Decimal Age Research Articles

ASSESSMENT OF SOMATIC MATURATION OF VENEZUELAN ADOLESCENTS.

beginning of adolescence comprises important physical modifications, which affects growth and changes in body composition, therefore it is important to consider maturation assessment. to develop a non-invasive method to assess maturity status in Venezuelan adolescents from peak height velocity (PHV) by means of anthropometric variables in a cross-sectional sample. data comprised 681 Venezuelan adolescents 9 up to 18 years of age. Mirwald equation was applied to derived PHV. Regression analysis was used in order to build a model for Venezuelan sample as well as, ROC curves to assess sensitivity and specificity of anthropometric variables. the predictive equations for both sexes, exhibited a high determination coefficient (< 0.99) and a minimal estimation error (0.06). Mean decimal age at categories of PHV obtained by both equations: criterion and model, were very similar (13.27 vs. 13.39) for boys, and (11.62 vs. 11.77) for girls. Bland-Altman plot showed a tight concordance between the two equations and all anthropometric indices, exhibited high area under the curve > 0.75, specially sitting height. in Venezuela, there is little work based on longitudinal studies of the maturation status. Giving the difficult faced in the longitudinal studies recent works have been used cross-sectional methodology in the assessment of the somatic maturation, both in non athletic and athletic populations. This study provides predicting equations for the assessment of the somatic maturation adjusted to Venezuelan population developed from Mirwald equation, which may be used to aid in evaluation of nutritional and general health, as well as, a reduction of risks associated with miss-classification for chronological age.

A 2-year prospective densitometric study on the influence of Fok-I gene polymorphism in young patients with thalassaemia major.

This study is to estimate the degree of genetic contribution of Fok-I gene polymorphism of Vitamin D receptor to bone mass in patients with thalassaemia. Results indicate a protective role of the f allele of the Fok-I gene polymorphism when found in homozygosity on bone mineral density of young thalassemic patients. The purpose of this study is to estimate prospectively the degree of genetic contribution of Fok-I gene polymorphism of vitamin D receptor (VDR) to the evolution of bone mass in patients with beta-thalassemia major (b-TH). Sixty-four children and young adults (33 males and 31 females) with mean decimal age of 23.20 ± 5.41 (range 9.25-32.41years) were recruited in this study. All patients were genotyping for Fok-I gene polymorphism and were assessed with dual energy X-ray absorptiometry (DXA) at baseline and 2years after. Z-scores were calculated based on normal age and sex matched Caucasian population. Metabolites of vitamin D, intact PTH, total calcium, inorganic phosphorous, and alkaline phosphatase were measured at the serum pre-transfusion. A moderate proportion of patients had decreased DXA Z-scores (Z-score ≤-2) predominately in total hip (31%) and secondary in lumbar spine (15.6%). Patients being homozygous for the f allele had apparently higher BMD Z-scores compared with those carrying the F allele in homo- or heterozygosity, however, with a difference that did not reached significance. Interestingly enough, a significant deterioration in BMD Z-scores measured at femur (FF: P = 0.004 Ff: P < 0.001, ff: P = 0.024) and total hip (FF: P = 0.022, Ff: P = 0.005) was recorded for all type of genotypes, except for ff genotype and with regard to the total hip DXA values. An increased prevalence of serum 25(OH)D3 deficiency (59.4%) and 25(OH)D3 borderline (12.5%) was recorded. Our study indicates a protective role of the f allele of the Fok-I gene polymorphism when found in homozygosity on bone mineral density of young patients with b-TM.

