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

Prevalence of hypertension and its associations with body composition across Chinese and American children and adolescents

BACKGROUND

The age of onset of hypertension (HTN) is decreasing, and obesity is a significant risk factor. The prevalence and racial disparities in pediatric HTN and the association between body composition and blood pressure are insufficiently studied. This study aimed to evaluate the prevalence of HTN in Chinese and American children and adolescents and to assess the relationship between various body composition indices and HTN.

METHODS

Seven thousand, five hundred and seventy-three Chinese and 6239 American children and adolescents aged 8-18 years from the 2013-2015 China Child and Adolescent Cardiovascular Health study and the 2011-2018 National Health and Nutrition Examination Surveys were analyzed. Blood pressure and body composition (fat and muscle) were measured by trained staff. The crude prevalence and age-standardized prevalence rate (ASPR) of primary HTN and its subtypes [isolated systolic hypertension (ISH) and isolated diastolic hypertension (IDH)] were calculated based on 2017 American Academy of Pediatrics guidelines. Multivariable-adjusted linear regression coefficients and odds ratios (ORs) were calculated to assess the associations of body composition indicators with HTN, ISH and IDH.

RESULTS

The ASPR of HTN was 18.5% in China (CN) and 4.6% in the United States (US), whereas the obesity prevalence was 7.4% and 18.6%, and the population attributable risk of HTN caused by overweight and obesity was higher in the US than in CN. Increased fat mass, muscle mass and body fat percentage mass were associated with a higher risk of HTN in both countries. The percent of muscle body mass had a protective effect on HTN and ISH in both countries [HTN (CN: OR = 0.83, 95% CI = 0.78-0.88; US: OR = 0.72, 95% CI = 0.64-0.81); ISH (CN: OR = 0.87, 95% CI = 0.80-0.94; US: OR = 0.71, 95% CI = 0.62-0.81)], and the protective effect was more common among children and adolescents with high levels of physical activity.

CONCLUSIONS

The burden of HTN in Chinese children and adolescents was substantial and much greater than that in the US, and the contribution of obesity to HTN was higher in the US than in CN. Augmenting the proportion of muscle mass in body composition has a protective effect against HTN in both populations. Optimizing body composition positively influences blood pressure in children and adolescents, particularly those with high-level physical activity. Video abstract (MP4 149982 KB).

Secular trends and age-specific distribution of blood pressure in Japanese adolescents aged 12-18 years in 2000-2019

Adolescent blood pressure is a predictor of future risk for hypertension and cardiovascular diseases, and therefore its status needs to be accurately determined. However, limited evidence is available regarding the secular trends and distribution of adolescent blood pressure. In the present study, we assessed the secular trends and age-specific distributions of blood pressure in Japanese adolescents aged 12-18 years by using data drawn from 20 years of annual health checkups conducted between 2000 and 2019. Participants underwent health checkups every year for three years at the same school and the data were divided into four 5-year cycles: 2000-2004, 2005-2009, 2010-2014, and 2015-2019. From a total of 124,460 records (33,496 individuals) retrieved, 3000 records (3000 individuals) from each year-cycle were randomly selected to avoid duplicating data from the same individuals. In the study period, in males systolic blood pressure showed a decreasing trend over time, whereas in females diastolic blood pressure showed an increasing trend. Subgroup analyses by school category (junior/senior high school) and by obesity category showed similar blood pressure trends as in the overall analysis. Age-specific blood pressure values in Japanese adolescents increased with age in males but not in females. Thus, different patterns of change in blood pressure values over the past 20 years were observed between males and females. Age-specific blood pressure distributions are also presented. Together, these findings will be useful for understanding blood pressure trends among adolescents.

Environments affect blood pressure in toddlers: The Japan Environment and Children's Study

BACKGROUND

The primary objective of this study was to examine risk factors for toddler's hypertension.

