Rossana Fiori

Glucose tolerance status in 510 children and adolescents attending an obesity clinic in Central Italy

Brufani C, Ciampalini P, Grossi A, Fiori R, Fintini D, Tozzi A, Cappa M, Barbetti F. Glucose tolerance status in 510 children and adolescents attending an obesity clinic in Central Italy.

Sexual dimorphism of body composition and insulin sensitivity across pubertal development in obese Caucasian subjects

Background Puberty is a period of rapid growth associated with metabolic, hormonal, and body composition changes that can influence risk factors for chronic diseases such as type 2 diabetes. Objective To evaluate body composition and insulin sensitivity (IS) modifications throughout puberty in a large group of obese Caucasian subjects. Methods Five hundred and nineteen obese subjects (4-19 years), grouped according to gender and Tanner stage (T), underwent oral glucose tolerance test. Quantitative insulin check index (QUICKI) and ISI were calculated as indexes of IS. In 309 subjects, body composition by dual-energy X-ray absorptiometry, IGF1, adiponectin, and leptin were also evaluated. Results Body composition modifications were sexually dimorphic, with girls not modifying fat and lean percentage and fat distribution (P>0.15), and boys decreasing fat percentage and increasing lean percentage and central fat depot (P<0.001) across Ts. IS decreased during mid-puberty and returned to prepubertal levels by the end of puberty. Girls showed lower IS than boys (P<0.01 and =0.03 for QUICKI and ISI respectively). In multivariate analysis factors that negatively influenced IS, independently from T or age, were total fat mass and central fat depot in girls (P<0.05 and <0.01, respectively), total fat and lean mass in boys (P<0.01). IGF1, adiponectin, and leptin were not related to pubertal IS. Conclusions In obese Caucasian subjects, further decrease of IS observed during puberty is a transient phenomenon. Factors that independently from T or age influence IS are central fat depot in girls, lean amount in boys, and total fat mass in both sexes.

Gender differences in bone mineral density in obese children during pubertal development

Objective: To investigate whether body mass index (BMI) and body composition can affect peak bone mass in a population of obese (OB) (BMI SDS>2.0) and normal-weight (NORM) (BMI-SD score <2.0) pubertal subjects (Tanner stage T3 to T5). Patients and methods: 151 subjects (81 OB, age14.5±2.4 yr) were analyzed using dual-X-ray absorbiometry technique to study Lumbar and whole body bone mineral density (BMD) (areal, normalized for height) and Z-score, lean mass (LM) and lean/fat ratio. Results: As a whole group, OB males did not show any significant difference in bone parameters vs NORM, while OB females showed higher bone density parameters (p<0.05). When grouped according to T, while OB males showed higher bone density at T3-4 stage (p<0.01 ), and lower at T5 (p<0.01 ) compared to NORM, OB females showed a tendency through increased BMD at T3–4 and T5 although statistically different only at T5. BMD was independently correlated to LM, lean/fat ratio, and testosterone in NORM males and, at lower level, in OB males, while to LM in NORM females and only to age in OB females. Conclusion: Our data seem to confirm the possible negative influence of obesity on bone density in boys, a possible explanation could be an unfavorable body composition during sexual maturation that seems not to affect bone development in adolescents girls.

Cardiovascular Fitness, Insulin Resistance and Metabolic Syndrome in Severely Obese Prepubertal Italian Children