Olgunluk Katsayısına Göre Çocukların Motorik İşlevleri

Objective: This study compares performance levels among early, average, and late maturing boys and girls. So, the purpose of this study is to compare the age and gender related differences in motoric functions of according to chronological and biological age. Material and Methods: Research groups consist of ngirl=362 nboy=331 with different academy of junior sports hall changing their age from 7 to 11 years, child players were instructed to give their maximal efforts during all tests. The research groups' training age (mean=1.77±0.28 year) was attained. All child trained three days a week (1-1.5 h of training day). Chronological age was calculated by subtracting the participant's date of birth from the observation date transformed into decimal age (in years) and maturity offsets were calculated. The research groups were measured for mass, standing height and sitting height. Leg length was calculated by subtracting the participant's sitting height from their standing height. Body mass was measured using a strain gauge scale and body mass index was calculated. For the physical and motoric attributes, stretching, high jump, long jump, hand grip, medicine ball throw, velocity and agility test were applied. Results: As a result, chronological age has an important influence on more complex tasks in which coordination, the performance superiority was appeared. When examining the performance parameters according to age change in terms of gender, the boys at every age except 10 years, are superior in velocity, hand grip, medicine ball, agility and long jump parameter adds to these superiorities after 9 years. From the differences obtained in terms of performace parameters, it is seen that who is at the level of early maturity is superior. Conclusion: In this context, as a result of the research, it can be said that the maturity coefficient has positive effects in performance at different ages

Validity of the Demirjian method for dental age estimation for Southern Turkish children.

The aim of this study was to evaluate the applicability of the Demirjian method for southern Turkish population. Panoramic radiographs of 535 patients (276 females, 259 males aged from 10 to 18 years) selected retrospectively. Dental age was calculated using the Demirjian's method. Chronologic age was calculated by subtracting the date of the birth from the date of the panoramic radiograph after having converted both to a decimal age. The chronologic and dental ages were compared using the paired t-test. The mean difference between the chronologic and dental ages ranged from 0.02 to 0.79 years in females. These differences in females between the chronologic and dental ages were statistically significant in total (P < 0.050) and in G1 (10-10.90 years) (P < 0.010) and G2 (11-11.90 years) (P < 0.001). The mean difference between the chronologic and dental ages ranged from 0.04 to 0.85 years in males. These differences in males between the chronologic age and dental age were statistically significant in total (P < 0.010) and in G4 (13-13.90 years) G5 (14-14.90 years) G6 (15-15.90 years) groups (P < 0.050). It is appropriate to use the Demirjian method in southern Turkish children; however, a revision is needed in some age groups.

Effect of birth month on physical fitness of soccer players (Under-15) according to biological maturity.

This study aims to clarify the relationship between the birth quarters, biological maturity and physical fitness (PF) in Under-15 youth soccer players. Each participant (n=133) was an Under-15 player from a top-elite soccer academy. The data collection period lasted 8 years (from Under-15 2002/2003 to 2009/2010 season). The athletes' birth dates were recorded and organized by birth quarters (Q1, first; Q2, second; Q3, third; Q4, fourth) and by semesters (S1, first; S2, second). Additionally recorded were each athlete's biological maturity (skeletal age, SA), anthropometric profile (stature; body mass; thigh, calf and upper arm girths), and fitness profile (10-m and 30-m sprint times; SJ; CMJ; shuttles in YYIR Test). Significant differences were found for (1) decimal age and SA by quarters (Q4-Q1, Q2) and semesters; and (2) stature (Q3-Q1, Q2, Q4; S1-S2), body mass (Q1-Q3; S1-S2), thigh girth (S1-S2), SJ (Q1-Q2) and sprint time (Q4-Q1, Q2; S1-S2). When maturity was considered as covariate all PF variables, with exception of SJ (Q1-Q2) and 10-m sprint time (S1-S2), were very similar among the studied groups. These findings suggest that (1) seasonal birth effect may result from the observed biological maturation differences, and (2) athletes may have been chosen due to their PF attributes.

Athletic performance and birth month: is the relative age effect more than just selection bias?

The aim of this study was to determine if month of birth affects performance in 3 tests of physical function in children and adolescents. We measured cardiorespiratory fitness, handgrip strength and lower-body power expressed them relative to (whole year) age then compared scores between calendar year birth-months. We also expressed test performance as the likelihood of achieving criterion-referenced fitness standards. There were significant main effects of birth-month for cardiorespiratory fitness (F=4.54, p<0.001), strength (F=6.81, p<0.001) and power (F=3.67, p<0.001). Children born in November were fitter and more powerful than those born at other times, particularly the summer months (April, May and June). October-born children were stronger than those born in all months except September and November. This relationship was evident despite controlling for decimal age and despite no significant inter-month differences in anthropometric characteristics.There is a clear physical advantage for those born in the autumn and this may explain some of the bias in sports selection attributed to the relative age effect, particularly when the British school-year (September) cut-off is used.

