Asthma and bronchodilator responsiveness are associated with polymorphic markers of ARG1, CRHR2 and chromosome 17q21.

OBJECTIVE: Asthma is caused by complex interactions between multiple genes. ß2-Agonist is the standard rescue treatment to relieve asthma symptoms and bronchoconstriction. A genetic study for spirometric parameters helps to predict the responses to this antiasthma treatment. This study investigated the relationship between asthma and bronchodilator responsiveness (BDR) and eight asthma genes. METHODS: Fifteen single-nucleotide polymorphisms in these genes were genotyped in 345 Chinese asthmatics and 464 controls. Gene-gene interactions were analysed by generalized multifactor dimensionality reduction (GMDR). RESULTS: The diagnosis of asthma was associated with rs7216389 in ORMDL3 [odds ratio (OR) 0.74 and 95% confidence interval (95% CI) 0.56-0.99] and rs3756780 in ARG1 (OR 0.67, 95% CI 0.51-0.89) and BDR with rs2749935 in ARG1. However, none of these associations remained significant at 5% when adjusted for multiple testing by the Bonferroni correction or a false discovery rate. GMDR analyses revealed that rs7216389 in ORMDL3 and rs3756780 in ARG1 might interact for a risk of asthma. Individuals with high-risk genotypes had OR 1.66 (95% CI 1.24-2.23) for asthma when compared with those with low-risk genotypes. GMDR suggested a two-locus model with rs2749935 in ARG1 and rs2190242 in CRHR2 to be associated with BDR. Specifically, reversibility of forced expiratory volume in 1 s was higher in high-risk than that in low-risk patients [mean (95% CI): 10.7 (8.6-12.9) vs. 6.8 (5.9-7.6)%]; with the latter group showing higher forced expiratory volume in 1 s reversibility compared with high-risk controls [2.8 (1.4-4.3)%]. CONCLUSION: ARG1 and ORMDL3 may interact to determine the risk of asthma and ARG1 and CRHR2 to alter BDR in asthmatics. Nonetheless, this study is only hypothesis-generating as none of the single marker comparisons is significant when adjusted for multiple testing. These findings need to be confirmed in independent populations.

Haplotype effect in the IGF1 promoter accounts for the association between microsatellite and serum IGF1 concentration.

OBJECTIVE: Systemic insulin-like growth factor 1 (IGF1) level is an important risk factor for various diseases. The inter-individual variation of serum IGF1 is determined by environmental and genetic factors, which are attributed to a microsatellite in IGF1 promoter. However, the exact nature of the underlying regulatory elements accounting for this association has not been characterized. Here, we defined the haplotype patterns, including both SNPs and the microsatellite, in the Chinese population, and investigated their regulatory effect on serum IGF1 level. This is the first study in which haplotype patterns of the microsatellite and SNPs in the IGF1 promoter are examined together. METHODS: The linkage disequilibrium (LD) patterns of IGF1 were examined using tagSNPs of the IGF1 regulatory region. The microsatellite, three tagSNPs and haplotypes were correlated with serum IGF1 concentration in 450 normal premenopausal Chinese women. RESULTS: Common alleles of the microsatellite were in strong LD with the three tagSNPs and were associated with particular haplotypes composed of SNPs. Neither the CA repeat number nor SNPs alone showed a robust association with serum IGF1 concentration. On the other hand, the haplotype T-19-A-T was significantly associated with serum IGF1 level. CONCLUSION: No association was found between SNPs and microsatellite alone. However, the haplotype showed better correlation with serum IGF1 level. The results indicate that the previously observed correlation with microsatellite was because of a haplotype effect in the IGF1 promoter. Microsatellite or tagSNPs alone are not the primary regulatory elements of IGF1 expression. The exact regulatory genetic variant needs to be defined by functional genetic studies.

A prospective longitudinal study to estimate the "adjusted cortisol percentile" in preterm infants.

