Effects of obstructive sleep apnea severity on serum lipid levels in Greek children with snoring

Although obstructive sleep apnea (OSA) is related to dyslipidemia in adults, limited data are available regarding its effects on serum lipids during childhood. Aim of this study was to assess the potential relationships between severity of OSA and cholesterol or triglyceride levels in a cohort of Greek children. Data from children with snoring who underwent polysomnography and complete serum lipids measurements during a specified study period were analyzed retrospectively. Overall, obese children (n = 261) had lower HDL cholesterol levels than non-obese subjects (n = 113) (49.6 +/- 10.5 vs. 53.9 +/- 11.4 mg/dL; p = 0.001) and higher triglyceride concentrations (69.8 +/- 32.2 vs. 63.2 +/- 27 mg/dL; p = 0.041). Non-obese subjects with moderate-to-severe OSA did not differ in triglycerides, total, and LDL cholesterol concentrations but had lower HDL cholesterol, when compared to non-obese children with primary snoring/mild OSA (50.4 +/- 13.1 vs. 54.9 +/- 10.7 mg/dL; p = 0.008). The risk for having low HDL cholesterol (a parts per thousand currency sign40 mg/dL) was threefold higher in non-obese subjects with moderate-to-severe OSA than in those with primary snoring/mild OSA, even after adjustment for age and gender [OR = 3.44 (95% CI 1.44 to 8.24; p = 0.006)]. Concentrations of serum lipids in obese children were not associated with severity of OSA. HDL cholesterol was 48.5 +/- 8.7 mg/dL in subjects with moderate-to-severe OSA and 50.0 +/- 11.1 mg/dL in children with primary snoring/mild OSA (p = 0.519). HDL cholesterol levels are inversely related to severity of OSA in non-obese children with snoring

Are there differences in performance, metabolism, and quadriceps muscle activity in black African and Caucasian athletes during brief intermittent and intense exercise?

The purpose of the present study was to determine whether there are any differences in power output (PO) and/or quadriceps muscle (Quad) activity between black African and Caucasian football players during a force-velocity (fv) exercise test, which consisted of performing maximal 6-s sprints against an increasing load. Each subject started the test with a load of 2 kg and then recovered for 5 min before repeating the same test with a load increased by 2 kg. When the pedal frequency did not exceed 130 rev·min–1, the load was increased by only 1 kg. Each subject attained the load corresponding to his maximal power if an additional increase in load (+1 kg) induced a power decrease. Nine black Africans (mean age 24.2 ± 3.3 years) and nine Caucasians (24.7 ± 4.2 years) (matched for stature and aerobic fitness) participated in the fv exercise test. During the test, PO, blood lactate, and the quadriceps electromyography (EMG) root mean square (Quad RMS) were assessed. Higher blood lactate was observed in Caucasians than in black Africans for POs over the load range from 4 kg up to the maximal power. However, PO and Quad RMS values were similar in Caucasians and black Africans. They also had similar lean leg volume (LLV) and consequently produced similar PO/LLV and Quad RMS/LLV values. Overall, our results suggest that Caucasians and black Africans matched for stature, max, and training background have similar PO and Quad RMS values, but different blood lactate concentrations during brief, intermittent, intense exercise performed on a cycloergometer