Reference Ranges for the Non-High-Density Lipoprotein Cholesterol Levels in Japanese Children and Adolescents

Age- and Gender-Specific Reference Intervals for the Fasting Serum Lipid Levels in a Pediatric Population Aged 0-＜15 Years in Nanjing, China

AIMS

The lipid reference intervals (RIs) that are currently used for children in China are not based on studies of the local population and normally do not consider age or gender differences. This study aimed to establish age- and sex-specific RIs for the fasting serum lipid levels in the pediatric population aged 0 - 15 years in Nanjing, China.

METHODS

5,866 children aged 3 days to ＜15 years were recruited to establish serum lipid RIs, and the triglyceride (TG), total cholesterol (TC), and high-density lipoprotein cholesterol (HDL-C) levels were analyzed using the Roche cobas702 automatic biochemical analyzer. Low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (nHDL-C) levels were calculated (LDL-C=TC-HDL-C-TG/5, and nHDL-C=TC-HDL-C). Smoothed percentile curves for the boys and girls were generated using the LMS method. Age- and sex-specific RIs were the determined according to the methods recommended by the Clinical and Laboratory Standards Institute EP28-A3c guidelines.

RESULTS

This study showed that the serum lipid levels varied considerably throughout childhood and adolescence, with sex differences, especially in infants aged less than 2 years and puberty. Based on the Harris-Boyd method, sex partitions were required for ages ＜6 months in the TC indicator and for ages ≤ 28 days in LDL-C and nHDL-C. Age partitions were also required for all serum lipid parameters.

CONCLUSIONS

We established age- and sex-specific RIs for TG, TC, HDL-C, LDL-C, and nHDL-C parameters in children aged 0 days to ＜15 years in Nanjing, China. These data are thus considered to be useful for the screening of dyslipidemia in children and adolescents.

An Alternative Approach to Determining Metabolic Syndrome Component Cutoffs in Children and Adolescents Using Segmental Regression Analysis

Background: The prevalence of metabolic syndrome is increasing in children and adolescents. Although some diagnostic criteria for metabolic syndrome exist, further research is needed to determine appropriate age-, sex-, and race-specific cutoffs for each component. Methods and Results: Health examinations were conducted in 1,679 children aged 6-15 years in 9 regions of Japan. Participants were divided into 3 age groups for each sex: 6-8, 9-11, and 12-15 years. For metabolic syndrome components in each group, inverse cumulative percentile graphs were drawn and approximated by 3 regression lines using segmented regression analysis. The intersection of each regression line was defined as the breakpoint, and the measured value corresponding to the breakpoint percentile as the breakpoint value. Breakpoint values for waist circumference were age dependent at approximately 60, 70, and 80 cm for ages 6-8, 9-11, and 12-15 years, respectively. Breakpoint values for blood pressure were age- and/or sex dependent, while those for triglycerides, high-density lipoprotein cholesterol, and fasting blood glucose were neither age nor sex dependent. Based on these results, we proposed new cutoffs for diagnosing metabolic syndrome in Japanese children and adolescents. Conclusions: Breakpoint values obtained by segmented regression analysis on inverse cumulative percentile graphs can be useful for determining metabolic syndrome component cutoffs in children and adolescents.

Sex differences in lipids: A life course approach

Differences between men and women in lipids and lipoproteins are observed in distribution and trajectory from infancy to adulthood in the general population. However, these differences are more pronounced in hereditary lipid disorders such as familial hypercholesterolemia (FH) when absolute cholesterol levels are higher from birth onwards. In the early life course, girls compared to boys have higher low-density lipoprotein cholesterol (LDL-C) levels and total cholesterol, while high-density lipoprotein cholesterol (HDL-C) levels are similar. In early adulthood to middle-age, women have lower LDL-C and higher HDL-C levels, as LDL-C levels increase and HDLC levels decrease in men. In the elderly, all lipids - total cholesterol, LDL-C, HDL-C and triglyceride levels decrease but are more pronounced in men. Lipid levels are also affected by specific transitions in girls/women such as the menstrual cycle, pregnancy, breastfeeding and menopause. Lipid levels fluctuate during the menstrual cycle. During pregnancy a physiological increase of LDL-C and even a larger increase in triglyceride levels are observed. Pregnancy has a double impact on LDL-C accumulation in women with FH as they have to stop statins, and the absolute increase in LDL-C is higher than in women without FH. In the menopausal transition, women develop a more adverse lipid profile. Therefore, it is important to take into account both sex and the life course when assessing a lipid profile.

