Bibliografia sobre puberdade

Puberty and body composition.

Siervogel RM, Demerath EW, Schubert C, Remsberg KE, Chumlea WC, Sun S, Czerwinski SA, Towne B.

Department of Community Health, Wright State University School of Medicine, Dayton, OH 45420, USA. roger.siervogel@wright.edu

Body composition during puberty is a marker of metabolic changes that occur during this period of growth and maturation, and, thus, holds key information regarding current and future health. During puberty, the main components of body composition (total body fat, lean body mass, bone mineral content) all increase, but considerable sexual dimorphism exists. Methods for measuring body composition (e.g. densitometry and dual-energy X-ray absorptiometry) and degree of maturity will be discussed in this review. Components of body composition show age-to-age correlations (i.e. 'tracking'), especially from adolescence onwards. Furthermore, adipose tissue is endocrinologically active and is centrally involved in the interaction between adipocytokines, insulin and sex-steroid hormones, and thus influences cardiovascular and metabolic disease processes. In conclusion, pubertal body composition is important, not only for the assessment of contemporaneous nutritional status, but also for being linked directly to the possible onset of chronic disease later in life and is, therefore, useful for disease risk assessment and intervention early in life. Copyright 2003 S. Karger AG, Basel

Publication Types:

• Research Support, U.S. Gov't, P.H.S.
• Review

PMID: 12955016 [PubMed - indexed for MEDLINE]

 

2: Am J Clin Nutr. 2004 Oct;80(4):966-72.

Related Articles, Links

Relation between hormones and body composition, including bone, in prepubertal children.

Garnett SP, Högler W, Blades B, Baur LA, Peat J, Lee J, Cowell CT.

Institute of Endocrinology and Diabetes and the Research and Development Office, The Children's Hospital at Westmead, Westmead, Australia. sarahg@chw.edu.au

BACKGROUND: Sex differences in body composition exist before puberty, but the reason for this phenomenon is unknown. The physical changes that occur during puberty are mediated, in part, through sex steroids, insulin-like growth factor I (IGF-I), and leptin. However, data are lacking that address the extent to which concentrations of these hormones influence body composition, bone mass, and density in prepubertal children. OBJECTIVE: We investigated the effects of IGF-I, dehydroepiandrosterone sulfate, and sex steroids on body composition and fat distribution and the effects of these hormones and leptin on total body bone mineral content (TBMC) and volumetric bone mineral density (vBMD) at the femoral neck and lumbar spine (LS) in 255 healthy children (137 girls), aged 7-8 y. DESIGN: Body composition, fat distribution, TBMC, and vBMD were derived by using dual-energy X-ray absorptiometry. Association between variables was examined by using regression analysis. RESULTS: No sex differences were found in age, height, or weight. However, girls had significantly more total body fat, trunk fat, and higher LS vBMD but significantly less fat-free soft tissue, TBMC, and femoral neck vBMD than did boys. Girls also had significantly (P < 0.001) higher IGF-I, estradiol, testosterone, and leptin concentrations than did boys. Estradiol concentrations predicted percentage body fat, which supported an effect of estrogen on fat storage. Leptin had an independent effect on LS vBMD, which suggests a positive effect for leptin on trabecular bone. CONCLUSIONS: The hormones examined explained 3-17% of the variations in body-composition measures, fat distribution, and bone density, which suggests that other factors are important predictors of prepubertal sexual dimorphism.

Publication Types:

• Research Support, Non-U.S. Gov't

PMID: 15447907 [PubMed - indexed for MEDLINE]

 

3: Best Pract Res Clin Endocrinol Metab. 2007 Sep;21(3):415-30.

Related Articles, Links

Sexual dimorphism of body composition.

Wells JC.

Pediatric Nutrition Childhood Nutrition Research Centre, Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK. j.wells@ich.ucl.ac.uk

Sexual dimorphism in human body composition is evident from fetal life, but emerges primarily during puberty. At birth, males have a similar fat mass to females but are longer and have greater lean mass. Such differences remain detectable during childhood; however, females enter puberty earlier and undergo a more rapid pubertal transition, whereas boys have a substantially longer growth period. After adjusting for dimorphism in size (height), adult males have greater total lean mass and mineral mass, and a lower fat mass than females. These whole-body differences are complemented by major differences in tissue distribution. Adult males have greater arm muscle mass, larger and stronger bones, and reduced limb fat, but a similar degree of central abdominal fat. Females have a more peripheral distribution of fat in early adulthood; however, greater parity and the menopause both induce a more android fat distribution with increasing age. Sex differences in body composition are primarily attributable to the action of sex steroid hormones, which drive the dimorphisms during pubertal development. Oestrogen is important not only in body fat distribution but also in the female pattern of bone development that predisposes to a greater female risk of osteoporosis in old age. Disorders of sex development are associated with significant abnormalities of body composition, attributable largely to their impact on mechanisms of hormonal regulation.

Publication Types:

• Review

PMID: 17875489 [PubMed - indexed for MEDLINE]

 

4: Horm Res. 1993;39 Suppl 3:25-40.

Related Articles, Links

Body composition during adolescence: methods, limitations and determinants.

Rolland-Cachera MF.

INSERM, ISTNA, CNAM, Paris, France.

