Meeli Saar

Elevated Serum IL-6, IL-8, MCP-1, CRP, and IFN-γ Levels in 10- to 11-Year-Old Boys with Increased BMI

Background/Aims: Many inflammation parameters are associated with obesity, but few comparable data are found in youth. This study aims to characterize the differences in serum levels of 13 biochemical inflammatory markers between boys with increased BMI and boys with normal BMI, and examine the relationships between inflammation markers, skinfold thicknesses, and body composition. Participants/Methods: The participants were 38 boys (BMI above 85th percentile) and 38 boys (normal BMI) at the age of 10–11 years. Measurements included BMI, 9 skinfold thicknesses, waist and hip circumferences, and total body and trunk fat mass and percentage as indices of obesity, fasting insulin, glucose, and serum concentrations of IL-2, IL-4, IL-6, IL-8, IL-10, VEGF, IFN-γ, TNF-α, IL-1α, IL-1β, monocyte chemoattractant protein-1 (MCP-1), epidermal growth factor, and CRP. Results: Overweight boys (OWB) were taller and more frequently in puberty than normal-weight boys (NWB). Skinfold thicknesses and body composition parameters were higher in OWB. They had significantly higher serum IL-6, IL-8, IFN-γ, MCP-1, and CRP values compared to NWB. Conclusions: Six of 13 measured biochemical markers were significantly increased in OWB, indicating that many low-grade inflammatory processes are already involved in the development of obesity in childhood.

Physical Activity and Bone Mineral Accrual in Boys with Different Body Mass Parameters during Puberty: A Longitudinal Study

The aim of our longitudinal study was to investigate the relationships between physical activity and bone mass in boys with different body mass status during the years surrounding pubertal growth spurt. Two hundred and six boys entering puberty took part in this study. The subjects were divided into underweight (), normal weight (), overweight () and obese () groups at baseline according to age related categories. Whole-body DXA scans were performed at baseline, after 12 and 24 months to assess body composition (lean body mass, fat mass), and total body (TB), lumbar spine (LS) and femoral neck (FN) bone mineral density (BMD) parameters. Physical activity was measured by 7- day accelerometry. For longitudinal analysis, multilevel fixed effects regression models were constructed. Biological age, height and lean body mass had an effect for explanation of TB BMD, FN BMD and LS BMD. Moderate to vigorous physical activity (MVPA), vigorous physical activity (VPA) and sedentary time (SED) had the significant effect only on FN BMD. Being an underweight boy at the baseline indicated greater chance (p<0.01) to have lower TB BMD in the future (2 years at follow up) development, compared to normal weight (estimates = −0.038), overweight (estimates = −0.061) and obese boys (estimates = −0.106).

Relationships between finger-length ratios, ghrelin, leptin, IGF axis, and sex steroids in young male and female swimmers

The aim of this study was to investigate possible relationships between different right-hand finger-length ratios and different fasting hormone concentrations in young swimmers. Fifty-five young swimmers participated in this study (26 boys and 29 girls, aged 10–17 years). The original method of Visnapuu and Jürimäe (J Strength Cond Res 21:923–929, 2007) was used for the measurement of length parameters of the hand. The following finger-length ratios were calculated: 1D:2D, 1D:3D, 1D:4D, 1D:5D, 2D:3D, 2D:4D, 2D:5D, 3D:4D, 3D:5D, and 4D:5D. All finger-length ratios were significantly higher in girls compared with boys. Ghrelin, leptin, testosterone in boys, estradiol in girls, insulin-like growth-factor I (IGF-I), IGFBP-3, and insulin were analyzed. Leptin and insulin concentrations were lower in boys compared with girls. In both groups, the relationships between finger-length ratios and basic anthropometric parameters were not significant. In girls, estradiol correlated negatively with 2D:3D (r = −0.51) and 2D:4D (r = −0.49) finger ratios. In boys, ghrelin concentration correlated with most of the finger-length ratios (r = 0.37–0.40). In girls, the relationship of ghrelin with the 2D:3D (r = 0.45) and 2D:4D (r = 0.48) finger ratios was significant. In boys, but not in girls, IGF-I (r = 0.42) and IGFBP-3 (r = 0.44) correlated only with the 2D:4D finger ratio. Leptin and insulin did not correlate with the finger-length ratios. In boys, the most important hormone to characterize several finger-length ratios was ghrelin (13.7–15.6% variance accounted for). Ghrelin and testosterone together accounted for 20.3% (R2 × 100) of the variance in the 2D:4D ratio. In girls, estradiol was correlated with the 2D:3D ratio (25.7%) and estradiol in combination with ghrelin with the 2D:4D ratio (30.0%). In conclusion, ghrelin appears to be a further biochemical parameter in addition to the sex steroids which correlated with different digit-length ratios at least in boys.

