Sex-specific Percentile Values Research Articles

Physical fitness trends in a nationally representative sample of Portuguese youth: What has changed from 2008 to 2018?

This investigation aimed to describe the current physical fitness (PF) status of Portuguese youth, compare secular trends from 2008 and 2018, and establish updated age- and sex-specific percentile values for distinct PF tests. In 2008 and 2018, 22 048 and 8960 children and adolescents (10-18 years) were included in two national cross-sectional investigations. PF was evaluated using the FITESCOLA® battery tests and the handgrip strength test. Independent sample t-tests and chi-squared tests were used to model the results. Weight smoothed percentile values were calculated using Cole's Lambda-Mu-Sigma (LMS) method. All analyses were weighted according to age, sex, and geographic region. In 2018, boys surpassed girls in the 20-m shuttle run, curl-ups, push-ups, standing long, and vertical jump tests, while girls performed better in the sit-and-reach (p < 0.05). The percentage of boys and girls meeting the healthy zone in the 20-min shuttle run test did not differ between 2008 and 2018 (p ≥ 0.05). In boys, a higher percentage fell in the healthy zone for the curl-up and push-up tests in 2018 compared to 2008 (85.8% vs. 83.4%, and 57.8% vs. 53.8%; p < 0.05). Girls improved their flexibility component (sit-and-reach test), with a higher percentage meeting the healthy zone in 2018 (32.6% vs. 36.9%; p < 0.05); an opposite trend was seen for boys (65.5% vs. 50.1%; p < 0.05). The present investigation provides new and updated PF percentile curves for Portuguese youth, which can be used as a general overview of the current PF state among the Portuguese young population.

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

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. 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. 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. 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. 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.

Percentiles for anthropometric measures in 11–18 years-old students of 73 developing countries

Background and aimsone of the health concerns for any society is to have its own standard of growth. The aim of this study was to provide the age- and sex-specific percentile values of anthropometric measures for adolescents of developing countries. The use of global percentiles in developing countries overestimates underweight and stunting while underestimates overweight and obesity. MethodsThe data were obtained from the Global School-based Student Health Survey (GSHS). This study was conducted on school students, selected by multistage random cluster sampling from 73 developing countries. A parametric method was used for constructing age-specific reference intervals (normal ranges). ResultsIn general, 210,045 11–18 years-old schoolchildren (14.38 ± 1.39) from 73 developing countries between 2003 and 2014 were included in this study, among which 103,080 (49.08%) were male and 106,965 (50.92%) were female. Calculation of body mass index (BMI) percentile showed that for all BMI percentile curves of both sexes, there was a gradual increase up to the age of around 15 years, and then remain stable (except for 95th percentile). Moreover in all weight percentile curves of boys, except 90th and above, there was a slight rise until the age of 18 years. In 10th height percentile curves and above in boys, there was a sharp increase up to the age of 17, followed by a decline. Similarly, this pattern was found for 50th height percentile and above in girls. ConclusionThe use of global percentiles in developing countries overestimates underweight and stunting while underestimates overweight and obesity.

Lower Quarter Y Balance Test performance: Reference values for healthy youth aged 10 to 17 years

BackgroundThe Lower Quarter Y Balance Test (YBT-LQ) has been widely used to register dynamic balance performance in children and adolescents. However, studies evaluating age- and sex-specific normative data to assess and classify YBT-LQ performance for these age-cohorts are missing. ObjectiveThus, we investigated YBT-LQ performance in healthy youth to provide age- and sex-specific reference values. MethodsSix-hundred and sixty-nine individuals (286 female, 383 male) aged 10–17 years performed the YBT-LQ with their left and right leg. Normalized maximal reach distances (% leg length) for all three directions (i.e., anterior, posterolateral, posteromedial) and the composite score were calculated. Further, age- and sex-specific percentile values (i.e., 10th to 90th percentile) were computed and plotted. ResultsIn boys, the oldest age group (16−17 years) performed better than the younger ones (14−15, 12−13, and 10−11 years). In girls, the youngest age group (10−11 years) often achieved better values compared to the 12−13-year olds. Further, 16−17-year old boys compared to the same aged girls showed better YBT-LQ performance in all but one measure (except left leg reach in posterolateral direction). For both sexes, curvilinear shaped curves were detected for percentile values across the reach directions. ConclusionsThe generated age- and sex-specific reference values for the YBT-LQ can be used by practitioners to evaluate dynamic balance performance in healthy youth aged 10–17 years.