Guidelines for the Diagnosis and Treatment of Pediatric Familial Hypercholesterolemia 2022

As atherosclerosis begins in childhood, early diagnosis and treatment of familial hypercholesterolemia (FH) is considered necessary. The basic diagnosis of pediatric FH (under 15 years of age) is based on hyper-low-density lipoprotein (LDL) cholesterolemia and a family history of FH; however, in this guideline, to reduce overlooked cases, "probable FH" was established. Once diagnosed with FH or probable FH, efforts should be made to promptly provide lifestyle guidance, including diet. It is also important to conduct an intrafamilial survey, to identify family members with the same condition. If the level of LDL-C remains above 180 mg/dL, drug therapy should be considered at the age of 10. The first-line drug should be statin. Evaluation of atherosclerosis should be started using non-invasive techniques, such as ultrasound. The management target level is an LDL-C level of less than 140 mg/dL. If a homozygous FH is suspected, consult a specialist and determine the response to pharmacotherapy with evaluating atherosclerosis. If the response is inadequate, initiate lipoprotein apheresis as soon as possible.

Subclass distribution of low-density lipoprotein triglyceride and the clustering of metabolic syndrome components in Japanese children

BACKGROUND

Recent studies demonstrated that low-density lipoprotein-tryglyceride (LDL-TG) may represent another marker of cardiovascular risks. We therefore measured LDL-TG including the low-density lipoprotein (LDL) subclass distribution and investigated the association between LDL-TG subclass profile and the clustering of metabolic syndrome (MetS) components and insulin resistance in Japanese children.

METHODS

The study included 237 schoolchildren (boys 115, girls 122). Four subclasses of low-density lipoprotein-tryglyceride (large, medium, small, and very small) was quantified using high-performance liquid chromatography. Total LDL-TG and TG levels in LDL subclasses were evaluated among four MetS component groups; non-abdominal obesity, abdominal obesity, pre-MetS, and MetS.

RESULTS

Total LDL-TG (P = 0.0003, P = 0.0175) and triglyceride levels in LDL subclasses were significantly different among four MetS component groups (large: P = 0.0002, P = 0.0084; medium: P = 0.0009, P = 0.0491; small: P =0.0025, P = 0.0509; very small: P = 0.0808, P = 0.0228; boys and girls, respectively). Total LDL-TG (r = 0.411, P < 0.0001, r = 0.378. P < 0.0001) and triglyceride levels in LDL subclasses correlated positively with the homeostasis model of assessment ratio (large: r = 0.396, P < 0.0001, r = 0.346, P < 0.0001; medium: r = 0.274, P = 0.0030, r = 0.228, P = 0.0115; small: r = 0.342, P = 0.0002, r = 0.292, P = 0.0011; very small: r = 0.385, P < 0.0001, r = 0.426, P < 0.0001, boys and girls, respectively).

CONCLUSIONS

Subclass distribution of LDL-TG was significantly associated with the clustering of MetS components in both sexes, and insulin resistance is a significant determinant of LDL-TG in all LDL subclasses. Lipoprotein-tryglyceride subclass analysis, rather than LDL-C, may provide a precise evaluation for cardiovascular disease risks in children with MetS.

