Growth velocity and final height in elite female rhythmic and artistic gymnasts

PURPOSE

The aim of this study was to determine the impact of intensive training on adult final height in elite female rhythmic and artistic gymnasts.

METHODS

The study included 215 rhythmic gymnasts (RG) and 113 artistic gymnasts (AG).

RESULTS

AG were below the 50th percentile, while RG were taller than average. Final adult height was lower than target height in AG, while in RG, it exceeded target height. AG started training earlier than RG (p<0.001) and reported lower intensity of training (p<0.001). RG were taller than AG, with higher target height, greater Δ final height-target height and lower body fat and BMI (p<0.001). Using multiple regression analysis, the main factors influencing final height were weight SDS (p<0.001), target height SDS (p<0.001) and age of menarche (p<0.001) for RG, and weight SDS (p<0.001) and target height SDS (p<0.001) for AG.

CONCLUSION

In both elite female RG and AG, genetic predisposition to final height was not disrupted and remained the main force of growth. Although in elite RG genetic predisposition for growth was fully preserved, in elite female AG final adult height falls shorter than genetically determined target height, though within the standard error of prediction.

Final height in elite male artistic gymnasts

OBJECTIVE

Elite male artistic gymnasts (AG) are exposed to high levels of physical and psychological stress during adolescence and experience a significant late maturation in both linear growth and pubertal development. The aim of the present study was to determine the impact of intensive physical training on the adult final height in elite male AG.

METHODS

This study is unique in character, as all variables were measured on the field of competition. The study was prospective and longitudinal; however, the current analysis of data is cross-sectional. Data from 86 elite male AG were obtained during the gymnastics competitions of European and World Championships. Clinical evaluation included height and weight measurements, as well as assessment of pubic hair and genital development according to Tanner's stages of pubertal development. The laboratory investigation included determination of skeletal maturation. All athletes completed a questionnaire that included questions on personal (onset and intensity of training, number of competitions per year) and family data (paternal and maternal heights).

RESULTS

Male AG were below the 50th percentile for both final height and weight. Elite male AG had final height standard deviation score (SDS) lower than their genetic predisposition. Final height SDS was correlated positively with target height SDS (r = 0.430, p < 0.001) and weight SDS (r = 0.477, p < 0.001) and negatively to the intensity of training (r = -0.252, p = 0.022). The main factors influencing final height, by multiple regression analysis were weight SDS (p < 0.001) and target height SDS (p = 0.003).

CONCLUSION

In elite maleAG, final height falls short of genetic predisposition, still well within normal limits. Considering medical and psychological risks in general, and based on the results of this research project, the International Federation of Gymnastics has increased the age limit for participants in international gymnastics competitions by 1 year.

Measurement of salivary resistin, visfatin and adiponectin levels

Hormonal determination in saliva offers several advantages. Peptides enter the salivary glands either by active transport mechanisms or are expressed and secreted by the salivary glands themselves. The collection of saliva is a noninvasive, easily repeatable and less stressful technique than blood withdrawal. The purpose of the present study was to introduce a method for measuring salivary resistin, visfatin and adiponectin levels and to evaluate their associations with serum levels. Resistin, visfatin and adiponectin levels were measured in serum and saliva of 50 healthy adult volunteers (17 male and 33 female) using commercial enzyme immunoassay kits for serum with minor modifications. The present study documented the determination of resistin and adiponectin levels in saliva and the significant correlation of salivary levels with serum levels (r=0.441, p<0.01 and r=0.347, p<0.05, respectively). Moreover, the identification of visfatin in saliva was achieved, but no significant correlation with serum visfatin levels was observed. To our knowledge, this is the first study to report the determination of resistin and visfatin in saliva and the significant correlation of salivary resistin with serum levels, while it confirmed the significant association between salivary and serum adiponectin. The introduction of salivary determinations of adipokines could contribute to the elucidation of the physiology and the role of the specific adipokines in various clinical conditions (obesity, insulin resistance, inflammation, reproduction, energy imbalance and stress response).

Impaired pharmacokinetics of levothyroxine in severely obese volunteers

BACKGROUND

Suppressive or replacement doses of levothyroxine (LT4) are affected by the rate and extent of the active ingredient absorbed, as well as by the lean body mass. Obesity has reached epidemic proportions worldwide and is related with many comorbidities. The aim of this study was to determine the pharmacokinetic parameters of LT4 in severely obese individuals and compared them with similar data in lean control subjects.

METHODS

We studied 62 euthyroid subjects who had negative tests for anti-thyroid peroxidise antibodies (Ab-TPO). Thirty eight of these subjects were severely obese but otherwise healthy (severe obese subjects [SOS] group). Twenty-four were healthy control subjects (control group), with a body mass index of 23.3 ± 1.7 kg/m(2). Subjects received 600 μg oral sodium LT4 after an overnight fast. Serum triiodothyronine (T3), T4, and thyroid-stimulating hormone were measured at baseline. Serum T4 and T3 was measured 0.5, 1, 1.5, 2, 2.5, 3, and 4 hours after LT4 administration.