Percentile values of serum zinc concentration and prevalence of its deficiency in Iranian children and adolescents: the CASPIAN-V study.

Background To determine the prevalence of serum zinc deficiency and provide the age- and sex-specific percentile values of serum zinc in children and adolescents. Methods We used the gathered data through the CASPIAN-V study, a national survey conducted on 3500 students aged 7-18 years from 30 provinces of Iran. In this study, 1370 blood samples were selected randomly, and serum zinc concentration was measured using a Hitachi automated analyzer. Zinc deficiency was defined as a serum zinc level of less than 75 μg/dL. Age-sex specific reference percentile values were developed for serum zinc concentration. Results The mean age of participants was 12.4 ± 3.0 years; 49.3% were girls and 73% were urban inhabitants. Mean (standard deviation [SD]) of serum zinc concentration was 107.23 (25.81) μg/dL with a significant sex difference; 109.03 ± 26.12 μg/dL for males compared to 105.41 ± 25.3 μg/dL for females (p = 0.009). The prevalence of subclinical zinc deficiency was 4.9% (95% confidence intervals [CI]: 3.0, 6.9) in children and adolescents. Both zinc deficient and sufficient groups were similar in terms of age, sex and residential areas (all p-value > 0.05). Overall, the 5th and 95th percentile values for serum zinc were 68.28 and 151.87 μg/dL, respectively. The value of all percentiles consistently decreased with age. The 10-99th percentile values for serum zinc were greater in boys than girls at all ages. Conclusions Nearly 5% of subjects had zinc deficiency. Age-sex specific percentile values were established for Iranian children and adolescents.

Body composition: population epidemiology and concordance in Australian children aged 11-12 years and their parents.

ObjectivesOverweight and obesity remain at historically high levels, cluster within families and are established risk factors for multiple diseases. We describe the epidemiology and cross-generational concordance of body composition among Australian children aged 11–12 years and their parents.DesignThe population-based cross-sectional Child Health CheckPoint study, nested within the Longitudinal Study of Australian Children (LSAC).SettingAssessment centres in seven major Australian cities and eight regional cities, or home visits; February 2015–March 2016.ParticipantsOf all participating CheckPoint families (n=1874), body composition data were available for 1872 children (49% girls) and 1852 parents (mean age 43.7 years; 88% mothers), including 1830 biological parent-child pairs.MeasuresHeight, weight, body mass index (BMI), waist circumference and waist-to-height ratio for all participants; body fat and fat-free mass by four-limb bioimpedence analysis (BIA) at assessment centres, or body fat percentage by two-limb BIA at home visits. Analysis: parent-child concordance was assessed using (i) Pearson’s correlation coefficients, and (ii) partial correlation coefficients adjusted for age, sex and socioeconomic disadvantage. Survey weights and methods accounted for LSAC’s complex sample design.Results20.7% of children were overweight and 6.2% obese, as were 33.5% and 31.6% of parents. Boys and girls showed similar distributions for all body composition measures but, despite similar BMI and waist-to-height ratio, mothers had higher proportions of total and truncal fat than fathers. Parent-child partial correlations were greatest for height (0.37, 95% CI 0.33 to 0.42). Other anthropometric and fat/lean measures showed strikingly similar partial correlations, ranging from 0.25 (95% CI 0.20 to 0.29) for waist circumference to 0.30 (95% CI 0.25 to 0.34) for fat-free percentage. Whole-sample and sex-specific percentile values are provided for all measures.ConclusionsExcess adiposity remains prevalent in Australian children and parents. Moderate cross-generational concordance across all measures of leanness and adiposity is already evident by late childhood.

Pediatric reference intervals for alkaline phosphatase.