Improvements in Physical Fitness are Associated with Favorable Changes in Blood Lipid Concentrations in Children

Although accumulating evidence suggests the benefits of cardiorespiratory fitness and muscular fitness, little knowledge exists on how other physical fitness (PF) components are associated with cardiovascular disease (CVD) risk markers in children. Additionally, much of the relevant evidence is from longitudinal studies with CVD risk markers at a single time point (i.e., baseline) rather than changes in PF. The purpose of the present study was to examine whether initial 1-year changes in different performance measures of PF (i.e., endurance performance, muscular strength/endurance, flexibility, agility, and speed) can predict the subsequent changes (2-year change) in blood lipid concentrations in children. This 2-year longitudinal study included a total of 251 Japanese children (mean age 9.2 ± 0.4). PF tests were performed to comprehensively evaluate the participant's fitness levels (handgrip strength [upper body muscular strength], bent-leg sit-ups [muscular endurance], sit-and-reach [flexibility], side-step [agility], 20-meter shuttle run [endurance performance], 50-meter sprint [speed], standing long jump [lower body muscular strength], and softball throw [explosive arm strength and throwing ability]). Fasting lipid profile was assayed for triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and non-HDL-C concentration. Multilevel linear regressions were used to examine the associations between the preceding changes (over 1-year) in PF and subsequent changes (over 2-years) in blood lipid concentrations. We also examined the simultaneous associations between 2-year changes in PF and 2-year changes in blood lipid concentrations. For boys, preceding improvement in handgrip strength was negatively associated with TG concentration (β = -0.260, p = 0.030); improvements in bent-leg sit-ups were negatively associated with clustered lipid scores (β = -0.301, p = 0.038) and non-HDL-C (β = -0.310, p = 0.044); and improvements in 50m sprinting were associated with subsequent changes in non-HDL-C (β = 0.348, p = 0.006) and LDL-C (β = 0.408, p = 0.001). For girls, improvements in handgrip strength was negatively associated with TG concentration (β = -0.306, p = 0.017); and improvements in standing long jump were negatively associated with non-HDL-C (β = -0.269, p = 0.021) and LDL-C (β = -0.275, p = 0.019). For boys and girls, there were no significant simultaneous associations between 2-year changes in PF and 2-year changes in blood lipid concentrations. In conclusion, preceding change in physical fitness in relation to change in blood lipid concentration likely reflect a physiological adaptation to growth and maturation since these associations diminished in the subsequent year.

Identifying reference values for serum lipids in Chinese children and adolescents aged 6-17 years old: A national multicenter study

BACKGROUND

Current reference values for pediatric dyslipidemia used in China were not developed based on local population studies and did not consider age and sex differences.

OBJECTIVE

In this study, we aimed to determine suitable reference values for total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), and non-high-density lipoprotein cholesterol (nonHDL-C) for Chinese children and adolescents using a national multicenter school-based study.

METHODS

A total of 15,830 students aged 6-17 years were recruited from seven provinces of China. Age- and sex-specific percentile values for each lipid indicator were derived based on levels measured in the fasting state, and percentile curves of each indicator were plotted using the LMS method.

RESULTS

Serum lipid levels varied considerably with age in both sexes. Among boys, the cut-off value for high TC, nonHDL-C, LDL-C, and TG, based on the value of the 95th percentiles, ranged from 4.58 to 5.39, 3.34 to 3.99, 2.69 to 3.31, and 1.22 to 1.83 mmol/L, respectively; among girls, the cut-off value for high TC, nonHDL-C, LDL-C, and TC ranged from 5.01 to 5.39, 3.66 to 3.97, 2.97 to 3.32, and 1.41 to 1.93 mmol/L, respectively. The cut-point for low HDL-C ranged from 0.84 to 1.08 mmol/L in boys and from 0.89 to 1.04 mmol/L in girls.

CONCLUSION

These findings may help to determine age- and sex-specific reference values for serum lipids among Chinese children and adolescents and provide valuable guidance for screening of dyslipidemia.

Age-wise trends in alkaline phosphatase activity in 167,625 Chinese children aged 0-18 years

OBJECTIVE

Alkaline phosphatase (ALP) serves as a biomarker for diagnosing several types of diseases in adults; nonetheless, its use is restricted in children because of changes in ALP activity during different physiological phases. The present study aimed to investigate ALP activity and its dynamics in children of different ages to establish the reference values for ALP activity in children.