METHODS

Subjects of this study were children and parents participating in a national birth cohort study in Japan, the Japan Environment and Children's Study. We measured the children's blood pressure (BP) at 2 and 4 years old. We obtained children's and parents' backgrounds from the questionnaire. We investigated the factors that affect BP elevation.

RESULTS

Within 4988 participants, the mean systolic BP at 2 years old was 91.2 mmHg for boys and 90.0 mmHg for girls. The mean systolic BP at 4 years old was 93.8 mmHg for boys and 93.1 mmHg for girls. Parental smoking was associated with elevated values of BP at 2 and 4 years old. Obesity, gestational hypertension, and parental lower education were associated with elevated values of BP at 4 years old. Hypertensive group had a significantly higher obesity rate. The mother's lower education and parental smoking were involved in hypertensive groups.

CONCLUSION

Parental smoking had a significant effect on BP even in early toddlers. We emphasize the importance of avoiding second-hand smoking from early infancy to prevent future lifestyle-related illnesses including hypertension.

IMPACT

The mean systolic BP at 2 years old was 91.2 mmHg for boys and 90.0 mmHg for girls. The mean systolic BP at 4 years old was 93.8 mmHg for boys and 93.1 mmHg for girls. Obesity, parental smoking, and lower education were associated with hypertension at 4 years old. Parental smoking was associated with hypertension at 2 and 4 years old. We emphasize the importance of avoiding second-hand smoking from early infancy.

Decrease in the prevalence of hypertension in Spanish schoolchildren from 2010 to 2017: Cuenca Study

AIMS

To examine the secular trends in blood pressure measurements and normal or high blood pressure classification among Spanish schoolchildren from 2010 to 2017, to analyze the persistence in the blood pressure category reported in 2017 compared with 2013 in those children born in 2007-08 and to compare in this cohort the prevalence of high blood pressure using both definitions, the 2004 and 2017 guidelines.

METHODS AND RESULTS

The data for the prevalence/trend analysis were obtained from cross-sectional analyses conducted in 2010, 2013, and 2017 of 2709 schoolchildren aged 4-6 and 8-11 years from 22 schools in the province of Cuenca, Spain. The data for the longitudinal analysis were obtained from cross-sectional analyses of measurements gathered in 2013 and 2017 in the same cohort of children (n = 275). The prevalence of normal blood pressure increased by 5.4% in children aged 4-6 years from 2013 to 2017 and by 2.2% in children aged 8-11 from 2010 to 2017. This increase was mainly driven by a decrease in the children classified in any stage of hypertension by 4.2% and 2.3% in each age range, respectively. In the same birth cohort, there was an increase of 7.6% in normal blood pressure prevalence.

CONCLUSION

The high blood pressure prevalence in Spanish children has clearly decreased over the last decade, but is still important to detect this condition to design specific school-based interventions and the evaluation of children classified as hypertensive who might need medical supervision and treatment.

High Blood Pressure and Changes in the Body Mass Index Category Among Japanese Children: A Follow-Up Study Using the Updated American Academy of Pediatrics Guidelines

Background

High blood pressure (HBP) has become a public health issue worldwide. The relationship between high BP and changes in the body mass index (BMI) category in Japanese pubertal children has not yet been examined. To resolve this issue, we examined existing data with a focus on the primordial prevention of high BP signs, including elevated BP, among pubertal children aged 12 and 15 years.

Methods

Height, body weight, and BP data were examined from health checkups of 18,247 children conducted between 1993 and 2000 in the Karatsu Study, which was a cohort of pediatric lifestyle-related disease prevention medical health checkups in Japan. BP and BMI were assessed using the updated American Academy of Pediatrics (AAP) guidelines and Endocrine Society’s clinical practice guidelines definitions, respectively.