To some extent body composition reflects nutritional status. It is also influenced by age, sex, race, physical activity and disease. The method used to measure body composition depends on the variable to be quantified. It may also depend on the practical conditions of the study. Detailed methods, such as densitometry, isotope dilution and electrical impedance give more accurate information, but they are commonly based on hypotheses established in adults. Anthropometric measurements can be used directly or as ratio or regression equations. At adolescence, the weight/height or body mass index (BMI) is preferred to weight for height as age is taken into account. In addition, the BMI pattern reflects real changes in body shape, and early in life it is an indicator of later development. In addition to measuring weight and height skinfold (SF) measurements should be carried out. The triceps SF is usually recommended and widely used as it is better than the subscapular SF to predict percent body fat. Trunk SFs, such as the subscapular, are better than extremity SF for their association with internal fat and their good correlations with risk factors and response to nutritional interventions. Chemical changes in the body are observed during growth. Chemical maturity does not occur until after puberty, but most changes occur early in life. Tracking is the maintenance of an individual in the same percentile range across age and varies according to the growth parameter and to the period of growth. Low tracking of fatness (up to the age of 8 years) corresponds to the period of rapid chemical changes. Low tracking of stature is observed at adolescence when height velocity is high. Nutrition affects fatness and stature, but the consequences of under- and over-nutrition differ between early childhood and adolescence. BMI curves show that most changes have their origin during the first years of life.

Publication Types:

• Review

PMID: 8262489 [PubMed - indexed for MEDLINE]

 

5: Pediatrics. 2004 Dec;114(6):1574-83.

Related Articles, Links

Effects of anorexia nervosa on clinical, hematologic, biochemical, and bone density parameters in community-dwelling adolescent girls.

Misra M, Aggarwal A, Miller KK, Almazan C, Worley M, Soyka LA, Herzog DB, Klibanski A.

Neuroendocrine Unit, and Harvard Medical School, Boston, Massachusetts 02114, USA.

OBJECTIVE: Anorexia nervosa (AN) is an eating disorder that leads to a number of medical sequelae in adult women and has a mortality rate of 5.6% per decade; known complications include effects on hematologic, biochemical, bone density, and body composition parameters. Few data regarding medical and developmental consequences of AN are available for adolescents, in particular for an outpatient community-dwelling population of girls who have this disorder. The prevalence of AN is increasing in adolescents, and it is the third most common chronic disease in adolescent girls. Therefore, it is important to determine the medical effects of this disorder in this young population. METHODS: We examined clinical characteristics and performed hematologic, biochemical, hormonal, and bone density evaluations in 60 adolescent girls with AN (mean age: 15.8 +/- 1.6 years) and 58 healthy adolescent girls (mean age: 15.2 +/- 1.8 years) of comparable maturity. Nutritional and pubertal status; vital signs; a complete blood count; potassium levels; hormonal profiles; bone density at the lumbar and lateral spine; total body, hip, and femoral neck (by dual-energy x-ray absorptiometry) and body composition (by dual-energy x-ray absorptiometry) were determined. RESULTS: All measures of nutritional status such as weight, percentage of ideal body weight, body mass index, lean body mass, fat mass, and percentage of fat mass were significantly lower in girls with AN than in control subjects. Girls with AN had significantly lower heart rates, lower systolic blood pressure, and lower body temperature compared with control subjects. Total red cell and white cell counts were lower in AN than in control subjects. Among girls with AN, 22% were anemic and 22% were leukopenic. None were hypokalemic. Mean age at menarche did not differ between the groups. However, the proportion of girls who had AN and were premenarchal was significantly higher compared with healthy control subjects who were premenarchal, despite comparable maturity as determined by bone age. Ninety-four percent of premenarchal girls with AN versus 28% of premenarchal control subjects were above the mean age at menarche for white girls, and 35% of premenarchal AN girls versus 0% of healthy adolescents were delayed >2 SD above the mean. The ratio of bone age to chronological age, a measure of delayed maturity, was significantly lower in girls with AN versus control subjects and correlated positively with duration of illness and markers of nutritional status. Serum estradiol values were lower in girls with AN than in control subjects, and luteinizing hormone values trended lower in AN. Levels of insulin-like growth factor-I were also significantly lower in girls with AN. Estradiol values correlated positively with insulin-like growth factor-I, a measure of nutritional status essential for growth (r = 0.28). All measures of bone mineral density (z scores) were lower in girls with AN than in control subjects, with lean body mass, body mass index, and age at menarche emerging as the most important predictors of bone density. Bone density z scores of <-1 at any one site were noted in 41% of girls with AN, and an additional 11% had bone density z scores of <-2. CONCLUSIONS: A high prevalence of hemodynamic, hematologic, endocrine, and bone density abnormalities are reported in this large group of community-dwelling adolescent girls with AN. Although a number of these consequences of AN are known to occur in hospitalized adolescents, the occurrence of these findings, including significant bradycardia, low blood pressure, and pubertal delay, in girls who are treated for AN on an outpatient basis is of concern and suggests the need for vigilant clinical monitoring, including that of endocrine and bone density parameters.

Publication Types:

• Research Support, U.S. Gov't, P.H.S.

PMID: 15574617 [PubMed - indexed for MEDLINE]

 

6: J Clin Endocrinol Metab. 2006 Jul;91(7):2534-41. Epub 2006 Apr 18.

Related Articles, Links

Adipose tissue stimulates bone growth in prepubertal children.

Clark EM, Ness AR, Tobias JH.

Rheumatology Unit, Bristol Royal Infirmary, Bristol BS2 8HW, United Kingdom.

CONTEXT: Fat mass represents a positive influence on bone mass in adults, independently of other factors such as lean mass, but whether a similar action occurs in children is unclear. OBJECTIVE: Our objective was to examine the relationship between fat mass and bone mass in children. DESIGN AND SETTING: We conducted combined cross-sectional and prospective analyses at university research clinics. PARTICIPANTS: Participants included children aged 9.9 yr from a large population-based birth cohort in southwest England. OUTCOMES: Relationships between total body fat mass were measured by dual-energy x-ray absorptiometry at age 9.9 yr, and 1) total-body-less-head bone mass and area at age 9.9 and 2) increase in bone mass and area over the following 2 yr. RESULTS: There was a strong positive relationship between total body fat mass and total-body-less-head bone mass and area, even after adjustment for height and/or lean mass (P < 0.001). There was a similar positive association between total body fat mass and increase in bone mass and area over the following 2 yr in boys and Tanner stage 1 girls. In contrast, no association was present between fat mass and gain in bone mass and size in Tanner stage 2 girls, whereas a negative association was seen in Tanner stage 3 girls (puberty-fat mass interaction, P < 0.001). CONCLUSIONS: In prepubertal children, fat mass is a positive independent determinant of bone mass and size and of increases in these parameters over the following 2 yr, suggesting that adipose tissue acts to stimulate bone growth. However, this relationship is attenuated by puberty.