RESULTS

Baseline serum T4 and thyroid-stimulating hormone concentrations were higher in the SOS group than in the control group; serum T3 was similar in the two groups. The corrected area under the curve and the maximum T4 concentration after LT4 administration were lower, whereas the time to maximum concentration from the baseline was higher in SOS than in the control group. The estimated plasma volume was higher in the SOS than in the control group. Mean serum T3 levels increased gradually during the four hours after LT4 administration in the control group. In contrast, they decreased gradually in the SOS group.

CONCLUSIONS

Severely obese individuals may need higher LT4 suppressive or replacement doses than normal-weight individuals due, among other factors, to impaired LT4 pharmacokinetic parameters. The latter could be attributed to their higher plasma volume and/or to delayed gastrointestinal LT4 absorption. T4 conversion to T3 might be defective in severe obesity.

Abolished circadian rhythm of salivary cortisol in elite artistic gymnasts

OBJECTIVE

The aim of this study was to evaluate the effects of intensive physical exercise and acute psychological stress during high level athletic competition as reflected on the levels of salivary cortisol in elite artistic gymnasts (AGs).

DESIGN

The study included 239 AGs (142 females-97 males) who participated in the European Championship of Gymnastics in 2006 and 81 adolescents (40 females-41 males), matched for age, as controls. All athletes participated voluntarily in all or parts of the study, providing samples or data for each of the variables measured. Height, weight, body fat, lean body mass (LBM), bone age and Tanner stage of puberty were assessed and data concerning the time of thelarche, adrenarche and menarche as well as, the onset and the intensity (hours per week) of training were obtained.

METHODS

Saliva samples were collected, the morning before training and in the afternoon shortly after the competition. From controls, the saliva samples were collected in the morning. Cortisol concentrations were measured using a chemiluminescence method. Acute stress was assessed using a questionnaire designed for the study.

RESULTS

No difference was found between morning and afternoon salivary cortisol levels in both male and female AGs (females: AM: 15.45±7.45nmol/l vs PM: 15.73±9.38nmol/l; males: AM: 10.21±5.52nmol/l vs PM: 9.93±13.8nmol/l, p>0.05). Female AGs presented higher levels of morning salivary cortisol than female controls (p<0.05). Both male and female AGs had higher degree of psychological stress in comparison with controls (p<0.001, p<0.013, respectively). Female AGs had higher morning and afternoon salivary cortisol levels (p<0.01, p<0.01, respectively) and higher degree of stress (p<0.003) than males.

CONCLUSIONS

In elite AGs the diurnal rhythm of salivary cortisol has been abolished, probably due to the strenuous training and competition conditions. Female AGs presented higher levels of morning salivary cortisol and psychological stress compared to both male AGs and female controls. The long term consequences of these modifications of the HPA axis remain to be elucidated.

Complications and risk factors related to the extent of surgery in thyroidectomy. Results from 2,043 procedures

OBJECTIVE

To evaluate the rate of complications and the risk factors in relation to the extent of surgery in patients undergoing thyroidectomy in a tertiary university center.

DESIGN

Data were collected retrospectively from 2,043 consecutive patients who underwent thyroid surgery for various thyroid diseases at the University Hospital of Patras, Greece, between January 1996 and December 2007. Recurrent laryngeal nerve palsy (RLNP) and hypoparathyroidism were set as the primary end points, while hematoma and wound infection were set as the secondary endpoints.

RESULTS

Total, near-total and subtotal thyroidectomy was performed in 1,149,777 and 117 patients, respectively. Transient RLNP occurred in 34 (1.6%) and permanent in 19 (0.9%) patients. Multivariate logistic regression analysis showed that extended resection (OR-odds ratio-1.6), Graves' disease (OR 2.7), thyroiditis (OR 2.1), recurrent goiter (OR 2.3) and thyroid malignancy (OR 1.7) were all independent risk factors for transient RLNP, whereas Graves' disease (OR 2.2) and recurrent goiter (OR 1.7) emerged as independent risk factors for permanent RLNP. The rates of transient and permanent hypoparathyroidism were 27.8% and 4.8%, respectively. Multivariate analysis for transient hypoparathyroidism revealed that the extent of surgical resection (OR 2.2), Graves' disease (OR 2.1), recurrent goiter (OR 1.7), female gender (OR 1.5) and specimen weight (OR 1.6) were independent predictors. However, the extent of surgical resection (OR 2.7), Graves' disease (OR 1.8), recurrent goiter (OR 1.5) and malignant disease (OR 1.5) were independent risk factors for permanent hypoparathyroidism. Postoperative wound infection and hematoma occurred in 6 (0.3%) and 27 (1.3%) patients, respectively. No correlation was observed between wound infection or postoperative hemorrhage and the extent of surgery.