Results

Follow-up data were obtained from 7,090 subjects (50.5% boys). Stage 2 hypertension (HTN) was detected in 3% and 2.7% of boys and girls aged 12 years, respectively, and in 2.7% and 1% of boys and girls aged 15 years, respectively. Among children aged 15 years, 1.4% were newly classified with stage 2 hypertension, and 15.6% exhibited improvements to a normal BP. A binomial logistic regression analysis of high BP and BMI category changes revealed odds ratios (OR) in the group with a deteriorated BMI category of 1.51 (95% confidence interval (CI), 1.17-1.94), 2.30 (95%CI, 1.66-3.17), and 6.83 (95%CI, 4.14-11.29) for elevated BP, stage 1 hypertension, and stage 2 hypertension, respectively.

Conclusion

High BP in puberty positively correlated with BMI category changes. Considering the presence of the tracking phenomenon in hypertension, BP monitoring is an essential part of the early strategy for the prevention of lifestyle-related diseases in childhood, and improvements in BP control are crucial in early life.

The opposing trends of body mass index and blood pressure during 1977-2020; nationwide registry of 2.8 million male and female adolescents

Background

Elevated blood pressure among adolescents has been shown to be associated with future adverse cardiovascular outcomes and early onset diabetes. Most data regarding systolic and diastolic blood pressure trends are based on surveys of selected populations within 10–20-year periods. The goal of this study was to characterize the secular trend of blood pressure given the rising prevalence of adolescent obesity.

Methods

This nationwide population-based study included 2,785,515 Israeli adolescents (41.6% females, mean age 17.4 years) who were medically evaluated and whose weight, height and blood pressure were measured, prior to mandatory military service between 1977 and 2020. The study period was divided into 5-year intervals. Linear regression models were used to describe the P for trend along the time intervals. Analysis of covariance was used to calculate means of blood pressure adjusted for body mass index.

Results

During the study period, the mean body mass index increased by 2.1 and 1.6 kg/m² in males and females, respectively (P for trend  < 0.001 in both sexes). The mean diastolic blood pressure decreased by 3.6 mmHg in males and by 2.9 mmHg in females (P  < 0.001 in both sexes). The mean systolic blood pressure increased by 1.6 mmHg in males and decreased by 1.9 mmHg in females. These trends were also consistent when blood pressure values were adjusted to body mass index.

Conclusion

Despite the increase in body mass index over the last four decades, diastolic blood pressure decreased in both sexes while systolic blood pressure increased slightly in males and decreased in females.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01433-0.

Comparison of Trends in Blood Pressure and the Prevalence of Obesity Among Korean and American Adolescents: A 12-Years Cross-sectional Study

OBJECTIVES

This study was conducted to explore recent trends in the prevalence of pediatric elevated blood pressure and hypertension (HTN) in Korea and the United States, applying the new HTN reference values for adolescents.

METHODS

This study analyzed 17 339 (8755 Korean and 8584 American) adolescents aged 10 to 17 who participated in the Korea National Health and Nutrition Examination Survey and the National Health and Nutrition Examination Survey, respectively, between 2005 and 2016. HTN was defined using percentile-based reference values for non-overweight adolescents from 7 nations, and obesity was defined by body mass index (BMI) based on country-specific growth charts. All analyses were stratified by sex and year-over-year changes were evaluated by calculating the p for trend.

RESULTS

Systolic blood pressure showed a statistically meaningful upward trend in Korean boys and girls, while diastolic blood pressure did not show any significant changes. Both systolic and diastolic blood pressure levels declined among United States boys and girls. The prevalence of elevated blood pressure and HTN remained similar in Korean adolescents, but declined in both sexes among United States adolescents. BMI increased in both sexes among Korean adolescents, although the overweight and obesity rates stayed the same. No significant trends were found in any obesity indices among United States adolescents. The prevalence of elevated blood pressure and HTN by obesity level was higher among Korean adolescents than among their United States peers in both sexes, and the gap became higher at more severe levels of obesity.

CONCLUSIONS

Despite the strong correlation between obesity and HTN, recent trends in the prevalence of HTN and obesity among Korean and United States adolescents were strikingly different. Follow-up studies are necessary to determine why the prevalence of HTN was more than twice as high among Korean adolescents than among their United States counterparts.

