Dorothy F.Y. Chan

Hepatic steatosis in obese Chinese children

OBJECTIVES: The aims of our study were: (1) to determine the prevalence of asymptomatic hepatic steatosis and presumed nonalcoholic steatohepatitis, in our local population of obese Chinese children referred for medical assessment; and (2) to assess the correlation between severity of ultrasonographic hepatic steatosis and degree of obesity, insulin resistance and serum biochemical abnormalities.DESIGN: Cross-sectional study.METHODS: In total, 84 obese children, 25 girls and 59 boys with median age and body mass index (BMI) of 12.0 years (interquartile range (IR): 9.5–14.0) and 30.3 kg/m2 (IR: 27.1–33.4), respectively, referred for medical assessment were studied. All subjects underwent physical examination, anthropometric and dual energy X-ray absorptiometry (DEXA) scan measurements and real-time ultrasonographic (US) examination of the liver. Fasting blood samples were collected for the measurement of liver function, hepatitis status, levels of serum glucose and insulin and lipid profile. Degree of fatty infiltration of the liver was graded according to ultrasonic appearance of liver echotexture, liver–diaphragm differentiation in echo amplitude, hepatic echo penetration and clarity of hepatic blood vessels.RESULTS: All recruited subjects had no history of alcohol abuse and tests for Hepatitis B or C virus were negative. Thorough examination showed all of them to be in general good health without signs of chronic liver disease. Hepatic steatosis identified by defined ultrasonic appearances was diagnosed in 65 subjects (77%); 17 girls and 48 boys. The severity of fatty liver was positively related to anthropometric measurements including BMI, waist and hip circumference, subscapular skinfold thickness; insulin resistance markers [QUICKI and homeostasis model assessment (HOMA)], and hypertriglyceridaemia. Multvariate ordinal regression analysis showed that BMI and raised alanine aminotransferase (ALT) were positively associated with fatty liver. Combination of hepatic steatosis with raised ALT (presumptive NASH) was found in 19 subjects (24%). This group of patients had significantly higher waist hip ratio and conicity index compared to those with isolated hepatic steatosis. Boys with presumed NASH were also found to have significantly higher insulin resistance.CONCLUSION: Nonalcoholic fatty liver disease (NAFLD) was common among our cohort of obese children referred for medical assessment. The prevalence of simple steatosis and presumed NASH was 77 and 24%, respectively. The severity of US steatosis was positively correlated with BMI, raised ALT, insulin resistance and hypertryglyceridaemia. Ultrasonography being noninvasive and readily available could be used for the monitoring of the progression of hepatic steatosis. Further longitudinal studies are required to determine the natural disease progression and the role of insulin resistance and other factors in the pathophysiology of NAFLD.

The effects of obesity on pulmonary function

Aims: (1) To determine the predominant pulmonary function abnormality in our population of obese children; and (2) to assess the correlation between the severity of lung function impairment and the degree of obesity as assessed by dual energy x ray absorptiometry (DEXA). Methods: Sixty four obese patients underwent physical examination, standardised pulmonary function tests (spirometry, lung volumes, and single breath diffusion capacity for carbon monoxide), and DEXA scan measurements. The trunk and subtotal (total − head) body fat mass were used as surrogate index of body adiposity. Results: Sixteen girls and 48 boys with median age and body mass index (BMI) of 12 years (interquartile range (IQR): 10–14) and 30.1 kg/m2 (IQR: 27.2–32.8) respectively were studied. None of the patients had clinical evidence of cardiopulmonary disease. Reduction in functional residual capacity (median FRC 93% predicted, IQR: 68.5–116.5%) and impairment of diffusion capacity (median DLco 83.5% predicted, IQR: 70.0–100.7%) were the most common abnormalities in our cohort, being observed in 30 (46%) and 21 (33%) patients respectively. Obstructive ventilatory impairment was found in three patients. There was significant negative correlation between the degree of reduction of FRC but not DLco with DEXA scan measurements, but such a relation was not found when BMI was used as the indicator of obesity. Conclusion: Reduction in FRC and diffusion impairment were the commonest abnormalities found in our cohort of obese patients. Reduction in static lung volume was correlated with the degree of obesity.

