifecourse methods and detailed weight gain measures during childhood. We examined associations between weight gain in infancy and early childhood and blood pressure at the age of 6.5 years in healthy children born at term.

METHODS

We carried out an observational analysis of data from a cluster-randomized breastfeeding promotion trial in Belarus. Of 17 046 infants enrolled between June 1996 and December 1997, 13 889 (81.5%) had systolic and diastolic blood pressure measured at 6.5 years; 10 495 children with complete data were analysed. A random-effects linear spline model with three knot points was used to estimate each individual's birthweight and weight gain from birth to 3 months, 3 months to 1 year and 1-5 years. Path analysis was used to separate direct effects from those mediated through subsequent weight gain.

RESULTS

In boys, after controlling for confounders and prior weight gain, the change in systolic blood pressure per z-score increase in weight gain was 0.09 mmHg [95% confidence interval (95% CI) -0.14 to 0.31] for birthweight; 0.41 mmHg (95% CI 0.19-0.64) for birth to 3 months; 0.69 mmHg (95% CI 0.47-0.92) for 3 months to 1 year and 0.82 mmHg (95% CI 0.58-1.06) for 1-5 years. Most of the associations between weight gain and blood pressure were mediated through weight at the age of 6.5 years. Findings for girls and diastolic blood pressure were similar.

CONCLUSIONS

Children who gained weight faster than their peers, particularly at later ages, had higher blood pressure at the age of 6.5 years, with no association between birthweight and blood pressure.

Trends in risk factors for cardiovascular disease among Iranian adolescents: the Tehran Lipid and Glucose Study, 1999-2008

OBJECTIVES

Data on secular trends in adolescent obesity and dyslipidemia are limited. Data on obesity status collected during 3 surveys were used to evaluate these trends in obesity and dyslipidemia among Tehranian adolescents and to assess the likelihood of risk factors for cardiovascular disease.

METHODS

We analyzed data for adolescents (age 10 to 19 years) from 3 cross-sectional surveys of the Tehran Lipid and Glucose Study: 1999-2001 (n = 3010, 47.2% males), 2002-2005 (n = 1107, 48.4% males), and 2006-2008 (n = 1090, 46.6% males). Overweight and abdominal obesity were defined using Iranian body mass index (BMI) percentiles, International Obesity Task Force (IOTF) criteria, and Iranian waist circumference (WC) charts. Hypertension was defined by using the National Heart, Lung, and Blood Institute's recommended cut points, and dyslipidemia was defined according to the recent recommendations of the American Heart Association.

RESULTS

The overall adjusted prevalences of "at risk for overweight" and overweight changed from 13% and 8% (using Iranian cutoffs), respectively, and 14.8% and 4.7% (using IOTF criteria) in 1999-2001 to 19% and 15% (Iranian cutoffs) and 23.0% and 9.2% (IOTF criteria) in 2006-2008 (P < 0.01 for all comparisons). The prevalence of abdominal obesity increased in males from 14.5% in 1999-2001 to 33.3% in 2006-2008 (P < 0.001). Almost half the adolescents had low high-density lipoprotein cholesterol (HDL-C) in the 3 surveys. In all surveys, as BMI and WC increased, multivariate age- and sex-adjusted odds ratios of low HDL-C and high triglyceride levels significantly increased. Overweight was associated with a greater likelihood of these risk factors, as compared with increased WC.

CONCLUSIONS

Overweight and abdominal obesity are increasing in Tehranian adolescents, and these increases are accompanied by abnormalities in levels of serum triglyceride and HDL-C.

Secular trends in blood pressure during early-to-middle adulthood: the Fels Longitudinal Study

BACKGROUND

Some studies have shown a decline in blood pressure (BP) over the second half of the twentieth century. However, the increasing prevalence of obesity may have opposite effects on recent cohorts.

METHOD

Using serial BP data from the Fels Longitudinal Study, we examined secular trends in mean BP, the rate of change in BP with age (slopes), and the influence of obesity (i.e., BMI) and height on these trends during young-to-middle adulthood. The study sample consisted of 970 adults, aged 18-40 years, who were born between 1920 and 1979. Participants were grouped into birth decade cohorts and had up to 11 serial measurements of SBP, DBP, and BMI. Sex-stratified mixed longitudinal analyses were used to identify cohort effects on mean BP at ages 19, 29, and 39 years, and on the rate of change in BP with age.

