Body fat composition: a predictive factor for obstructive sleep apnea

OBJECTIVE: To investigate body fat composition, measured by bioelectrical impedance assay (BIA), for predicting the presence and severity of obstructive sleep apnea-hypopnea syndrome (OSAHS). Body fat composition was also compared with other well-known OSAHS predictors such as body mass index (BMI), neck circumference, and abdominal visceral fat. STUDY DESIGN: A prospective study was designed. Fifty-one patients (41 male, 10 female), who were referred to Hacettepe University Faculty of Medicine, Department of Otorhinolaryngology, Head and Neck Surgery with suspected OSAHS, between April 2003 and June 2004, were included in the study. METHODS: All patients underwent polysomnography (PSG) and were classified according to their apnea-hypopnea index (AHI) into four groups. The cross-sectional area of abdominal visceral fat was measured by computed tomography (CT) scanning in 33 of the patients. Neck circumference and BMI was measured for all patients. BIA was performed to determine body fat composition. The groups were compared, and correlation of the variables with AHI was investigated. RESULTS: Of the variables, BMI and percentage of body fat (determined by BIA) were found to be significantly correlated with AHI (r = 0.782, r = 0.647). CT of cross-sectional area of abdominal visceral fat provided 100% sensitivity and specificity (P < .001) in differentiating simple snorers from OSAHS patients. By combining percentage of body fat and body fat mass, higher levels of sensitivity (95%) and specificity (100%) were achieved for diagnosis of OSAHS. CONCLUSION: It was concluded that the BIA could be an inexpensive and practical alternative to prePSG screening tests and should be included in the evaluation of OSAHS patients.     

Pancreatic enzyme therapy and clinical outcomes in patients with cystic fibrosis

OBJECTIVE: To assess the relationship between pancreatic enzyme therapy (PET) and the clinical outcomes of growth, abdominal pain, constipation, gassiness, and number of stools in cystic fibrosis (CF). STUDY DESIGN: Patients (n = 1215) >4 weeks of age from 33 Cystic Fibrosis Foundation accredited sites who had a sweat chloride >60 mmol/L or two CF-causing mutations were enrolled using a proportionate sampling strategy in a nonblinded study. Patients submitted a stool sample and completed a questionnaire. The study coordinator also completed a questionnaire for each patient. Enzyme dosing and growth, abdominal pain, gassiness, constipation, and number of stools were compared. RESULTS: Of the 1215 enrolled patients, 1131 (93.1%) were prescribed PET. Only 14.9% had pancreatic function assessed before enrolling in this study. Stool elastase-1 analysis identified 1074 (89%) patients as pancreatic insufficient (PI). There was no association between PET and the outcomes: growth, abdominal pain, gassiness, constipation, and number of stools. CONCLUSION: PET dose is not correlated with growth or gastrointestinal symptoms. More sensitive outcome measures of the effectiveness of PET in patients with CF are needed to guide treatment of PI.     

Effect of long-term transfusion on growth in children with sickle cell anemia: results of the STOP trial

OBJECTIVE: To determine whether long-term transfusion improves growth in children with sickle cell anemia. STUDY DESIGN: In the Stroke Prevention Trial for Sickle Cell Anemia Study, patients were randomized to receive long-term transfusion (CTX) or standard care (STC). Transfusions were administered every 3 to 5 weeks, and hemoglobin S levels were maintained at 30% pretransfusion for an average of 2 years. Serial height and weight measurements (obtained every 3 months), body mass index (BMI) values, and growth z-scores were analyzed. RESULTS: Children in the CTX (n=53) and STC (n=41) groups were similar at baseline. After 24 months, the z-scores for height, weight, and BMI of those receiving CTX had improved significantly, whereas no changes occurred in the STC group. Patients in the CTX group approached normal height-for-age and weight-for-age z-scores. Patients from a large historical control group had significantly lower weight and height growth velocities than patients in the CTX group. CONCLUSIONS: Patients in the Stroke Prevention Trial for Sickle Cell Anemia Study who received CTX had improved height and weight and BMI over a 2-year period. Higher hemoglobin levels resulting from transfusion may improve growth by lowering energy expenditure. In addition to the prevention of vasoocclusive events, CTX results in significant improvement in the growth of children with sickle cell disease.     