Publication Types:

• Research Support, Non-U.S. Gov't

PMID: 16621904 [PubMed - indexed for MEDLINE]

 

7: Endocr Rev. 2005 Feb;26(1):114-46.

Related Articles, Links

Endocrine control of body composition in infancy, childhood, and puberty.

Veldhuis JD, Roemmich JN, Richmond EJ, Rogol AD, Lovejoy JC, Sheffield-Moore M, Mauras N, Bowers CY.

Division of Endocrinology and Metabolism, Department of Internal Medicine, Mayo Medical and Graduate Schools of Medicine, General Clinical Research Center, Mayo Clinic, Rochester, Minnesota 55905, USA. veldhuis.johannes@mayo.edu

Body composition exhibits marked variations across the early human lifetime. The precise physiological mechanisms that drive such developmental adaptations are difficult to establish. This clinical challenge reflects an array of potentially confounding factors, such as marked intersubject differences in tissue compartments; the incremental nature of longitudinal intrasubject variations in body composition; technical limitations in quantitating the unobserved mass of mineral, fat, water, and muscle ad seriatim; and the multifold contributions of genetic, dietary, environmental, hormonal, nutritional, and behavioral signals to physical and sexual maturation. From an endocrine perspective (reviewed here), gonadal sex steroids and GH/IGF-I constitute prime determinants of evolving body composition. The present critical review examines hormonal regulation of body composition in infancy, childhood, and puberty.

Publication Types:

• Research Support, U.S. Gov't, P.H.S.
• Review

PMID: 15689575 [PubMed - indexed for MEDLINE]

 

8: J Bone Miner Metab. 2005;23(6):476-82.

Related Articles, Links

Bone mineral density in girls and boys at different pubertal stages: relation with gonadal steroids, bone formation markers, and growth parameters.

Yilmaz D, Ersoy B, Bilgin E, Gümüşer G, Onur E, Pinar ED.

Department of Pediatrics, School of Medicine, Celal Bayar University, Manisa, Turkey.

Puberty has a key role in bone development. During puberty, several nutritional and hormonal factors play a major role in this process. The aim of this study was to determine the changes in areal bone mineral density (BMD), gonadal steroids, bone formation markers, and growth parameters in healthy Turkish pubertal girls and boys at different pubertal stages. In additional, we aimed to detect the relationship between BMD, sex steroids, and growth parameters, and to reveal the most important determinant of BMD in the pubertal period. BMD of the lumbar spine and total body was performed by dual-energy X-ray absorptiometry (Lunar DPX series) in 174 healthy pubertal children (91 girls, 83 boys), aged 11-15 years. Height and weight were measured. Pubertal stages were assesed. Bone formation markers and gonadal steroids were measured. BMD values significantly increased until stage IV in girls. In boys, BMD values also increased during puberty (P < 0.05), but it was significantly higher in stage IV compared with that in other pubertal stages (P < 0.01). Testosterone levels increased until stage IV in both sexes, particularly in boys. Estrogen levels significantly increased during puberty in girls, whereas it was significantly higher at stage IV in boys (P < 0.001). Bone-specific alkaline phosphatase (BAP) level was higher in early and midpuberty, and decreased in late puberty in girls (P < 0.001). BAP level was higher in stage IV in boys. Osteocalcin level was shown not to change significantly in pubertal stages. There was a modest correlation between BMD values and estrogen and testosterone levels in boys. In girls, there was a correlation between BMD values and estrogen levels only (P < 0.05). Weight was significantly associated with BMD in both sexes (P < 0.05). Estrogen had a significant influence on BMD in boys and girls. In conclusion, bone mass increased throughout puberty in both sexes. Peak bone mass was not achieved in girls, but was obtained at stage IV in boys. Bone formation markers were good predictors of bone mass in girls, but not in boys. Estrogen level made the greatest contribution to bone mineral acquisition in boys and girls. The achievement of peak bone mass was sustained by estrogen in boys. The major independent determinant of BMD in both sexes was weight.

PMID: 16261455 [PubMed - indexed for MEDLINE]

 

9: Ann Hum Biol. 2004 Jan-Feb;31(1):75-86.

Related Articles, Links

Pubertal development and sedentary behaviour during adolescence.

Murdey ID, Cameron N, Biddle SJ, Marshall SJ, Gorely T.

Department of Human Sciences, Loughborough University, Leicestershire, UK. I.D.Murdey@lboro.ac.uk

BACKGROUND: Assessing time spent in sedentary behaviours in relation to pubertal status, anthropometric differences, and body image will improve insight into the prevalence and determinants of such behaviours during adolescence. AIM: The study aimed to investigate the effects of age, puberty, gender, body composition, and sleep on sedentary behaviour. PARTICIPANTS AND METHODS: Participants were 64 boys and 55 girls in Year 6 (10.0-10.9 years of age), Year 8 (12.0-12.9 years) and Year 10 (14.0-14.9 years). Body mass index and percentage body fat were calculated from anthropometric measures. Sedentary behaviour and sleep time were computed using momentary-time sampling. Body image was measured using the Children's Physical Self-Perception Profile. Pubertal status was assessed from self-report of secondary sexual characteristics. RESULTS: After controlling for sleep time, no differences in sedentary time were seen for puberty onset or increased pubertal development. Correlations between pubertal status, body composition, and body image were stronger in girls than in boys. Correlations between body image and sedentary behaviour were not strong enough to infer behavioural choice differences. CONCLUSIONS: Reduced sleep time rather than changing body image and body composition during adolescence is associated with greater sedentary behaviour.