RESULTS

For both sexes, mean SBP did not vary significantly by birth cohort, before and after adjusting for height and BMI. Mean DBP exhibited a U-shaped secular trend even after adjusting for BMI and height that was influenced by age-by-cohort effects. By age 39 years, those born most recently had the highest mean DBP.

CONCLUSION

There were cohort effects on the rate of change in DBP with age, but not on rate of SBP change. The most recent cohorts had higher rates of DBP change with age compared to the earlier cohorts. The secular trend was partially influenced by the trends in BMI.

Exploring determinants of secular decreases in childhood blood pressure and hypertension

BACKGROUND

Childhood blood pressure is largely uninfluenced by medical treatment and behavioral changes associated with hypertension diagnosis. Examining secular trends in childhood blood pressure and its contributing factors will help us better understand population-level determinants of blood pressure and hypertension.

METHODS AND RESULTS

Data were from 4 waves of the Korean National Health and Nutrition Examination Survey between 1998 and 2008, including a total of 5909 boys and girls 10 to 19 years of age. Over the past 10 years, age- and height-adjusted mean systolic blood pressure decreased substantially from 115.6 to 106.9 mm Hg (by 8.7 mm Hg) among boys and from 111.8 to 101.8 mm Hg (by 10.0 mm Hg) among girls. Associated childhood hypertension and prehypertension/hypertension prevalences decreased by 52% to 86%. These remarkable decreases were found among all age and socioeconomic groups and were not explained by secular changes in childhood obesity (body mass index and waist circumferences), health behaviors (cigarette smoking and physical activity), nutritional factors (sodium, potassium, total energy, protein, and fat intake), psychological factors (perceived stress and sleep duration), and sociodemographic factors (annual household income and family size).

CONCLUSIONS

We observed important population declines in blood pressure in Korea over a 10-year period in children 10 to 19 years of age, but the likely causes for these secular trends remain to be determined.

Life course trajectories of systolic blood pressure using longitudinal data from eight UK cohorts

BACKGROUND

Much of our understanding of the age-related progression of systolic blood pressure (SBP) comes from cross-sectional data, which do not directly capture within-individual change. We estimated life course trajectories of SBP using longitudinal data from seven population-based cohorts and one predominantly white collar occupational cohort, each from the United Kingdom and with data covering different but overlapping age periods.

METHODS AND FINDINGS

Data are from 30,372 individuals and comprise 102,583 SBP observations spanning from age 7 to 80+y. Multilevel models were fitted to each cohort. Four life course phases were evident in both sexes: a rapid increase in SBP coinciding with peak adolescent growth, a more gentle increase in early adulthood, a midlife acceleration beginning in the fourth decade, and a period of deceleration in late adulthood where increases in SBP slowed and SBP eventually declined. These phases were still present, although at lower levels, after adjusting for increases in body mass index though adulthood. The deceleration and decline in old age was less evident after excluding individuals who had taken antihypertensive medication. Compared to the population-based cohorts, the occupational cohort had a lower mean SBP, a shallower annual increase in midlife, and a later midlife acceleration. The maximum sex difference was found at age 26 (+8.2 mm Hg higher in men, 95% CI: 6.7, 9.8); women then experienced steeper rises and caught up by the seventh decade.

CONCLUSIONS

Our investigation shows a general pattern of SBP progression from childhood in the UK, and suggests possible differences in this pattern during adulthood between a general population and an occupational population. Please see later in the article for the Editors' Summary.

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.

Trajectories of overweight and body mass index in adulthood and blood pressure at age 53: the 1946 British birth cohort study

OBJECTIVE

To assess the relationship between patterns of overweight during adulthood and systolic (SBP) and diastolic (DBP) blood pressure (BP) at age 53.

METHOD

Data are from 3035 male and female participants of the 1946 British birth cohort study. Body mass index (BMI) was obtained at ages 20, 26, 36, 43 and 53 years. Censored regression models accounting for medication were used to investigate associations of BP at 53 years with overweight (BMI > 25 kg/m) at each age, age at first overweight and conditional weight gain. Sex interactions were also examined.

