Distribution of cardiorespiratory fitness in children and adolescents at different latitudes.

OBJECTIVE: To explore the differences and characteristics of cardiorespiratory fitness (CRF) among children and adolescents in regions with different latitudes in China. METHODS: A total of 9892 children and adolescents aged 7-22 years were selected from seven administrative regions in China by the stratified cluster random sampling method. CRF was measured by performance on the 20 m shuttle run test (20mSRT) and estimated maximal oxygen consumption (VO2max ). One-way ANOVA, one-way ANCOVA, and the Lambda Mu and Sigma methods were used to analyze the data. RESULTS: Overall, the VO2max of children and adolescents at high latitudes was significantly lower than that of children at low and middle latitudes. The P10 , P50 , and P90 20mSRT values for children and adolescents of most age groups in high latitudes were less than those in low and middle latitudes. The 20mSRT-Z and VO2max -Z scores among children and adolescents aged 7-22 in high latitudes were lower than those in middle and low latitudes after adjusting for age, per capita gross domestic product (GDP), and per capita disposable income. CONCLUSION: In general, the CRF of children and adolescents at high latitudes was less than that at low and middle latitudes. Effective measures should be taken to improve CRF in children and adolescents at high latitudes.

Medium-term follow-up of clinically insignificant residual fragments after minimal invasive percutaneous nephrolithotomy: prognostic features and risk factors.

Minimal invasive percutaneous nephrolithotomy (MPCNL) has been commonly used in removing urinary stones. However, the detrimental effects of clinically insignificant residual fragments (CIRF) after MPCNL have not been entirely clarified. This study is aimed at investigating the clinical outcomes of CIRF after MPCNL. From July 2004 to June 2010, 1862 cases of urolithiasis underwent MPCNL. 185 cases of CIRF were subsequently diagnosed using CT scanning and followed up. During follow-ups, medical history, physical examination, routine blood and urine tests, subjective symptoms were recorded. A multiple-variable Cox regression was performed to evaluate the prognostic significance of different factors for CIRF after MPCNL. Of 185 cases of CIRF followed up for 31.4 months on average, 58 cases (31.4%) suffered symptomatic episodes, including 30 cases of hematuresis, 21 cases of low urinary tract symptoms and 7 cases of hematuresis complicated with renal colic. The results of Cox regression showed that past history of extracorporeal shock wave lithotripsy (ESWL), CIRF size, hypercalcuria and CIRF located in ureteropelvic junction (UPJ) are independent risk factors for medium-term symptomatic episodes of CIRF after MPCNL. We suggest that regular follow-ups should be considered for patients with CIRFs after MPCNL for timely treatments, especially for those who are hypercalcuria-complicated, have history of ESWL, or suffer relatively large CIRFs located in the UPJ.