The normal range of serum cortisol concentrations and the appropriate levels of circulating cortisol in different clinical situations in preterm infants are not well defined. This study aimed to evaluate the impact of perinatal factors on circulating cortisol levels in preterm infants and to create a quantitative model that could estimate the "adjusted cortisol percentile." Serial serum cortisol concentrations were measured in 209 infants ≤ 32 wk gestation on d 1, 4, 7, 14, and 21 of life. Seven perinatal factors or conditions that could affect circulating cortisol level were identified. Serum cortisol levels were higher on d 4 (p = 0.007) and d 7 (p = 0.007) but lower on d 21 (p = 0.001) compared with d 1. Serum cortisol was also higher in infants on nasal continuous positive airway pressure (p = 0.003); requiring a second vasopressor (p < 0.001); with intraventricular hemorrhage (≥ grade 3; p < 0.001); with histologic chorioamnionitis (p = 0.007); with severe lung disease (p = 0.046); and with decreasing GA (p < 0.001). A mathematical equation was proposed based on factors derived in this preliminary study for estimating the adjusted cortisol percentile. Frontline neonatologists could now access the equation on our Web site (http://www.sta.cuhk.edu.hk/pswong/ACortP.html) to calculate the adjusted cortisol percentile, which could potentially improve the interpretation of circulating cortisol in different clinical situations.

Specific IgE of common foods in Chinese children with eczema.

Food atopy is important but inadequately studied among children with atopic dermatitis (AD). We evaluated whether any association existed between AD severity, quality of life, total IgE, eosinophil counts, and the number of food items sensitized. Specific IgE of ten common food items was measured for a group of consecutive AD patients (n=85) enrolled during a randomized trial and correlated the findings with eczema severity. Twenty-four patients (28%) were negative for any of the ten common food items. The most commonly sensitized foods were shrimp (54%), egg white (43%), wheat (42%), and peanut (41%). Atopy to beef as a protein and orange as a fruit were least common among the food items studied, even among patients positive for 8-9 IgE items. Patients with severe AD (objective SCORAD>40) were more likely to be positive for at least one of the food items (Yates corrected p=0.024 for ≥1 food-specific IgE in severe vs. moderate AD, OR 3.42 and 95% CI 1.15-10.32); and for at least seven of the food items (p=0.001 for ≥7 food-specific IgE vs. nil with OR 11.67 and 95% CI 2.29-67.77), respectively. The Spearman coefficients between the number of positive food-specific IgE and total SCORAD, objective SCORAD, area of AD involvement, Children's Dermatology Life Quality Index (CDLQI), total IgE levels, and eosinophil counts were 0.42 (p<0.001), 0.45 (p<0.001), 0.50 (p<0.001), 0.17 (p=0.116), 0.80 (p<0.001), and 0.22 (p=0.043), respectively. Specific IgE levels for beef correlated with all the other food-specific IgE levels, including cow's milk (ρ=0.061, p<0.001) and soy (ρ=0.70, p<0.001). The number of common food items sensitized correlated with disease severity, extent, and total IgE levels. IgE sensitization to beef protein is unlikely in the majority of children with AD, but its serum IgE level is associated with disease severity and risk of sensitization to other foods.

Indoor determinants of endotoxin and dust mite exposures in Hong Kong homes with asthmatic children.

BACKGROUND: Domestic endotoxin enhances airway inflammation and increases asthma severity in Caucasian children, but little data are published on indoor endotoxin exposure in Asian countries. This study investigated house dust endotoxin and Der p 1 levels in Hong Kong families with asthmatic children, and their effects on asthma severity. METHODS: 115 asthmatics from a pediatric clinic underwent fractional exhaled nitric oxide (FeNO) and spirometric measurements. Home visits were then made within 2 weeks, during which parents completed the International Study of Asthma and Allergies in Childhood questionnaire. Settled dust was collected from patients' mattresses, bedroom floors and living room floors. Endotoxin and Der p 1 were measured by limulus amebocyte lysate and immunoassay, respectively. RESULTS: Endotoxin was detectable in all locations from all families, whereas Der p 1 was detectable in 58-70% of indoor sites. Floors of both bedroom and living rooms had higher endotoxin but lower Der p 1 levels than mattresses (p < 0.001 for both). Mattress endotoxin level correlated inversely with Der p 1 level (r = -0.308, p = 0.001). Household smoker, feather bedding and vacuum cleaning were independent determinants of indoor endotoxin. Timing of last bedding change was associated with Der p 1 levels at all sites. Mattress endotoxin level was associated with frequency of wheezing episodes (p = 0.044), but neither endotoxin nor Der p 1 was associated with FeNO and spirometric parameters. CONCLUSIONS: Domestic endotoxin levels are associated with frequency of wheezing episodes in asthmatic children but not their FeNO or spirometric measurements.

