Aim To determine the influence of Type 1 diabetes mellitus on circulating adipocytokines in children.Methods The circulating concentrations of leptin, adiponectin, resistin and turnout necrosis factor (TNF)-alpha were measured in 91 children,aged 11.1 +/- 2.7years, with Type 1 diabetes mellitus (T1DM). Ninety-one healthy children were selected as control subjects.Results Body mass index-adjusted leptin concentrations were higher in the pubertal diabetic children compared with the control children. There was a significant positive correlation between leptin and daily insulin dose in the diabetic group. Circulating adiponectin concentrations were higher in the prepubertal diabetic children and were positively associated with HbA(1c). Resistin concentrations were lower in the prepubertal non-diabetic subjects compared with the pubertal non-diabetic children, whose values were higher than those of the diabetic children. TNF-alpha concentrations were similar in non-diabetic and diabetic children.Conclusions Circulating concentrations of adipocytokines are abnormal in Type 1 diabetic children, although the direction of change differs by cytokine. Pubertal development, in addition to insulin treatment and glycaemic control, also influences the concentrations.

Controversial data are available on the association between the retrovirus-like long-terminal repeat (LTR) DQ-LTR13 and genetic susceptibility to type 1 diabetes and other autoimmune diseases. We analyzed DNA samples from 315 type 1 diabetic patients, 166 autoimmune Addison's disease (AAD) patients, 1,054 healthy subjects, and 144 families of type 1 diabetic offspring. DQ-LTR13 was more frequent among patients than healthy subjects (P(c) < 0.0006), and a preferential transmission of DQB1*0302-LTR13(+) from parents to type 1 diabetic offspring was observed. DQ-LTR13 was in linkage disequilibrium (LD) with DQB1*0302 but not DQB1*0201. The presence of DQ-LTR13 increased the odds ratio of DQB1*0302 2.9- to 3.2-fold for type 1 diabetes and AAD. DRB1*0403 was absent in all of the 169 DRB1*04-positive patients but present in 27% (34 of 127) DRB1*04-positive healthy subjects (P(c) < 0.001). DQ-LTR13 was detected in 1 of 34 (3%) DRB1*0403-positive healthy subjects and 36 of 93 (39%) individuals carrying another DRB1*04 allele (P(c) = 0.002). Multivariate logistic regression analysis revealed that DQ-LTR13 is not independently associated with type 1 diabetes and AAD after correction for DQB1*0302 and DRB1*0403. Conversely, DQB1*0201, DQB1*0302, DRB1*0401, and DRB1*0403 were all significantly associated with disease risk also after correction for DQ-LTR13. We provide conclusive evidence that the genetic association of DQ-LTR13 with type 1 diabetes and AAD is primarily due to a LD with DQB1*0302 and DRB1*0403.

Objective To study the circulating levels of two gut-derived peptides in children with type 1 (insulin-dependent) diabetes mellitus (IDDM).Research Design and Methods Plasma levels of ghrelin, both total ghrelin (TG) and the acylated form (AG), and galanin and their relationships with insulin dosage, metabolic control, IGFBP-1, body mass and pubertal development were evaluated in 91 children, aged 11.1 +/- 2.7 years, affected by IDDM and treated with insulin. Ninety-one healthy children were selected as controls.Results Body mass index (BMI)-adjusted levels of both forms of ghrelin were reduced in IDDM compared with healthy subjects, with greater values in prepubertal than pubertal IDDM subjects. A negative association was found between AG and fasting insulin serum levels and insulin resistance [measured by using the homeostasis model assessment of insulin resistance (HOMA IR)] among the healthy children. IDDM children showed a negative association of their plasma ghrelin (both acylated and total) with daily insulin dosage, and the three adiposity indices (BMI, skinfold thickness and percentage fat mass). IGFBP-1 levels were higher among the IDDM children without any association with ghrelin serum values. BMI-adjusted plasma levels of galanin were higher among IDDM compared to healthy subjects, irrespective of sex or pubertal development. Greater values for galanin were found among pubertal than prepubertal subjects in both groups without any significant differences between the genders. A positive association was found between galanin and BMI in both groups and between galanin and haemoglobin A(1c) (HbA(1c)) among the IDDM children. No relationship existed between either galanin and fasting serum insulin among the healthy subjects or galanin and both insulin dosage or duration of treatment among the IDDM subjects.Conclusions The associations found between both ghrelin and galanin with adiposity indices could be considered as an indirect signal of involvement of the two peptides in the development of the nutritional status of the IDDM adolescents. The reduction in both forms of ghrelin could be involved in the development of the body mass increase of IDDM subjects with opposite effects, either influencing insulin sensitivity or exerting a compensatory restraint of feeding.

