Thyroid hormone levels and BMI-SDS changes in adolescents with obesity.

Background: Thyroid hormones play an important role in energy metabolism and weight control, explained mostly by inducing thermogenesis and increasing basal metabolic rate. It has recently been shown that FT4 levels are associated with food preferences, which might also play a role in modulating body weight. The aim of this longitudinal follow-up study was to analyze the relationship of thyroid hormones levels (FT4, TSH) at baseline with weight/BMI-SDS changes in children and adolescents with obesity. Methods: Three hundred seventy-seven children and adolescents have been enrolled to this study and followed up without a systematic intervention program for 5.59 ± 1.85months. Children and adolescents were divided into three subgroups: 1) 144 adolescents with obesity (15-19 years), 2) 213 children with obesity (10-14.9 years), and 3) 20 lean adolescents (15-19 years). Thyroid hormones were measured at the baseline, and anthropometry was performed at the baseline and during the follow-up. For further analyses, participants were divided according to the BMI-SDS change into two groups: 1. with BMI-SDS decrease, and 2. with BMI-SDS increase. Results: Adolescents with obesity from the BMI-SDS decrease group had significantly lower baseline serum levels of TSH compared to the BMI-SDS increase group (2.4 ± 1.0 vs. 3.2 ± 2.0mIU/l; p=0.005). Similar difference was found for FT4 levels (14.7 ± 2.2 in the BMI-SDS decrease group vs. 15.5 ± 2.7pmol/l in the BMI-SDS increase group, p=0.048). Moreover, the BMI-SDS decrease was present in significantly higher percentage of adolescents with obesity with lower than median TSH level compared to those with higher than median TSH level at baseline (61.1% vs 38.6%, p=0.011). Likewise, the BMI-SDS decrease was present in significantly higher percentage of adolescent females with obesity and lower than median FT4 compared to those with higher than median FT4 level at baseline (70.6% vs. 23.5%, p<0.001). No associations of baseline thyroid hormones with the BMI-SDS change were observed in children with obesity or lean adolescents. Conclusion: Adolescents with obesity and increased BMI-SDS during the follow-up had significantly higher baseline levels of both TSH and FT4 compared to BMI-SDS decrease group. These results support the previous findings that higher FT4 in individuals with obesity may influence weight gain.

Food preferences and thyroid hormones in children and adolescents with obesity.

Background: Thyroid hormones profoundly affect energy metabolism but their interrelation with food preference, which might contribute to childhood obesity development, are much less understood. In this study, we investigated if thyroid hormone levels are associated with specific modulation of food preference and potentially linked to the level of obesity in children and adolescents. Methods: Interrelations between food preference and peripheral thyroid activity were examined in a population of 99 non-obese and 101 obese children and adolescents (12.8 ± 3.6 years of age, 111/89 F/M) randomly selected from the patients of the Obesity and Metabolic Disease Out-patient Research Unit at National Institute for Children's Diseases in Bratislava in a period between December 2017 and March 2020. Results: Children and adolescents with obesity had a lower preference for food rich in high sucrose and high-complex carbohydrates, while the preference for protein and fat-containing food and that for dietary fibers did not differ between obese and nonobese. In adolescents with obesity, free thyroxine (FT4) correlated positively with the preference for a high protein and high fat-rich diet, irrespective of the fatty acid unsaturation level. Moreover, FT4 correlated negatively with the preference for dietary fibers, which has been also exclusively found in obese adolescents. Individuals with obesity with higher FT4 levels had higher systemic levels of AST and ALT than the population with lower FT4. Multiple regression analysis with age, sex, BMI-SDS, and FT4 as covariates revealed that FT4 and male gender are the major predictors of variability in the preference for a diet high in protein, fat, and monounsaturated fatty acids. FT4 was the sole predictor of the preference for a diet containing saturated and polyunsaturated fatty acids as well as for a diet low in fiber. Conclusion: The link between free thyroxin levels and dietary preference for food rich in fat and protein is present exclusively in individuals with obesity. Higher serum FT4 was linked with elevated AST and ALT in children and adolescents with obesity, and FT4 was the best predictor for preference for food rich in fat and low in fiber. This may indicate that FT4 could contribute to the development of childhood obesity and its complications by modulating food preference.

The prevalence of melanocortin-4 receptor gene mutations in Slovak obese children and adolescents.

Melanocortin-4 receptor (MC4R) deficiency is the most frequent monogenic form of obesity. The contribution of MC4R mutations to the Slovak population has not been investigated as yet. We screened the coding sequence of the MC4R gene in a cohort of 210 Slovak obese children and adolescents. We identified four different mutations in four patients, giving a mutation detection rate of 0.95%. Of these, three were missense mutations previously identified and characterized by other research groups (p.R7C, p.S127L and p. R305W, respectively). One was a novel nonsense mutation p.W174* detected in a severely obese 7-year-old boy. This mutation was further analyzed in family segregation analysis and exhibited variable penetrance. Two known amino acid polymorphisms (p.V103I and p.I251L) were also identified in seven subjects of our cohort group. We also performed multifactorial statistical analysis to determine the influence of genotypes on standard biochemical blood markers. No significant influence was observed in carriers of DNA variants on tested parameters. We conclude that rare heterozygous MC4R mutations contribute to the onset of obesity only in a few cases in the Slovak population.