Overweight and Physical Activity as a Measure of Age at Menarche in Females

The present study is conducted on 62 girls, out of which 31 girls belong to physically active group with a training age of 8.95 years and 31 girls are from physically inactive group considered as control group. The girls were evaluated for their decimal age, age at menarche, height, weight body fat percentage and BMI. The body mass index and body fat percentages were significantly correlated and an inverse correlation was found. The higher body mass index, the lower was the age at menarche. The physically inactive girls were overweight and also early mature. The age of menarche of physically active girls was significantly delayed as compared to their inactive counterparts.

Assessment of Anthropometric and Metabolic Follow-Up Characteristics of Patients with Type 1 Diabetes Mellitus

Objective: Type 1 diabetes mellitus (T1DM) is characterized by inability to produce insulin due to the autoimmune destruction of the beta cells in the pancreas. In this study we aimed to evaluate anthropometric and metabolic parameters of patients diagnosed with T1DM. Material and Methods: Clinical and laboratory data of patients with T1DM were analyzed from medical records, retrospectively. Results: A total of 89 patients (45 male, 44 female) were evaluated in this study. The mean age of the patients was 12 ± 3.7 decimal years (DY) and age at diagnosis was 7.5 ± 3.9 DY (0.3-16.2 DY). Gender ratio was equal in patients and the mean follow-up time was 4.5 ± 3.4 years (0.1 – 16.2 years). While the mean height in standard deviation score (HSDS) of the patients at diagnosis was -0.07 ± 1, mean final HSDS was found to be -0.37 ± 1 (p = 0.002). Remission was achieved in 46 (51.6%) patients. 12 patients (13.5%) were classified in ‘good’; 32 patients (35.9%) in ‘moderate’ and 45 (50.6%) patients in ‘bad’ metabolic control groups, but four patients could not be classified in a metabolic control group. There was a slight correlation between body mass indexes and the mean insulin doses of the patients (r=0.20, P 0.05) or daily insulin dose requirement (p>0.05) and delta-HSDS. While there was no significant difference in terms of age, age at diagnosis, pubertal stage and insulin requirement between the patients with goodmoderate metabolic control and bad metabolic control, final HSDS was significantly lower in patients with bad metabolic control (-0.2 ± 0.9 vs. -0.8 ± 1.1; p = 0.04).

Standardizing Anthropometric Measures in Children and Adolescents with Functions for Egen: Update

In this article, we describe an extension to the egen functions zanthro() and zbmicat() (Vidmar et al., 2004, Stata Journal 4: 50–55). All functionality of the original version remains unchanged. In the 2004 version of zanthro(), z scores could be generated using the 2000 U.S. Centers for Disease Control and Prevention Growth Reference and the British 1990 Growth Reference. More recent growth references are now available. For measurement-for-age charts, age can now be adjusted for gestational age. The zbmicat() function previously categorized children according to body mass index (weight/height2) as normal weight, overweight, or obese. “Normal weight” is now split into normal weight and three grades of thinness. Finally, this updated version uses cubic rather than linear interpolation to calculate the values of L, M, and S for the child's decimal age between successive ages (or length/height for weight-for-length/height charts).

Physical Activity and Physical Self‐Concept in Adolescence: A Comparison of Girls at the Extremes of the Biological Maturation Continuum

This study examined differences in physical activity and physical self‐concept between the least and most biologically mature female adolescents within chronological age and academic year groups. A total of 252 British female adolescents (M age = 12.9 years; SD = .7) in Years 7–9 completed self‐report measures to assess physical activity and physical self‐concept. Percentage of predicted adult (mature) stature served as the index of biological maturation. Univariate analyses of covariance, controlling for decimal age, revealed that the least mature girls generally held higher perceptions of physical self‐concept but were no more, or less, active than the most mature girls. A subsequent meta‐analysis suggested, however, that across age and year groups the least mature girls were more active than the most mature girls.

OC-077 Jejunal tube feeding experience in paediatric nutrition support

IntroductionThere is an emerging group of children in whom poor and worsening upper GI dysmotility limits feed toleration and impacts growth; we wished to evaluate the role of jejunal tube...