Waist circumference and body mass index in Chinese children: cutoff values for predicting cardiovascular risk factors

Background:Body mass index (BMI) and waist circumference (WC) correlate with cardiovascular (CV) risk factors in childhood which track into adulthood. WC provides a measure of central obesity, which has been specifically associated with CV risk factors. Reference standards for WC, and for WC and BMI risk threshold values are not established in Chinese children.Objectives:To construct reference percentile charts of WC, establish relationships between WC, BMI and other risk factors, and propose WC and BMI threshold values predictive of CV risk factors in Hong Kong ethnic Chinese children.Methods:Weight, height, waist and hip circumference were measured in 2593 (52% boys, 47% girls) randomly sampled Hong Kong school children aged 6–12 years. In 958 of these and 97 additional overweight children (n=1055), the relationships between WC, BMI, waist/hip and waist/height ratio and six age-adjusted CV risk factors (>85% percentile levels of blood pressure (BP), fasting triglycerides, low-density lipoprotein (LDL) cholesterol, glucose and insulin levels, and <15% percentile levels of high-density lipoprotein (HDL) cholesterol) were studied. Receiver-operating characteristic analysis was employed to derive optimal age-adjusted sex-specific WC and BMI thresholds for predicting these measures of risk.Results:WC percentiles were constructed. WC correlated slightly more than BMI with CV risk factors and most strongly with insulin and systolic BP, but poorly or not with LDL and glucose. Optimal WC and BMI risk thresholds for predicting four of these six CV risk factors were ca. the 85th percentiles (sensitivities ∼0.8, specificities ∼0.87) with age-specific cutoff values in girls/boys from ∼57/58 to ∼71/76 cm and 17/18 to 22/23 kg/m2.Conclusion:These are the first set of WC reference data for Chinese children. WC risk cutoff values are proposed which, despite a smaller waist in Chinese children, are similar to those reported for American children. WC percentiles may reflect population risk.

Renal screening in children after exposure to low dose melamine in Hong Kong: cross sectional study

Objective To investigate the renal outcomes of children after exposure to low dose melamine in Hong Kong. Design Cross sectional study. Setting Special assessment centres, Hong Kong. Participants 3170 children (1422 girls and 1748 boys) aged 12 years or less referred from territory-wide primary care clinics after daily consumption for one month or more of milk products tainted with melamine. Main outcome measures Presence of renal stones and haematuria. Results One child had a confirmed renal stone, seven were suspected of having melamine related renal deposits, and 208 (6.6%) were positive for blood in urine by reagent strip. A proportion of these children were followed up at the special assessment centre, but only 7.4% of those positive for blood on reagent strip were confirmed by microscopy, suggesting an overall estimated prevalence of less than 1% for microscopic haematuria. Conclusions No severe adverse renal outcomes, such as acute renal failure or urinary tract obstruction, were detected in children after exposure to low dose melamine. Our results were similar to territory-wide findings in Hong Kong. Even including the seven children with suspected renal deposits, the prevalence of suspected melamine related abnormalities on ultrasonography was only 0.2%. None of these children required specific treatment. The prevalence of microscopic haematuria was probably overestimated by the reagent strip. These data suggest that large scale and urgent screening programmes may not be informative or cost effective for populations who have been exposed to low dose melamine.

Dynamic Magnetic Resonance Imaging in Assessing Lung Volumes, Chest Wall, and Diaphragm Motions in Adolescent Idiopathic Scoliosis Versus Normal Controls

Study Design. Dynamic breath-hold (BH)- magnetic resonance (MR) imaging was used to evaluate lung function in adolescent idiopathic scoliosis (AIS). Objectives. Changes in lung volume, chest wall, and diaphragmatic motions were evaluated in AIS patients and compared with normal controls. Summary of Background Data. Little is known about whether pulmonary function impairment in AIS is related to restriction of lung volume, poor chest wall expansibility, or impaired diaphragmatic motion. This is a study on the underlying pathophysiology of the abnormal pulmonary function in AIS using the ultrafast BH-MR imaging technique. Methods. Forty-two patients with moderate to severe right thoracic scoliosis (Cobb angle, 40°–98°), 22 patients with mild right thoracic scoliosis (Cobb angle 10°–30°), and 12 healthy subjects (age ranged, 11–18 years; all girls) were recruited for the following assessments: 1) inspiratory, expiratory, and change in lung volume; 2) change in anteroposterior (AP) and transverse (TS) diameter of the chest wall at two levels: carina and apical vertebra level; and 3) change in diaphragmatic heights. Results. Inspiratory, expiratory lung volume and diaphragmatic heights were significantly reduced in the severe scoliosis group (P < 0.05), but the change in lung volume was not affected. There was no significant difference in the change of AP or TS diameter of the chest wall as well as diaphragmatic motions among groups. Conclusion. Impairment in lung function in AIS patients is predominantly due to restriction of lung volume.