Publication Types:

• Research Support, Non-U.S. Gov't

PMID: 14742166 [PubMed - indexed for MEDLINE]

 

10: J Clin Endocrinol Metab. 2004 Dec;89(12):6185-92.

Related Articles, Links

Divergent effect of endogenous and exogenous sex steroids on the insulin-like growth factor I response to growth hormone in short normal adolescents.

Coutant R, de Casson FB, Rouleau S, Douay O, Mathieu E, Gatelais F, Bouhours-Nouet N, Voinot C, Audran M, Limal JM.

Department of Pediatrics, University Hospital, 49000 Angers, France. recoutant@chu-angers.fr

The lower responsiveness to GH in women than in men is probably due to a divergent effect of gonadal steroids. It is unknown, however, how the progressive increase in sex steroid production that occurs during puberty affects this responsiveness. To compare the effects of puberty and sex steroid administration on responsiveness to GH, we used the IGF-I generation test, in which the peak IGF-I level 24 h after a single injection of GH (2 mg/m2) was studied in 117 healthy short subjects (56 females and 61 males). The subjects, aged 8-16 yr, were divided into four groups: prepuberty, early puberty, midpuberty, or pubertal delay. In the latter group, the IGF-I response was determined before and after priming with oral 17beta-estradiol in girls and im testosterone in boys. We also tested for an association between body composition (by dual energy x-ray absorptiometry) and the IGF-I response to GH. The IGF-I increment in response to GH (change in IGF-I from baseline) was correlated with the growth velocity sd score (P < 0.05). Progression throughout puberty was associated with an increase in both baseline IGF-I (P < 0.05) and the IGF-I increment in response to GH (P < 0.05), with no gender difference. Pubertal category (pre-, early, and midpuberty; P < 0.05) and fat percentage (P < 0.05) were the main positive predictors of the IGF-I increment in response to GH, expressed as micrograms per liter as well as sd score, independently of baseline IGF-I. After sex steroid priming, both the GH peak in response to insulin-induced hypoglycemia and baseline IGF-I were increased (P < 0.05, after vs. before sex steroid). However, the IGF-I increment in response to GH decreased after oral 17beta-estradiol (P < 0.05), whereas it was unchanged after testosterone administration. Endogenous gonadal steroid secretion appears to result in increased responsiveness to GH in peripubertal girls and boys. By contrast, exogenous estrogen and testosterone, respectively, produce a relative decrease and no change in responsiveness to GH in similar populations, possibly through the achievement of sex steroid concentrations exceeding physiological ranges for age. Fat percentage was a positive determinant of the responsiveness to GH, suggesting a link between the energy stores and the anabolic action of GH.

Publication Types:

• Research Support, Non-U.S. Gov't

PMID: 15579776 [PubMed - indexed for MEDLINE]

 

11: J Nutr. 2006 Mar;136(3):648-55.

Related Articles, Links

Malnourished children treated in day-hospital or outpatient clinics exhibit linear catch-up and normal body composition.

das Neves J, Martins PA, Sesso R, Sawaya AL.

Department of Medicine, Discipline of Nephrology, Federal University of São Paulo, Brazil.

The nutritional programming hypothesis proposes that early life malnutrition is related to an increase in body fat later in life. Brazilian boys and girls (n = 94; 4-14 y old) were studied. Malnourished children treated in a Nutrition Recovery Center, were followed up and divided into 2 groups: the Outpatient group (recovered after outpatient care, n = 28), and the Day-hospital group (recovered after day-hospital care, n = 38). They were compared with a Control group (healthy individuals without intervention, n = 28). Nutritional recovery was confirmed by anthropometry. Body composition was evaluated by dual-energy X-ray absorptiometry. Both recovered groups had a greater increase in height-for-age Z-scores than in weight-for-age Z-scores after treatment (P < 0.03). Body fat mass (kg) and the percentage of body fat were significantly lower in recovered groups of girls and boys compared with controls. Among boys, lean mass/height (kg/cm), fat-free mass (kg) and the fat-free mass index (kg/m(2)) were significantly lower in the Outpatient and Day-hospital groups than in Controls, but girls did not differ. Bone mineral content (BMC)/height (g/cm) did not differ between the recovered girls and the girls in the Control group (P < 0.15) or between the boys in the Day-hospital group and those in the Control group (P = 0.06). The Outpatient boys group had lower BMC/height than boys in the Control group (P = 0.02). This study demonstrates that when malnourished children receive adequate treatment, linear catch-up growth occurs and is followed by appropriate gain in lean body mass and BMC.

Publication Types:

• Research Support, Non-U.S. Gov't

PMID: 16484538 [PubMed - indexed for MEDLINE]

 

12: Am J Clin Nutr. 2004 Aug;80(2):514-23.

Related Articles, Links

Obesity during childhood and adolescence augments bone mass and bone dimensions.

Leonard MB, Shults J, Wilson BA, Tershakovec AM, Zemel BS.