Does jejunal feeding promote growth in children with worsening upper GI dysmotility?

<h3>Background and aim</h3> Promotion of optimal growth and development in children with underlying chronic disease is a goal of nutrition support teams (NST). NST are faced with a challenging group of children (usually with profound underlying neurodisability) in whom worsening upper GI dysmotility limits feed toleration and impacts growth. Jejunal feeding is increasingly used in this group when changes in feed type, method of feed delivery and maximal medical management of reflux have all failed to promote growth. We aimed to evaluate the effect of jejunal feeding on subsequent growth in children with severe GI dysmotility. <h3>Methods</h3> A retrospective cohort study (database/clinical note review) in a tertiary paediatric centre to investigate the impact on growth of jejunal feeding (&gt;6 months) in children with worsening GI dysmotility. All children (&lt;18 years) receiving home enteral tube feeding (HETF) during the period 01.01.02-30.09.11 were included. Data on weight at time of commencing jejunal feeding and at 6 or 12 months (whichever duration was exceeded) post establishment was collected and expressed as standard deviation or Z-score. Change in Z-score was calculated using paired t-test. <h3>Results</h3> A total of 866 children received HETF during the study period, of whom 38 (4%) were jejunally fed. Growth data was collected on 25 (56% female) children fed via a transgastric gastrojejunostomy (GJ) tube, PEG-J or a surgical roux-en Y jejunostomy &gt;6 months. Median (range) decimal age at commencement of jejunal feeding was 2.6 (0.1-16.2) years. The median (range) weight Z-score at the start of jejunal feeding was –1.3 (−5.2 to 2.1) and rose to –1.0 (−3.4-2.3) by 6-12 months post-start. A significant improvement in mean (95% CI) change in weight Z-score of 0.7 (0.1-1.3) (p=0.02) was found. As the majority of children were non-ambulatory (and knee heights are not routinely recorded), there was minimal height (and thus BMI) data recorded. Children received a range of jejunal feed types - 42% whole protein, 41% hydrolysed and 17% elemental feeds. <h3>Conclusions</h3> Jejunal feeding is an effective intervention to improve growth during the management of children with severe and worsening upper GI dysmotility on HETF.

Temporal relationships between screen-time and physical activity with cardiorespiratory fitness in English Schoolchildren: A 2-year longitudinal study

ObjectiveTo determine the temporal relationships screen-time and physical activity have with cardiorespiratory fitness. MethodMeasures were made over two years (2008–2010) in 1500 participants aged 11.5 (SD 0.5) years at baseline. ResultsTracking coefficients were low-to-moderate for all measures. At follow-up, 25% of participants moved from having low (<2h) to high (≥2h) daily screen-time and 6% became unfit according to FITNESSGRAM standards. Baseline screen-time was the strongest univariate predictor of becoming unfit. Multivariate analysis controlling for decimal age, BMI and deprivation confirmed baseline screen-time as the strongest independent predictor of becoming unfit over the 2-year study period (OR 2.4; 95%CI:1.4–4.0). Current (OR 2.3; 95%CI:1.3–4.0) and previous (OR 1.7; 95%CI:1.0–2.9) physical activity levels also independently predicted becoming unfit. ConclusionThere is currently no guidance for limiting screen-time in UK children. These longitudinal data add to the cross-sectional evidence of lower physical activity and fitness in children reporting ≥2h daily screen-time. More importantly, these data demonstrate that high screen-time during childhood is an independent predictor of lower cardiorespiratory fitness in adolescence.