RESULTS

Overweight at all ages except for 20 years in men was positively associated with BP at 53 years. After adjusting for current BMI, only overweight at age 43 contained additional information on BP in men. Men who were overweight at age 26 had a SBP 8.7 mmHg higher [95% confidence interval (CI) 4.4-13.0] than those first overweight at 53 years. Similar patterns but smaller associations were seen in women [P(interaction) < 0.001). All periods of adult weight gain (26-36, 36-43, 43-53 years) were associated with a higher BP. BMI tracked strongly through adulthood, the BMI at 53 years in men first overweight at 26 was 30.9 kg/m (95% CI 30.5-31.4) compared to 26.4 (95% CI 26.3-26.6) in those first overweight at age 53.

CONCLUSIONS

Early adult overweight and all periods of adult weight gain irrespective of earlier BMI were associated with higher BPs. This highlights the importance for later health of preventing overweight in early adulthood.

Trends in blood pressure and hypertension among Chinese children and adolescents: China Health and Nutrition Surveys 1991-2004

OBJECTIVE

To observe the trends in blood pressure (BP) and prevalence of hypertension among Chinese children and adolescents.

METHODS

Data were extracted from the China Health and Nutrition Survey conducted from 1991 to 2004; 8247 children and adolescents aged 6-17 years were selected for this study. Multivariate linear regression analysis and multivariate logistic regression analysis were performed to evaluate the secular trends in BP levels and prevalence of hypertension, respectively.

RESULTS

During the study period, there was an upward trend in BP in Chinese children and adolescents. After adjustment for gender, age and weight status, the prevalence of pre-hypertension and hypertension increased dramatically from 1991 to 2004, with average relative increases of 6.38% and 8.13% in children and adolescents, respectively. Overweight was strongly associated with pre-hypertension and hypertension in comparison with normal weight, with odds ratios (95% confidence intervals) of 2.21 (1.58-3.11) and 4.13 (3.32-5.13), respectively.

CONCLUSION

BP levels and prevalence of hypertension increased dramatically among Chinese children and adolescents from 1991 to 2004.

Evolution of cardiovascular risk factors among 18-year-old males in Austria between 1986 and 2005

OBJECTIVE

The aims of the study were to determine time trends in cardiovascular risk factors among young Austrian males between 1986 and 2005 and to examine socioeconomic and geographic differences.

METHODS

Data on Austrian conscripts were derived from the nationwide compulsory medical investigations held at military induction at 18 years of age. Four cohorts (1986-1990: n = 252,799; 1991-1995: n = 209,266; 1996-2000: n = 208,427; 2001-2005: n = 209,168) were examined with respect to their place of residence and level of education. Height, weight, waist circumference, blood pressure, serum total-cholesterol and triglycerides were measured. Mean body mass index (BMI) was calculated: overweight was defined as BMI between 25 and <30 and obesity as BMI >or= 30. The Chi-squared test and ANOVA were used to test group differences.

RESULTS

During the 20-year observation period the prevalence of overweight increased from 13.3% to 15.7% (p < 0.001) and that of obesity from 2.6% to 5.4% (p < 0.001); in accordance, mean BMI and waist circumference increased significantly. Blood pressure and serum total-cholesterol level decreased (p < 0.001) during the period studied, although triglyceride levels (p < 0.001) increased. A significant east-west gradient was identified for the prevalence of overweight and obesity, waist circumference and mean BMI, with lower values in the urban population compared with those of rural inhabitants. Mean BMI and the prevalence of overweight and obesity were higher in conscripts belonging to lower socioeconomic strata.

CONCLUSION

Our study demonstrates a clear increase of mean BMI, waist circumference and the prevalence of overweight and obesity in Austrian male adolescents during the past 20 years. Conscripts from rural regions and with lower levels of education showed the highest values. The investigation of conscript health appears to be a useful tool for risk surveillance in the male population.

Blood pressure references for Polish children and adolescents

The objective of this study was to develop age- and gender-specific reference ranges for blood pressure in a large national database on blood pressure levels throughout childhood and adolescence in young Poles. A prospective cross-sectional study was performed in 2002-2005 in the representative sampling sites, selected randomly from the entire Poland. Altogether, 6,447 school pupils, aged 7-18 years, were involved in the study of which 3,176 were boys and 3,271 were girls. Statistical analysis was performed using STATISTICA for Windows 7.1. The normal range of blood pressure, determined by age and the category of body height percentiles, revealed percentiles values which might serve as reference values to identify cases of high normal blood pressure (the mean blood pressure between 90th and 95th percentiles for age and gender) and hypertension (the mean blood pressure equals or exceeds the 95th percentiles on at least three occasions).