Department of Pediatrics, The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, 34th Street and Civic Center Boulevard, Philadelphia. PA 19104, USA. leonard@email.chop.edu

BACKGROUND: Studies of the effect of childhood obesity on bone accrual during growth have yielded conflicting results, largely related to the failure to adequately characterize the confounding effects of growth, maturation, and body composition. OBJECTIVE: The objective of this study was to determine the effect of childhood obesity on skeletal mass and dimensions relative to height, body composition, and maturation in males and females. DESIGN: In 132 nonobese (body mass index < 85th percentile) and 103 obese (body mass index > or = 95th percentile) subjects aged 4-20 y, whole-body and vertebral bone mineral content (BMC) was determined by using dual-energy X-ray absorptiometry, and bone area, areal bone mineral density (BMD), and fat and lean masses were measured. Vertebral volumetric BMD was estimated as BMC/area(1.5). RESULTS: Obesity was associated with greater height-for-age, advanced maturation for age, and greater lean mass for height (all P < 0.001). Sex-specific multivariate regressions with adjustment for maturation showed that obesity was associated with greater vertebral areal BMD for height, greater volumetric BMD, and greater vertebral BMC for bone area (all P < 0.05). After adjustment for maturation and lean mass, obesity was associated with significantly greater whole-body bone area and BMC for age and for height (all P < 0.001). CONCLUSIONS: In contrast with the results of prior studies, obesity during childhood and adolescence was associated with increased vertebral bone density and increased whole-body bone dimensions and mass. These differences persisted after adjustment for obesity-related increases in height, maturation, and lean mass. Future studies are needed to determine the effect of these differences on fracture risk.

Publication Types:

• Research Support, Non-U.S. Gov't
• Research Support, U.S. Gov't, P.H.S.

PMID: 15277178 [PubMed - indexed for MEDLINE]

 

13: BMC Public Health. 2006 Jun 6;6:147.

Related Articles, Links

A school-based physical activity program to improve health and fitness in children aged 6-13 years ("Kinder-Sportstudie KISS"): study design of a randomized controlled trial [ISRCTN15360785].

Zahner L, Puder JJ, Roth R, Schmid M, Guldimann R, Pühse U, Knöpfli M, Braun-Fahrländer C, Marti B, Kriemler S.

Institute of Exercise and Health Sciences, University of Basel, Brüglingen 33, 4052 Basel, Switzerland. lukas.zahner@unibas.ch

BACKGROUND: Childhood obesity is the result of a long lasting imbalance between energy intake and energy expenditure. A major contributing factor is physical inactivity which is closely linked to bone health, cardiovascular disease risk, fitness and psychological factors. The school seems to provide an excellent setting to enhance levels of physical activity (PA). However, there is insufficient data from previous school-based intervention trials on how to enhance overall PA. It is also unknown whether an intervention aimed at increasing PA is effective in improving the children's health. The purpose of this paper is to outline the design of a school-based randomized, controlled trial (RCT) aiming to increase overall PA and to improve fitness and health in 6- to 13-year-old children. METHODS/DESIGN: 15 schools were randomized to the intervention (n = 9) or the control (n = 6) group, stratified by geographic region (urban vs. rural) and by age (1st and 5th grade). Participation was given for all children in the intervention group since in this group the intervention was part of the normal school curriculum. The intervention during one academic year consisted of: 1. two additional physical education classes per week given by trained physical education teachers adding up to a total of five PA classes per week, 2. short PA breaks (2-5 min each) during academic lessons, 3. PA home work, and 4. adaptation of recreational areas around the school. All children underwent anthropometric measurements, blood pressure assessment, fitness testing, measurement of PA and they filled out questionnaires. At least 70% of all children agreed to blood sampling and measurements of body composition and bone mineral measurements by dual energy x-ray absorptiometry. The primary endpoints of the study after one year were an increase in total PA by accelerometry, an increase in aerobic fitness measured by the 20 m shuttle run, a decrease in percent body fat derived from skinfold measurements and an increase in quality of life as assessed by the child health questionnaire in the intervention group compared to the control group. Secondary outcomes were overall fitness, differences in body composition including body fat distribution, cardiovascular risk factors, psychosocial health, bone mineral content and density of femur, lumbar spine and total body and food intake. DISCUSSION: Our preliminary data suggest that the children were representative of Swiss children with respect to sex, socio-demographic status, and body mass index. Short-term results can be expected by the beginning of 2007. We hypothesized that our intervention will lead to an increase in PA, fitness and overall health. Based on our data, we aim to provide important information regarding the influence of such an intervention on these outcome measures in school-aged children and to provide nationwide guidelines to improve PA in children.

Publication Types:

• Research Support, Non-U.S. Gov't

PMID: 16756652 [PubMed - indexed for MEDLINE]

PMCID: PMC1513202

Short-term changes in sedentary behaviour during adolescence: Project STIL (Sedentary Teenagers and Inactive Lifestyles).

Murdey ID, Cameron N, Biddle SJ, Marshall SJ, Gorely T.

Department of Human Sciences, Loughborough University, UK. I.D.Murdey@lboro.ac.uk

HYPOTHESIS: Changes in body composition and body image during puberty will impact on sedentary behavioural choices. AIM: The study aimed to investigate the effects of changes in pubertal status, body composition and body image on changes in time spent being sedentary. PARTICIPANTS AND METHODS: Eighty-three school students aged 10-15 years were studied at 6-month intervals. BMI and percentage body fat (%BF) were calculated from anthropometric measures. Sedentary behaviour and sleep time were computed for weekday and weekend days using momentary-time-sampling diaries. Body image was measured using the Physical Self-Perception Profile for Children. Pubertal status was assessed from self-reported secondary sexual characteristics. RESULTS: During weekdays, boys' sedentary behaviour increased by a significantly greater amount for those who increased pubertal level compared with those who did not. No significant correlations were found between changing pubertal status, body composition, and body image for either gender. For girls, but not boys, a significant amount of the variance of the change in weekend day sedentary behaviour was explained by changing %BF, independent of changing pubertal status. CONCLUSION: Only a part of the hypothesis was supported by these data. Changes in sedentary behaviour were not associated with behavioural choices triggered by body compositional changes.

Publication Types:

• Research Support, Non-U.S. Gov't

PMID: 16099774 [PubMed - indexed for MEDLINE]

 

2: Eur J Nutr. 2000 Aug;39(4):157-63.