CONCLUSIONS

Despite the higher morbidity, total thyroidectomy is emerging as an attractive surgical option even for benign thyroid disease due to the risk of subclinical (occult) malignancy, the possibility of goiter relapse as well as of the increased risk of complications following reoperation.

Bone acquisition during adolescence in athletes

Bone mass (BM) and skeletal size are similar in prepubertal girls and boys and double between the onset of puberty and early adult life. Sex steroids are responsible for the maturation in human skeleton, as well as for the sexual dimorphism, observed after the onset of puberty. Physical activity in childhood is critical for maximizing bone growth and thus for preventing osteoporosis during older age. Therefore, it constitutes the most effective prevention strategy available. In athletes, high-impact loading activities have been shown to improve BM, whereas in sports requiring a lean somatotype (therefore leading to a negative energy balance), the delay in skeletal maturation and pubertal development predisposes athletes to osteopenia and osteoporosis. Although the early onset of training, the continuous intensive exercise and its long duration attenuate bone acquisition, the excess mechanical load to which these athletes are exposed from a young age exerts beneficial effects on bone formation that lead to a positive net-effect on BM.

The influence of intensive physical training on growth and pubertal development in athletes

Genetic potential for growth can be fully expressed only under favorable environmental conditions. Although moderate physical activity has beneficial effects on growth, excessive physical training may negatively affect it. Sports favoring restricted energy availability, in the presence of high energy expenditure, are of particular concern. In gymnastics, a different pattern in skeletal maturation and linear growth was observed, resulting in an attenuation of growth potential in artistic gymnasts (AG), more pronounced in males than in females. In female rhythmic gymnasts (RG), the genetic predisposition to growth was preserved owing to a late catchup growth phenomenon. In all other sports not requiring strict dietary restrictions, no deterioration of growth has been documented so far. Intensive physical training and negative energy balance alter the hypothalamic pituitary set point at puberty, prolong the prepubertal stage, and delay pubertal development and menarche in a variety of sports. In elite RG and AG, prepubertal stage is prolonged and pubertal development is entirely shifted to a later age, following the bone maturation rather than the chronological age.

Basal metabolic rate is decreased in women with polycystic ovary syndrome and biochemical hyperandrogenemia and is associated with insulin resistance

OBJECTIVE

To evaluate basal metabolic rate (BMR) in women with PCOS and to determine its association with insulin resistance (IR).

DESIGN

Prospective assessment of BMR in women with PCOS.

SETTING

Outpatient clinic of the Division of Reproductive Endocrinology.

PATIENT(S)

The study included 91 Greek women with PCOS and biochemical hyperandrogenemia, with mean age 24.03 +/- 0.55 years and mean body mass index (BMI) 26.67 +/- 0.69 kg/m(2), and 48 matched regularly menstruating women, with mean age 26.33 +/- 0.93 years and mean BMI 23.35 +/- 0.85 kg/m(2), as control subjects.

INTERVENTION(S)

Assessment of BMR by indirect calorimetry, IR by HOMA and QUICKI indices, fasting insulin, and fasting glucose/insulin ratio.

MAIN OUTCOME MEASURE(S)

Reduced BMR in PCOS with or without IR.

RESULT(S)

Adjusted BMR was 1,868 +/- 41 kcal/day in the control group, 1,445.57 +/- 76 in all PCOS women, 1,590 +/- 130 in PCOS women without IR and 1,116 +/- 106 in PCOS women with IR. Adjusted BMR showed a statistically significant difference between women with PCOS and control subjects, with lowest values in the group of PCOS women with IR, even after adjusting all groups for age and BMI.

CONCLUSION(S)

Women with PCOS, particularly those with IR, present a significantly decreased BMR.

Association of the 17-hydroxysteroid dehydrogenase type 5 gene polymorphism (-71A/G HSD17B5 SNP) with hyperandrogenemia in polycystic ovary syndrome (PCOS)

OBJECTIVE

To evaluate the association of an activating single-nucleotide polymorphism (SNP) at position -71 of the promoter of 17beta-hydroxysteroid dehydrogenase type 5 gene (-71A/G HSD17B5 SNP) and polycystic ovary syndrome (PCOS) in a well characterized cohort of caucasian PCOS women with biochemical hyperandrogenemia.

DESIGN

The PCOS patients and unrelated healthy control subjects were genotyped for the -71A/G HSD17B5 SNP. The acquired genotypic data was tested for association with PCOS and other quantitative phenotypic traits of the syndrome in PCOS patients.

SETTING

Subjects were recruited from the Division of Reproductive Endocrinology, Department of Obstetrics and Gynecology, at the University Hospital of Patras, Greece. Genotyping and biochemical determinations took place at the Laboratory of Molecular Endrocinology, University of Patras Medical School, Rion, Greece.

PATIENT(S)

Participants comprised 150 caucasian Greek PCOS women with biochemical hyperandrogenism and chronic anovulation and polycystic ovarian morphology on ultrasound and 51 healthy control subjects.