Discordant secular trends in elevated blood pressure and obesity in children and adolescents in a rapidly developing country

BACKGROUND

The effect of the increasing prevalence of obesity on blood pressure (BP) secular trends is unclear. We analyzed BP and body mass index secular trends between 1998 and 2006 in children and adolescents of the Seychelles, a rapidly developing island state in the African region.

METHODS AND RESULTS

School-based surveys were conducted annually between 1998 and 2006 among all students in 4 school grades (kindergarten and 4th, 7th, and 10th years of compulsory school). We used the Centers for Disease Control and Prevention criteria to define obesity and elevated BP. The same methods and instruments were used in all surveys. Some 25 586 children and adolescents 4 to 18 years of age contributed 43 867 observations. Although the prevalence of obesity in boys and girls increased from 5.1% and 6.0%, respectively, in 1998 to 2000 to 8.0% and 8.7% in 2004 to 2006, the prevalence of elevated BP decreased from 8.4% and 9.8% to 6.9% and 7.8%. During the interval, mean age-adjusted body mass index increased by 0.57 kg/m(2) in boys and 0.58 kg/m(2) in girls. Mean age- and height-adjusted systolic BP decreased by -3.0 mm Hg in boys and -2.8 mm Hg in girls, whereas mean diastolic BP did not change substantially in boys (-0.2 mm Hg) and increased slightly in girls (0.4 mm Hg).

CONCLUSIONS

At a population level, the marked increase in the prevalence of obesity in children and adolescents in the Seychelles was not associated with a commensurate secular rise in mean BP.

Tracking of blood pressure from childhood to adulthood: a systematic review and meta-regression analysis

BACKGROUND

A large number of studies have examined the tracking of blood pressure (BP) from childhood to adulthood, but the reported findings are inconsistent and few systematic analyses have been conducted.

METHODS AND RESULTS

We conducted a systematic search of PubMed for studies that examined the tracking of BP from childhood to adulthood published between January 1970 and July 2006. From 301 retrieved papers, 50 cohort studies met our inclusion criteria and provided 617 data points (Pearson/Spearman correlation coefficients) for systolic BP (SBP) and 547 data points for diastolic BP (DBP) for our meta-analysis. Information on sample characteristics and BP measurement protocols was extracted. Fisher z transformation and random-effects meta-regression analysis were conducted. The reported BP tracking correlation coefficients varied from -0.12 to 0.80 for SBP and from -0.16 to 0.70 for DBP, with an average of 0.38 for SBP and 0.28 for DBP. BP tracking varied significantly by baseline age and length of follow-up. The strength of BP tracking increased with baseline age by 0.012 for SBP (P<0.001) and 0.009 for DBP (P<0.001) and decreased with follow-up length by 0.008 for SBP (P<0.001) and 0.005 for DBP (P<0.001). BP tracking did not vary markedly across the number of BP measurements or race/population groups.

CONCLUSIONS

Data from diverse populations show that the evidence for BP tracking from childhood into adulthood is strong. Childhood BP is associated with BP in later life, and early intervention is important.

Modifiable maternal exposures and offspring blood pressure: a review of epidemiological studies of maternal age, diet, and smoking

Prenatal programming of adult disease is well established in animals. In humans the impact of common in utero exposures on long-term offspring health is less clear. We reviewed epidemiology studies of modifiable maternal exposures and offspring blood pressure (BP). Three maternal exposures were identified for review and meta-analyzed where possible: smoking during pregnancy, diet, and age at childbirth. Meta-analysis suggested there was a modest association between higher offspring BP and prenatal exposure to smoke (confounder-adjusted beta = 0.62 mm Hg, 95% confidence interval: 0.19-1.05, I = 16.4%). However, the level of confounder adjustment varied between studies, which in some studies attenuated the association to the null. There was no strong evidence that any component of maternal diet during pregnancy (maternal protein, energy, calcium, and various other nutrients) influences offspring BP. The results of studies of maternal age varied and there was strong evidence of heterogeneity in the pooled analysis. The association with maternal age, if present, was modest (confounder-adjusted beta = 0.09 mm Hg/y, 95% confidence interval: -0.03 to 0.21, I = 89.8%). In sum, there is little empirical evidence that the maternal exposures reviewed program offspring BP. Other components of offspring health may be more susceptible to effects of programming in utero.