In order to define serum leptin values in children, its concentration was assayed in 3,453 children, 5-14 years old, and body mass index (BMI) and pubertal development were recorded. Insulin, testosterone (in males) and 17beta-estradiol (in females), the sum of four skinfold thicknesses (SST), waist-to-hip ratio, and body fat mass were also determined in 1,601 children. Analysis of multicollinearity effects on estimated models demonstrated a quasi-linear correlation between SST and BMI, the former being prevalent. Although other variables were strongly correlated with leptin, assuming only SST as predictor, R2 yielded a value of 0.711 in males and 0.607 in females. When the other variables were added, R2 increased by about 0.03 in both sexes. BMI and SST were the most important of all the predictors and each can act as a sort of proxy for the others. When the z-scores of BMI of all 3,453 children were subdivided into deciles, any correlation with leptin was no more significant inside each BMI z-score range. This study demonstrates that subcutaneous fat mass may be considered the prevalent determinant factor. The adopted statistical procedure furnished results useful for reference values based on BMI z-score as a simple and appropriate evaluation for serum leptin concentrations in children.

Objective: To examine the hypothesis of an influence of leptin on growth factors and on biochemical markers of bone turnover of prepubertal overweight children. Design and Methods: 395 prepubertal children, 6–13 years of age, were selected and the relationships between circulating serum levels of leptin and insulin-like growth factor I (IGF-I), insulin growth factor binding protein-3 (IGFBP-3) and some biochemical markers of bone turnover (osteocalcin, OC; carboxyterminal propeptide of type I procollagen, PICP, and carboxyterminal propeptide of type I collagen, ICTP) were analyzed. The subjects were subdivided into normal weight (NW, n = 163) and weight excess (WE, n = 232) subjects. Results and Conclusions: Significant differences between the two groups were found for leptin (p < 0.01), IGF-I (p < 0.01) and IGFBP-3 (p < 0.01), with higher values in WEs, and for OC (p < 0.01) with higher values in NWs. A significant reduction of leptin (p < 0.01) and IGFBP-3 (p < 0.01) serum values and an increase of those of OC (p < 0.01) and PICP (p < 0.05), but not of ICTP, were registered in 103 WEs who showed a drop in weight excess during a weight-excess reduction program. No variations were observed in 26 non-responsive subjects. In a multivariate analysis in which leptin, corrected by BMI and sex, was the independent variable, a significant negative correlation was found with PICP (β = –0.235, p < 0.01), IGF-I (β = –0.180, p < 0.01) and height velocity (β = –0.155, p < 0.01). There was no correlation with OC, ICTP and IGFBP-3. The results demonstrate that nutritional status and leptin levels are involved in the regulation of growth factors and biochemical markers of bone formation.

