The relationship of body mass index distribution to relatively high blood pressure among children and adolescents in Shandong, China

The longitudinal trajectory of body mass index in the Chinese population: A latent growth curve analysis

Aims

The objective of this study was to investigate the longitudinal trajectory of BMI in the Chinese population, and to assess whether the gender or other personal characteristics were related to BMI, and whether there was a change in trajectory over time.

Methods

Data were obtained from 3,574 Chinese (5 to 89 years of age) who participated in the 2000–2011 of the China Health and Nutrition Survey. Latent growth curve models were used to investigate the longitudinal trajectory of BMI, and to examine the effect of some personal characteristics on BMI trajectory.

Results

The linear model resulted in a mean initial BMI value of 22.90 and a significant mean slope (Ms = 0.19, t = 10.73, p<0.001), suggesting a steady increase in BMI over time for the whole sample. For covariates, the educational level, alcohol and physical activity had differences on initial scores for BMI (β = 0.05, p<0.001; β = -0.12, p<0.05; β = -0.08, p<0.05; respectively.), and the age had differences on both the initial scores and slope for BMI (β = 0.01, p = <0.05; β = -0.03, p<0.01; respectively.). Baseline measures revealed gender-associated differences on initial scores for BMI, and the slope for male was significantly steeper than that for female (β = -0.11, p<0.05). The initial BMI status of Chinese living in the rural areas was significantly higher than that of Chinese living in the urban areas, and the slope for rural status was significantly steeper than that for urban status (β = 0.21, p<0.001).

Conclusions

Results indicated a linear trajectory of BMI in the Chinese population over a 12-year period. The longitudinal trajectories differed by age, gender and urban-rural status, suggesting different interventions should be adopted for different groups.

Blood pressure effects of adiposity in non-overweight children aged 6-17 years

BACKGROUND

Obesity is a well-established risk factor of elevated blood pressure; however, the relationships between normal weight status and the risk of hypertension and pre-hypertension are not clear.

AIM

The aim of this study is to describe the blood pressure effects of adiposity in non-overweight children.

METHODS AND RESULTS

In total, 588 097 non-overweight children aged 6-17 years were included from the National Surveys on Students' Constitution and Health. A non-linear relationship was found between age- and gender-standardised body mass index (BMI) z-score and pre-hypertension and hypertension, respectively. The odds ratios and 95% confidence intervals [ORs (95% CIs)] of pre-hypertension were 0.61 (0.59-0.63), 0.67 (0.65-0.68), 0.83 (0.83-0.84), 1.00 (reference), 1.13 (1.12-1.14), 1.18 (1.16-1.20) and 1.20 (1.18-1.22) for BMI z-scores of -1.2, -1.0, -0.5, 0 (reference), 0.5, 0.7 and 0.8, respectively. The ORs (95% CIs) of hypertension were 0.56 (0.54-0.58), 0.62 (0.61-0.64), 0.81 (0.80-0.82), 1.00 (reference), 1.17 (1.16-1.18), 1.23 (1.22-1.5) and 1.27 (1.24-1.29) for BMI z-scores of -1.2, -1.0, -0.5, 0 (reference), 0.5, 0.7 and 0.8, respectively. The above-mentioned associations were consistent in sub-group analysis by age, gender and height.

CONCLUSIONS

Non-linear relationships of BMI z-scores with pre-hypertension and hypertension were found in non-overweight children. Interventions to control blood pressure are also important in non-overweight children.

Profiles of blood pressure among children and adolescents categorized by BMI and waist circumference

BACKGROUND

BMI and waist circumference (WC) are two commonly used measurements for defining general and central obesity. The present study examined the profiles of blood pressure (BP) among children and adolescents categorized by BMI and WC in Shandong, China.

PARTICIPANTS AND METHODS

A total of 38 810 students (19 453 boys and 19 357 girls) aged 7-17 years participated in this study. Height, weight, WC, and BP of all participants were measured, and BMI was calculated. Relatively high BP status was defined as systolic BP and/or diastolic BP ≥95th percentile for age and sex. All individuals were classified into four groups (Q1-Q4) according to the age-specific and sex-specific quartiles of BMI and WC; the BP level and the prevalence of relatively high BP among the four groups were compared.

RESULTS

In both boys and girls, significant differences in BP level and the prevalence of relatively high BP were observed among the four groups categorized by BMI and WC separately (P<0.01). Children and adolescents in the high BMI group (Q4) had higher systolic BP and diastolic BP than their counterparts in the low BMI group (Q1) in all age groups (P<0.01), the range of differences being 5.7-10.3, 3.6-5.6 mmHg for boys and 3.9-8.7, 2.2-5.3 mmHg for girls, respectively. Similar differences were also observed among different groups categorized by WC.

CONCLUSION

High BMI and WC are associated with elevated BP. Our findings emphasize the importance of the prevention of general and central obesity to prevent future-related problems such as hypertension in children and adolescents.