Effect of Overweight and Obesity on High Blood Pressure in Chinese Children and Adolescents

OBJECTIVE

This study aimed to compare the secular trends of high blood pressure (HBP) and the effects of overweight and obesity on HBP between Chinese ethnic minority and Han children and adolescents .

METHODS

Data were collected from 224,151 Chinese ethnic minority and 664,094 Han children and adolescents aged 7 to 18 years during three successive, national cross-sectional surveys (2005, 2010, and 2014). Logistic regression and population-attributable risk analyses were used to evaluate the association between HBP and overweight and obesity.

RESULTS

HBP prevalence in ethnic minorities increased from 4.8% in 2005 to 6.3% in 2014, which was significantly higher than the variable HBP trends (4.1% to 5.5%) in Han children and adolescents. Both ethnic minority and Han children and adolescents experienced a rapid increase in overweight and obesity, but the pace of growth for HBP, overweight, and obesity was faster in ethnic minorities than in their Han peers. Moreover, the effects of obesity on HBP in ethnic minorities showed a sustained increase over time but were stable for the Han.

CONCLUSIONS

Higher HBP prevalence, faster obesity increases, and a stronger impact of obesity on HBP in children and adolescents of Chinese ethnic minorities predict their looming burden of HBP, which suggests that attention to the cardiovascular disease risks in children and adolescents from ethnic minorities is indicated to reduce their future adult risk.

Prevalence of high blood pressure and high normal blood pressure among 7- to 17-year-old children and adolescents in developed regions, China from 2014 to 2017: using new national blood pressure reference for Chinese children and adolescents

As the first blood pressure (BP) reference considering influence of height in China, national blood pressure reference for Chinese han children and adolescents aged 7 to 17 years (CCBP) was issued in 2017. The current study aimed to observe the short-term trends in BP and prevalence of high blood pressure (HBP) and high normal blood pressure (HNBP) using this CCBP reference in Suzhou, China. Data of children and adolescents aged 7 to 17 years were collected from 2014 to 2017. Total population of 2014 to 2017 were 617,383, 684,453, 695,302, and 774,605, respectively, and proportions of males were 54.1%, 54.0%, 53.9%, and 53.8%, respectively. P-trend tests were conducted to examine the trends of BP among different age, region, body mass index, and socioeconomic status groups for each gender. Multivariate logistic regression analyses found secular decreases in prevalence of HBP and HNBP, after adjustment for potential confounders. Compared with that in 2014, the odds ratios (95% confidence intervals) for total study population were 0.936 (0.928, 0.944) in 2015, 0.879 (0.872, 0.887) in 2016, and 0.934 (0.926, 0.941) in 2017. In conclusion, prevalence of HBP and HNBP decreased among children and adolescents in developed regions of China from 2014 to 2017, and a slight rise were found in 2017.

Secular Trends in Blood Pressure and Overweight and Obesity in Chinese Boys and Girls Aged 7 to 17 Years From 1995 to 2014

The current study aimed to assess the secular trends in overweight and obesity status and high blood pressure (HBP) in Chinese children and adolescents for 2 decades. Data on 943 128 participants aged 7 to 17 years were obtained from the Chinese National Survey on Students' Constitution and Health from 1995 to 2014. The population attributable risk of overweight status for HBP was calculated. The prevalence of overweight increased from 4.3% in 1995 to 18.4% in 2014, whereas HBP prevalence fluctuated in the range of 4.4% to 6.4% during the same time period, the lowest in 2005. Within each survey year, blood pressure levels and HBP prevalence increased with higher body mass index. Notably, the population attributable risk of HBP because of being overweight steadily increased from 6.3% in 1995 to 19.2% in 2014. The same trends of linear growth for obesity, fluctuating blood pressure, and its sustained increasing population attributable risk for overweight also occurred among the domestic 29 provinces. Despite dramatic increases in overweight prevalence among Chinese children from 1995 to 2014, the HBP prevalence remained relatively stable, suggesting that other independent factors are affecting HBP trends to a greater extent. Yet, over time, the magnitude of the impact of being overweight or obese on HBP increased sharply, predicting looming heavy burden of HBP. Reductions in overweight status may aid in preventing HBP so as to prevent coronary risk in adulthood.