BACKGROUND:Leptin concentrations as a predictor of weight excess (WE) variations in obese children continue to be controversial.AIM AND DESIGN:To evaluate the relationship between fasting leptin serum concentrations and the ability to maintain loss of WE during obesity treatment, 172 (82 males and 90 females) overweight children and adolescents (OW), 6-16 yr old, were recruited. The subjects were retrospectively selected among those who had demonstrated a reduction of their WE during an initial phase of 12 months of a WE reduction programme (WERP). Fasting serum levels of leptin were assayed, together with insulin, triacylglycerol and cholesterol, before (time 0) and at the end of the first phase of WERP (time 1), and BMI (Z-score) was determined at time 0, time 1 and at the end (time 2) of a subsequent second phase of 12 months. OW were subdivided according to wether their Z-BMI showed a persistent reduction also during the second phase (maintaining WE reduction subjects or MS) or showed a subsequent increase after the reduction observed during the first phase (relapsing WE subjects or RS).RESULTS:A significant reduction in serum levels of leptin, insulin and lipids, paralleling Z-BMI reduction, was observed at the end of the first phase of WERP, during which we found a correlation between the decrease in serum leptin concentrations and the decrease in Z-BMI. The decrease in RS during the first phase ((deltalgL(0-1) was significantly greater when compared to that observed in MS (p < 0.05). In two different multiple logistic regression analyses, where RS = 0 and MS = 1, serum leptin at time 1 [odds ratio (OR) = 1.08; 95% confidence interval (CI) = 1.04-1.13] and deltalgL(0-1) (OR = 0.48; 95% CI = 0.25-0.92), together with final pubertal stage (OR = 0.78; 95% CI = 0.63-0.96), were significantly associated with final subject status.CONCLUSIONS:Leptin serum levels after a previous WE reduction and its parallel decline are related to subsequent adiposity outcome. The lower the leptin serum concentration after previous WE reduction and/or the greater its decrease, the greater was the probability of WE relapse.

Objective : The prevalence of overweight and obesity was estimated among the school children and adolescents of three provinces of central Italy, and the role of several possible influencing factors was analysed. Design, subjects and measurements : Body mass index (BMI) was measured in 44 231 subjects, age 3–17.5 y, and a household questionnaire was filled out by the parents of 12 143 subjects to collect the following data: subjects , only child or firstborn status, prematurity, birth weight, type of feeding until the fifth month, menarche status in girls; parents , age at the time of the subject's birth; BMI (mean of the two parents) at the time the subject was measured, mother's age of menarche, socioeconomic status. BMI was measured in a subgroup of 10 795 subjects 1 y later to study the yearly sex- and age-related variations from the categories of normal weight to overweight or obesity and vice versa. All females aged 11–14 y were asked if they had their menarche. Results : Striking differences in the proportions of overweight and obesity resulted from the use of two different criteria for defining cutoff points. The overall prevalence of overweight was 13.2 and 20.7% in males, and 13.7 and 18.6% in females, and the overall prevalence of obesity varied between 24.2 and 6.3% in males, and between 22.9 and 6.1% in females, respectively. Parents' BMI, birth weight, firstborn status and post-menarche status in girls showed a significant association with overweight and/or obesity in logistic regression models. Conclusions : A large prevalence of overweight and obesity was observed in school subjects from three provinces of central Italy. From the comparisons of the prevalence rate, the new internationally agreed criteria seem more appropriate for epidemiological studies in this population. Sponsor : University of Perugia, Region of Umbria, Commune of Perugia.