Development of anthropometry-based equations for the estimation of the total body water in Koreans

For developing race-specific anthropometry-based total body water (TBW) equations, we measured TBW using bioelectrical impedance analysis (TBW(BIA)) in 2,943 healthy Korean adults. Among them, 2,223 were used as a reference group. Two equations (TBW(K1) and TBW(K2)) were developed based on age, sex, height, and body weight. The adjusted R2 was 0.908 for TBW(K1) and 0.910 for TBW(K2). The remaining 720 subjects were used for the validation of our results. Watson (TBW(W)) and Hume-Weyers (TBW(H)) formulas were also used. In men, TBW(BIA) showed the highest correlation with TBW(H), followed by TBW(K1), TBW(K2) and TBW(W). TBW(K1) and TBW(K2) showed the lower root mean square errors (RMSE) and mean prediction errors (ME) than TBW(W) and TBW(H). On the Bland-Altman plot, the correlations between the differences and means were smaller for TBW(K2) than for TBW(K1). On the contrary, TBW(BIA) showed the highest correlation with TBW(W), followed by TBW(K2), TBW(K1), and TBW(H) in females. RMSE was smallest in TBW(W), followed by TBW(K2), TBW(K1) and TBW(H). ME was closest to zero for TBW(K2), followed by TBW(K1), TBW(W) and TBW(H). The correlation coefficients between the means and differences were highest in TBW(W), and lowest in TBW(K2). In conclusion, TBW(K2) provides better accuracy with a smaller bias than the TBW(W) or TBW(H) in males. TBW(K2) shows a similar accuracy, but with a smaller bias than TBW(W) in females.     

Body shape and composition in HIV-infected women: an urban cohort

OBJECTIVES: Alterations in body shape and composition are associated with HIV/AIDS. Wasting remains prevalent; increasingly, lipodystrophy is reported. Obesity is also epidemic in the USA. In this study, we sought to characterize the body changes reported by women attending a US urban clinic, and to evaluate contributing factors using inexpensive methods that are readily available in clinical practice. METHODS: In an urban Maryland clinic, a cross-section of HIV-infected women were evaluated by self report, anthropomorphic measurements, bioelectric impedance analysis (BIA) and chart review; they were categorized as no change, lipodystrophy, weight loss/wasting or weight gain/obesity. RESULTS: One hundred and sixty-one women were evaluated: 144 (89%) were African-American; 100 (62%) had used intravenous drugs and 40 (25%) were actively injecting drugs, while 39 (24%) smoked crack. Ninety-five (59%) were on highly active antiretroviral therapy (HAART) for a median period of 11.7 months [interquartile range (IQR)=4.5-24.2]. Since starting current HAART or in the previous year, 12 (7.4%) reported lipodystrophy changes, 85 (52.8%) weight gain, 27 (16.8%) overall weight loss, and 37 (23.0%) no change. Lipodystrophy was associated with higher CD4 percentage (P=0.03), lower frequency of crack use (P=0.04) and higher educational level (P=0.03). Weight loss correlated with longer duration of infection (P=0.01), select BIA results and increased rate of crack use (P=0.005). Weight gain was associated with higher fat mass (P=0.005), higher peak viral load (P=0.02), and lower rate of intravenous drug use (P=0.03). CONCLUSIONS: Self-reported changes in body shape were common. Obesity and complications of illicit drug use were more prevalent than lipodystrophy in this inner-city population of HIV-positive women.     

Effects of body posture on local sweating and sudomotor outflow as estimated using sweat expulsion

To estimate the effects of changes in body posture on sudomotor function, sweat rates on the forearm, chest and thigh, tympanic temperature (Tty), and skin temperatures were recorded in an upright sitting and a supine position under a hot environment of 40 degrees C Ta and 40% relative humidity for 60 min. Sweat expulsions were identified on sweat rate curves and their rates (Fsw) were calculated. Tty was higher, and its initial fall was greater, in the supine position than in the sitting position. On the forearm and the chest, the regression line relating sweat rate to mean body temperature (Tmb) had a gentler slope in the supine position, whereas on the thigh, it showed a steeper slope. The regression line relating Fsw to Tmb had a steeper slope in the supine position than in the sitting position, suggesting that the gain in the mechanisms for central integration and rhythm-generation was enhanced in the supine position. The parameter of sweat rate divided by Fsw was lower on the forearm and the chest, whereas it was higher on the thigh in the supine position than in the sitting position, suggesting that sudomotor outflow was modified at the spinal cord in association with skin pressure. It was concluded that body posture affects sudomotor functions through both brain and spinal mechanisms.     