Interpretation of alkaline phosphatase activity in children is challenging due to extensive changes with growth and puberty leading to distinct sex- and age-specific dynamics. Continuous percentile charts from birth to adulthood allow accurate consideration of these dynamics and seem reasonable for an analyte as closely linked to growth as alkaline phosphatase. However, the ethical and practical challenges unique to pediatric reference intervals have restricted the creation of such percentile charts, resulting in limitations when clinical decisions are based on alkaline phosphatase activity. We applied an indirect method to generate percentile charts for alkaline phosphatase activity using clinical laboratory data collected during the clinical care of patients. A total of 361,405 samples from 124,440 patients from six German tertiary care centers and one German laboratory service provider measured between January 2004 and June 2015 were analyzed. Measurement of alkaline phosphatase activity was performed on Roche Cobas analyzers using the IFCC's photometric method. We created percentile charts for alkaline phosphatase activity in girls and boys from birth to 18 years which can be used as reference intervals. Additionally, data tables of age- and sex-specific percentile values allow the incorporation of these results into laboratory information systems. The percentile charts provided enable the appropriate differential diagnosis of changes in alkaline phosphatase activity due to disease and changes due to physiological development. After local validation, integration of the provided percentile charts into result reporting facilitates precise assessment of alkaline phosphatase dynamics in pediatrics.

Percentile Values for the Anthropometric Dimensions of Triplet Neonates - Analysis of German Perinatal Survey Data of 2007-2011 from all States of Germany

We aimed to develop national reference values for birth weight, length, head circumference, and weight for length for newborn triplets based on data from the German perinatal survey of 2007-2011. Perinatal survey data of 3,690 newborn triplets from all the states of Germany were kindly provided to us by the AQUA Institute in Göttingen, Germany. Data of 3,567 newborn triplets were included in the analyses. Sex-specific percentile values were calculated using cumulative frequencies. Percentile values at birth were computed for the 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentiles for 21-36 completed weeks of gestation. We present the first German reference values (tables and curves) for the anthropometric dimensions of triplet neonates and compare selected birth weight and length percentiles of triplets (after 32 and 34 completed weeks of gestation) to those of singletons and twins. The differences in the 50th birth weight percentiles between singletons and triplets after 32 completed weeks of gestation were 180 g for girls and 210 g for boys; after 34 weeks of gestation the differences were 320 and 325 g, respectively. The differences between twins and triplets after 32 weeks of gestation were 100 g for girls and 120 g for boys; after 34 weeks of gestation they were 130 and 135 g, respectively. The data presented here enable the classification of newborn triplets according to somatic parameters making reference to German perinatal data.

Percentiles for anthropometric measures in Iranian children and adolescents: the CASPIAN-IV study.

The aim of the study was to provide the age- and sex-specific percentile values of anthropometric measures for Iranian children and adolescents. This cross-sectional nationwide survey was conducted on a representative sample of 14,880 school students, selected by multistage random cluster sampling from urban and rural areas of 30 provinces in Iran. Anthropometric measures including body mass index (BMI), waist circumference (WC), hip circumference (HC), and wrist circumference were measured under standard protocols by using calibrated instruments. Age- and gender-specific reference values were developed for anthropometric measures by the maximum penalized likelihood approach [Cole's least mean square (LMS) method]. In the present study, 13,486 out of the 14,880 invited subjects completed all the required data of the study (participation rate: 90.6%). Participants consisted of 6640 girls (49.2%) and 75.6% urban residents; their mean and standard deviation (SD) age was 12.47±3.36 years. The BMI percentile curves of girls had a sharp increase from 14 to 18 years, and then began to plateau, but among boys, these curves had a consistent increase until the age of 18 years. In addition, the higher percentiles were higher in adolescent boys than girls. The HC percentile curves of both sexes had a persistent increase and the percentiles for HC were higher in adolescent girls than in boys. WC had a sharp increase from 7 to 18 years of age for boys, whereas for girls, these curves had a less sharp increase with age. In all ages, the percentiles for wrist circumference were higher in adolescent boys than girls. The findings of this study highlight the necessity of paying special attention to developing age- and gender-specific percentiles of anthropometric measures in children and adolescents.