High blood pressure trends in children and adolescents in national surveys, 1963 to 2002

BACKGROUND

Secular trend data on hypertension in children and adolescents are scarce and inconsistent. In the face of growing obesity, we sought to assess high blood pressure (HBP) secular trends in children and adolescents enrolled in national surveys and to determine whether the HBP trend reversed its course with the rise in obesity.

METHODS AND RESULTS

National survey data obtained from multistage probability sampling of the US noninstitutionalized population from 1963 to 2002 were examined; 8- to 17-year-old non-Hispanic blacks and whites and Mexican Americans were included. HBP ascertainment was based on age-, gender-, and height percentile-specific systolic and diastolic BPs. Weighted analyses were performed to account for the complex design. The BP, pre-HBP, and HBP trends were downward from 1963 to 1988 and upward thereafter. Pre-HBP and HBP increased 2.3% (P=0.0003) and 1% (P=0.17), respectively, between 1988 and 1999. Obesity increase, more so abdominal than general obesity, partially explained the rise in HBP and pre-HBP from 1988 to 1999. BP and HBP reversed their downward trends 10 years after the increase in the prevalence of obesity. Additionally, an ethnic and gender gap appeared in 1988 for pre-HBP and in 1999 for HBP; non-Hispanic blacks and Mexican Americans had a greater prevalence of HBP and pre-HBP than non-Hispanic whites, and males had a greater prevalence than females.

CONCLUSIONS

HBP and pre-HBP in children and adolescents are on the rise. These new findings have implications for the cardiovascular disease public health burden, particularly the risk of a new cardiovascular disease transition. They reinforce the urgent call for early prevention of obesity and HBP and illustrate racial/ethnic disparities in this age group.

Trends in body mass index, blood pressure and parental smoking habits in middle socio-economic level Turkish adolescents

Patterns of cardiovascular risk factors in populations are not static over time. We examined trends in body mass index (BMI), parental smoking and blood pressure over a 15-year period in Turkish children aged 15-17 years. Two cross-sectional studies were performed in secondary schools in Turkey in 1989-1990 and 2004-2005. Study participants were 673 children in 1989-1990 and 640 adolescents in 2004-2005. Main outcome measures were weight, height, BMI, presence and amount of parental smoking, systolic and diastolic blood pressure. Age and sex matched comparisons were performed to assess temporal trends in these measures. Children in 2004-2005 had increased weight, height, BMI and decreased systolic and diastolic blood pressure in all age groups compared with children in 1989-1990. According to the international criteria, 3.4% of children were obese and 15.8% were overweight in 2005, compared to 0.7% obese and 4.2% overweight in 1990 (P<0.001). However, a decrease was noted in blood pressure; 16% were classified as hypertensive in 1989-1990 versus 8% in 2004-2005 (P<0.001). The prevalence and amount of parental smoking also decreased over the last 15 years. We observed significant changes in BMI and blood pressure in Turkish children over the last 15 years. Temporal trends in these parameters may indicate a change in the pattern of cardiovascular disease in this population.

Blood pressure and hypertension in an American colony (Puerto Rico) and on the USA mainland compared, 1886-1930

We compare blood pressure and hypertension between adult men on the USA mainland and in Puerto Rico born during 1886-1930 to test hypotheses about the link between cardiovascular health and large socioeconomic and political changes in society: (a) 8853 men surveyed in Puerto Rico in 1965 and (b) 1449 non-Hispanic White men surveyed on the mainland during 1971-1975. Systolic and diastolic blood pressure and hypertension were regressed separately on demographic and socioeconomic variables and cardiovascular risk factors. Mainland men not taking anti-hypertensive medication showed statistically significant improvements in systolic blood pressure and hypertension at the beginning of the century and men in Puerto Rico showed improvements in diastolic blood pressure but only during the last two quinquenniums. An average man born on the mainland during the last birth quinquennium (1926-1930) had 7.4-8.7 mmHg lower systolic blood pressure and was 61% less likely to have systolic hypertension than one born before 1901. On average Puerto Rican men born during 1921-1925 had approximately 1.7 mmHg lower diastolic blood pressure than men born before 1901. Analyses of secular trends in cardiovascular health complements analyses of secular trends in anthropometric indicators and together provide a fuller view of the changing health status of a population.