MAIN OUTCOME MEASURE(S)

HSD17B5 genotype, serum testosterone, serum androstenedione.

RESULT(S)

No association of the -71A/G HSD17B5 SNP with PCOS was detected. However, the -71G HSD17B5 variant was associated with increased serum testosterone levels and decreased androstenedione/testosterone ratio.

CONCLUSION(S)

The -71G HSD17B5 variant is not a major component of the molecular pathogenetic mechanisms of PCOS, although it might contribute to the severity of hyperandrogenemia in women with PCOS and biochemical hyperandrogenism.

The odyssey of nontoxic nodular goiter (NTNG) in Greece under suppression therapy, and after improvement of iodine deficiency

BACKGROUND

Nontoxic nodular goiter (NTNG) is common in endemic goiter regions. Thyroxine (T4) is often used to treat NTNG. There is little information regarding T4 treatment in regions that have recently become iodine sufficient. We studied the effect of T4 treatment on thyroid function tests in southwestern Greece (SWG), a recently iodine-sufficient area.

METHODS

We studied 827 residents of SWG (group A) to determine goiter prevalence, thyroid function, and urinary iodine concentration (UIC). Group B: 385 consecutive patients with thyroid dysfunction. Of these, 89 had NTNG and followed for 10 years on T4 treatment, and 296 had hyperthyroidism. Group C: 29 patients with NTNG, treated with triiodothyronine (T3) 50 mug/day and followed for 6 months. Measurements included serum T4 and 24-hour radioactive iodine uptake (RAIU) before and at the end of T3 administration.

RESULTS

The median UIC in group A was 114 microg/L. In group B (89 patients), the incidence of newly diagnosed hyperthyroidism was 5-7% per year with a cumulative percentage of 33% at the 10th year. The initial thyrotropin (TSH) was lower (0.78 +/- 0.51 mIU/L) in those who developed thyrotoxicosis compared to those who remained euthyroid (1.17 +/- 0.74 mIU/L) (p < 0.05). In 296 thyrotoxic patients, the incidence of autoimmune hyperthyroidism and toxic multi-nodular goiter (TMNG) was similar. In group C, 10/29 patients remained euthyroid and the 24-hour RAIU decreased by 49% during T3 treatment. Similarly, serum T4 decreased by 49%. In the remaining patients who developed hyperthyroidism, 24-hour RAIU and T4 were decreased by 19% and 22%, respectively.

CONCLUSIONS

In SWG, a recently iodine-sufficient region, the risk of developing hyperthyroidism in patients with NTNG after administration of 100-150 microg T4 is relatively high in those whose serum TSH before T4 treatment is in the lower normal range. Therefore, T4 treatment should be avoided in these patients.

Treating iodine deficiency: long-term effects of iodine repletion on growth and pubertal development in school-age children

BACKGROUND

Iodine deficiency (ID) is still a major universal health problem. Iodine deficiency disorders (IDDs) affect people of all ages, among whom the most vulnerable are children and adolescents. The aim of the present study was to assess the long-term effects on growth and pubertal development of correcting severe ID in areas of Azerbaijan between 1999 and 2000.

METHODS

Iodized oil was administered orally to 293,000 children, aged 6-16 years. Among those, 364 children were randomly selected and were examined 1 year before the administration of iodized oil (Group I-neg, iodine negative) and 295 children (Group I-Rx, iodine treated) were examined 4 years (Group I-R x 4, iodine treated 4 years later; n = 173) or 5 years (Group I-R x 5, iodine treated 5 years later; n = 122) after the last dose of iodide.

RESULTS

In Group I-neg the median urine iodine concentration (UIC) (mcg/L) was 36 (mean: 36.272 +/- 11.036) and increased significantly (p < 0.001) in Group I-R x 4: 188 (mean: 230.969 +/- 155.818) and in Group I-R x 5: 175 (mean: 201.176 +/- 130.369). The prevalence of goiter was 99% in Group I-neg and 2% in Group I-R x 4. Children in Group I-Rx had a greater standard deviation score (SDS) for height (-0.1364 +/- 1.279, n = 294) than children in Group I-neg (-0.5019 +/- 1.17, n = 363) (p < 0.001, t = -3.817), which was more significant for boys. SDS for weight was similar in both groups (Group I-neg: -0.17 +/- 0.78, n = 363; Group I-Rx: -0.115 +/- 0.917, n = 294). The rate of puberty development as judged by the development of breast and pubic hair was normalized in both sexes after the correction of ID.

CONCLUSIONS

Our results demonstrate that long-term correction of severe ID leads to sustained improvement of linear growth accompanied by a normalization of the time of onset of pubertal development for both sexes.