Elevated blood pressure among primary school children in Dar es salaam, Tanzania: prevalence and risk factors

Background

Whilst the burden of non-communicable diseases is increasing in developing countries, little data is available on blood pressure among Tanzanian children. This study aimed at determining the blood pressure profiles and risk factors associated with elevated blood pressure among primary school children in Dar es Salaam, Tanzania.

Methods

We conducted a cross sectional survey among 446 children aged 6–17 years from 9 randomly selected primary schools in Dar es Salaam. We measured blood pressure using a standardized digital blood pressure measuring machine (Omron Digital HEM-907, Tokyo, Japan). We used an average of the three blood pressure readings for analysis. Elevated blood pressure was defined as average systolic or diastolic blood pressure ≥ 90th percentile for age, gender and height.

Results

The proportion of children with elevated blood pressure was 15.2% (pre-hypertension 4.4% and hypertension 10.8%). No significant gender differences were observed in the prevalence of elevated BP. Increasing age and overweight/obese children were significantly associated with elevated BP (p = 0.0029 and p < 0.0001) respectively. Similar associations were observed for age and overweight/obesity with hypertension. (p = 0.0506 and p < 0.0001) respectively. In multivariate analysis, age above 10 years (adjusted RR = 3.63, 95% CI = 1.03–7.82) was significantly and independently associated with elevated BP in this population of school age children.

Conclusions

We observed a higher proportion of elevated BP in this population of school age children. Older age and overweight/obesity were associated with elevated BP. Assessment of BP and BMI should be incorporated in school health program in Tanzania to identify those at risk so that appropriate interventions can be instituted before development of associated complications.

Influence of eating quickly and eating until full on anthropometric gains in girls: A population-based, longitudinal study

BACKGROUND

In examining childhood overweight/obesity, there is a need to consider both eating quickly and eating until full. This longitudinal study investigated the influence of eating quickly and/or eating until full on anthropometric variables and becoming overweight/obese among Japanese schoolgirls.

METHODS

Study participants were fourth-grade schoolgirls (aged 9 or 10 years) in Ina Town, Japan. Physical examinations and a questionnaire survey were performed at baseline (fourth grade) and after 3 years (seventh grade). Height, weight, and waist circumference were measured in the physical examinations, while the data on eating quickly and eating until full were collected in the questionnaire survey. Analysis of variance and analysis of covariance were used to compare the differences in each anthropometric variable between fourth and seventh grade among groups.

RESULTS

Data on 425 non-overweight/obese schoolgirls in fourth grade were analyzed. Gains in anthropometric variables (body mass index, waist circumference, and waist-to-height ratio) from fourth to seventh grade were significantly larger in the "eating quickly and eating until full" group than in the "not eating quickly and not eating until full" group. In contrast, there were no significant differences in the gains between the "eating quickly or eating until full" group and the "not eating quickly and not eating until full" group. The proportion of overweight/obese girls in seventh grade was higher in the "eating quickly and eating until full" group than in the other groups.

CONCLUSIONS

Eating quickly and eating until full had a substantial impact on excess gains in anthropometric variables among schoolgirls, suggesting that modifying these eating behaviors may help prevent non-overweight/obese girls from the excess gains. Accordingly, school health programs need to focus on not eating quickly and/or not eating until full to prevent overweight/obesity; it is necessary to emphasize "the risk of overweight/obesity associated with these eating behaviors" in schools.

Trends in cardiometabolic parameters among Spanish children from 2006 to 2010: The Cuenca study

OBJECTIVE

The aim of this study was to examine the trends in cardiometabolic risk factors among schoolchildren in Cuenca, Spain, from 2006 to 2010.