Has blood pressure increased in children in response to the obesity epidemic?

The associations between elevated blood pressure and overweight, on one hand, and the increasing prevalence over time of pediatric overweight, on the other hand, suggest that the prevalence of elevated blood pressure could have increased in children over the last few decades. In this article we review the epidemiologic evidence available on the prevalence of elevated blood pressure in children and trends over time. On the basis of the few large population-based surveys available, the prevalence of elevated blood pressure is fairly high in several populations, whereas there is little direct evidence that blood pressure has increased during the past few decades despite the concomitant epidemic of pediatric overweight. However, a definite conclusion cannot be drawn yet because of the paucity of epidemiologic studies that have assessed blood pressure trends in the same populations and the lack of standardized methods used for the measurement of blood pressure and the definition of elevated blood pressure in children. Additional studies should examine if favorable secular trends in other determinants of blood pressure (eg, dietary factors, birth weight, etc) may have attenuated the apparently limited impact of the epidemic of overweight on blood pressure in children.

Relations between obesity and hypertension: preliminary data from a cross-sectional study in primary schoolchildren: The children study

OBJECTIVE

To record the prevalence of overweight, obesity and hypertension in primary schoolchildren living in one of the poorest regions in Europe and furthermore to identify certain behavioural, lifestyle and physiological parameters associated with body mass index (BMI) and blood pressure (BP).

DESIGN

Cross-sectional study.

SETTING

Nineteen primary schools within the county of Ioannina, Greece.

SUBJECTS AND METHODS

Demographic, dietary and physical activity data as well as anthropometrical, BP and cardiorespiratory fitness measurements were obtained from a representative sample of 312 school children (153 boys and 159 girls) attending 5th grade. Inclusion of subjects in the study was voluntary. One-way analysis of variance and multiple linear regression analysis were mainly applied for the evaluation of the tested hypotheses.

RESULTS

The prevalence of overweight and obesity was 29.4 and 11.8% for boys and 39.0 and 7.5% for girls. The prevalence of systolic and diastolic hypertension was 28.1 and 7.8% for boys and 26.4 and 17.0% for girls. Furthermore, BMI and BP (systolic and diastolic) were positively related to frequency of fast food meals (rho: + 0.28, P = 0.033, rho: + 1.09, P = 0.03 and rho: +0.86, P = 0.014, respectively) but negatively to leisure time physical activity (rho: -5.55, P = 0.005, rho: -3.32 x 10(-2), P < 0.001 and rho: -2.08 x 10(-2), P < 0.001, respectively).

CONCLUSIONS

The current study revealed an increased prevalence of overweight, obesity and hypertension among schoolchildren in Ioannina, indicating the need for early preventive measures in one of the less privileged regions of Europe.

Period prevalence of abnormal glucose tolerance and cardiovascular risk factors among obese children attending an obesity centre in Italy

BACKGROUND AND AIM

Several reports have described an increasing prevalence and incidence of type 2 diabetes among children. Limited information is available about the prevalence of impaired glucose tolerance (IGT) and type 2 diabetes in obese children, particularly in Europe. The aim of this study was to examine the prevalence of glucose intolerance and other cardiovascular risk factors in obese children over a 24-year period.

METHODS AND RESULTS

The study population consisted of 1376 consecutive subjects who attended a national centre for the study of obesity between 1979 and 2002. Subjects were divided into three successive 8-year cohorts: cohort 1 (period 1979-1986, n=453, male: 39%), cohort 2 (period 1987-1994, n=409, male: 46%), cohort 3 (period 1995-2002, n=514, male: 48%). All subjects underwent an oral glucose tolerance test. Lipids, blood pressure, uric acid, C-reactive protein (CRP), fasting insulin and birth weight were recorded. Insulin resistance was measured by homeostasis model assessment (HOMA-IR). The degree of obesity was higher in the more recent cohorts (standard deviation score of body mass index: 3.3+/-0.04 vs. 3.7+/-0.04 vs. 3.8+/-0.03, P<0.0001). The proportion of subjects with glucose intolerance was lower in the last two cohorts compared with the first one (11.2% vs. 3.9% vs. 6.0%, P<0.0001). This was predominantly due to changes in the frequency of IGT (9.1% vs. 3.2% vs. 5.4%, P<0.001 in cohorts 1, 2 and 3, respectively) while the prevalence of undiagnosed type 2 diabetes and impaired fasting glucose was similar in the three cohorts (0.9% vs. 0% vs. 0.2% and 1.3% vs. 0.7% vs. 0.4%, respectively). After adjustment for differences in age, sex, pubertal status and birth weight the levels of fasting insulin, HOMA-IR, total cholesterol, triglycerides and blood pressure, were significantly lower in cohorts 2 and 3 than in cohort 1 while CRP and uric acid were higher in the last two cohorts.