Association of plasma soluble CTLA-4 with lung function and gene polymorphism in Chinese asthmatic children.

BACKGROUND: Cytotoxic T lymphocyte antigen 4 (CTLA-4) is known to downregulate the T(H)2 immune response. Recent studies have suggested an association of CTLA-4 polymorphisms with allergic diseases. We investigated the effects of single nucleotide polymorphisms (SNPs) of CTLA-4 on asthma traits and plasma sCTLA-4 in 298 Chinese asthmatic children and 175 controls. METHODS: Plasma sCTLA-4, total and allergen-specific IgE concentrations were measured by enzyme immunoassay. Six SNPs, namely -1147CT, +49AG, CT60, JO31, JO30 and JO27_1, in CTLA-4 were genotyped by restriction fragment length polymorphism. RESULTS: Plasma sCTLA-4 was negatively associated with FEV(1)/FVC (r = -0.146, p = 0.036) among our asthmatic patients. Analysis of locus-locus interaction by generalized multifactor dimensionality reduction showed that -1147CT was the best model for plasma sCTLA-4 with a cross-validation consistency of 10 out of 10 and a prediction error of 40.9% (p < 0.001). Multivariate regression analysis confirmed the association between plasma sCTLA-4 concentration with -1147CT among the 6 SNPs tested (p = 0.002) after adjustment for gender and age. The plasma sCTLA-4 concentration was significantly lower in patients homozygous for the C allele than in T allele carriers (p = 0.001). There was also a significant association between the most common haplotypes with low sCTLA-4 in asthmatics. We could not find any significant association between plasma total IgE, atopy and lung function with the 6 SNPs after Bonferroni correction. CONCLUSIONS: Plasma sCTLA-4 is associated with lung function and -1147CT polymorphism in Chinese asthmatic children. This may help to identify CTLA-4 signaling as a potential therapeutic target in asthma.

Reference intervals of spot urine copper excretion in preschool children and potential application in pre-symptomatic screening of Wilson disease.

The objectives were to determine the reference intervals of spot urine copper excretion indexes in pre-school children and to evaluate their utility in screening for Wilson disease (WD). With spot urine collected from a control sample of preschool children (aged 3-7 years, n=153), the reference intervals of spot urine copper excretion indexes and their biological variation were defined. In order to investigate their utility performance in screening for WD in this age group, multiple spot urine samples from six WD patients who were diagnosed at presymptomatic stage were also analysed and compared. Cut-off values useful for detection of WD were defined by receiver operator curve (ROC) analysis. Biological (inter-individual) variation of spot urine copper indexes expressed as coefficient of variation (CVg) were around 60% at this age group, which was moderate and similar to other clinically useful urine tests, such as urine albumin excretion ratio. Spot urine copper excretion strongly correlated with both urine creatinine and osmolality. Linear regression against both creatinine and osmolality showed that ∼94% of data points in healthy preschool children fell within the prediction interval, suggesting that both were useful normalisation factors. ROC showed that copper to osmolality ratio was the best index with an area under curve (AUC) greater than 0.98. Cut-off values of 0.5 µmol/L, 0.1 µmol/mmol and 0.00085 µmol/mOsmol (32 µg/L, 56 µg/g creatinine and 0.054 µg/mOsmol, respectively, in conventional units) for spot urine copper concentration, copper to creatinine ratio and copper to osmolality ratio, respectively, have potential application in the differentiation of WD patients. Based on the data, a new WD screening strategy targeting preschool children is proposed. Application of a bivariate screening strategy using spot urine copper concentration and urine osmolality may be useful in a population-wide screening program for WD among preschool children.