SELF-PERCEIVED AND ACTUAL INDICATORS OF MOTOR ABILITIES IN CHILDREN AND ADOLESCENTS

The aim of the study was to estimate the correlations between self-perceived and actual indicators of fitness in children and adolescents of different age and sex. A total of 525 boys and girls, ages 10 to 17 years (divided into the four age groups) were studied. Self-perceived fitness (fitness, endurance, strength, flexibility, and body composition) was assessed using a slightly modified version of a questionnaire by Delignieres, Marcellini, Brisswalter, and Legros, which was described by Lamb and Haworth. The following EUROFIT tests were used: 20-m endurance shuttle-run, hand-grip dynamometry, and sit-and-reach. Nine skinfolds were summarized as a body-composition parameter. The subjects significantly perceived their endurance, flexibility (except 10- to 11-yr.-olds), and body composition (except 10- to 11-yr.-old boys). Correlations between handgrip dynamometry and perceived strength were not significant.

Negative correlation between serum IL-6 level and cardiorespiratory fitness in 10- to 11-year-old boys with increased BMI

Abstract Background/Aims: Some markers of inflammation have been found to be associated with cardiorespiratory fitness levels, but only few studies have studied this in overweight children. The aim of this study was to investigate associations between markers of inflammation and the fitness levels measured by peak oxygen consumption (VO2peak and VO2peak/kg) in boys with increased body mass index (BMI) and with normal BMI. Participants/Methods: Subjects were 38 boys with BMI above 85th percentile (OWB) and 38 boys with normal BMI (NWB) at the age of 10 to 11 years. Serum concentrations of IL-2, IL-4, IL-6, IL-8, IL-10, VEGF, IFNγ, TNF-α, IL-1α, IL-1β, MCP-1, EGF, CRP and associations with measured cardiorespiratory fitness levels were studied. High-sensitive chips were used to measure 13 markers of inflammation. Results: Mean VO2peak was significantly higher (2.1±0.3 vs. 1.8±0.3 L/min; p<0.05) and mean VO2peak/kg significantly lower (33.7±4.7 vs. 48.9±6.4 mL/min/kg; p<0.05) in OWB than in NWB group. Out of 13 measured biochemical markers IL-6 correlated with VO2peak/kg (r=–0.37; p<0.05) and TNF-α with VO2peak (r=0.41; p<0.01) in OWB. BMI and IL-6 together explained 44.5% of the variability of VO2peak/kg in the OWB group. Conclusions: Overweight boys had lower cardiorespiratory fitness level measured by VO2peak/kg and this was negatively correlated with serum IL-6 level. Measurement of serum IL-6 level in overweight boys may help to identify subjects who need specific exercise formats to achieve maximal beneficial health effects and to reduce their risk for the development of type 2 diabetes and atherosclerosis later in life.

Sports participation outside school in total physical activity of children.

This study of associations of sports participation with perceived and actual physical fitness, and total physical activity for 525 10- to 17-yr.-old boys and girls in groups of 10–11-yr. (56 boys and 64 girls), 12–13-yr. (68 boys and 68 girls), 14–15-yr. (70 boys and 71 girls), and 16–17-yr. (68 boys and 60 girls) was based on the Physical Activity Index derived from a questionnaire by Telama, Leskinen, and Young, and self-perceived endurance, strength, flexibility, and body composition. Questions about satisfaction with physical activity, participation in organized physical activity and competitions, or watching competitions were asked. Two EUROFIT tests were used, the 20-m endurance shuttle-run and sit-and-reach, plus the sum of 9 skinfold thicknesses. Children who participated in organized physical activity and in competitions had a higher Physical Activity Index. Passive watching of competitions was not related to childrens physical activity or their perceived or measured motor abilities.