Related Articles, Links

Longitudinal changes in body composition, physical capacities and energy expenditure in boys and girls during the onset of puberty.

Bitar A, Vernet J, Coudert J, Vermorel M.

Animal Physiology Laboratory, Faculty of Sciences, Chouaib Doukkali University, El Jadida, Morocco.

BACKGROUND: The onset of puberty is a period of rapid anatomical and physiological alterations expected to induce changes in metabolic rate and energy requirements of children. AIM OF THE STUDY: To evaluate the changes in anthropometrical features, body composition, physical capacities, and energy expenditure (EE) of boys and girls during the period of onset of puberty. METHODS: Sixteen children (8 boys and 8 girls were recruited in the same school-class and studied both at 10.4 and 12.8 years of age. Body composition was assessed by bioimpedance analysis. Peak oxygen uptake (peak VO2) was measured using an automated on-line system during exercising on a cycle ergometer. Energy expenditure (EE) was determined by whole-body indirect calorimetry over a 24-h period after a 12-h period of adaptation to the calorimeters. Volunteers followed the same activity programme that included four 15-min periods of exercise. RESULTS: During the onset of puberty, boys and girls gained 4.7 +/- 2.1 kg x y(-1) (P < 0.0003) fat-free mass (FFM), whereas fat mass gain was 1.0 +/- 1.2 kg x y(-1) (P < 0.05) in girls and 0.20 +/- 0.66 kg x y(-1) in boys (NS). Peak VO2 adjusted for differences in FFM was not significantly affected by gender or pubertal stage. However, adjusted external mechanical power performed at peak VO2 was higher in pubertal than in prepubertal children, by 40% (P < 0.0001) and 22% (P < 0.003) in boys and girls, respectively. It was also 17% (P < 0.0002) higher in pubertal boys than in pubertal girls. Daily and sleeping EE increased by 38% and 32% in boys and girls, respectively, during the 2.4-y period (P< 0.0001). Adjusted EEs were also significantly higher in pubertal than in prepubertal boys (P< 0.05 and P< 0.003), but not in girls. The main significant determinants of daily EE were FFM (r2 = 0.866, P < 0.0001), peak VO2 (r2 = 0.017, P < 0.04), and age (r2 = 0.014, P < 0.05). Tanner's stage was an additional determinant of sleeping EE (r2 = 0.025, P < 0.006). CONCLUSIONS: The increases in physical capacities and EE during the onset of puberty indicated clear gender differences, which could be explained mainly by alterations of body composition in boys and girls, and by changes in hormonal status in boys. They also stressed the significant increase in energy requirements of children, especially boys, at an early stage of puberty.

Publication Types:

• Research Support, Non-U.S. Gov't

PMID: 11079735 [PubMed - indexed for MEDLINE]

 

3: Br J Sports Med. 2007 Mar;41(3):140-4. Epub 2006 Dec 18.

Related Articles, Links

Trends in physical activity and sedentary behaviour in adolescence: ethnic and socioeconomic differences.

Brodersen NH, Steptoe A, Boniface DR, Wardle J.

Cancer Research UK Health Behaviour Unit, Department of Epidemiology and Public Health, University College London, London WC1E 6BT, UK.

OBJECTIVE: To assess developmental trends in physical activity and sedentary behaviour in British adolescents in relation to sex, ethnicity and socioeconomic status (SES). DESIGN: A 5-year longitudinal study of a diverse cohort of students aged 11-12 years at baseline in 1999. SETTING: 36 London schools sampled using a stratified random sampling procedure. PARTICIPANTS: A total of 5863 students categorised as white, black or Asian, and stratified for SES using the Townsend Index. MAIN OUTCOME MEASURES: Number of days per week of vigorous activity leading to sweating and breathing hard. Hours of sedentary behaviour, including watching television and playing video games. Data were analysed using multilevel, linear, mixed models. RESULTS: Marked reductions in physical activity and increases in sedentary behaviour were noticed between ages 11-12 and 15-16 years. Boys were more active than girls, and the decline in physical activity was greater in girls (46% reduction) than in boys (23%). Asian students were less active than whites, and this was also true of black girls but not boys. Black students were more sedentary than white students. Levels of sedentary behaviour were greater in respondents from lower SES. Most differences between ethnic and SES groups were present at age 11 years, and did not evolve over the teenage years. CONCLUSIONS: Physical activity declines and sedentary behaviour becomes more common during adolescence. Ethnic and SES differences are observed in physical activity and sedentary behaviour in British youth that anticipate adult variations in adiposity and cardiovascular disease risk. These are largely established by age 11-12 years, so reversing these patterns requires earlier intervention.

Publication Types:

• Multicenter Study
• Research Support, Non-U.S. Gov't

PMID: 17178773 [PubMed - indexed for MEDLINE]

 

4: Scand J Med Sci Sports. 2001 Feb;11(1):54-60.

Related Articles, Links

Body proportions, body composition and pubertal development of children in competitive sports.

Damsgaard R, Bencke J, Matthiesen G, Petersen JH, Müller J.

Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark.