Increased frequency of thyroid nodules and breast fibroadenomas in women with uterine fibroids

Fibroids or leiomyomas or myomas of the uterus are the most common benign gynecologic disease, while fibroadenomas of the breast are most frequently seen in young women, usually within 20 years after puberty. Multiple tumors in one or both breasts are found in 10-15% of patients. Single thyroid nodules are much more common in women than in men, and their prevalence increases with age. The aim of the present study was to determine cross-sectionally the incidence of solitary thyroid nodules and fibroadenomas of the breast in women with uterine fibroids. In women with uterine adenomas, the frequency of fibroadenomas of the breast was 65% and of thyroid nodules was 38.7%, while in women with a normal uterus, the frequency was 35% and 20%, respectively. Therefore, women with uterine fibroids have an increased incidence of thyroid nodules (t = 4.68, p = 0.030) and of fibroadenomas of the breast (t = 11.74, p = 0.001).

Thyroid hormone synthesis and secretion in humans after 80 milligrams of iodine for 15 days and subsequent withdrawal

CONTEXT

In animals, acute iodine administration results in acute intrathyroidal inhibition of iodinations followed by escape of the inhibition if the excessive iodine intake continues. In humans, the intrathyroidal nonhormonal and hormonal iodine concentration after exposure to large doses of iodine for a relatively long period of time is not known.

OBJECTIVE

To determine whether, in human thyroid, administration of large doses of iodine for a relatively long time results in alterations of intrathyroidal hormonal (HI) T4 and T3 and total iodine (TI) content, as well as whether changes in serum concentration of thyroid hormones and TSH would occur after iodine administration or discontinuation.

DESIGN

In 33 euthyroid patients with single thyroid nodule or hyperparathyroidism, Lugol solution (80 mg iodine) was administered for 15 d before operation. Groups of six to eight patients underwent operation 0, 5, 10, and 15 d after iodine withdrawal. TI, HI in a sample of thyroid tissue, and serum concentration of T4, T3, and TSH were measured. In 21 normal euthyroid subjects who did not undergo operation, a similar protocol was used and serial blood measurements were taken.

MAIN OUTCOME MEASURE

Intrathyroidal TI, HI, and serum thyroid hormone and TSH measurements were the main outcome measure.

RESULTS

Intrathyroidal HI content and serum T4 and T3 were unchanged during and after iodine discontinuation. TI was increased during iodine administration and returned to control values 5 d after discontinuation of iodine. The ratio of HI/TI was decreased and returned to control values 15 d after the iodine was discontinued. Serum TSH was increased during iodine administration and returned to control values 10 d after iodine withdrawal.

CONCLUSIONS

In humans, administration of iodine for a relatively long period of time was accompanied by increased intrathyroidal TI, but no changes in HI or demonstrable increases of serum T4 and T3 were observed. It is hypothesized that the maintenance of normal intrathyroidal HI is the result of the combined inhibitory effect of iodine on thyroid hormone synthesis and on the release of T4 and T3 from the thyroid.

Adequacy of saliva 17-hydroxyprogesterone determination using various collection methods

Steroids determination in saliva offers several advantages. The collection of saliva is a noninvasive, less stressful technique than blood withdrawal and reflects the circulating unbound fractions. The suitability of saliva for 17-hydroxyprogesterone and cortisol determinations has been documented in healthy subjects as well as in diseases like Congenital Adrenal Hyperplasia and Cushing syndrome. The aim of the study was to compare the influence of different collection methods on the results of 17-hydroxyprogesterone measurement in saliva collected by different ways, using commercially available RIAs developed for plasma. 17-hydroxyprogesterone was determined in 64 healthy adult volunteers (30 males, 34 females) in serum (Group SE) and in saliva collected before meals at 8-10 p.m. by directly spitting into a plastic tube (Group SP), using a cotton swab (Group SA) and using a polyester swab Salivette (Group SB). We used a commercially available direct radioimmunoassay without separation technique. The 17-hydroxyprogesterone mean values (ng/ml) were 1.16+/-1.3 (Group SE), 0.056+/-0.046 (Group SP), 0.089+/-0.048 (Group SA) and 0.058+/-0.049 (Group SB). The detection limit was 0.010 ng/ml. The correlations between the values in serum (Group SE) and in saliva were: r=0.77, p<0.05 (Group SP); r=0.62, p<0.05 (Group SA); r=0.70, p<0.05 (Group SB). The saliva values corresponding to the serum cut-off point of 3 ng/ml upper limit of normal values were in ng/ml 0.13 (Group SP), 0.16 (Group SA) and 0.11 (Group SB). In conclusion, 17-hydroxyprogesterone determinations in saliva using commercially available RIAs primarily developed for serum, is a reliable and easy to perform procedure. The three different methods of saliva collection showed 17-hydroxyprogesterone concentrations to have good agreement.

Delayed but normally progressed puberty is more pronounced in artistic compared with rhythmic elite gymnasts due to the intensity of training

CONTEXT

Elite gymnasts are subjected to intense training, which may alter pubertal development.