Changes in Cardiorespiratory Fitness in 9- to 10.9-Year-Old Children

The study's purposes were to 1) assess changes in cardiorespiratory fitness (CRF) from 1998 to 2010, controlling for decimal age and body mass index (BMI), and 2) repeat the analysis in cohorts from 2005 to 2010, controlling for maturation, deprivation, and BMI. A total of 27,942 (n = 14,247 boys) 9- to 10.9-yr-old participants from one UK city were included in this serial cross-sectional study from 1998-1999 to 2009-2010. An indices of multiple deprivation (IMD) score was assigned to each participant on the basis of home postcode. Stature, sitting stature, and body mass were estimated. BMI and somatic maturity were calculated. Performance on the 20-m multistage shuttle run test (20mSRT) was used to estimate CRF (total shuttles). One-way ANCOVAs were completed to assess temporal trends in CRF, separately by sex. Model 1 assessed changes from 1998 to 2010 and included decimal age and BMI as covariates. Model 2 assessed changes from 2005 to 2010 and included maturity, IMD, and BMI as covariates. Results indicate that 20mSRT performance has declined in UK schoolchildren. An annual decline of 1.34% and 2.29% was observed in boys and girls, respectively. In model 1, for boys, the baseline cohort performed better than all other groups with the exception of the 1999-2000 group. For girls, declines in 20mSRT performance were observed from 2003 onward. In model 2, for boys, the 2007-2008 and 2008-2009 cohorts completed fewer 20mSRT shuttles than all other groups. For girls, the 2007-2008 and 2008-2009 cohorts also performed worse than all other years. The decline in CRF suggests children in the more recent SportsLinx cohorts may be at an increased risk of cardiometabolic illness in comparison with earlier cohorts. The promotion of vigorous physical activity is urged to promote CRF in children.

Age- and height-based prediction bias in spirometry reference equations

Prediction bias in spirometry reference equations can arise from combining equations for different age groups, rounding age or height to integers or using self-reported height. To assess the bias arising from these sources, the fit of 13 prediction equations was tested against the Global Lungs Initiative (GLI) dataset using spirometric data from 55,136 healthy Caucasians (54% female). The effects on predicted values of using whole-year age versus decimal age, and of a 1% bias in height, were quantified. In children, the prediction bias relative to GLI ranged from -22% to +17%. Switching equations at 18 yrs of age led to biases of between -846 (-14%) and +1,309 (+38%) mL. Using age in whole years rather than decimal age introduced biases from -8% to +7%, whereas a 1% overestimation of height introduced bias that ranged from +1% to +40%. Bias was greatest in children and adolescents, and in short elderly subjects. Using a single spirometry equation applicable across all ages and populations reduces prediction bias. Measuring and recording age and height accurately are also essential if bias is to be minimised.

Fok-I Polymorphism of Vitamin D Receptor Gene and the Presence of Renal Dysfunction in Patients with β-Thalassemia Major

Recent evidence supports the presence of renal dysfunction even among young patients with β-thalassemia major. However, the possible genetic contribution has never been investigated. The aim of this study was to correlate the presence of Fok-I polymorphism of the vitamin D receptor gene with abnormal levels of early markers of renal impairment in children and young adults with thalassemia. Thirty-four patients (19 male and 15 female) with β-thalassemia major on conventional treatment, with a mean decimal age of 14.62 ± 5.47 years (range: 5–22 years), were included in the study. Markers of renal function were determined in serum and in urine and patients were genotyped for Fok-I gene polymorphism. Genotype frequencies were similar to those previously reported for other populations: 47.06% of the patients were homozygous for the F allele, 41.18% were heterozygous, and 11.76% were homozygous for the f allele. A considerable number of patients demonstrated impaired renal function with increased serum cystatin C levels (29.41%), glomerular dysfunction with proteinuria (68%), as well as significant tubulopathy with hypercalciuria (73.08%), and increased levels of urinary β2-microglobulin (29.41%). When patients were stratified according to Fok-I polymorphism, a significantly higher prevalence of abnormally increased serum levels of cystatin C was observed in patients being homozygous for the f allele (75%) compared with those being heterozygous (Ff) or homozygous for the F allele (14.29% and 31.25%, respectively, P = .02). Further studies are needed to confirm these preliminary results and elucidate the possible mechanisms involved.