Impact of exercise on overnight glycemic control in children with type 1 diabetes mellitus

OBJECTIVE: To examine the effect of exercise on overnight hypoglycemia in children with type 1 diabetes mellitus (T1DM). STUDY DESIGN: At 5 clinical sites, 50 subjects with T1DM (age 11 to 17 years) were studied in a clinical research center on 2 separate days. One day included an afternoon exercise session on a treadmill. On both days, frequently sampled blood glucose levels were measured at the DirecNet central laboratory. Insulin doses were similar on both days. RESULTS: During exercise, plasma glucose levels fell in almost all subjects; 11 (22%) developed hypoglycemia. Mean glucose level from 10 pm to 6 am was lower on the exercise day than on the sedentary day (131 vs 154 mg/dL; P=.003). Hypoglycemia developed overnight more often on the exercise nights than on the sedentary nights (P=.009), occurring on the exercise night only in 13 (26%), on the sedentary night only in 3 (6%), on both nights in 11 (22%), and on neither night in 23 (46%). Hypoglycemia was unusual on the sedentary night if the pre-bedtime snack glucose level was>130 mg/dL. CONCLUSIONS: These findings indicate that overnight hypoglycemia after exercise is common in children with T1DM and support the importance of modifying diabetes management after afternoon exercise to reduce the risk of hypoglycemia.     

Annual increase in body mass index in children with asthma on higher doses of inhaled steroids

There is a greater annual increase in body mass index in children with asthma receiving inhaled steroids at a dose > or =400 microg/day (0.5 kg/m2/year; n=100) compared with those receiving < or =200 microg/day (0.1 kg/m2/year; n=98) (P=.0003). This is consistent with an annual increase in body fat in children with asthma receiving > or =400 microg/day of inhaled steroids.     

哌甲酯对学龄期注意缺陷多动障碍患儿生长发育影响的评价

目的探讨长期服用哌甲酯对广州地区青春期前注意缺陷多动障碍(ADHD)患儿身高、体重增长的影响。方法以146例ADHD患儿为用药组,其中男126例,女20例,在连续服用哌甲酯0.27~0.64mg/kg的过程中追踪2~4年余。另观察29例能坚持不服用哌甲酯的ADHD患儿作为对照组,其中男23例,女6例,同样随访2~4年。以1995年全国学生体质调查数据为正常生长指标对照,记录其身高、体重的变化,并分析相关影响因素。结果用药组治疗前、后身高与同龄均值绝对差距(简称身高绝对差距)的变化值为(-1.86±0.82)cm(P<0.001);治疗前、后身高标准差评分(SDS)变化为-0.14±0.23(P<0.001)。对照组身高绝对差距变化值为(-0.26±0.51)cm,身高SDS变化值为+0.05±0.10。经Pearson相关分析和多元逐步回归分析均提示疗程是治疗前、后身高绝对差距变化值的最主要影响因素(P<0.001)。第1~4年的平均生长速度,第1年下降,第2年起回升(分别为4.28cm/年、4.90cm/年、4.98cm/年和4.95cm/年,P<0.001)。治疗前、后体重与身高别体重绝对差距(简称体重绝对差距)的变化值为(-0.14±1.25)kg(P>0.05)。结论长期服用哌甲酯对ADHD患儿生长发育的抑制作用,表现为身高增长的减慢。而且疗程越长,身高增长减慢越明显。其中身高增长减速以第1年最显著。对体重无显著影响。     

The Preterm Prediction Study: association between maternal body mass index and spontaneous and indicated preterm birth

OBJECTIVE: The purpose of this study was to evaluate the relationship between prepregnancy maternal body mass index and spontaneous preterm birth and indicated preterm birth. STUDY DESIGN: This was a secondary analysis of the Maternal-Fetal Medicine Units Network, Preterm Prediction study. Patients were classified into categories that were based on their body mass index. Rates of indicated and spontaneous preterm birth were compared. RESULTS: Five hundred ninety-seven (20.5%) of 2910 women were obese. Obese women had fewer spontaneous preterm births at < 37 weeks of gestation (6.2% vs 11.2%; P < .001) and at < 34 weeks of gestation (1.5% vs 3.5%; P = .012). Women with a body mass index of < 19 kg/m2 had 16.6% spontaneous preterm birth, with a body mass index of 19 to 24.9 kg/m 2 had 11.3% spontaneous preterm birth, with a body mass index of 25 to 29.9 kg/m2 had 8.1% spontaneous preterm birth, with a body mass index of 30 to 34.9 kg/m2 had 7.1% spontaneous preterm birth, and with a body mass index of > or = 35 kg/m2 had 5.2% spontaneous preterm birth (P < .0001). Indicated delivery was responsible for an increasing proportion of preterm births with increasing body mass index (P = .001). Obese women had lower rates of cervical length < 25 mm (5% vs 8%; P = .012). Multivariable regression analysis confirmed a lower rate of spontaneous preterm birth in obese gravid women (odds ratio, 0.57; 95% CI, 0.39-0.83; P = .003). CONCLUSION: Obesity before pregnancy is associated with a lower rate of spontaneous preterm birth.