Early-onset metabolic syndrome in prepubertal obese children and the possible role of alanine aminotransferase as marker of metabolic syndrome.

INTRODUCTION: Obesity is often associated with increased serum alanine aminotransferase (ALT), and elevation of ALT is a marker of non-alcoholic fatty liver disease which is caused in part by insulin resistance, the essential characteristic of metabolic syndrome (MS). We evaluated the prevalence of MS in prepubertal obese children and the usefulness of ALT as an MS marker. PATIENTS: 120 obese children (6.3 ± 1.6 years old) and 50 normal-weight controls (5.3 ± 2.0 years old) were included. Patients were classified as having MS if they met ≥ 3 of the following criteria: body mass index >97th percentile, triglycerides >95th percentile, high-density lipoprotein cholesterol <5th percentile, systolic (SBP) and/or diastolic (DBP) blood pressure >95th percentile, fasting blood glucose 100 mg/dl and/or impaired insulin sensitivity with homeostasis model assessment for insulin resistance >97.5th percentile. ALT levels were also evaluated. RESULTS: MS occurred in 16.6% of obese patients. Significant differences were present in body mass index (p < 0.001), SBP (p = 0.002) and DBP (p < 0.001) between non-MS and MS obese patients; laboratory data, except total cholesterol, were significantly different in the two groups. The strongest association with MS (as evaluated by the c-statistic) was found for insulin and homeostasis model assessment for insulin resistance (c = 0.92 and 0.91, respectively); also, DBP and SBP showed good discrimination ability (c = 0.73 and 0.72, respectively). ALT levels in the MS group were higher than in the non-MS group (p = 0.02) and associated with MS (p = 0.001; c = 0.69). CONCLUSION: MS is a consequence of obesity already in very young children. Also, pathological serum ALT levels were significantly correlated with MS and might be considered a marker for defining MS, though confirmation in a longitudinal study is called for.

Thyroid ultrasound in patients with Turner syndrome: influence of clinical and auxological parameters.

OBJECTIVES: To determine thyroid volume and structure by ultrasound (US) in patients with Turner syndrome (TS) compared to healthy controls; to evaluate the frequency and characteristics of autoimmune thyroid disease (ATD) and its association with clinical and auxological parameters. PATIENTS: 73 patients and 93 height-matched healthy female controls in the same age range were included in the study. RESULTS: Thirty-two TS patients (43.8%) presented ATD. They had a larger body mass index (BMI) and presented the 45,X karyotype more frequently than those without. They were older, with a higher prevalence of lymphoedema at birth and pterygium colli without statistical significance. Thyroid volume was 20% larger in the presence of ATD (p=0.037). A dyshomogeneous thyroid structure was observed in all patients with ATD and less frequently in those without (p=0.016). Dyshomogeneity in TS without ATD was also associated with older age (p<0.001), larger BMI (p=0.003) and larger thyroid volume (p=0.006). Six TS patients presented solitary thyroid nodules (5 benign nodules). We observed a significant interaction between diagnosis and height (p=0.035) and age (p=0.047), indicating that both age and height conditioned the observed differences in thyroid volume. CONCLUSIONS: Most TS patients presented ATD with a normal thyroid function or subclinical hypothyroidism, without goiter. Dyshomogeneous thyroid structure was also observed in TS patients without ATD. In TS, the evaluation of thyroid volume according to chronological age does not seem to be efficient because of a link between height and thyroid volume. The prevalence of nodular thyroid disease is similar to that observed in the general population.

Prevalence of metabolic syndrome (MS) in children and adolescents with varying degrees of obesity.

OBJECTIVE: Childhood obesity is increasingly common and is associated with health problems; in particular, obesity plays a central role in the metabolic syndrome (MS). We estimated the prevalence of MS in Caucasian children and adolescents with varying degrees of obesity. PATIENTS AND METHODS: We studied 191 obese [body mass index (BMI) > 97th percentile] children and adolescents. Obesity was stratified on the basis of a threshold BMI z-score and subjects were classified as moderately (z-score 2-2.5) or severely obese (z-score > 2.5). Seventy-six, nonobese subjects were recruited into a comparison group. Thirty-one of them were of normal weight (BMI < 75th percentile) and 45 overweight (BMI 75th-97th percentile). Patients were classified as having MS if they met three or more of the following criteria for age and sex: BMI > 97th percentile, triglyceride levels > 95th percentile, high density lipoprotein (HDL) cholesterol level < 5th percentile, systolic or diastolic blood pressure > 95th percentile and impaired glucose tolerance (blood glucose level: 7.8-11.1 mmol/l at 2 h). Insulin resistance was calculated using the homeostasis model assessment for insulin resistance (HOMA-IR) and impaired insulin sensitivity was defined as a HOMA-IR > or = 2.5 in prepubertal patients and HOMA-IR > 4 in pubertal subjects. RESULTS: The overall prevalence of MS was 13.9% and was present in 12.0% of moderately obese and 31.1% of severely obese subjects; no overweight or normal weight subjects met the criteria for MS. The rate of the MS increased progressively with increasing BMI categories (P < 0.001). Severely obese patients had a threefold increased risk with respect to moderately obese patients. CONCLUSIONS: The prevalence of the MS is higher in obese as opposed to nonobese subjects and increases with severity of obesity.