METHODS

Total 167,625 samples of children aged 0-18 years were enrolled in this study. ALP activity was measured using the 4-nitrophenyl-1-phosphate disodium salt (4-NPP)-2-amino-2-methyl-1-propanol (AMP) method with an automatic biochemical analyzer. Patients with known diagnoses that may affect ALP activity were excluded. A percentile curve was plotted using MATLAB software, and the curve was fitted using the skewness-median-coefficient of variation (LMS) method.

RESULTS

ALP activity reached the highest peak at 12-13 years of age and then gradually decreased to the lowest peak at 18-19 years of age in boys, whereas it reached the highest at 10-11 years and then gradually reduced to the lowest at 17-18 years in girls. Furthermore, the highest peak of ALP activity appeared substantially earlier in children of either sex in China than in those in Germany.

CONCLUSIONS

We showed the dynamics of ALP activity in both boys and girls between the ages of 0 and 18 years in China and compared the difference in ALP activity between children in China and Germany. Our findings provide a reference for clinicians.

Associations of non-high-density lipoprotein cholesterol with metabolic syndrome and its components in Korean children and adolescents: the Korea National Health and Nutrition Examination Surveys 2008-2014

BACKGROUND

In this study, we aimed to investigate the relationship between single-gender Korean references for non-high-density lipoprotein cholesterol (non-HDL-C) and metabolic syndrome (MetS) in childhood.

METHODS

A total of 5742 Korean children aged 10-18 years who participated in a national survey were included. The subjects were classified into three groups based on single-gender non-HDL-C levels as follows: < 120 mg/dL (desirable), ≥ 120 and < 150 mg/dL (borderline high), and ≥ 150 mg/dL (high).

RESULTS

Males in the borderline high non-HDL-C group had odds ratios (ORs) of 2.86 (95% confidence interval, 2.30-3.56) for elevated triglycerides (TG), 1.73 (1.08-1.79) for reduced high-density lipoprotein cholesterol (HDL-C) and 1.73 (1.08-2.78) for MetS compared with males in the desirable non-HDL-C group after adjusting for covariates. Males in the high non-HDL-C group had ORs of 1.65 (1.14-2.41) for elevated blood pressure (BP), 6.21 (4.27-9.05) for elevated TG, and 3.29 (1.49-7.26) for MetS compared with males in the desirable non-HDL-C group. Females in the borderline high non-HDL-C group had ORs of 3.03 (2.43-3.76) for elevated TG, 1.63 (1.13-2.35) for reduced HDL-C, and 4.53 (2.47-8.31) for MetS compared with females in the desirable non-HDL-C group. Females in the high non-HDL-C group had ORs of 1.43 (1.00-2.04) for elevated BP, 6.36 (4.45-9.08) for elevated TG, and 7.64 (3.65-15.96) for MetS compared with females in the desirable non-HDL-C group.

CONCLUSION

Our results suggest that, in a Korean population, a non-HDL-C level of 120 mg/dL for males and 150 mg/dL for females is the threshold between borderline high and high risk for MetS.

Effects of Growth Hormone Treatment on Lipid Profiles

OBJECTIVES

To assess the effects of growth hormone (GH) on lipid profiles in children and whether the effect is pharmacological.

METHODS

The authors determined serum levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), non-high-density lipoprotein cholesterol (non-HDL-C), and low-density lipoprotein cholesterol (LDL-C) every year during 3-y GH treatment in 48 GH deficient (GHD) short children and 22 children with short stature born small for gestational age (SGA).

RESULTS

The abnormally high levels of TC, non-HDL-C, and LDL-C showed a high frequency in GHD short children compared with epidemiological studies in Japan. The high prevalence of high level of TC was also shown in SGA short children. Three-year GH treatment decreased serum TC, non-HDL-C, and LDL-C levels in both patient groups.

CONCLUSIONS

GH treatment is clearly a pharmacological therapy in SGA short children and so may also be in GHD short children at the Japanese standard therapeutic dose. Taken together, GH improves lipid profiles, and its effect has the possibility of medical properties.

Usefulness of non-fasting lipid parameters in children

BACKGROUND

This study assessed whether non-fasting lipid markers could be substituted for fasting markers in screening for dyslipidemia, whether direct measurement of non-fasting low-density lipoprotein cholesterol [LDL-C (D)] could be substituted for the calculation of fasting LDL-C [LDL-C (F)], and the utility of measuring non-high-density lipoprotein cholesterol (non-HDL-C).