Objective: To evaluate the dependence of body mass index (BMI) values on pubertal stage in subjects similar in age. Design, subjects and measurements: Height and weight were recorded cross-sectionally in school subjects from three provinces in central Italy. The subjects were subdivided into three groups: (1) 4271 school subjects (2125 males and 2146 females; 8.5–15.5 y old), in whom the pubertal development was also recorded, were selected to subdivide BMI values according to pubertal stage and age; (2) 6345 females (10.5–14.5 y old), who were asked whether or not they had had their first menstrual period, were selected to subdivide BMI values according to age in pre-menarche and post-menarche girls, separately; and (3) 1919 females (10.5–14.5 y old), who had presented their menarche within the previous 6 months, were selected to subdivide short-term post-menarche BMI values according to age. Results: The medians and interquartile ranges of BMI varied according to age and pubertal stage. Kruskall–Wallis test performed in subjects similar in age demonstrated that significant differences existed among the medians of BMI values of subjects at different pubertal stages in 12–14-y-old males (P<0.05), and in 11–14-y- old females (P<0.001). The difference also proved to be significant between stage I and stage II (P<0.05) in 10-y-old females, but not in 10–11-y-old males. The Kruskal–Wallis test performed in subjects similar in pubertal stage demonstrated that significant differences among the medians of BMI at different ages existed only in females at stages II and III. A significant positive trend was observed in both genders according to pubertal stage for BMI values of subjects similar in age (z-test for trend, P<0.01). On the contrary, a negative age trend proved to be significant in females at stages I (P<0.01), II (P<0.01) and III (P<0.001), but not in males when the subdivision of BMI was made according to age in subjects similar in pubertal stage. BMI values were significantly higher in post-menarche girls as compared to pre-menarche girls similar in age (P<0.001). However, at partial regression analysis BMI values were influenced by pubertal stage and, to a lesser extent, by age, but not by menarcheal status. An inverse association between short-term post-menarche BMI and age was observed, with the highest values in girls presenting menarche at 11 y of age (P<0.05). The negative trend was demonstrated at the z-test for trend (P<0.001). Conclusions: BMI values depend on pubertal degree of maturation, especially in girls. This influence should be taken into account when BMI is evaluated in adolescents. Sponsor: University of Perugia, Region of Umbria. Eyropean Journal of Clinical Nutrition (2000) 54, 214–218

BACKGROUND: A role for leptin to predict weight gain is still controversial. OBJECTIVE AND DESIGN: To determine the relationship between baseline serum leptin values and responsiveness to an educational-based weight excess reduction program (WERP), 418 (241 males and 185 females) obese subjects, aged 9–15 y, were recruited. WERP required 2 y of follow-up. Body mass index (BMI) was evaluated at baseline and at each semester of follow-up. The obese subjects were subdivided into responsives and non-responsives, according to reduction or not of their BMI Z -scores during the WERP. Leptin concentrations were assayed at baseline and were included together with other independent variables in statistical multiple regression analysis. RESULTS: At a preliminary multiple regression analysis, a significant positive correlation between leptin values and BMI Z -score reduction at the second, third and fourth semester of follow-up was registered. To determine the odds ratio of the subjects who were responsive or non-responsive at the various semesters of WERP follow-up, a stepwise logistic regression was used incorporating the same predictors, with the serum leptin values subdivided into quintiles and responsiveness and non-responsiveness as a binary outcome variable. The model offered a satisfying goodness of fit as shown by the sensitivity and specificity. The odds ratio of being responsive were significantly increased by greater quintiles of leptin serum concentrations. Furthermore, such odds ratios were much higher in pubertal than in prepubertal subjects. CONCLUSIONS: These findings support a significant role for serum leptin concentration in predicting BMI changes as a response to an educational excess weight reduction program.

Objective: The influence of weight excess reduction on height and height velocity of obese subjects should be evaluated on the basis of appropriate standards, since the pattern of growth of obese subjects is different from that of normal weight subjects. Design, subjects and measurements: Height, weight and triceps skinfold thickness were recorded from 17 987 school subjects (9256 males and 8731 females), 3–18 y of age, from three provinces of central Italy, and a growth reference curve of height was constructed. Using BMI (as computed using the tables of Rolland-Cachera et al) and triceps skinfold thickness, normal-weight subjects (NWS) and obese subjects (OS) were identified and specific reference curves (mean±s.d. every sixth month of age) were developed for both groups. Centiles of height were also calculated for OS. Various (2–4) measurements of height in school subjects were performed and a graph of height velocity (HV) was constructed in NWS and in OS using the JPPS method. The yearly mean ±s.d. of HV was also calculated, based on square root transformed data (in order to realise a Gaussian distribution), deriving from successive measurements in total subjects, in NWS and in OS. The z-scores of height and of the square root of HV were calculated in 217 obese subjects (125 males and 92 females) before and during a weight excess reduction programme (WERP). Obese subjects in WERP who showed a reduction of z-score of BMI were considered as ‘responsive’; those who either maintained or showed an increase of z-score of BMI were considered as ‘non-responsive’. Obese subjects in WERP were followed for 1–4 y, giving the following results: 0–1 y, 142 responsives and 75 non-responsives; 0–2 y, 76 responsives and 33 non-responsives; 0–3 y, 35 responsives and 30 non-responsives; 0–4 y, 24 responsives and 18 non-responsives. Results: Compared to NWS, OS showed a significantly greater HV in 4–9 y males and in 4–8 y females, but in older children the pubertal spurt was reduced and more precocious. As a result, the height of OS, which was greater in 3–13 year-old males and in 3–11.5 year-old females, subsequently showed a reduction, as compared to that of NWS, in 16–18 year-old males and in 13–18 year-old females. In both responsive and non-responsive groups of obese subjects in WERP, the z-scores of height showed a reduction during WERP when evaluated using the reference curve of the total school population. In contrast, when their growth was evaluated according to the obese-specific reference curve, no significant variation was observed comparing both z-scores before and during the WERP. Conclusions: More appropriate information on the growth of obese subjects may be obtained when evaluating the height and HV according to obese-specific reference standards from the same population of origin. Adopting this modality, no significant variation of height resulted during WERP in obese children.