Osteocalcin is inversely associated with adiposity and leptin in adolescent boys.

Abstract Background/Aims: Recently, osteocalcin (OC), an osteoblast-derived hormone, has been found to correlate with adiposity, adipocytokines and insulin resistance in adults, but few studies have investigated this in children. The aim of this study was to investigate these associations in adolescent boys, for whom it is a time of significant bone mineral accrual, taking into account possible confounders related to adipose and bone tissues. Participants/Methods: Participants were 141 adolescent boys (mean age 13.9±0.7 years), who were divided into tertiles according to OC levels. Across these groups, differences in total body fat mass (FM), body fat distribution, adiponectin, leptin and insulin resistance values were examined with relation to age, pubertal stage, daily energy and calcium intakes, and physical activity. Results: Mean body mass index (BMI), FM, body fat% and leptin differed significantly between subjects in the three OC tertiles after adjustment for age, pubertal stage, energy and calcium intakes, and physical activity. There were no differences in fat free mass (FFM), bone mineral content, energy and calcium intakes, physical activity, adiponectin and insulin resistance values between study groups. For the entire cohort, mean serum OC was 130.2±45.2 ng/mL and was related to body mass, BMI, FM, body fat distribution and leptin. Circulating OC was not associated with FFM, daily energy and calcium intakes, physical activity, adiponectin or insulin resistance (insulin, glucose, homeostasis model assessment-insulin resistance) values. Conclusions: In male adolescents, OC is inversely related to body adiposity and leptin values, even after consideration of several factors that may affect bone and adipose tissues.

Adipocytokine and Ghrelin Levels in Relation to Body Composition in Rhythmic Gymnasts Entering into Puberty: A Three-Year Follow-Up Study

The aim of this study was to describe longitudinal changes in body composition, leptin, adiponectin, and ghrelin over a 36-month period in prepubertal rhythmic gymnasts (RG) and their age-matched untrained controls (UC) entering into puberty. Thirty-five RG (8.0 ± 0.6 yrs) and 33 UC (8.2 ± 0.6 yrs) were followed at 12-month intervals for the next 3 years. Height, weight, pubertal stage, body composition, leptin, adiponectin, and ghrelin were measured at each time points. The pubertal development over the next 36 months was slower in the RG compared with UC. Leptin was increased in UC and remained unchanged in RG over 3-year study period (3.7 ± 3.6 vs. 0.2 ± 1.1 ng/ml; p < .05). In RG, baseline leptin was negatively correlated with the change in body fat percentage over a 36-month period (r = -0.34; p < .05). The change in adiponectin over the study period was negatively correlated with the change in BMI (r = -0.43; p < .05). RG had relative leptin deficiency per body fat mass. In conclusion, relatively high leptin concentration at the beginning of puberty may predict those girls who do not increase their body fat percentage through coming years and therefore may have increased risk for delayed puberty.

Plasma visfatin and adiponectin concentrations in physically active adolescent girls: relationships with insulin sensitivity and body composition variables.

Abstract The purpose of this study was to evaluate the associations of visfatin and adiponectin concentrations with insulin resistance and body composition in regularly physically active pubertal girls. In 129 girls, aged 13–15 years (pubertal stages 3–5), visfatin, adiponectin, insulin resistance measured by homeostasis model assessment (HOMA), and body composition measured by dual-energy X-ray absorptiometry were evaluated. Visfatin concentration was related to HOMA and overall adiposity (body mass index, fat mass) markers, whereas adiponectin concentration was related to overall adiposity (fat mass), central adiposity (trunk fat) and fat free mass values. These relationships remained significant (p<0.05) after adjusting for pubertal stage. Visfatin was independently related to body mass index (β=0.936; p=0.0001) and HOMA (β=0.444; p=0.039) indices, whereas adiponectin was independently related to fat free mass (β=0.889; p=0.003) and trunk fat (β=–0.468; p=0.042) values. In conclusion, visfatin could be related to insulin resistance and overall adiposity indices, whereas adiponectin was related to different body composition values in regularly physically active pubertal girls.

Role of physical activity in bone health in peripubertal boys.

The aim of the present cross‐sectional study was to investigate the relationship of physical activity level to bone mineral parameters in 11–13‐year‐old boys.