Association between obesity and atopy in Chinese schoolchildren.

BACKGROUND: Despite parallel increases in asthma and obesity prevalence, there is little data on obesity as a risk factor for atopy. The latter is an important phenotype in asthmatic patients. This study investigates the association between asthma traits, atopy and obesity-related markers in Chinese adolescents. METHODS: 486 schoolchildren were recruited among participants of our population-based study on the epidemiology of obesity, and their allergy status was ascertained using a standardized questionnaire. Subjects' anthropometry was recorded on-site, and fasting blood was collected for allergen-specific immunoglobulin E (IgE), lipids and systemic inflammatory biomarkers. RESULTS: 98 (20.2%) subjects were classified as overweight or obese. Obesity status was not associated with asthma, allergic rhinitis or eczema (p > 0.25). Atopy was not associated with age-adjusted body mass index (BMI) or waist circumference. Atopy and presence of allergen-specific IgE did not differ between overweight or obese children and those with normal BMI (p > 0.25), although subgroup analysis suggested that cockroach sensitization was more common among males who were obese or overweight (p = 0.045). White cell count (WCC) was higher among atopic than nonatopic children (mean values 6.5 x 10(9)/l vs. 6.2 x 10(9)/l, p = 0.006). Logistic regression revealed WCC to be the only risk factor for atopy (OR 18.97, p = 0.004). CONCLUSIONS: Obesity is not associated with asthma or atopy in Chinese children. High WCC is an important risk factor for atopy in both males and females. Gender does not exert any consistent effect on the association between obesity and allergen sensitization in children.

Association of early growth response-1 gene polymorphisms with total IgE and atopy in asthmatic children.

Early growth response-1 (Egr-1) is expressed in human airways and found to modulate tumor necrosis factor, immunoglobulin E (IgE), airway responsiveness, and interleukin-13-induced inflammation in mice. We investigated the effects of Chinese-tagging single nucleotide polymorphisms (SNPs) of Egr-1 on asthma traits in 298 Chinese asthmatic children and 175 controls, and a replication community cohort of 191 controls. Tag SNP (-4071 A-->G) and three additional SNPs (-1427 C-->T, -151 C-->T and IVS1 -42 C-->T) were genotyped by restriction fragment length polymorphism (RFLP). Significant associations were found between plasma total IgE concentration and -4071 A-->G (p = 0.008) and IVS1 -42 C-->T (p = 0.027) in asthmatic patients. After Bonferroni correction, only -4071 A-->G showed significant association. Multivariate regression analysis confirmed this significant association with a standardized coefficient beta of 0.156 (95% CI: 0.046-0.317; p = 0.009) in asthmatics among the three SNPs with age and gender-adjusted. In -4071 A-->G, IgE(log) was significantly higher in patients with the GG genotype than the AA genotype (p = 0.009). In addition, -4071 A-->G was significantly associated with atopy (p = 0.016) and high total IgE concentration (p = 0.030) among asthmatics. Patients with the G allele had a 3.5-fold risk of having atopy and a 2.0-fold risk of having high total IgE concentration than those homozygous for the A allele. This is the first report to show significant association of Egr-1 polymorphisms with plasma total IgE and atopy in asthmatics. It may help to explore the pharmacogenetics of Egr-1 inhibitors.

PTGDR is not a major candidate gene for asthma and atopy in Chinese children.

Airway sensitization requires the expression of prostanoid DP receptor in mice. Recent studies reported that polymorphisms in the gene encoding prostanoid DP receptor (PTGDR) were associated with asthma in White people and Black people, but this association could not be replicated among Latinos and Koreans. This study investigated the association between asthma-related traits and six single nucleotide polymorphisms (SNPs) of PTGDR in Chinese children, consisted of 308 asthmatics and 368 non-allergic controls. Plasma total and aeroallergen-specific immunoglobulin E were measured by immunoassays. PTGDR SNPs were determined by multiplex SNaPshot genotyping. All polymorphic markers followed Hardy-Weinberg equilibrium except G1044A in the controls (p = 0.021). The linkage disequilibrium (LD) scores for these SNPs were moderate to high, and in particular, T-549C and C-441T were in strong LD. Significant interethnic variations in PTGDR alleles and haplotypes (up to 41%) were found in our subjects when compared with White people or Latinos. Asthma diagnosis, atopy and aeroallergen sensitization did not differ among children with different PTGDR genotypes (p > 0.15 for all). Linear regression showed weakly significant associations between T-197C and G1044A of PTGDR and spirometric variables. PTGDR haplotypes were not associated with asthma and atopy phenotypes (p > 0.09 for all). Our results do not support PTGDR to be a major candidate gene for asthma traits in Chinese children.