OBJECTIVE: Body mass index (BMI) was determined in a population of school students from three provinces of central Italy. Fasting serum leptin concentrations were assayed in a large number of subjects from the same area, to determine their distribution as plotted against the standard deviation score ( z -score) of BMI. DESIGN, SUBJECTS AND MEASUREMENTS: Height and weight were recorded from 31 170 subjects (16 175 male and 14 995 female), aged 3–18 y, to construct BMI charts of children and adolescents from central Italy. Percentiles and z -score were calculated using the LMS method of Cole. Serum leptin concentrations were assayed in 1929 subjects (996 male and 933 female) after overnight fasting. RESULTS: BMI percentiles of central Italy were higher than those from standards of other European and USA populations. When plotted against the z -score of BMI, serum leptin values were distributed according to an exponential curve, showing a steep pattern and a wide distribution, as BMI values increased. The hypothesis of the existence of two subgroups, based on a different relation between leptin and BMI, was verified and a separation point between the two subgroups was identified using cluster analysis, discriminant analysis and a novel method developed by our group, hereafter referred to as ‘regression clustering’. This method allows identification of the value of the independent variable ( z -score of BMI) which can be taken as a separation point. This analysis provided the best results and indicated the following separation points: central Italy standard, z -score=0.72 (76.4 th percentile) for males and z -score=0.69 (75.5 th percentile) for females; French standard (the one suggested for a European population by the European Childhood Obesity Group, ECOG), z -score=1.46 (92.8 th percentile) for males and z -score=1.96 (97.5 th percentile) for females. Similar but variable results were obtained when the same analysis was performed on serum leptin concentration, subdivided according to pubertal development (stage I, stage II–III, stage IV–V). CONCLUSIONS: Children and adolescents from central Italy had greater BMI percentiles when compared to other European populations. Fasting serum leptin concentrations showed a distribution pattern related to z -score, thus allowing to identification of two different subgroups. The z -scores of BMI, identified as separation points, indicated a trend to leptin production by adipocytes that could be taken as indicators of significant increases of fat mass. This study proposes criteria and a statistical approach that could be useful in the identification of BMI cut-off values when screening children and adolescents for overweight.