METHODS

Data were taken from two cross-sectional surveys conducted in 2006 and 2010 among schoolchildren aged 8-12 years from 20 public schools in the province of Cuenca. The final sample consisted of 2148 participants with measured anthropometric variables, biochemical assessment, and blood pressure.

RESULTS

We observed an increase in mean serum total cholesterol (8.5 mg/dL and 10.7 mg/dL), LDL-cholesterol (13.7 mg/dL and 17.3 md/dL), triglycerides (3.6 mg/dL and 2.6 md/dL), fasting insulin (1.2 µU/mL and 0.3 µU/mL) and HOMA-IR (0.2 and 0.02) and a decrease in mean serum HDL-cholesterol (4.4 mg/dL and 5.7 mg/dL), systolic blood pressure (3.8 mmHg and 5.4 mmHg) and diastolic blood pressure (0.8 mmHg and 2.0 mmHg) in both sexes. In girls, mean arterial pressure (3.2 mmHg) also decreased in this period. In addition, we found an increase in the prevalence of adverse total cholesterol concentration (≥200 mg/dL) (7.8% and 8.9%), HDL-cholesterol concentration (<40 mg/dL) (1.9% in boys and 3.5% in girls) and LDL cholesterol concentration (≥130mg/dL) (4.8% and 5.8%) in boys and girls, respectively.

CONCLUSIONS

There has been a worsening of the lipid profile in schoolchildren from Cuenca, independent of weight status and age.

Trends in Elevated Blood Pressure Among US Children and Adolescents: 1999-2012

BACKGROUND

The prevalence of elevated blood pressure (BP) has been reported to increase significantly among the US children and adolescents from 1988-1994 to 1999-2008. We aimed to examine the recent trends in BP levels and prevalence of elevated BP, as well as related influencing factors among US children and adolescents.

METHODS

Data of National Health and Nutrition Examination Survey (NHANES) 1999-2012 were combined into 3 time periods (1999-2002, 2003-2008, and 2009-2012) for the analysis. A total of 14,270 US children and adolescents aged 8-17 years were included in the current analysis. The sex-, age-, and height-BP standards recommended by the US Fourth Report were used to define high BP and elevated BP (including pre-HBP and HBP).

RESULTS

Mean systolic BP (SBP) and diastolic BP (DBP) decreased by 0.7 and 4.2mm Hg from 1999-2002 to 2009-2012, respectively. In 2009-2012, the prevalence of elevated BP and HBP in children and adolescents were 9.6% and 1.6%, with the absolute reduction of 2.8% and 1.3% from 1999-2002 to 2009-2012, respectively. In addition, daily intakes of total energy, carbohydrate, total saturated fatty acids, and caffeine decreased during the period between 1999-2002 and 2009-2012 (all P < 0.05), whereas daily intake of total polyunsaturated fatty acids and dietary fiber increased (P < 0.05).

CONCLUSIONS

Mean BP levels as well as the prevalence of elevated BP and HBP among US children and adolescents have declined during the past decade. In addition, there might be an associated change in dietary factors.

Understanding trends in blood pressure and their associations with body mass index in Chinese children, from 1985 to 2010: a cross-sectional observational study

OBJECTIVE

Understanding trends in blood pressure (BP) in childhood is crucial to addressing and reducing the burden of adulthood hypertension and associated mortality in the future. In view of growing obesity in Chinese children, we sought to investigate the trends in BP and the influence of body mass index (BMI) on them.

DESIGN, SETTING AND PARTICIPANTS

We included 1,010,153 children aged 8-17 years, with completed records from a large national successive cross-sectional survey, the Chinese National Survey on Students' Constitution and Health, between 1985 and 2010.

MAIN OUTCOME MEASUREMENTS

BP was measured according to the recommendation of the National High Blood Pressure Education Program Working Group, and the elevated BP was based on sex-, age- and height-specific 95th centile of the recommendation.