Comparative study of quantitative ultrasonography and dual-energy X-ray absorptiometry for evaluating renal osteodystrophy in children with chronic kidney disease

Our aim was to assess bone parameters in children with chronic kidney disease (CKD) with both dual-energy X-ray absorptiometry (DXA) and quantitative ultrasonography (QUS) and additionally with biochemical markers of bone turnover. Twenty children (12 boys and 8 girls) with CKD and a mean decimal age of 9.47±4.44years were included in the study where anthropometric parameters (height and weight), pubertal status, bone mineral density (BMD) at lumbar spine, speed of sound (SOS) measured by QUS at radius and at tibia, and biochemical markers of bone metabolism were measured. Six patients (30%) had tibial SOS Z score <-1, and 52.7% had radial SOS Z score <-1, whereas only 16.67% had BMD Z score <-1. Patients had significantly increased levels of serum intact parathormone (p<0.001), serum bone alkaline phosphatase (BAP) (p<0.001) and serum N-terminal-mid fragment (aminoacids 1-43) of osteocalcin (p<0.001) compared to controls, whereas serum osteoprotegerin was significantly decreased in patients compared to controls (p=0.001). SOS was significantly correlated to BAP (r=-0.586, p=0.013 and r=-0.709, p=0.001, respectively, for radius and tibia). In conclusion no association between DXA and QUS measurements was documented in our study, whereas QUS was better correlated to biochemical indices of ROD.

Comparative study of dual energy X‐ray absorptiometry and quantitative ultrasonography with the use of biochemical markers of bone turnover in boys with haemophilia

Our aim was to evaluate bone status in boys with haemophilia using dual energy X-ray absorptiometry (DXA) and quantitative ultraSonography (QUS), and in addition, to compare these two methods with the use of biochemical markers of bone turnover. Twenty-six boys with a mean decimal age of 12.08 ± 4.44 years were included in the study which included a DXA scan at lumbar spine and radial, as well as tibial QUS. Serum levels of soluble receptor activator of nuclear factor κB ligand (sRANK-L), osteoprotegerin (OPG) and osteocalcin (OC) were measured and joint evaluation was performed using the Hemophilia Joint Health Score (HJHS). With regard to the study results, only 2 of 26 patients (7.7%) had bone mineral density (BMD) Z-scores < -2, and 4 patients (15.4%) had BMD Z-scores between -1 and -2. Only one patient had radial and other two had tibial QUS Z-scores < -2. No agreement was recorded between QUS and DXA in identifying patients at risk for osteoporosis (k = 0.275, P = 0.063). Haemophiliacs had significantly higher serum levels of sRANK-L (21.04 ± 4.78 vs. 18.58 ± 2.28 ng mL(-1), P = 0.038) and of OC (5.35 ± 2.29 vs. 3.09 ± 0.61 ng mL(-1), P = 0.002) and significantly decreased levels of OPG (15.78 ± 2.53 vs. 23.79 ± 4.39 pg mL(-1), P < 0.001) compared with controls. QUS Z-scores at tibia significantly correlated with HJH Scores (r = -0.450, P = 0.040), whereas lumbar BMD Z-scores significantly correlated with body mass index Z-scores (r = 0.500, P = 0.009). More studies are warranted to identify the most accurate densitometric method for assessing bone status in haemophiliacs.

Reference Values for Quantitative Ultrasonography (QUS) of Radius and Tibia in Healthy Greek Pediatric Population: Clinical Correlations

The aim of this study was to provide reference standards for measurements of quantitative ultrasonography (QUS) of radius and tibia in normative Greek pediatric population. Analysis was performed in 1549 healthy subjects (814 girls and 735 boys) with a mean decimal age of 11.41 ± 3.52 yr (range: 3.78–18.33 yr). Results showed a gradual increase of absolute values of radial and tibial speed of sound (SOS), with aging and with pubertal progressing, in both girls and boys. Gender comparison showed significantly increased SOS values measured both at radius and at tibia in girls more than 13 yr of age compared with aged-matched boys. Significant but mild correlation was noted between standard deviation scores (SDS) of SOS at radius and at tibia ( r = 0.259, p < 0.001). Additionally, tibial SOS SDS were significantly negatively correlated with body mass index (BMI) SDS ( r = −0.230, p < 0.001). Finally, subjects that spend more than 3 h of daily “screen time” (television and personal computer) showed significantly decreased SOS values measured both at radius and at tibia. On the contrary, no correlation was observed between SOS values and the amount of physical activity reported.

Underweight and overweight among children and adolescents in Tuscany (Italy). Prevalence and short-term trends.