We measured fasting serum levels of type I procollagen C-terminal propeptide (PICP), insulin-like growth factor-I (IGF-I), and IGF binding protein-3 (IGFBP-3) in obese children and adolescents (obese subjects [OS]) to evaluate their relationship to growth, gender, pubertal stage, and weight excess (WE). The influence of insulin, growth hormone (GH), and weight loss was also studied. The study population consisted of 244 OS and 236 normal-weight subjects (NWS) matched for age, gender, and pubertal stage. At stage I, OS had a higher standard deviation score (SDS) for height than NWS of both genders. During the prepubertal phase, growth velocity (GV) was greater in OS than in NWS of both genders, but it was lower in female OS at stage II and male OS at stage III. PICP increased in puberty, with a more rapid decrease later in female OS and NWS; prepubertal values were higher in OS but were reduced at pubertal stage IV to V in comparison to NWS. Stepwise multiple regression analysis demonstrated that GV was the only anthropological variable correlating with PICP. IGF-I serum values increased significantly in puberty and were higher in OS than in NWS at stage I for both genders. IGFBP-3 values of OS exceeded those of NWS at stages I to III in males and I to II in females. No difference was observed for males versus females in each group, nor was any difference observed for the IGF-I/IGFBP-3 molar ratio between the two groups. Using stepwise analysis, a positive correlation between IGF-1 and IGFBP-3 was observed in prepubertal but not in pubertal NWS. Fasting insulin values correlated with IGFBP-3 in OS, accounting for 24.8% of the variation in prepubertal subjects and 17.1% in pubertal subjects. No such correlation was observed in NWS. In prepubertal NWS, PICP and SDS of body mass index (BMI) correlated with IGF-I, accounting for 12.9% of the variation, and SDS of BMI correlated with IGFBP-3, explaining 27.8% of the variation. In prepubertal OS, no such correlations could be observed, but PICP and SDS of BMI accounted for 14.3% of the variation in the IGF-I/IGFBP-3 molar ratio. A significant reduction of IGFBP-3 and an increase of the IGF-I/IGFBP-3 molar ratio were detected after weight loss in 40 OS. In conclusion, we demonstrated that IGF-I and IGFBP-3 are influenced by age, gender, sexual development, and nutritional status. Also, an influence of insulin on IGFBP-3 serum levels was observed in OS. The relations of IGF-I to PICP in NWS and of the IGF-I/IGFBP-3 molar ratio to PICP in OS support the concept of IGF-I influence on skeletal growth. The increased IGFBP-3 serum values in OS suggest a possible role in controlling the growth stimulus induced by nutritional status.

OBJECTIVE: Leptin, the product of the ob gene, is present in higher concentrations in blood of obese subjects than of lean subjects. There is scarce information on the role of leptin in the pathogenesis of human obesity and little is known about leptin serum levels in obese children. DESIGN, SUBJECTS AND MEASUREMENTS: To evaluate the influences of age, sex, pubertal development and weight excess on serum leptin levels, we have studied 390 obese subjects (OS) and 320 normal weight subjects (NWS) aged 5–16 y. Fasting insulin concentrations were assayed in NWS, and an oral glucose tolerance test was carried out in OS and total insulin area under the curve (TIA) was calculated. RESULTS: Log-transformed values of leptin serum concentrations appeared to be distributed according to an acceptable Gaussian pattern. As observed in adults, serum leptin concentrations in children and adolescents were also increased (4–5 times) in OS as compared to NWS. In both males and females, subdivided according to pubertal stages, serum leptin varied significantly in stage IV–V as compared to the lower stages, with a reduction in males and an increase in females. On comparing the two sexes, greater serum leptin concentrations were observed in females of both NWS and OS. A significant linear correlation was found in both groups, subdivided according to sex and pubertal stage, between log values of serum leptin and standard deviation scores (SDS) of body mass index (BMI), and log-transformed relative body weight (RBW). Using partial correlation analysis in subjects subdivided according to sex and pubertal stages, log values of serum leptin and fasting insulin values, adjusted by age and SDS of BMI, correlated significantly with a weaker correlation in males than in females. In OS, the leptin concentrations correlated better with TIA than with fasting insulin. A weight reduction program (WRP) was carried out in 141 OS and significant reductions of serum leptin and fasting insulin were observed, showing a reduction of RBW. There was a correlation between the reduction of RBW and of serum leptin, but not of fasting insulin. No variation was found in non-responsive OS. RBW reduction correlated with leptin, but not with insulin (fasting and TIA), evaluated before the therapeutic program started. CONCLUSION: As observed in adults, obese children and adolescents have higher serum leptin concentrations. However, several conditions should be taken into account when evaluating leptin concentrations in children. There are differences, independent of BMI, relative to pubertal stage and sex, females having greater leptin concentrations than males. There is evidence of a possible role for leptin in the effectiveness of a weight reduction program in OS.