RESULTS

The adjusted mean systolic BP in boys and girls decreased by 3.9 and 5.6 mm Hg between 1985 and 2005, and increased by 1.3 and 1.0 mm Hg between 2005 and 2010, respectively. Corresponding adjusted prevalence of elevated systolic BP in boys and girls declined from 5.1% and 5.5% to 3.5% and 2.5% between 1985 and 2005, and increased to 4.9% and 3.5% in 2010, respectively. Adjusted mean BMI of boys and girls in 2010 was 2.0 and 1.2 kg/m(2) higher than those in 1985, respectively. The prevalence of obesity rose from 0% to 3.4% in boys and 0.9% in girls. Further adjusting for BMI did not change these trends in systolic BP. A similar pattern was also observed in diastolic BP.

CONCLUSIONS

After declining for 20 years, BP levels in Chinese children started to climb upwards. These trends in BP cannot be fully explained by BMI. The investigation of other determinants of BP may provide additional opportunity to curb the current upward BP trend in Chinese children.

Trends of Underweight and Overweight/Obesity Among Japanese Schoolchildren From 2003 to 2012, Defined by Body Mass Index and Percentage Overweight Cutoffs

BACKGROUND

We investigated the prevalence and trends of underweight and overweight/obesity in a population-based sample of Japanese schoolchildren from 2003 to 2012, defined by body mass index (BMI) and percentage overweight (POW).

METHODS

Subjects comprised fourth and seventh graders from the town of Ina, Japan, from 2003 to 2012. The height and weight of each subject were measured. Children were classified as underweight, normal weight, or overweight/obese using two criteria: BMI cutoff points proposed by the International Obesity Task Force and cutoffs based on POW in Japan.

RESULTS

Data from 4367 fourth graders and 3724 seventh graders were analyzed. The prevalence of underweight and overweight as defined by POW criteria were lower than those based on BMI criteria. There was a decrease in the prevalence of overweight among fourth-grade boys and girls and seventh-grade girls according to BMI; this decrease was also observed when POW criteria were used for the definition of overweight.

CONCLUSIONS

The prevalence and trends of both underweight and overweight as defined by POW were underestimated among Japanese schoolchildren compared to those determined using BMI. The results of this study also suggest that trends in underweight and overweight/obesity using POW criteria are similar to those based on BMI criteria among schoolchildren in Japan.

LDL-cholesterol and body mass index among Japanese schoolchildren: a population-based cross-sectional study

Background

Serum low-density lipoprotein cholesterol (LDL-C) is one of the most important risk factors for coronary heart disease. The aim of the present study was to investigate the relationship between LDL-C and body mass index (BMI) in population-based Japanese schoolchildren.

Methods

The subjects comprised all fourth graders and seventh graders in Ina Town, Saitama Prefecture, Japan, during 2002-2009. Information about each subject’s age, sex, and family history of hypercholesterolemia was collected using a self-administered questionnaire. The body height, weight, and LDL-C were measured for each child. LDL-C was measured using the direct method. According to the LDL-C criteria of the Japan Atherosclerosis Society, LDL-C level was categorized into three subgroups: acceptable, < 110 mg/dL; borderline, 110-139 mg/dL; and high, ≥ 140 mg/dL. Children with either borderline or high LDL-C level were considered to have high-normal LDL-C (HLDL-C).

Results

Data from a total of 5869 subjects were analyzed. A higher BMI category was associated with a higher prevalence of HLDL-C regardless of sex or grade level (P < 0.05). When compared with the <50th percentile BMI category, the odds ratio (OR) for HLDL-C was statistically significant in the 75th to 84th percentile category of fourth-grade boys (OR: 1.95, 95% confidence interval (95% CI): 1.28-2.97), the 85th to 94th percentile of fourth-grade girls (2.52, 1.74-3.64), and the 85th to 94th percentile of seventh-grade boys (2.04, 1.31-3.20) and girls (1.90, 1.24-2.91).

Conclusion

A statistically significant association between LDL-C levels and BMI was observed in Japanese school children.