The recent increase in both childhood obesity and adolescent anorexia nervosa in developed countries has underlined the important consequences that these trends may have on public health, as there is an increased risk that these conditions may become chronic diseases in adulthood. Therefore, it is necessary to monitor prevalence rates and trends in thinness and overweight (including obesity) among children and adolescents at different levels: international, national and sub-national. Since 2001/2002, a nutritional surveillance system has been implemented in the Tuscany Region to estimate the nutritional status and lifestyles of children and adolescents. The main objectives were to assess the prevalence of thinness, overweight and obesity among Tuscan children and adolescents and to provide baseline information on the prevalence of thinness, for the first time calculated according to the new international definitions, for geographical comparisons and descriptions of time trends. Independent cross-sectional sample surveys were conducted in 2002, 2004 and 2006 in Tuscany, North-Central Italy. Data were collected from stratified two-stage cluster samples of children aged 9 years (n = 3,048 in 2002 and n = 1,430 in 2006) and of adolescents aged 11-13-15 years (n = 1,066, n = 1185 and n = 1,160 in 2004 and n = 1,189, n = 1,211 and n = 1,178 in 2006, respectively). Weights and heights of primary school children were measured by means of standardized methods, while those of adolescents were self-reported. Decimal age was calculated from the date of birth to the date of measurement. Body Mass Index classes were calculated according to the International Obesity Task Force standards. Instead of the term underweight in children, we used the term thinness, which the World Health Organization uses to mean low Body Mass Index for age in adults and adolescents. According to Cole's recently published cut-offs for thinness, we divided our Body Mass Index values below 18.5 into three grades. This study presents data on the prevalence of different grades of nutritional status (thinness, normal weight, overweight and obesity) among Tuscan school-aged children from primary to high school (9-11-13-15-y-old), assessed by means of Body Mass Index, according to international definitions. From 2002 to 2006 the prevalence of thinness among children aged 9 years decreased from 4.6% to 4.2%, and the prevalence of normal weight from 63.7% to 62.4%; the prevalence of overweight (including obesity) rose from 31.7% to 33.4%. From 2004 to 2006, among pre-adolescents aged 11 years, the prevalence of thinness declined from 11.0% to 10.1%; the prevalence of normal weight rose from 68.4% to 70.2%, and the prevalence of overweight declined from 20.7% to 19.6%. Among adolescents aged 13 years, the prevalence of thinness declined from 9.8% to 8.0%; the prevalence of normal weight rose from 73.5% to 74.0%, and the prevalence of overweight from 16.8% to 17.9%. Among adolescents aged 15 years, the prevalence of thinness declined from 9.8% to 8.7%, and the prevalence of normal weight from 77.0% to 71.6%, while the prevalence of overweight rose from 13.3% to 19.7%. The 2006 data showed that the trend in the prevalence of overweight (including obesity) tended to decrease with age for both sexes, though more markedly in girls (from 34.0% at 9-y of age to 12.2% at 15-y of age) than in boys (from 32.8% at 9-y of age to 22.8% at 13-y of age to 27.5% at 15-y of age). By contrast, the prevalence of thinness increased with age in girls (from 4.9% at 9-y of age to 14,1% at 15-y of age), while boys presented a similar low prevalence at 9 and 15-y of age (3.3% and 3.1%), doubling the values at 11 and 13-y of age (7.5% and 6.5%). The trend in the prevalence of normal weight increased with age from 62.4% at 9-y of age to 74.0% at 13-y of age and to 71.6% at 15-y of age. Boys displayed a higher prevalence than girls only at 9-y of age (63.9% vs. 61.0%). The results of this study allow us to analyze data from the nutritional surveillance system in Tuscany using recent definitions of Body Mass Index cut-off points among children, pre-adolescents and adolescents. As a rule, the trend in the prevalence of overweight (including obesity) among girls from 9-y to 15-y-old strongly decreased, while the prevalence of thinness increased. In boys, this decrease was less marked and the prevalence of thinness displayed an irregular trend, with an increment from 9-y to 11-y-old and a decrease from 13-y to 15-y old. The trend in the prevalence of normal weight increased with age, with a higher prevalence among boys than girls.