OBJECTIVE

The objective of the investigation was to study the impact of gymnastics on pubertal development in rhythmic (RGs) and artistic gymnasts (AGs).

DESIGN

Evaluation of somatometric parameters, pubertal stage, and intensity of training in the competition field were studied.

SETTING

The study was conducted at European and world championships of years 1997-2004.

SUBJECTS

Subjects included 433 elite RGs and 427 AGs, aged 11-23 yr.

INTERVENTION

There were no interventions.

MAIN OUTCOME MEASURES

Mean chronological and bone ages of each pubertal stage and their relation to the intensity of training were measured.

RESULTS

AGs and RGs showed a delay in skeletal maturation (Delta age-bone age, 2.13 and 1.28, respectively; P < 0.001). AGs were subjected to higher levels of physical training. Thelarche occurred at 12.9 yr for RGs and 13.2 yr for AGs (P = 0.003) and pubarche at 12.5 and 12.9 yr, respectively (P = 0.002). Puberty was delayed but normally progressed. AGs entered each pubertal stage later than RGs. The delay was influenced by the amount of energy output. Menarcheal age was 14.6 yr for RGs and 14.9 yr for AGs. Menarche was influenced in AGs by bone age (b = 0.333; t = 2.521; P = 0.020), pubarche (b = 0.322; t = 2.401; P = 0.026), and body fat (b = -0.458; t = -3.412; P = 0.003) and in RGs by bone age (b = 0.378; t = 3.689; P < 0.001) and pubarche (b = 0.525; t = 6.017; P < 0.001).

CONCLUSION

In RGs and AGs, pubertal development was shifted to a later age, maintaining a normal rate of progression, which followed the bone age. AGs, who were exposed to a greater and more sustained energy output than RGs, presented a more pronounced delay in both skeletal maturation and pubertal development.

Growth, pubertal development, skeletal maturation and bone mass acquisition in athletes

The genetic potentials for growth can be fully expressed only under favourable environmental conditions. Excessive physical training may negatively affect growth, especially during puberty. Sports that require a strict control of energy input in the presence of a high energy output are of particular concern. In gymnastics, a different pattern in skeletal maturation was observed, leading to an attenuation of growth potential ins Artistic Gymnasts (AG), more pronounced in males than in females, whereas in female Rhythmic Gymnasts (RG) the genetic predisposition to growth was preserved because of a late catch-up growth phenomenon. In all other sports not requiring strict dietary restrictions, no deterioration of growth has been documented. Intensive physical training and negative energy balance modify the hypothalamic pituitary set point at puberty, prolong the prepubertal stage and delay pubertal development and menarche in a variety of sports. In elite RG and AG the prepubertal stage is prolonged and pubertal development is entirely shifted to a later age, paralleling the bone age rather than the chronological age. Bone formation, and, consequently, BMD are enhanced by physical activity. In athletes, high-impact loading activities have been shown to improve BMD, while in sports requiring a lean somatotype, the delay in skeletal maturation and pubertal development, resulting from hypoestrogenemia, predisposes athletes to osteopenia. In AG, an increase in bone density is observed using the bone age as denominator.

The influence of intensive physical exercise on bone acquisition in adolescent elite female and male artistic gymnasts

Physical exercise enhances bone acquisition during adolescence. The aim of the study was to evaluate the influence of intensive physical exercise on bone acquisition in adolescent elite artistic gymnasts. The study included 262 athletes (93 males and 169 females, aged 13-23 yr) participating in the 24th European Championship held in Greece. Bone age compared with chronological age was delayed by 2 yr for females (n = 120) and 1 yr for males (n = 68). For both sexes, the growth chart of bone mineral density (BMD) followed a normal pattern when estimated according to bone age rather than chronological age. For females, BMD was positively correlated with bone age, chronological age, height, body weight, body mass index, body fat, lean body mass, and with age of onset of training, and negatively with duration of exercise and intensity of training (P values range from <0.05 to <0.0001). Multiple regression analysis revealed that age of onset of training was the major parameter attenuating the effect of exercise on BMD (P < 0.001). The latter was related to the stage of puberty (P < 0.05). For males, BMD was correlated positively with bone age, height, body weight, and lean body mass (P values range from <0.01 to 0.0001). Multiple regression analysis revealed that the more powerful factor influencing BMD was weight (P < 0.01). In conclusion, bone acquisition in adolescents under intensive physical training follows the normal pattern only when estimated according to bone age. The age of onset, the duration, and the intensity of exercise attenuate the bone acquisition, at least in female artistic gymnasts.