Effects of valproate or lamotrigine monotherapy on the reproductive endocrine and insulin-related metabolic profile in Chinese adults with epilepsy: a prospective randomized study.

Cross-sectional studies have suggested that valproate treatment may be associated with hyperinsulinemia and hyperandrogenism in women. Few prospective data are available. We evaluated the reproductive endocrine and insulin-related metabolic parameters in men and women with untreated epilepsy randomized to valproate (n=44) or lamotrigine (n=37) monotherapy for 12 months. On treatment, there was no significant difference in fasting serum insulin concentrations between the two groups. In women (n=40), there was no significant difference between the two groups in change from baseline in serum total testosterone, dehydroepiandrosterone sulfate, luteinizing hormone, or follicle-stimulating hormone. In men (n=41), follicle-stimulating hormone concentration significantly decreased in patients taking valproate compared with those on lamotrigine as early as 3 months after treatment. Greater attention should be paid to investigate the potential impact of valproate on reproductive function in men.

C-reactive protein in children with obstructive sleep apnea and the effects of treatment.

OBJECTIVE: To evaluate C-reactive protein (CRP) concentration in children with OSA and to determine the effects of treatment for OSA on its serum concentration. METHODS: Consecutive children with habitual snoring and symptoms suggestive of OSA were recruited. They completed a sleep apnea symptom questionnaire, underwent physical examination and an overnight polysomnography (PSG). Fasting serum CRP and lipid profile were taken after overnight PSG. OSA was diagnosed if obstructive apnea index (OAI)>1. RESULTS: One hundred forty-one children with a median (IQR) age of 10.8 (8.5-12.8) years were recruited. There were 96 boys and the commonest presenting symptoms were nocturnal mouth breathing, prone sleeping position and poor attention at school. Forty-five children were found to have OSA and those with moderate disease (OAI>5) had significantly higher CRP levels compared to their non-OSA counterparts [1.3 (0.8-3.6) vs. 0.7 (0.2-2.0), P=0.01]. Stepwise linear multiple regression analysis indicated that OAI was independently associated with CRP (beta coefficient=0.013, P=0.001). Sixteen children underwent treatment and there was significant reduction in their serum CRP after intervention [pre vs. post-CRP, 1.3 (0.6-4.1) vs. 0.4 (0.2-1.3), P=0.033]. A significant correlation was also demonstrated between change in CRP and change in OAI (r=0.593, P=0.042) following treatment for OSA. CONCLUSION: Children with OSA may have associated systemic inflammation as reflected by a raised CRP that decreased significantly following treatment.

Inflammatory cytokines and childhood obstructive sleep apnoea.

OBJECTIVE: To evaluate serum cytokine concentrations in children with and without obstructive sleep apnoea (OSA) and to investigate the effects of OSA treatment on cytokines. MATERIALS AND METHODS: Consecutive children with habitual snoring and symptoms suggestive of OSA were recruited. They completed a sleep apnoea symptom questionnaire, underwent physical examination and overnight polysomnography (PSG). OSA was diagnosed if obstructive apnoea index (OAI) >1. A blood sample was collected for analysis of IL-6, IL-8, and TNF-alpha after PSG. RESULTS: One hundred forty-two children (97 males) with a median (IQR) age of 11.1 years (9.0-12.8) were recruited. The commonest presenting symptoms were nocturnal mouth breathing, prone sleeping position and poor attention at school. Forty-seven children were found to have OSA and they had higher serum IL-6 [0.1 (0.1-0.4) vs 0.1 (0.1-0.1) pg/mL, P = 0.001] and IL-8 [1.7 (1.0-2.3) vs 1.3 (0.9-1.7) pg/mL, P = 0.029] concentrations compared to their non-OSA counterparts. Multiple regression analysis indicated that OAI was significantly associated with both IL-6 (r = 0.351, P <0.001) and IL-8 (r = 0.266, P = 0.002). Sixteen children underwent treatment and there was significant reduction in mean (SD) serum IL-8 after intervention [pre vs post levels of 1.9 (1.0) vs 1.1 (0.6) pg/mL, P = 0.001] independent of weight loss. CONCLUSION: Children with OSA had elevated levels of pro-inflammatory cytokines that normalised following treatment suggesting that the inflammatory response is potentially reversible. Early detection and intervention may be beneficial.