METHODS

In 33 children, the lipid profile was measured in the non-fasting and fasting states within 24 h. Correlations were examined between non-fasting LDL-C (D) or non-HDL-C levels and fasting LDL-C (F) levels.

RESULTS

Non-fasting triglyceride (TG), total cholesterol (TC), HDL-C, LDL-C (D), and non-HDL-C levels were all significantly higher than the fasting levels, but the mean difference was within 10% (except for TG). Non-fasting LDL-C (D) and non-HDL-C levels were strongly correlated with the fasting LDL-C (F) levels.

CONCLUSIONS

In conclusion, except for TG, non-fasting lipid parameters are useful when screening children for dyslipidemia. Direct measurement of non-fasting LDL-C and calculation of non-fasting non-HDL-C could replace the calculation of fasting LDL-C because of convenience.

Reference Values for The Triglyceride to High-Density Lipoprotein Cholesterol Ratio and Non-High-Density Lipoprotein Cholesterol in Korean Children and Adolescents: The Korean National Health and Nutrition Examination Surveys 2007-2013

Aim: Cholesterol levels vary throughout childhood and adolescence. The aim of the present study was to evaluate and identify age- and gender-specific reference values for serum lipid concentrations including non-high-density lipoprotein cholesterol (non-HDL-C) and the triglyceride to HDL-C ratio (TG/HDL-C ratio) in apparently healthy Korean children and adolescents.

Methods: A total of 6197 participants aged 10 to 19 years old from the 2007–2013 Korean National Health and Nutrition Examination Survey were analyzed. Serum lipid concentrations were evaluated according to age and gender.

Results: The overall mean concentration of non-HDL-C was 105.5 ± 25.6 mg/dL, with a significant gender difference: 103.3 ± 26.1 mg/dL in boys and 107.9 ± 24.7 mg/dL in girls (p = 0.028). The median values of non-HDL-C concentrations in boys and girls, respectively, were 111 and 112 mg/dL in the 10-year-old age group, 95 and 103 mg/dL in the 15-year-old age group, and 109 and 103 mg/dL in the 19-year-old age group. The overall mean TG/HDL-C ratio was 1.74 ± 1.22, and there were no significant gender differences: 1.77 ± 1.25 in boys and 1.72 ± 1.22 in girls (p = 0.183). The median values of the TG/HDL-C ratio in boys and girls were 1.16 and 1.00 in the 10-year-olds, 1.54 and 0.95 in the 15-year-olds, and 1.74 and 0.84 in the 19-year-olds, respectively.

Conclusions: Age- and gender-specific reference values for non-HDL-C and for the TG/HDL-C ratio in children and adolescents could provide valuable information for individualized interpretations of lipid profiles and interventions as well as for strategies to prevent and manage childhood and adolescent dyslipidemia.

Non-high-density Lipoprotein Cholesterol Levels in Japanese Obese Boys with Metabolic Syndrome

AIM

To investigate the relationship between the clustering of metabolic syndrome (MetS) components and non-high-density lipoprotein cholesterol (non-HDL-C) levels in Japanese obese boys.

METHODS

Subjects were 58 obese boys aged 12.0±2.6 years, which were categorized into three subgroups: abdominal obesity, pre-MetS (abdominal obesity＋1 component), and MetS (abdominal obesity＋2 or more components).

RESULTS

Sixteen (27.6%) and 32 (55.2%) of the obese boys were diagnosed as pre-MetS and MetS, respectively. The mean non-HDL-C level in total subjects was 139.0±36.4 mg/dl and that in boys with abdominal obesity, pre-MetS, and MetS were 112.9±34.4, 135.4±37.9, and 149.0±32.6 mg/dl, respectively (p=0.0183, ANOVA).

CONCLUSIONS

Japanese obese boys with MetS exhibited elevated non-HDL-C levels, suggesting that they may have a higher risk for the development of atherosclerotic diseases.