Growth and skeletal maturation in male and female artistic gymnasts

We studied 262 athletes who were 13-23 yr old. There were 93 male and 169 female artistic gymnasts (AG). This study is unique in character, because all variables were measured on the field of competition (24th European Championship). Male AG had a higher height SD score than female (P < 0.001), with a higher reported target height SD score (P < 0.001), a higher predicted final height (P = 0.007), a lower Delta height - target height (P < 0.001), a less delayed bone age (P < 0.001), a greater body mass index (BMI) (P < 0.001), a lower mean body fat (P<0.001), and an older age of onset of training (P < 0.001). In a subgroup of athletes who had reached final height, male AG had a higher weight SD score than female (t = 4.322, P < 0.001), with a higher reported target height SD score (t = 18.9, P<0.001), but a greater Delta final height-target height (t= 6.641, P < 0.001). Height SD score was positively correlated to reported target height SD score (P = 0.009 and P = 0.006, respectively) and to weight SD (P < 1 and P < 0.001, respectively) for both male and female AG, as well as to BMI for female AG (P<0.001), and negatively to Delta age - bone age (P < 0.001 and P = 0.003, respectively) and to predicted height SD score (P = 0.001 and P < 0.001, respectively). Using multiple regression analysis, height SD score was positively correlated to predicted height SD score for both male (P < 0.001) and female (P = 0.005) AG, as well as to weight SD score (P < 0.001) for female AG and negatively to BMI (P < 0.001) for female AG and to Delta age - bone age (P < 0.001) for male AG. In conclusion, a deterioration of growth in AG was observed. For both sexes, genetic predisposition to final height, although altered, was not disrupted.

Autonomously functioning thyroid nodules in a former iodine-deficient area commonly harbor gain-of-function mutations in the thyrotropin signaling pathway

BACKGROUND

Somatic activating mutations of the thyrotropin (thyroid-stimulating hormone (TSH)) receptor (TSHR) and G(alphas) protein have been detected in solitary toxic adenomas and toxic multinodular goiters, but their role in the pathogenesis of autonomous nodules is debated. The frequency of mutations is highly variable among populations and is inversely proportional to iodine intake.

DESIGN AND PATIENTS

We screened 28 clinically and histologically heterogeneous autonomous nodules from 24 Greek patients for the presence of TSHR and G(alphas) mutations.

RESULTS

By direct sequencing of genomic DNA, we detected 11 somatic heterozygous gain-of-function mutations in TSHR and one in G(alphas). Forty-three percent (12 of 28) of all nodules and 57% (four of seven) of solitary toxic adenomas harbored an activating mutation. Typical adenomas and hyperplastic nodules did not differ in mutation frequency. Substitutions I568T and T632I were detected in both histological types of nodules.

CONCLUSIONS

Our findings indicate that activating somatic mutations in the TSH signaling pathway are frequent in autonomous nodules in Greece. This may be due to earlier exposure of the population to iodine deficiency, which was corrected in Greece only over the past two decades. Gain-of-function mutations are shared by nodules with varying histological and clinical presentations. Thus, they may represent a common molecular mechanism underlying the pathogenesis of non-autoimmune thyroid autonomy.

Functional significance of the thyrotropin receptor germline polymorphism D727E

In a toxic thyroid adenoma we identified a novel somatic mutation that constitutively activates the thyrotropin receptor (TSHR). Two heterozygous point mutations at adjacent nucleotides led to a substitution of alanine with asparagine at codon 593 (A593N) in the fifth transmembrane helix of TSHR. This somatic mutation resided on the same TSHR allele with the germline polymorphism D727E. The functional characteristics of the single TSHR mutants A593N and D727E and of the double mutant A593N/D727E were studied in transiently transfected COS-7 cells. The TSHR mutants A593N and A593N/D727E constitutively activated the cAMP cascade, whereas the D727E mutant did not differ from the wild-type TSHR. Surprisingly, the double mutant's specific constitutive activity was 2.3-fold lower than the A593N mutant. Thus, the polymorphism significantly ameliorates G(alphas) protein activation in the presence of the gain-of-function mutation A593N, although it is functionally inert in the context of the wild-type TSHR.

Hyperthyrotropinemia during iodide administration in normal children and in children born with neonatal transient hypothyroidism

The aim of the present study was to examine the effects of chronic iodide administration in pharmacological doses on thyroid function in children with a history of transient congenital hypothyroidism (TCH). We hypothesized that such children may carry a previously undisclosed intrinsic intrathyroidal defect, rendering them susceptible to TCH. We administered for this 60-65 mg iodide daily for 60 d in 13 individuals with TCH (group A), 8 of their siblings (group B), 8 healthy controls (group C), and 11 normal adults (group D). Thyroid function was evaluated by measuring serum T(3), T(4), free T(3), free T(4), TSH, and thyroglobulin concentrations and autoantibodies against thyroid peroxidase and thyroglobulin at baseline at 15, 30, and 60 d during iodide administration, and 2 months after iodide withdrawal. Hyperthyrotropinemia greater than 4.2 mU/liter but not higher than 10 mU/liter with normal thyroid hormone concentrations was observed in one of the TCH group and in two of the group B siblings. During iodide administration, hyperthyrotropinemia was observed in 8 of 13 (62%) adolescents in group A, 4 of 7 (57%) in group B, and 6 of 8 (75%) in group C. None of the 11 adults (group D) developed hyperthyrotropinemia during iodide administration. Serum T(4) and free T(4) concentrations were decreased in all groups when compared with baseline values. The magnitude of the decrease of serum T(4) was identical in all groups (0.7-0.8 microg/dl). Thyroid enlargement was observed in all subjects and was more pronounced in children. There were no cases of subclinical and/or overt hyperthyroidism. After iodine withdrawal, serum TSH decreased in all groups and returned to baseline levels, as well as the thyroid volume. In conclusion, the hypothalamic-pituitary-thyroid axis of adolescents with TCH responds to pharmacological doses of iodide similarly to that observed in normal children. The hyperthyrotropinemia observed in the adolescents exposed to iodides may reflect incipient transient hypothyroidism or simply a brisk TSH response to a small serum T(4) decrease. Whatever the mechanism, chronic use of excessive quantities of iodide should be avoided until the end of puberty.