Fetal methylmercury exposure as measured by cord blood mercury concentrations in a mother-infant cohort in Hong Kong.

This study was designed to examine newborn infants in Hong Kong prenatally exposed to levels of methylmercury considered to increase risk of neurotoxic effects and to examine subject characteristics that modify the degree of prenatal mercury exposure. Mercury concentrations in 1057 sets of maternal and cord blood samples and 96 randomly selected maternal hair samples were measured. Subject characteristics were measured or collected by questionnaire. Of the 1057 cord blood samples collected only 21.6% had mercury concentrations less than 29 nmol/L (5.8 micro g/L). Median maternal hair mercury concentration was 1.7 ppm. The geometric mean cord to maternal blood mercury ratio was 1.79 to 1. Increasing maternal fish consumption and maternal age were found to be associated with increased cord blood mercury concentrations. Marine fish consumption increased cord blood mercury concentrations more than freshwater fish (5.09%/kg vs 2.86%/kg). Female babies, maternal alcohol consumption and increasing maternal height were associated with decreased cord blood mercury concentrations. Pregnant women in Hong Kong consume large amounts of fish and as a result, most of their offspring have been prenatally exposed to moderately high levels of mercury. In this population, pregnant women should choose freshwater over marine fish and limit fish consumption.

Lack of association between NOS2 pentanucleotide repeat polymorphism and asthma phenotypes or exhaled nitric oxide concentration.

Nitric oxide (NO) plays an immunoregulatory role in balancing cellular immunity. The expression of inducible nitric oxide synthase gene (NOS2) is upregulated upon exposure to proinflammatory cytokines and microbial exposure. The (CCTTT)n polymorphism in NOS2 promoter confers protection against infections and immunological disorders including atopy. We investigated the association between (CCTTT)n and asthma traits in Chinese children. Asthmatic children between 5 and 18 years of age and non-allergic controls were recruited. Plasma total and specific IgEs were measured by immunoassays, and exhaled NO concentration was quantified online by chemiluminescence. NOS2 (CCTTT)n was genotyped by GeneScan analysis. The mean (SD) age of 291 asthmatics and 172 controls were 11.1 (3.8) years and 11.6 (4.0) years, respectively (P = 0.259). NOS2 (CCTTT)n followed Hardy-Weinberg equilibrium in both groups, and its uni-modal allele distribution peaks at 12-repeat. Significant interethnic differences in (CCTTT)n alleles were observed, with our Chinese having less 13-repeat (Pc = 0.022) but more 17-repeat (Pc = 0.033) than Caucasians. The frequency of 14-repeat allele was similar in our Chinese as compared to Japanese (Pc = 0.32). Multivariate regression analyses failed to detect any association between this polymorphic marker and asthma diagnosis (P = 0.949), atopy (P = 0.305), IgE sensitization to aeroallergens (P > 0.2 for all), or FeNO (P = 0.847). These findings do not support NOS2 to be a major candidate gene for asthma or IgE-mediated allergic diseases in Chinese children.

Insulin and obstructive sleep apnea in obese Chinese children.

