Adiposity Criteria in Assessing Increased Cardiometabolic Risk in Prepubertal Children.

Objective: Adiposity induces the clustering of cardiometabolic risk factors, and pediatric adiposity is a better indicator for adulthood cardiometabolic diseases than pediatric metabolic syndrome. However, the observed prevalence of pediatric adiposity depends on the methods and cut-points used. Therefore, we aimed to define diagnostic criteria for adiposity which enable more valid identification of prepubertal children at increased cardiometabolic risk. Methods: The participants were 470 prepubertal children (249 boys) aged 6-8 years. The measures of adiposity included body mass index-standard deviation score (BMI-SDS), waist-to-height ratio (WHtR) and body fat percentage (BF%) assessed by bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA). Criteria for adiposity were determined by increased cardiometabolic risk. Cardiometabolic risk factors which correlated with BF% assessed by DXA in the upper but not lower half of BF% (serum insulin and plasma high-density lipoprotein cholesterol, triglycerides, gamma-glutamyl transferase, high-sensitivity C-reactive protein and uric acid) were included in the cardiometabolic risk score (CMS). We computed receiver operating characteristics curves for the measures of adiposity using the ≥90th percentile of CMS as a measure of increased cardiometabolic risk, and local regression curves were graphed to demonstrate the associations of the measures of adiposity with CMS. Results: In girls, WHtR of 0.445 (area under curve 0.778, its 95% confidence interval 0.65-0.91, sensitivity and specificity 0.73) and BF% of 19.5% assessed by BIA (0.801, 0.70-0.90, 0.73) were the best overall criteria for increased cardiometabolic risk. In boys, BMI-SDS of 0.48 (0.833, 0.75-0.92, 0.76) was the best overall criterion for increased cardiometabolic risk. While local regression curves in girls showed that WHtR of 0.445 corresponds well to a point where CMS began to increase, in boys local regression curves suggest that CMS began to increase even at a lower level of BMI-SDS than 0.48. Moreover, the diagnostic ability of the measures of adiposity to exclude increased cardiometabolic risk was poorer than the ability to detect it. Conclusions: In general, the measures of adiposity have sufficient diagnostic accuracy to be utilized as the screening tool for increased cardiometabolic risk. The observed cut-points for adiposity were lower than the traditional cut-points for adiposity.

Comparison between parameters from maximal cycle ergometer test first without respiratory gas analysis and thereafter with respiratory gas analysis among healthy prepubertal children.

It is important to distinguish true and clinically relevant changes and methodological noise from measure to measure. In the clinical practice, maximal cycle ergometer tests are typically performed first without respiratory gas analysis and thereafter, if needed, with respiratory gas analysis. Therefore, we report a comparison of parameters from maximal cycle ergometer exercise tests that were done first without respiratory gas analysis and thereafter with it in 38 prepubertal and healthy children (20 girls, 18 boys). The Bland-Altman method was used to assess agreement in maximal workload (WMAX), heart rate (HR), and systolic blood pressure (SBP) between rest and maximum. Girls achieved higher WMAX in the exercise tests with respiratory gas analysis compared with exercise tests without respiratory gas analysis (p = 0.016), whereas WMAX was similar in the tests among boys. Maximal HR (proportional offset, -1%; coefficients of variation, 3.3%) and highest SBP (proportional offset, 3%; coefficients of variation, 10.6%) were similar in the tests among children. Precision and agreement for HR improved and precision for SBP worsened with increasing exercise intensity. Heteroscedasticity was not observed for WMAX, HR, or SBP. We conclude that maximal cycle ergometer tests without and with respiratory gas analysis can be used consecutively because measurement of respiratory gases did not impair performance or have a significant effect on the maximality of the exercise tests. Our results suggest that similar references can be used for children who accept or refuse using a mask during a maximal exercise test.

Determinants of cardiorespiratory fitness in men aged 42 to 60 years with and without cardiovascular disease.

Good cardiorespiratory fitness has been found to protect against cardiovascular diseases and type 2 diabetes. The purpose of this study was to investigate determinants of directly measured cardiorespiratory fitness (maximal oxygen uptake [VO2max]), including age, body composition, prevalent diseases, cardiovascular and pulmonary functions, biochemical factors, physical activity, nutrition, smoking, and alcohol consumption, in a population-based study of 936 men 42 to 60 years of age. Variables that had the strongest direct associations with VO2max (milliliters per minute) in a linear multivariate step-up regression model were body weight, heart rate at maximal exercise, mean intensity and frequency of conditioning physical activity, intake of carbohydrates, blood hemoglobin, and forced expiratory volume in 1 second. The strongest inverse associations with VO2max were heart rate at rest, age, fasting serum insulin, waist-to-hip ratio, coronary heart disease, and asthma. This model accounted for 67% of the variation of VO2max. In conclusion, mean intensity, frequency, and duration of conditioning physical activity were associated directly with VO2max. However, measurements of the function of pulmonary and cardiovascular systems, carbohydrate intake, and body composition were powerful determinants of cardiorespiratory fitness, especially in older middle-aged men.