CONCLUSION

Over a recent period spanning 24 years, the degree of obesity has risen but the prevalence of glucose intolerance has fallen in obese children admitted to an obesity centre. This was accompanied by an improvement in traditional but a worsening in non-traditional risk factors for cardiovascular disease.

Secular stroke trends: early life factors and future prospects

Stroke mortality rates have declined during the second half of the 20th century in developed countries. Possible reasons for this include preventive measures, recent environmental changes impacting on adult health risks, and more distant environmental influences on childhood health. Data from a number of populations in Europe and the USA suggest that a decrease in early life blood pressure, occurring since the beginning of the 20th century, may have been an important determinant of declining stroke incidence rates and cardiovascular disease mortality in general. Advances in stroke epidemiology are increasing the accuracy of case ascertainment, and neuroimaging refinements (particularly MRI) are improving the accuracy of stroke type and subtype diagnoses. Although some risk factors are common to ischaemic and haemorrhagic stroke, there is accumulating evidence of differing aetiology. There is also an increasing recognition that early life factors may influence stroke risk. Despite the encouraging decline in stroke incidence, there is evidence of a recent increase in mean blood pressure in young people observed in the USA and UK, prompting concern that favourable trends in stroke risk may not be maintained. Reducing early life blood pressure in a population and delaying the onset of hypertension, along with effective measures to combat obesity, are required to avoid a reversal in stroke incidence trends in developed countries, and to prevent the anticipated increase in the burden of stroke in developing countries.

Early Socioeconomic Position and Blood Pressure in Childhood and Adulthood

Studies have found an association between low socioeconomic position in childhood and high adult blood pressure. It is unclear whether this association is explained by a pathway directly linking disadvantage to elevated blood pressure in childhood and adolescence, which then tracks into adulthood. We assessed parental socioeconomic position and systolic blood pressure in 1807 children and adolescents ages 3 to 18 years at baseline. Adult systolic blood pressure was measured 21 years later at ages 24 to 39 years. There was strong tracking of blood pressure from childhood to adulthood. Lower parental socioeconomic position was associated with higher blood pressure in childhood, adolescence ( P <0.01), and adulthood ( P <0.0001), with the mean age- and sex-adjusted systolic pressure differences between the highest and lowest socioeconomic groups varying between 2.9 and 4.3 mm Hg. With adjustment for blood pressure in childhood and adolescence, the regression coefficient between parental socioeconomic position and adult blood pressure attenuated by 32%. A similar level of attenuation (28%) occurred with adjustment for adult body mass index (BMI). With adjustment for both preadult blood pressure and adult BMI, the association between parental socioeconomic position and adult blood pressure was attenuated by 45%. Other factors, including birth weight and BMI in childhood and adolescence, had little impact on the association between parental socioeconomic position and adult blood pressure. These data suggest that early socioeconomic disadvantage influences later blood pressure in part through an effect on blood pressure in early life, which tracks into adulthood, and in part through an effect on BMI.

Blood pressure and related cardiovascular disease risk factors in 6-18 year-old students in Italy

OBJECTIVES

The aims of this study were to provide data on blood pressure (BP) levels, to measure prevalence of high-normal or high BP and to identify a set of conditions that may predict high BP (HBP) in a population of children and adolescents in Italy.

METHODS

A random sample of students 6-18 years old attending randomly selected schools in Catanzaro, Italy, was recruited. All students completed a questionnaire on their health and on health behaviours, such as physical activity, diet, drinking and smoking. Blood pressure, heart rate, height, weight and body mass index (BMI) were recorded.