Is high waist circumference and body weight associated with high blood pressure in Iranian primary school children?

INTRODUCTION AND OBJECTIVES

The prevalence of overweight, abdominal obesity and hypertension among children has increased worldwide including Iran over several decades. We carried out a study to provide current estimates of the prevalence and trends of hypertension, overweight and obesity along with the relationship between weight status and hypertension in Iranian school-children.

METHOD

This study was carried out among 1184 fifth-grade students, whose ages ranged from 11 to 14 years. Body weight, body mass index (BMI), height and waist circumference (WC), systolic (SBP) and diastolic blood pressure (DBP) were measured.

RESULTS

22.04 and 5.32 % of students were overweight and obese, respectively. The prevalence of overweight and obesity was significantly higher among girls than boys (all p = 0.02), whereas the prevalence of hypertension was significantly higher in boys than girls (p = 0.001). Although 27 % of boys and 24.32 % of girls had abdominal obesity, no significant associations were reported between abdominal obesity and sex (p = 0.12). The prevalence of hypertension in children with normal weight, overweight and obesity, was 3, 9.7 and 17.8 %, respectively (p < 0.01). We have obtained that the mean values of weight and WC were significantly higher in boys than girls. Based on linear regression, every 1 cm increase in abdominal circumference leads to an estimated DBP and SBP increase of 0.173 and 0.164 mmHg, respectively (p < 0.05).

CONCLUSIONS

This study showed a high prevalence of hypertension and obesity in a school-based population in Tehran, Iran, in which the prevalence of hypertension was significantly and positively correlated with weight and WC.

Children and adolescents with low body mass index but large waist circumference remain high risk of elevated blood pressure

BACKGROUND

Body mass index (BMI) and waist circumference (WC) are two commonly used measurements for defining general and central obesity. The present study examined the profiles of blood pressure (BP) among children and adolescents with low BMI but large WC in a large population in Shandong, China.

METHODS

A total of 38,810 students (19,453 boys and 19,357 girls) aged 7-17years participated in this study. Height, weight, WC, and BP of all subjects were measured, and BMI was calculated. Relatively high BP (RHBP) status was defined as systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) ≥95th percentile for age and gender. 'Low BMI with large WC' was defined as BMI<25th and WC≥75th.

RESULTS

The Z-scores for SBP and DBP in the 'low BMI with large WC' group were 0.21 and 0.31 for boys and 0.19 and 0.35 for girls respectively, significantly higher than the average level of the total sample (P<0.01). The prevalence of RHBP in the 'low BMI with large WC' group was significantly higher than the average level of the total sample (34.1% vs. 26.2% for boys and 29.5% vs. 20.3% for girls).

CONCLUSION

Children and adolescents with low BMI but large WC might have an increased risk of elevated BP, their health risks would be underestimated if screening by BMI alone. These findings suggest that measurement of WC may be an assistive tool when using BMI to identify high BP risks.

Early-life risk factors for chronic nonrespiratory diseases

We have witnessed a change in disease patterns contributing to the global burden of disease, with a shift from early childhood deaths due to the classic infectious communicable diseases to years lived with disability from chronic noncommunicable diseases. In both developing and developed countries, the years lived with disability attributable to chronic disease have increased: cardiovascular diseases by 17.7%; chronic respiratory disease by 8.5%; neurological conditions by 12.2%; diabetes by 30.0%; and mental and behavioural disorders by 5.0% over the past 20 years. Recognition of the contribution made by adverse environmental exposures in early life to noncommunicable diseases in later life is increasing. These early-life exposures appear to contribute to both chronic respiratory and chronic nonrespiratory diseases. In this State of the Art article, we aim to examine early-life environmental exposures that have an epidemiological association with chronic nonrespiratory diseases, such as obesity and type II diabetes, cardiovascular disease, and neurocognitive and behavioural problems. We will highlight the potential overlap in environmental risks with respiratory diseases, and point out knowledge gaps and research opportunities.

Prevalence of overweight and obesity and their associations with blood pressure among children and adolescents in Shandong, China

BACKGROUND

Obesity and high blood pressure (BP) are public health problems all over the world. Some studies have reported a positive association between them in children and adolescents. The purpose of this study was to assess the prevalence of overweight and obesity and their associations with BP among school children and adolescents in Shandong, an important province in eastern China.

METHODS

In 2011, we conducted a cross-sectional population-representative survey in Shandong, China. A total of 4 898 children and adolescents aged 6-17 years were randomly selected from 140 counties/districts using a multistage random cluster sampling. Weight, height and BP were measured by a trained physician or pediatrician, and information about age, gender and place of residence was obtained using questionnaires. Obesity and high BP were defined according to age- and gender-specific Chinese reference data for children.