Physical Fitness Percentiles of German Children Aged 9-12 Years: Findings from a Longitudinal Study.

BackgroundGenerating percentile values is helpful for the identification of children with specific fitness characteristics (i.e., low or high fitness level) to set appropriate fitness goals (i.e., fitness/health promotion and/or long-term youth athlete development). Thus, the aim of this longitudinal study was to assess physical fitness development in healthy children aged 9–12 years and to compute sex- and age-specific percentile values.MethodsTwo-hundred and forty children (88 girls, 152 boys) participated in this study and were tested for their physical fitness. Physical fitness was assessed using the 50-m sprint test (i.e., speed), the 1-kg ball push test, the triple hop test (i.e., upper- and lower- extremity muscular power), the stand-and-reach test (i.e., flexibility), the star run test (i.e., agility), and the 9-min run test (i.e., endurance). Age- and sex-specific percentile values (i.e., P10 to P90) were generated using the Lambda, Mu, and Sigma method. Adjusted (for change in body weight, height, and baseline performance) age- and sex-differences as well as the interactions thereof were expressed by calculating effect sizes (Cohen’s d).ResultsSignificant main effects of Age were detected for all physical fitness tests (d = 0.40–1.34), whereas significant main effects of Sex were found for upper-extremity muscular power (d = 0.55), flexibility (d = 0.81), agility (d = 0.44), and endurance (d = 0.32) only. Further, significant Sex by Age interactions were observed for upper-extremity muscular power (d = 0.36), flexibility (d = 0.61), and agility (d = 0.27) in favor of girls. Both, linear and curvilinear shaped curves were found for percentile values across the fitness tests. Accelerated (curvilinear) improvements were observed for upper-extremity muscular power (boys: 10–11 yrs; girls: 9–11 yrs), agility (boys: 9–10 yrs; girls: 9–11 yrs), and endurance (boys: 9–10 yrs; girls: 9–10 yrs). Tabulated percentiles for the 9-min run test indicated that running distances between 1,407–1,507 m, 1,479–1,597 m, 1,423–1,654 m, and 1,433–1,666 m in 9- to 12-year-old boys and 1,262–1,362 m, 1,329–1,434 m, 1,392–1,501 m, and 1,415–1,526 m in 9- to 12-year-old girls correspond to a “medium” fitness level (i.e., P40 to P60) in this population.ConclusionsThe observed differences in physical fitness development between boys and girls illustrate that age- and sex-specific maturational processes might have an impact on the fitness status of healthy children. Our statistical analyses revealed linear (e.g., lower-extremity muscular power) and curvilinear (e.g., agility) models of fitness improvement with age which is indicative of timed and capacity-specific fitness development pattern during childhood. Lastly, the provided age- and sex-specific percentile values can be used by coaches for talent identification and by teachers for rating/grading of children’s motor performance.

New percentile values for the anthropometric dimensions of twin neonates: analysis of perinatal survey data of 2007-2011 from all 16 states of Germany

The aim of this study was to develop new national standards for birth weight, length, head circumference, and weight for length for newborn twins based on the German perinatal survey of 2007-2011. We also assessed trends in anthropometric measurements by comparing these new percentile values with the percentile values of 1990-1994. Perinatal survey data of 110,313 newborn twins from all the states of Germany collected in the years 2007-2011 were kindly provided by the AQUA Institute in Göttingen, Germany. Sex specific percentile values were calculated using cumulative frequencies. Percentile values at birth were computed for the 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentiles for 21-40 completed weeks of gestation. Percentile curves and tabulated values for the years 2007-2011 were compared with the published values of 1990-1994. The new percentile curves (2007-2011) closely resemble the previous ones (1990-1994). Small differences can nonetheless be found. For example, for birth weight the new values for the 10th percentile are a little higher. We recommend using the new percentile values instead of the old ones.