RESULTS

Of the 603 subjects examined, 12.8% had high-normal BP, 3.5% hypertension (HTN) and 11.1% were obese. High-normal or high diastolic BP (DBP) was significantly more likely in older subjects with a higher BMI, in those with a smoker mother and in preterm children, whereas high-normal or high systolic BP (SBP) was significantly more likely to be found in older subjects with a higher BMI and in those who had at least one parent with HTN. High-normal or high DBP or SBP were significantly predicted by BMI and age.

CONCLUSIONS

Interventions should focus at reducing obesity and encouraging proper dietary habits, sufficient exercise and cessation of smoking habit in parents too, especially in children with a family history of HTN.

Early life determinants of adult blood pressure

PURPOSE OF REVIEW

While treating high blood pressure in middle age is beneficial in terms of reducing the occurrence of cardiovascular disease, treated and well controlled hypertensive adults still have a substantial excess mortality and reduced survival compared with normotensives. Therefore, identification of the means of preventing hypertension in earlier life is an important objective. There is increasing evidence that adult blood pressure is determined by a range of characteristics from the intrauterine period, through infancy and childhood. The purpose of this review is to provide a summary of the current evidence concerning the early life determinants of adult blood pressure.

RECENT FINDINGS

Children from poorer socioeconomic positions, those whose mothers experience pregnancy-induced hypertension, those whose mothers smoke throughout pregnancy, those with low birthweight, who are not breast-fed, who have high sodium diets in infancy and who are obese in childhood or adolescence tend to have higher blood pressure in adulthood. However, the mechanisms linking these early life factors to later blood pressure and the most appropriate means of preventing adult hypertension by intervening in early life are unclear.

SUMMARY

There is clear evidence that early life factors are important determinants of adult blood pressure. However, there is a need for randomized trials with sufficient resources for long-term follow-up to assess the effects that interventions such as preventing pregnancy-induced hypertension, reducing maternal smoking, increasing breast-feeding, reducing salt consumption in infancy and preventing childhood obesity have on adult blood pressure and cardiovascular disease.

Associations of Parental, Birth, and Early Life Characteristics With Systolic Blood Pressure at 5 Years of Age

Background— We examined the associations of a range of parental and early life characteristics with systolic blood pressure at 5 years of age.

Methods and Results— Information from 3864 children who were followed up prospectively from their mother’s first antenatal clinic assessment was used. Maternal age, body mass index, and smoking during pregnancy were all positively associated with offspring systolic blood pressure at 5 years of age. The systolic blood pressure of children whose mothers had smoked throughout pregnancy was on average 0.92 mm Hg (95% CI 0.17 to 1.68) greater than that of children whose mothers had never smoked, after full adjustment. Children who had been breast fed until at least 6 months had lower systolic blood pressure than those who were breast fed for a shorter duration. Paternal body mass index and child’s weight, height, and body mass index were all positively associated with blood pressure at age 5.

Conclusions— Because childhood blood pressure tracks into adulthood, interventions aimed at early life risk factors, such as quitting smoking during pregnancy, breast feeding, and prevention of obesity in all family members, may be important for reducing the population distribution of blood pressure and thus cardiovascular disease risk.

Trends in blood pressure over 10 years in adolescents: analyses of cross sectional surveys in the Northern Ireland Young Hearts project

OBJECTIVE

To examine secular trends in blood pressure over a 10 year period between two representative cohorts of adolescents from Northern Ireland.

DESIGN

Repeat cross sectional study.

SETTING

Randomly selected post-primary schools from Northern Ireland.

PARTICIPANTS

1015 adolescents studied between 1989 and 1990, and 2017 adolescents studied between 1999 and 2001. Participants were aged 12 or 15 years.

MAIN OUTCOME MEASURES

Systolic and diastolic blood pressure measured by one observer in each study.

RESULTS

The four groups for sex and age showed decreases in both systolic blood pressure (mean decrease 7.7 mm Hg to 10.0 mm Hg) and diastolic blood pressure (8.8 mm Hg to 11.0 mm Hg). These decreases were not accounted for by adjustment for potential confounders including age, height, body mass index, smoking, physical activity, aerobic fitness, and stratification of school by education board area and type. The findings were not altered by additional adjustment for social class, pubertal status, birth weight, and infant feeding. No evidence was found of systematic variation between observers.

CONCLUSIONS

Substantial decreases in systolic and diastolic blood pressure over the past decade in adolescents from Northern Ireland are likely to have important benefits to public health and may help offset the increasing risk of cardiovascular disease due to increases in obesity.