RESULTS

A total of 4 898 (100%) children and adolescents provided complete information. The prevalence of overweight, obesity and overweight plus obesity were 10.9%, 8.7% and 19.6%, respectively. Boys were more likely to be overweight or obese than girls (P < 0.05 for overweight; P < 0.001 for obesity). The prevalence of overweight plus obesity was highest among children aged 6-11 years (22.3%). BP and the prevalence of high BP increased with increasing body mass index (BMI). With age and sex adjusted, odds ratios (ORs) for high BP were [OR 2.2;95% CI 1.7-2.8) in overweight and [OR 3.6;95% CI 2.6-4.9] in obese children.

CONCLUSION

The representative survey confirms high prevalence of overweight and obesity among children and adolescents in Shandong. Childhood obesity is a strong risk factor for high BP. Intervention programs should be implemented to combat the growing obesity epidemic.

Association between body mass index, skinfold thickness and blood pressure in 12-year-old children

The present study examined the association between body mass index (BMI) and skinfold thickness (SFT) with blood pressure (BP) in 12-year-old children in Shandong, China. A total of 920 (464 boys and 456 girls) 12-year-old students participated in this study. All subjects were divided into four groups (BMI < 25th, 25th ≤ BMI < 50th, 50th ≤ BMI < 75th, and BMI ≥ 75th) according to the percentile of BMI and into four groups (SFT < 25th, 25th ≤ SFT < 50th, 50th ≤ SFT < 75th, and SFT ≥ 75th) according to the percentile of SFT, respectively. Comparisons of BP among different groups were made by one-way ANOVA. High BP status was defined as systolic blood pressure (SBP) ≥ 95th and/or diastolic blood pressure (DBP) ≥ 95th percentile for age and gender. BMI and SFT were all significantly (P < 0.001) and positively related to SBP and DBP in both boys and girls. The prevalence of high BP in each group is rising with the percentiles of BMI and SFT in both boys and girls.

CONCLUSION

There is a strong positive relationship between BMI, SFT, and BP in 12-year-old children; the present findings emphasize the importance of preventing excess BMI and SFT in order to prevent future-related problems such as hypertension in children and adolescents.

Comparison of blood pressure levels among children and adolescents with different body mass index and waist circumference: study in a large sample in Shandong, China

PURPOSE

Several anthropometric indicators [such as body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR)] have been used to investigate the association between adiposity and high blood pressure (BP) in both adults and children. The present study compared the BP levels among children and adolescents with different BMI and WC in a large population in Shandong, China.

METHODS

A total of 38,822 students (19,456 boys and 19,366 girls) aged 7-17 years participated in this study. Height, weight, WC, and BP of all subjects were measured, and BMI was calculated. The prevalence of overweight and obesity was obtained according to the International Obesity Task Force (IOTF) cutoffs; central obesity was defined as WC ≥ 90th percentile (P 90); relatively high BP status was defined as systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) ≥ 95th percentile for age and gender.

RESULTS

Within each BMI categories (normal weight, overweight, and obesity), children and adolescents with WC ≥ P 90 had higher BP levels than those with WC < P 90 (p < 0.01). When BMI and WC were combined, the highest and lowest prevalences of relatively high BP were noted in obese with WC ≥ P 90 group (54.52% for boys and 48.71% for girls) and normal weight with WC < P 90 group (17.00% for boys and 14.13% for girls).

CONCLUSION

Children and adolescents with high BMI and high WC might have an increased risk of elevated BP. Our results suggest that the additional measurement of WC is better than BMI alone to help identify high BP risks.

Monitoring of blood pressure among children and adolescents in a coastal province in China: results of a 2010 survey

BACKGROUND

Several studies have provided ample evidence that hypertension in adults has its onset in childhood; children and adolescents with elevated blood pressure (BP) are more likely to become hypertensive adults. The present study examined the prevalence of relatively high BP among children and adolescents in Shandong, China.

SUBJECTS AND METHODS

Data for this study were obtained from a large cross-sectional survey of schoolchildren carried out in 2010. A total of 38 860 students (19 481 boys and 19 379 girls) aged 7 to 17 years participated in this study. Relatively high BP status was defined as systolic blood pressure and/or diastolic blood pressure ≥95th percentile for age and gender.

RESULTS

Shandong children had a high BP level, with the 50th percentiles of systolic and diastolic blood pressure of children and adolescents aged 7 to 17 years in Shandong being above the reference values for Chinese children and adolescents by 3 to 12 mm Hg and 3 to 7 mm Hg for boys, and by 3 to 6 mm Hg and 3 to 5 mmHg for girls, respectively. The overall prevalence of relatively high BP was 26.22% for boys and 20.27% for girls.

CONCLUSION

There is a high prevalence of relatively high BP among children and adolescents in Shandong, China. It has become a threatening hazard to children and adolescents and should arouse special attention.