Aim: To evaluate if insulin resistance (IR) and metabolic syndrome (MS) were associated with poor cardiovascular fitness in very obese prepubertal Italian subjects. Methods: Children referred to the Endocrinology and Diabetes Unit of Bambino Gesù Children’s Hospital underwent an OGTT with glucose and insulin assays. QUICKI, ISI and HOMA-IR were calculated. Total and HDL cholesterol, triglycerides and percentage of body fat (DEXA) were determined. Cardiovascular fitness (maximal treadmill time) was evaluated using a treadmill protocol. The MS was defined as having 3 or more of following risk factors: obesity, impaired glucose tolerance, high blood pressure, low HDL-cholesterol, high triglycerides. Results: Fifty-five very obese prepubertal Italian children were enrolled in the study. Unadjusted correlation revealed maximal treadmill time negatively related to fasting insulin (r = –0.53, p < 0.0001) and HOMA-IR (r = –0.57, p < 0.0001) and positively to QUICKI (r = 0.51, p < 0.0001) and ISI (r = 0.46, p = 0.0035). These relationships remained significant when in multivariate analysis age, gender, BMI SD and body composition were accounted for (all p < 0.01). The presence of the MS was independently associated with maximal treadmill time. Conclusion:Poorcardiovascular fitness, IR and MS were independently related, suggesting that the relationship between fitness and insulin action develops early in life.

Bone mineral density and body composition in male children with hypogonadism

Estrogen deficiency in females and androgen deficiency in males may harm periosteal and endosteal apposition, reduce bone size and both cortical and trabecular thickness, modifying in this way the bone structure later in life. To date, few systematic studies on bone mineral density (BMD) and hypogonadism in adolescents are available. Therefore we aimed to determine if sexual hormone deficiency during pubertal age might have an impact on peak bone mass and body composition. We compared areal BMD (L-aBMD), volumetric lumbar spine BMD (L-vBMD), lumbar spine Z-score (L-Z-score), lumbar spine bone mineral content (L-BMC), whole body (wbBMD), normalized whole body (n-wbBMD) BMD, and whole body BMC (wb-BMC) of 25 male children with hypogonadism (HYPO) with 37 sex-, age-, and body mass indexmatched healthy subjects (CNT) using dual-energy X-ray absorptiometry. Furthermore we analyzed whether a difference in lean (lean%) and fat (fat%) mass as percentage of body weight and as a lean/fat ratio is present in the two groups of children. HYPO demonstrated a statistically lower L-aBMD, L-vBMD, L-BMC, Z score, wbBMD, n-wbBMD, and wb-BMC compared to CNT. CNT showed a higher lean% and lower fat% and a higher lean/fat ratio when compared with HYPO group. Lean mass correlated positively with L-aBMD, L-BMC, and wb-BMC. Our study seems to confirm previous observations that sex hormone deficiency during puberty reduces bone mass accrual. Body composition alterations may play a role in bone parameters during development in healthy as such as in hypogonadal children during developmental age.

Young elite athletes of different sport disciplines present with an increase in pulsatile secretion of growth hormone compared with non-elite athletes and sedentary subjects

Acute exercise is a well-known stimulus for GH secretion but the effect of chronic training on GH secretion still remains equivocal. The aim of our study was to analyse spontaneous pulsatile GH secretion (during a period of 2 hours in the morning) in a group of young elite athletes (EA) compared with non-elite athletes (NEA), and sedentary subjects (SS). Mean and peak GH levels proved significantly higher in EAthan in NEA and SS (p=0.0004 and p<0.0001, respectively). The same differences in mean and peak GH levels were also demonstrated in males and females when considered separately (males: p=0.0062 and p=0.0025; females: p=0.0056 and p=0.0032). In addition, GH levels (mean and peak) were higher in females than in males in SS while no differences were demonstrated between the 2 sexes in the EA and NEA groups. IGF-I levels were within the normal range for age in all the subjects with no difference between the 3 groups. Body mass index (BMI) exhibited no difference between groups, while EA showed higher lean mass (p=0.0063) and lower fat mass (p=0.0139) than NEA and SS measured by dual-energy x-ray absorptiometry. A strong positive correlation between GH levels (mean and peak) and hours of training a week was demonstrated (p=0.0101; r2=0.1184; p=0.0022; r2=0.1640, respectively). In conclusion, GH levels were higher in EA than NEA and SS without any modification of IGF-I levels; a strong positive correlation was present between GH levels and intensity of training. An increase in the knowledge of the effect of chronic training on GH secretion could improve the training programme to elicit the greatest exercise-induced GH response.