Is arterial stiffness predicted by continuous metabolic syndrome score in obese children?

The aim of the article was to evaluate arterial stiffness, an early marker of increased cardiovascular risk, in relation to obesity. The continuous metabolic syndrome (cMetS) score was calculated as sum of Z score of mean arterial pressure, body mass index, serum glucose, triglyceride, and high-density lipoprotein cholesterol in 144 obese patients and 66 nonobese controls. Ambulatory arterial stiffness index (AASI) was calculated as 1 minus regression slope of diastolic on systolic blood pressure from ambulatory blood pressure measurements. The mean AASI increased progressively with severity of obesity. The receiver operator curve analysis of body mass index and AASI showed area under the curve of 0.64 ± 0.06; cMetS area under the curve was 0.72 ± 0.05 suggesting a better predictive power of the cMetS for an increased AASI (>0.3). Patients with obesity have significantly higher arterial stiffness. A composite score such as cMetS seems to be better predictor of an increased stiffness than individual risk factors.

Evaluation of lipid and glucose metabolism and cortisol and thyroid hormone levels in obese appropriate for gestational age (AGA) born and non-obese small for gestational age (SGA) born prepubertal Slovak children.

AIM: Obesity is the major determinant of metabolic syndrome. Being born small for gestational age (SGA) may be co-responsible. We aimed at evaluating the association between 1. obesity and 2. being born SGA and the presence of endocrine-metabolic abnormalities in prepubertal Slovak children. METHODS: The study included 98 children, aged 3-10.9 years: 36 AGA-born obese children (OB), 31 SGA-born children (SGA) and 31 appropriate for gestational age born non-obese children (AGA). Fasting serum levels of glucose, total cholesterol, LDL, HDL, triglycerides, fT4, TSH, cortisol and insulin were determined. HOMA-IR was calculated. Personal data about birth weight and length and family history were collected. Actual anthropometric measurement was done. RESULTS: In every group, high prevalence of positive family history of metabolic disorder was found. In comparison with AGA children, OB children were taller (p<0.01) with higher body mass index (BMI) (p<0.001), and had increased insulin levels and homeostasis model assessment for insulin resistance (HOMA-IR) (p<0.001), decreased high-density lipoprotein (HDL) (p<0.001), and a trend to higher cortisol levels (p=0.069) was noted. SGA-born children were shorter (p<0.001), with BMI comparable to the AGA group. They had higher glucose levels (p<0.001), a trend to decreased HDL levels (p=0.085) and increased fT4 levels (p<0.001). A three-fold higher occurrence of metabolic abnormalities was present in obese children and twice more metabolic abnormalities were present in SGA-born children in comparison with AGA-born children. CONCLUSIONS: SGA-born children are more prone to developing endocrine-metabolic abnormalities than non-obese children born AGA, but they are at less risk than obese AGA-born children. We should provide specialized care for obese children already in prepubertal age and pay attention to SGA-born children.

Food intake, leisure time activities and the prevalence of obesity in schoolchildren in Slovakia.

AIM OF THE STUDY: In 2006-2008 a survey analyzing food patterns, intake of main food items and leisure time activities of 5,410 schoolchildren was carried out. METHODS: The study was performed in 13 randomly selected regions of Slovakia. 5,410 elementary school children (2,848 girls and 2,562 boys) aged from 6.3 to 15.9 years, mean age was 11 +/- 2.6 years, were included. The data collected by questionnaire concerned nutrition and leisure time activities. RESULTS: Noteworthy results are that only 63% of participants eat breakfast regularly. Almost all of the children eat lunch during workdays regularly and 60.9% prefer a cooked (hot) dish for supper. Although dairy products are a substantial part of child nutrition, in general their consumption in our sample was low. Only 50.1% of children consume these daily and 62% of children drink milk daily, more often boys than girls. A striking observation is that only 65.5% of interviewed pupils eat fruit every day and 30.9% of them eat vegetables daily. The frequency of consumption of poultry and pork in our sample was almost the same, however, the analysis showed that only 14% of children consume fish once per week. Moreover, only 12.6% of subjects prefer wholegrain bread. In our sample 56.8% of children eat sweets daily, 32% prefer a salty snack almost 2 times per week. Within the group of pupils 35.8% do not attend physical trainings even once a week. Almost every child is used to watch TV and 64% of them play PC games daily. While both girls and boys watched TV on average over 2 hours, boys spend more time on PC per day than girls (girls 0.72 hours per day vs. boys 1.13 hours per day, p < 0.001). The food patterns and leisure time activities of children older than 11 years and rural pupils were less favourable. CONCLUSIONS: According to results of our analysis we recommend to increase the consumption of dairy products, fresh fruits and vegetables in Slovak schoolchildren and spare no effort in making children to take breakfast regularly. It is necessary to promote daily moderate physical activity. Nutritional and lifestyle education should begin already in childhood.