OBJECTIVE: In adults, obstructive sleep apnea (OSA) is associated with insulin resistance and dyslipidemia. We aimed to establish correlation between OSA, serum lipid profile, and insulin levels in obese snoring children. METHODS: Consecutive obese children with habitual snoring were recruited. They underwent physical examination, overnight polysomnography (PSG), and metabolic studies. OSA was diagnosed if apnea hypopnea index (AHI) > 1.0, and cases were considered to have moderate to severe OSA if AHI > 10. RESULTS: Ninety-four obese subjects with habitual snoring were studied. Seventy-three subjects were male and the median age of the studied group was 12.0 years (IQR 9.7-13.9). None of the subjects had active cardiopulmonary disease, and the BMI values of our subjects were >95th percentile using local reference charts. Sixty subjects had OSA, 47 being mild, and 13 being moderate to severe OSA. Multiple logistic regression analysis revealed that saturation nadir and insulin levels were significantly associated with OSA. CONCLUSION: OSA is prevalent among obese children with habitual snoring and insulin is independently associated with the condition. Its role in the cardiovascular complications of childhood sleep apnea is worthy of further exploration.

Steroid-induced osteonecrosis in severe acute respiratory syndrome: a retrospective analysis of biochemical markers of bone metabolism and corticosteroid therapy.

AIM: We investigated the effect of massive doses of corticosteroid therapy on bone metabolism using specific biochemical markers of bone metabolism, and the prevalence of osteonecrosis in severe acute respiratory syndrome (SARS) patients at a university teaching hospital in Hong Kong. METHODS: Seventy-one patients with a clinical diagnosis of SARS were studied according to the modified World Health Organization case definition of SARS who were involved in the SARS epidemic between 10 March and 20 June 2003. The clinical diagnosis was confirmed by serological test and/or molecular analysis. Biochemical markers of bone metabolism were analysed retrospectively using serial clotted blood samples collected from each patient during the course of hospital admission to discharge and subsequent follow-up at out-patient clinic using the arbitrary time periods: (i) Day <10; (ii) Day 28-44; (iii) Day 51-84; and (iv) Day >90 after the onset of fever. Magnetic resonance imaging of the knee and hip joints were performed post-admission to evaluate the prevalence of osteonecrosis amongst these SARS patients. Various risk factors for the development of osteonecrosis were assessed using receiver operating characteristics curve comparison with appropriate test statistics and Spearman's coefficients of rank correlation with biochemical bone markers. RESULTS: Biochemical markers of bone metabolism showed significant bone resorption as evidenced by a marked increase in serum C-terminal telopeptide concentration (CTx) from Day 28-44 after the onset of fever. With tapering down of corticosteroid dosage, CTx started to return to previous baseline level from Day 51 onwards, while other bone formation markers, serum osteocalcin and bone-specific alkaline phosphatase concentrations (OC and BALP, respectively), started to increase. The latter effect was even more marked after Day >90. Seven patients developed radiological evidence of osteonecrosis. The prevalence of osteonecrosis in this cohort was 9.9%. A total corticosteroid dosage of >1900 mg hydrocortisone, >2000 mg methylprednisolone, >13 340 mg hydrocortisone-equivalent corticosteroid therapy, and >18 days on corticosteroid therapy were found to be significant risk factors for the subsequent development of osteonecrosis. There were also significant positive correlations amongst various biochemical bone markers in this patient cohort. CONCLUSIONS: Both bone resorption and formation markers were unable to predict the subsequent development of osteonecrosis. The use of high dose of hydrocortisone or methylprednisolone for an extended duration was shown to be a significant risk factor for osteonecrosis. Its prevalence in this cohort is comparable to those reported in the literature for SARS patients with high-dose corticosteroid therapy. The Day 28-44 increase in the serum CTx coincided with the timing of corticosteroid use. The Day >51 increase in serum OC and BALP coincided with the timing of corticosteroid withdrawal.

Specific biochemical markers of bone metabolism and cytokine study confirm the diagnosis of malignant infantile osteopetrosis at birth using cord blood sample.