The aim of this study was primarily to investigate anthropometric variables, body composition and pubertal development in children aged 9-13 participating in competitive sports. Secondly, the influence of age, sport, training hours and pubertal development/maternal menarcheal age on body composition and pubertal development was explored. A total of 183 (96 girls, 87 boys) children performing swimming (Sw), tennis (Te), European team handball (TH), and gymnastics (Gy) took part in the study. Anthropometric measurements and pubertal development were determined. The participants completed a questionnaire regarding hours of training per week and maternal menarcheal age. Significant differences in stature (z-scores) were found in both boys (Sw=0.06; Te=0.04; TH=0.05; Gy=-0.66, P<0.004) and girls (Sw=0.12; Te=0.19; TH=0.25; Gy=-0.96, P<0.004). In girls, sum of skinfolds in millimetres (Sw=33.4; Te=33.3; TH=41.0; Gy= 27.2, P<0.02) and body mass index z-scores (SW=0.00; Te=-0.27; TH=0.35; Gy=-0.25, P<0.001) were different between the sports. A regression analysis revealed that in girls, age and maternal menarcheal age were significantly associated with pubertal development (P<0.005 and P<0.01), respectively, and sport was associated with the sum of skinfolds (P<0.05). In boys, only age was significantly associated with pubertal development (P<0.005). In conclusion, anthropometric and body composition differences exist in athletes of both sexes from different sports but are more evident in females. Most importantly, we did not find any effect of training on body composition or pubertal development, confirming previous data that children in competitive sports are selected due to constitutional factors.

Publication Types:

• Research Support, Non-U.S. Gov't

PMID: 11169236 [PubMed - indexed for MEDLINE]

 

5: Pediatrics. 2003 Apr;111(4 Pt 1):815-21.

Related Articles, Links

Percent body fat at age 5 predicts earlier pubertal development among girls at age 9.

Davison KK, Susman EJ, Birch LL.

Department of Human Development and Family Studies, Pennsylvania State University, University Park, Pennsylvania 16802, USA. kdavison@psu.edu

OBJECTIVE: This study examines the causal direction of the relationship between weight status and pubertal timing in girls using a longitudinal sample of 183 white girls followed from ages 5 to 9. METHODS: Girls' weight status (body mass index percentile, percent body fat, waist circumference) was assessed when they were 5, 7, and 9 years old, and their pubertal development was assessed when they were 9 years old (breast development, Estradiol, Pubertal Development Scale). Information from all measures of pubertal development at 9 years was combined to identify girls exhibiting earlier (N = 44) and later (N = 136) pubertal development relative to the sample. Girls' weight status at each age (5, 7, and 9 years old) and change in weight status across the ages of 5 to 9 years were used to predict their pubertal timing at 9 years of age. RESULTS: Girls with higher percent body fat at 5 years, and girls with higher percent body fat, higher BMI percentile, or larger waist circumference at 7 years, were more likely to be classified with earlier pubertal development at 9 years. In addition, girls showing larger increases in percent body fat from 5 to 9 years of age, and larger increases in waist circumference from 7 to 9 years of age, were more likely to exhibit earlier pubertal development at 9 years. Results were still present after controlling for accelerated growth. CONCLUSIONS: Girls with higher weight status in early childhood were more likely to exhibit earlier pubertal development relative to peers at 9 years, indicating that weight status preceded pubertal timing in girls.

Publication Types:

• Research Support, U.S. Gov't, P.H.S.

PMID: 12671118 [PubMed - indexed for MEDLINE]

 

6: BMC Public Health. 2007 Jan 31;7:16.

Related Articles, Links

Patterns in sedentary and exercise behaviors and associations with overweight in 9-14-year-old boys and girls--a cross-sectional study.

te Velde SJ, De Bourdeaudhuij I, Thorsdottir I, Rasmussen M, Hagströmer M, Klepp KI, Brug J.

Erasmus University Medical Center Rotterdam, Department of Public Health, Rotterdam, The Netherlands. s.tevelde@erasmusmc.nl

BACKGROUND: Before starting interventions addressing energy-balance related behaviors, knowledge is needed about the prevalence of sedentary behaviors and low physical exercise, their interrelationships, possible gender differences. Therefore this study aimed to describe gender differences in sedentary and physical exercise behaviors and their association with overweight status in children from nine European countries. Additionally, to identify clusters of children sharing the same pattern regarding sedentary and physical exercise behavior and compare these groups regarding overweight status. METHODS: Cross-sectional study among 11-year-old children in nine countries (n = 12538). Self-administered questionnaires assessed the time spent on TV viewing during dinner and during the day, PC use and on physical exercise. The parents reported children's weight and height. Descriptive statistics, cluster analyses, and logistic regression analyses were used for data analyses. RESULTS: Boys spent more time on sedentary behaviors but also more on physical exercise than girls. High TV viewing and low exercise behavior independently increased the risk of being overweight. Based on the behaviors, five clusters were identified. Among boys, clear associations with being overweight were found, with the most unhealthy behavior pattern having the highest risks of being overweight. Among girls, high TV viewers and high PC users had increased risk of being overweight. In girls sedentary behaviors seemed more important than physical exercise with regard to overweight status. CONCLUSION: Despite selective non-response on BMI and reliance on self-reports, the associations between clusters and overweight in boys were clear, and differences between boys and girls regarding the behaviors and risks for overweight are noteworthy. These differences need to be considered when developing tailored intervention strategies for prevention of overweight.

Publication Types:

• Research Support, Non-U.S. Gov't

PMID: 17266745 [PubMed - indexed for MEDLINE]

PMCID: PMC1800840

 

7: Arch Pediatr Adolesc Med. 2004 Apr;158(4):385-90.

Related Articles, Links

Diet, physical activity, and sedentary behaviors as risk factors for overweight in adolescence.

Patrick K, Norman GJ, Calfas KJ, Sallis JF, Zabinski MF, Rupp J, Cella J.