Neue Perzentilwerte für die Körpermaße neugeborener Einlinge: Ergebnisse der deutschen Perinatalerhebung der Jahre 2007–2011 unter Beteiligung aller 16 Bundesländer

The aim of this study was to derive percentile values for birth weight, length, head circumference, and weight for length for singleton neonates based on the German perinatal survey of 2007-2011 (using data from all 16 states of Germany). We also compared these new percentile values with the percentile values of 1995-2000 that so far have been considered standard values. Data of 3 187 920 singleton neonates from the German perinatal survey of the years 2007-2011 were kindly provided to us by the AQUA Institute in Göttingen, Germany. Sex specific percentile values were calculated using cumulative frequencies. Percentile values at birth were computed for the 3(rd), 10(th), 25(th), 50(th), 75(th), 90(th), and 97(th) percentiles for 21-43 completed weeks of gestation. Percentile curves and tabulated values for the years 2007-2011 were compared with the published values of 1995-2000. Overall the new percentile curves closely resemble the previous ones. Minimal differences can be found for the 10(th) percentile and generally for early weeks of gestation. Values for the 10(th) percentile in the 2007-2011 dataset are somewhat higher than values of 1995-2000 for birth weight, length, and weight for length. We recommend the use of these new percentile values instead of the old ones.

Growth Curves for Cardio-Metabolic Risk Factors in Children and Adolescents

This study developed percentile curves for anthropometric (waist circumference) and cardiovascular (lipid profile) risk factors for US children and adolescents. A representative sample of US children and adolescents from the National Health and Nutrition Examination Survey from 1988 to 1994 (NHANES III) and the current national series (NHANES 1999-2006) were combined. Percentile curves were constructed, nationally weighted, and smoothed using the Lambda, Mu, and Sigma method. The percentile curves included age- and sex-specific percentile values that correspond with and transition into the adult abnormal cut-off values for each of these anthropometric and cardiovascular components. To increase the sample size, a second series of percentile curves was also created from the combination of the 2 NHANES databases, along with cross-sectional data from the Bogalusa Heart Study, the Muscatine Study, the Fels Longitudinal Study and the Princeton Lipid Research Clinics Study. These analyses resulted in a series of growth curves for waist circumference, total cholesterol, LDL cholesterol, triglycerides, and HDL cholesterol from a combination of pediatric data sets. The cut-off for abnormal waist circumference in adult males (102 cm) was equivalent to the 94(th) percentile line in 18-year-olds, and the cut-off in adult females (88 cm) was equivalent to the 84(th) percentile line in 18-year-olds. Triglycerides were found to have a bimodal pattern among females, with an initial peak at age 11 and a second at age 20; the curve for males increased steadily with age. The HDL curve for females was relatively flat, but the male curve declined starting at age 9 years. Similar curves for total and LDL cholesterol were constructed for both males and females. When data from the additional child studies were added to the national data, there was little difference in their patterns or rates of change from year to year. These curves represent waist and lipid percentiles for US children and adolescents, with identification of values that transition to adult abnormalities. They could be used conditionally for both epidemiological and possibly clinical applications, although they need to be validated against longitudinal data.

Secular changes in height, weight and body mass index in Hong Kong Children.

BackgroundLarge population growth surveys of children and adolescents aged 6 to 18 y were undertaken in Hong Kong in 1963 and 1993. The global epidemic of obesity is a major public health concern. To monitor the impact of this epidemic in Hong Kong children and to identify secular changes in growth, a further growth survey was undertaken in 2005/6.MethodsCross-sectional height and weight measurements of 14,842 children and adolescents aged 6 to 18 y from Hong Kong's 18 districts were obtained during the 2005/6 school year. Percentile curves were constructed using LMS method and sex-specific percentile values of weight-for-age, height-for-age, and BMI-for-age were compared with those data from 1963 and 1993.ResultsSecular changes in height, weight and BMI were noted between 1963 and 1993 and between 1993 and 2005/6. In the latter period, greater changes were observed at younger ages, and particularly in boys. On an annual basis, the 1993–2005/6 changes were less than those during 1963–1993. Using the International Obesity Task Force cut-offs, 16.7% of children were overweight or obese in 2005/6, which was a 5.1% increase since 1993.ConclusionThese data provide policy-makers with further evidence of the secular changes in child growth and the increasing obesity epidemic among Hong Kong children.