Cough frequency in children with mild asthma correlates with sputum neutrophil count

Background: A study was undertaken to measure cough frequency in children with stable asthma using a validated monitoring device, and to assess the correlation between cough frequency and the degree and type of airway inflammation. Methods: Thirty six children of median age 11.5 years (interquartile range (IQR) 9–14) with stable asthma were recruited. They underwent spirometric testing, exhaled nitric oxide (eNO) measurement, sputum induction for differential cell count, and ambulatory cough monitoring for 24 hours. Coughing episodes were counted both as individual spikes and as clusters. Results: All children had mild intermittent asthma and their median forced expiratory volume in 1 second and eNO were 83.3% (IQR 81.1–97.6) and 56.1 ppb (IQR 37.4–105), respectively. The median number of cough episodes per day was 25.5 (IQR 16–42.8). Sputum induction was successful in 69% of the subjects and cough frequency was found to have a significant positive correlation with sputum neutrophil count (r = 0.833, p = 0.0001). Conclusions: Children with stable mild asthma have increased cough frequency that might be driven by a neutrophilic inflammatory pathway.

Hurler's syndrome with cor pulmonale secondary to obstructive sleep apnoea treated by continuous positive airway pressure.

Abstract:  A 6‐year‐old boy with Hurlers syndrome presented with right heart failure and pulmonary hypertension secondary to severe obstructive sleep apnoea. Both his sleep apnoea and cor pulmonale were effectively controlled with continuous positive airway pressure therapy.

Effects of short-term resistance training on serum leptin levels in obese adolescents

The purpose of this study was to examine the effects of a short-term resistance training program on serum leptin concentrations in obese adolescents. Eighteen Chinese obese adolescents participated in the supervised weight management program. Resistance training was conducted three times a week on alternate days for 6 weeks. Body composition [body fat mass (FM) and body lean mass (LM)] determined by dual-energy X-ray absorptiometry, muscle strength and leptin, insulin and glucose were measured before and after training. Subjects demonstrated significantly improved strength of leg, chest and bicep under conditions of stability in weight, FM and LM. There were positive correlations between leptin and body mass index, FM, %FM, waist girth and hip girth, and negative correlations between leptin and %L M at the resting state before and after 6 weeks of resistance training. No significant relationship was found between leptin concentration and the parameters of muscular strength or concentrations of insulin and glucose. Compared to pre-training values, serum leptin levels were not significantly altered, while relative leptin (leptin/FM) decreased significantly after the short-term resistance training. These results indicate that short-term resistance training enhances muscle strength but does not alter leptin levels in obese adolescents with weight and FM stability. The results also suggest that 6 weeks of resistance training decreases the requirement of leptin per unit of FM and improves leptin sensitivity in obese adolescents.

Respiratory function in patients with thalassaemia major: relation with iron overload

Aims: (1) To determine the pattern of respiratory impairment in children with thalassaemia major (TM); (2) to assess the relation between the degree of respiratory impairment and total body iron content. Methods: Twenty nine TM patients were recruited. All underwent physical examination, standardised pulmonary function tests (spirometry, lung volume, and single breath diffusion capacity for carbon monoxide), and magnetic resonance imaging measurements of the liver. Serum ferritin was measured. The signal intensity ratio of liver to that of paraspinal muscle (T1 weighted sequence) and serum ferritin were used as surrogate index of body iron content. Results: Sixteen boys and 13 girls (median age 14.2 years) were studied. None had clinical evidence of congestive heart failure. Sixteen had normal lung function. Impairment of diffusion capacity (median DLco 83.5% predicted) was the most common abnormality, being observed in 34% of patients. Pure restrictive and obstructive ventilatory impairment was found in one and two patients respectively. Five patients had a combination of ventilation and diffusion defects. There was no correlation between the degree of impairment of each respiratory abnormality and body iron content. Conclusion: Diffusion impairment was the commonest abnormality found in our cohort of paediatric TM patients. Our data did not support the notion that respiratory function impairment was correlated with body iron content.

Ex utero intrapartum treatment (EXIT) for congenital giant ranula

Congenital giant ranula causing life‐threatening upper airway obstruction is a rare condition. A well‐planned ex utero intrapartum treatment (EXIT) procedure for aspiration and decompression of the cystic lesion is simple, efficacious and effective in securing a patent airway before the fetus is completely delivered, and may prevent lifelong neurodevelopmental complications associated with perinatal asphyxia in such cases.