Cardiovascular fitness is impaired in children born small for gestational age

Small for gestational age (SGA) refers to a child whose weight and, or, length at birth is less than a 2 standard deviation score (SDS) (1). Subjects born SGA have an increased risk of developing permanent metabolic changes as a result of intrauterine programming, leading to increased cardiometabolic risk in adulthood, including hypertension, excess abdominal fat deposition and type 2 diabetes (2). An appropriate lifestyle, based on a balanced diet and adequate physical activity, is the primary preventive intervention for reducing long-term cardiometabolic risk. To our knowledge, while physical activity and aerobic capacity have been extensively investigated in adolescents or adults born preterm (3), no data on cardiovascular fitness in children born SGA have so far been reported. The aim of this prospective study was to evaluate cardiovascular fitness capacity in a group of 22 consecutive children born SGA at term, defined as a gestational age of between 37 and 42 weeks, and referred to the Endocrinology and Diabetes Unit of the Bambino Ges u Children’s Hospital between January 2012 and September 2012. The SGA children were compared to 21 healthy children born at an appropriate for gestational age, with a birth weight of > 2 SDS and <+2 SDS at term, matched for age, gender and body mass index. Children with a birth weight of < 2 SDS were diagnosed as SGA (1). All the SGA children showed catch-up growth that was defined as having attained a height centile within the midparental height range (4). Children with intrauterine growth restriction (IUGR) defined as a weight below the 10th percentile for its gestational age by ultrasound measurements were excluded (5). The control group was recruited on a voluntary basis in the outpatient clinic and comprised children referred to our hospital for minor surgery or electrocardiographic screening. None of the children in either of the groups took part in organised physical activities. Subjects with chronic diseases, genetic syndromes or on chronic therapies were excluded from this study. All children underwent assessment of their anthropometric and physical activity parameters. Puberty development was clinically assessed on the basis of secondary sex characteristics (6). Only subjects with stage I or II gonadal or breast development were considered for the analysis. Maximal cardiovascular fitness capacity was assessed using the standard Bruce treadmill test (7) with increasing belt speed and per cent grade (Tecnogym Runrace, Tecnogym Gambettola, Italy). The parameters measured during the cardio pulmonary exercise test were as follows: time of exercise, maximal oxygen uptake (VO2 max) (L/min and mL/kg/min), maximum heart rate and maximum blood pressure. The cardiopulmonary exercise test was considered adequate if one or more of the following conditions were achieved: at least 80% of the maximum predicted heart rate (determined as 220 b/m minus age), a respiratory exchange ratio of 1.0 for a period of at least one minute or exhaustion of the subject (7). Time of exercise, maximal oxygen uptake and maximum heart rate and blood pressure were also calculated as a percentage of predicted values, as previously reported (8,9). The same physician performed all the examinations. Metabolic profile was analysed in the SGA patients by routine laboratory analyses, including the oral glucose tolerance test (10). The homoeostasis model assessments of fasting insulin resistance (HOMA-IR) (11) were calculated as the index of insulin resistance derived from basal values of glucose and insulin. The whole-body insulin

Non-conventional use of growth hormone therapy

UNLABELLED Human growth hormone therapy is allowed in certain clinical conditions according to national healthcare criteria. Growth hormone, however, produces a wide spectrum of effects. Linear growth is only one of the many expected results, and there are interesting possibilities to explore which could provide additional means of improving the quality of life for the ever-increasing numbers of chronic paediatric patients. CONCLUSION In this review, we discuss the rationale for and possibility of using growth hormone therapy in some conditions not strictly related to growth hormone deficiency.

Non-conventional use of growth hormone therapy: Non-conventional use of GH

Human growth hormone therapy is allowed in certain clinical conditions according to national healthcare criteria. Growth hormone, however, produces a wide spectrum of effects. Linear growth is only one of the many expected results, and there are interesting possibilities to explore which could provide additional means of improving the quality of life for the ever‐increasing numbers of chronic paediatric patients.