AIMS: To investigate the serum creatine kinase isoenzyme pattern, specific biochemical markers of bone metabolism, and cytokines in a Chinese family with osteopetrosis, and correlate abnormalities with the pathophysiology of this condition. METHODS: A Chinese female baby was diagnosed with malignant infantile osteopetrosis at the age of 3 weeks by clinical history and biochemical investigations. We studied the laboratory and radiological manifestations of this index case and her family members. RESULTS: Serum CK-BB fraction of our index patient was elevated to 18.0% (normal 1.6-7.6%). Her biochemical markers of bone resorption including serum C-terminal telopeptide concentration and urine N-terminal telopeptide to creatinine ratio were decreased to 0.54 microg/L (normal 0.72-1.56 microg/L) and 159 x 10(-6) (normal 372-900 x 10(-6)), respectively. Serum cytokines including soluble receptor activator of nuclear factor kappa-B ligand (sRANKL) concentration was suppressed to 0.11 pmol/L (normal 0.23-0.82 pmol/L) and osteoprotegerin (OPG) concentration was 4.9 pmol/L (normal 2.8-4.9 pmol/L), resulting in an elevated OPG to sRANKL ratio of 44.5 (normal 3.8-19.4) in favour of bone formation. CONCLUSIONS: If left untreated, this condition is usually fatal within the first year of life. With early diagnosis, management including bone marrow transplantation can be planned ahead and will result in a better survival.

Relationship between passive smoking exposure and urinary heavy metals and lung functions in preschool children.

Environmental tobacco smoke (ETS) exposure is a risk factor for asthma in school-age children, but there is limited data of ETS exposure on respiratory health in preschool children. This study investigated the relationship between ETS, lead (Pb), and cadmium (Cd) exposures and asthma symptoms and spirometric indices in Chinese preschoolers. Preschool children from 30 nurseries and kindergartens performed spirometry with incentives of animation programs, and their urinary cotinine, Pb and Cd concentrations were measured by immunoassay and inductively coupled plasma-mass spectrometry, respectively. Two thousand seven hundred sixty-three preschoolers participated, and 1,505 and 893 provided valid spirometric data and urine samples, respectively. Current domestic smoking was reported in 37.5% of children, but only 95 (10.6%) had high urinary cotinine-to-creatinine ratio (≥30 ng/mg). Pb was measurable in 3.9% of samples, whereas 406 (45.5%) children had high Cd. Reported ETS exposure was not associated with any spirometric index, whereas cotinine-to-creatinine ratio was inversely associated with forced expiratory volume in 0.5-sec (ß = -0.093, P = 0.003), forced expiratory flow between 25% and 75% of expiration (ß = -0.138, P = 0.002) and peak expiratory flow (ß = -0.106, P = 0.002). Cd exposure was not associated with reported respiratory symptom or spirometric indices. This community study shows that ETS exposure defined by urinary cotinine is a strong risk factor for lung function impairment measured by spirometry in Chinese preschool children. Urinary cotinine is more reliable than questionnaire for assessing ETS exposure in young children. Although high urinary Cd is common in Hong Kong preschoolers, such biomarker is not associated with any clinical or spirometric outcome.

Cadmium and lead in Hong Kong school children.

AIM: Cadmium (Cd) and lead (Pb) are toxic elements in our environment. This study is to determine the reference intervals of Cd and Pb in blood and urine from Hong Kong school children and to identify their determinants. METHODS: A total of 2209 secondary school children and 893 preschool children were recruited. Cd and Pb in blood and urine were measured by inductively-coupled plasma mass spectrometry. RESULTS: Blood Cd was affected by age, smoking and residential district, while urine Cd was influenced by age and blood Cd. Blood Cd was positively correlated with smoking as confirmed by urinary cotinine (rho  = 0.183, p  <  0.001, n = 2074). Blood Pb was dependent on gender and residential district, while urinary Pb was dependent on gender and blood Pb. Students from schools of lower academic grading had higher blood Cd and Pb than those from higher academic grading schools (p < 0.001, respectively). Urinary albumin was positively associated with urinary Cd and Pb. CONCLUSIONS: Using a non-occupationally exposed population, the reference ranges are: blood Cd < 21.9  nmol/L for smokers and < 8.8  nmol/L for non-smokers, and blood Pb < 203.8  nmol/L. Reference intervals for urinary Cd and Pb are also reported.