University of California, San Diego, San Diego State University, and Kaiser Permanente Medical Group, San Diego, CA 92093-0811, USA. kpatrick@ucsd.edu

BACKGROUND: The proportion of overweight adolescents has increased, but the behavioral risk factors for overweight youth are not well understood. OBJECTIVE: To examine how diet, physical activity, and sedentary behaviors relate to overweight status in adolescents. DESIGN AND SETTING: Baseline data from the Patient-Centered Assessment and Counseling for Exercise Plus Nutrition Project, a randomized controlled trial of adolescents to determine the effects of a clinic-based intervention on physical activity and dietary behaviors. PARTICIPANTS: A total of 878 adolescents aged 11 to 15 years, 42% of whom were from minority backgrounds. MAIN OUTCOME MEASURE: Centers for Disease Control and Prevention body mass index-for-age percentiles divided into 2 categories: normal weight (<85th percentile) and at risk for overweight plus overweight (AR + O) (>or=85th percentile). RESULTS: Overall, 45.7% of the sample was classified as AR + O with a body mass index for age at the 85th percentile or higher. More girls from minority backgrounds (54.8%) were AR + O compared with non-Hispanic white girls (42%) (chi(2)(1) = 7.6; P =.006). Bivariate analyses indicated that girls and boys in the AR + O group did fewer minutes per day of vigorous physical activity, consumed fewer total kilojoules per day, and had fewer total grams of fiber per day than those in the normal-weight group. Boys in the AR + O group also did fewer minutes per day of moderate physical activity and watched more minutes per day of television on nonschool days than normal-weight boys. Final multivariate models indicated that independent of socioeconomic status (as assessed by household education level), girls had a greater risk of being AR + O if they were Hispanic or from another minority background (odds ratio [OR] = 1.65; 95% confidence interval [CI], 1.09-2.49) and a reduced risk of being AR + O as minutes per day of vigorous physical activity increased (OR = 0.93; 95% CI, 0.89-0.97). A low level of vigorous physical activity was the only significant risk factor for boys being AR + O (OR = 0.92; 95% CI, 0.89-0.95). Analyses based on meeting behavioral guidelines supported these findings and showed that failing to meet the 60 min/d moderate to vigorous physical activity guideline was associated with overweight status for both girls and boys. In addition, boys who failed to meet sedentary behavior and dietary fiber guidelines were more likely to be overweight. CONCLUSIONS: Of the 7 dietary and physical activity variables examined in this cross-sectional study, insufficient vigorous physical activity was the only risk factor for higher body mass index for adolescent boys and girls. Prospective studies are needed to clarify the relative importance of dietary and physical activity behaviors on overweight in adolescence.

Publication Types:

• Clinical Trial
• Randomized Controlled Trial
• Research Support, U.S. Gov't, P.H.S.

PMID: 15066880 [PubMed - indexed for MEDLINE]

 

8: Adolescence. 1999 Spring;34(133):69-79.

Related Articles, Links

Association between self-concept and body weight, gender, and pubertal development among male and female adolescents.

O'Dea JA, Abraham S.

Department of Obstetrics and Gynaecology, University of Sydney, New South Wales, Australia.

This study examined the effects and interactions of gender, pubertal status, and body weight on the self-concept of 462 young adolescent Australian students from two different schools. All students enrolled in Years 7 and 8 completed the Self-Perception Profile for Adolescents, which includes several self-concept subscales and ratings of the importance of each subscale. The self-concept subscales ranked as most important by male and female students were Close Friendship, Scholastic Competence, and Job Competence. Females rated their ability to form close friendships significantly higher and of greater importance than did males. Standard body weight was related to students' Physical Appearance subscale scores, with higher weight students having lower self-concept, and postmenarcheal females having the poorest opinion of their physical appearance. Higher body weight males had lower scores on Athletic Competence, Job Competence, and Behavioral Conduct than did other males. Overweight females and normal weight males considered athletic competence to be more important than did other students. Pubertal status was related to students' scores on Athletic Competence, with postpubertal males who were not overweight scoring highest, and on Physical Appearance, with postmenarcheal females having the lowest opinion of their appearance. The mean self-concept score was significantly related to students' standard body weight, and there was an interaction between gender and puberty, with postpubertal males having the highest and postmenarcheal females the lowest self-concept score. The discrepancy score suggested that females felt they had failed to meet their ideal self-concept significantly more than did males. The results suggest that school programs should be implemented to provide exercise and job skill training suitable for all students, especially those who are overweight. These programs, while taking into account students' pubertal status, should aim to improve self-image without resulting in feelings of failure.

PMID: 10234368 [PubMed - indexed for MEDLINE]

 

9: Soc Sci Med. 2007 Jun;64(12):2391-404. Epub 2007 Apr 23.

Related Articles, Links

Why are early maturing girls less active? Links between pubertal development, psychological well-being, and physical activity among girls at ages 11 and 13.

Davison KK, Werder JL, Trost SG, Baker BL, Birch LL.

Department of Health Policy, Management and Behavior, University at Albany, Rensselaer, NY 12309, USA. kdavidson@albany.edu

Previous research has shown that early maturing girls at age 11 have lower subsequent physical activity at age 13 in comparison to later maturing girls. Possible reasons for this association have not been assessed. This study examines girls' psychological response to puberty and their enjoyment of physical activity as intermediary factors linking pubertal maturation and physical activity. Participants included 178 girls who were assessed at age 11, of whom 168 were reassessed at age 13. All participants were non-Hispanic white and resided in the US. Three measures of pubertal development were obtained at age 11 including Tanner breast stage, estradiol levels, and mothers' reports of girls' development on the Pubertal Development Scale (PDS). Measures of psychological well-being at ages 11 and 13 included depression, global self-worth, perceived athletic competence, maturation fears, and body esteem. At age 13, girls' enjoyment of physical activity was assessed using the Physical Activity Enjoyment Scale and their daily minutes of moderate-to-vigorous physical activity (MVPA) were assessed using objective monitoring. Structural Equation Modeling was used to assess direct and indirect pathways between pubertal development at age 11 and MVPA at age 13. In addition to a direct effect of pubertal development on MVPA, indirect effects were found for depression, global self-worth and maturity fears controlling for covariates. In each instance, more advanced pubertal development at age 11 was associated with lower psychological well-being at age 13, which predicted lower enjoyment of physical activity at age 13 and in tu