Improvement of iodine deficiency after iodine supplementation in schoolchildren of Azerbaijan was accompanied by hypo and hyperthyrotropinemia and increased title of thyroid autoantibodies

OBJECTIVE

In the mountainous areas of Azerbaijan the schoolchildren suffer from severe Iodine Deficiency (ID) with median Urinary iodine excretion (UIE) 36 mcg/l and prevalence of goiter 99% (estimated by US). In a population of 293,000 schoolchildren aged 8-14 y.o. we administered capsules containing 190 mg of iodized oil (Lipiodol-Guerbet, Cedex, France) twice yearly in 6 months apart (total 380 mg). The aim of the present study was to evaluate the efficacy, the benefits, as well as the possible side-effects in a follow-up period of 6 and 12 months after the initial administration of iodized oil.

METHODS

Six and 12 months after the initial administration of iodide, two representative samples of 391 and 326 children respectively were examined. The evaluation included: estimation of goiter by US, determination of UIE and serum measurements of T3, T4, TSH, Tg, autoantibodies against thyroid peroxidase (anti-TPO) and thyroglobulin (anti-Tg).

RESULTS

There was an improvement in median UIE which increased from 36 mcg/l to 68 and 81 mcg/l after 6 and 12 months of treatment respectively. The prevalence of goiter decreased from 99% to 54% and 26% respectively. Tg was decreased at 6 and 12 months from the first administration, whereas TSH remained unchanged at 6 months and decreased at 12 months when compared to the latter value. Hypothyroidism was detected in 7% of children after iodide administration both at 6 and 12 months, but overt hypothyroidism was observed only in 0.5% at 12 months. Subclinical hyperthyroidism was detected in 2% and 6% after iodide administration both at 6 and 12 months. There was a significant increase in the title of thyroid auto antibodies in 6 months which was retained and increased in 12 months. There was no relation between the appearance of thyroid dysfunction and the positive thyroid auto antibodies.

CONCLUSION

The dose of 190 mg iodide administered twice yearly, improved iodine deficiency and endemic goiter in schoolchildren. The increase of UIE resulted from iodide administration, was accompanied by an increased title of thyroid auto-antibodies and an increased prevalence of hyper- and hypothyrotropinemia apparently of no autoimmune etiology.

Growth retardation in artistic compared with rhythmic elite female gymnasts

We studied 129 female rhythmic gymnasts (RG) and 142 female artistic gymnasts (AG) who participated in the 1999 Gymnastics World Championship for RG in Osaka, Japan, and the 1999 and 2001 Gymnastics World Championships for AG in Tianjin, China (n = 48), and Ghent, Belgium (n = 94), respectively. RG were taller than average, with a mean height SD score above the 50th percentile, whereas AG were relatively short, with a mean height SD score below the 50th percentile. Both RG and AG followed their respective reported target height SD score, which was above the 50th percentile for the RG and below the 50th percentile for the AG. The RG followed a growth pattern that was higher than their reported target height, whereas AG exhibited a negative growth pattern. RG and AG weighed less than the population mean, with the mean weight for age below the 50th percentile for both groups. RG were taller than AG (t = 17.15; P < 0.001), with a higher reported target height SD score (t = 6.44; P < 0.001), a greater Delta height-reported target height (t = 2.74; P < 0.001), and a lower mean body fat (t = -11.83; P < 0.001) and body mass index (t = -10.73; P < 0.001) than AG. AG started their training at an earlier age than RG (t = 4.13; P < 0.001). Using multiple regression analysis, actual height SD score was independently influenced positively by weight SD score for both RG (b = 0.421; t = 4.317; P < 0.001) and AG (b = 1.404; t = 16.514; P = <0.001), and by reported target height only for RG (b = 0.299; t = 3.139; P = 0.002), and negatively by body mass index only for AG (b = -0.80; t = -9.88; P < 0.001). In conclusion, in elite female AG, a deterioration of growth potential was observed, whereas in RG the genetic predisposition to growth was preserved.