Biomedical subjects

R Leung

Publications and source records attributed to R Leung.

At least 19 recordsLinked to original sources

PubMed2001

Utility of routine chest radiographs in a medical-surgical intensive care unit: a quality assurance survey.

OBJECTIVE: To determine the utility of routine chest radiographs (CXRs) in clinical decision-making in the intensive care unit (ICU). DESIGN: A prospective evaluation of CXRs performed in the ICU for a period of 6 months. A questionnaire was completed for each CXR performed, addressing the indication for the radiograph, whether it changed the patient's management, and how it did so. SETTING: A 14-bed medical-surgical ICU in a university-affiliated, tertiary care hospital. PATIENTS: A total of 645 CXRs were analyzed in 97 medical patients and 205 CXRs were analyzed in 101 surgical patients. RESULTS: Of the 645 CXRs performed in the medical patients, 127 (19.7%) led to one or more management changes. In the 66 surgical patients with an ICU stay <48 hours, 15.4% of routine CXRs changed management. In 35 surgical patients with an ICU stay > or = 48 hours, 26% of the 100 routine films changed management. In both the medical and surgical patients, the majority of changes were related to an adjustment of a medical device. CONCLUSIONS: Routine CXRs have some value in guiding management decisions in the ICU. Daily CXRs may not, however, be necessary for all patients.

Critical Care↗

PubMed2001

Exhaled nitric oxide: the effects of age, gender and body size.

Since little is known of the effects of age, gender, and body size on exhaled nitric oxide (NO) production, we have conducted a prospective study to examine these factors in a healthy nonsmoking women (mean age +/- SD 47.7 +/- 15.8, range 20-79 years). Exhaled NO was measured by an automatic chemiluminescence analyzer (Sievers NO Analyser 280) at steady expiration. Men had significantly higher exhaled NO levels than women (p = 0.001). Although exhaled NO levels did not correlate with age (r = 0.12, p = 0.17), it correlated significantly with height (r = 0.23, p = 0.02), weight (r = 0.34, p

Adult↗

PubMed2001

Temporal relationship between air pollution and hospital admissions for asthmatic children in Hong Kong.

BACKGROUND: Many epidemiological studies have shown positive association between respiratory health and current levels of outdoor air pollution in Europe and America. OBJECTIVE: The aim of this study was to investigate the association between air pollution and the number of childhood admissions for asthma in Hong Kong. METHODS: Daily counts of childhood admission for asthma to a large teaching Hospital were obtained from the computerized database for the period 1993-1994. A Poisson regression allowing for seasonal patterns and meteorological conditions was used to assess the associations between the number of Hospital admissions and the three pollutants: nitrogen dioxide, sulphur dioxide and inhalable particles (measured as PM10, particles < 10 microm in aerodynamic diameter). RESULTS: A total of 1217 children under 15 years of age were admitted for asthma during the study period. The calculated annual hospitalization rates were 283 and 178 per 100 000 for boys and girls, respectively. The mean PM10, NO2 and SO2 levels were 44.1 microg/m3, 43.3 microg/m3, and 12.2 microg/m3, respectively. Daily admission for asthma increased significantly with increasing ambient level of nitrogen dioxide (relative risk (RR) = 1.08 per 10 microg/m3 increase), sulphur dioxide (RR = 1.06) and inhalable particles (RR = 1.03). No association was found between hospital admission and humidity, temperature or atmospheric pressure. CONCLUSION: This is the first daily time series study of childhood admissions for asthma and air pollution in Hong Kong. The results support that current levels of air pollution contribute to the respiratory morbidity in asthmatic children in Hong Kong.

Adolescent↗

PubMed2001

Prevalence of respiratory and atopic disorders in Chinese schoolchildren.

BACKGROUND: Epidemiological surveys have shown that the prevalence of asthma in the Asian population is relatively low. Within the Chinese population, schoolchildren from Hong Kong were found to have the highest rate of asthma. OBJECTIVE: To compare the prevalence of respiratory and atopic disorders, and to assess the role of atopy in the development of asthma, in Chinese schoolchildren from Hong Kong, Beijing and Guangzhou. METHODS: Community-based random samples of schoolchildren aged 9-11 years from three Chinese cities (Hong Kong, Beijing and Guangzhou) were recruited for study using the International Study of Asthma and Allergies in Childhood (ISAAC) Phase II protocol. Subjects were studied by parental questionnaires (n = 10902), skin-prick tests (n = 3479) and skin examination (n = 3479). RESULTS: The prevalence rates of current wheeze, speech limiting wheeze, rhinoconjunctivitis and flexural dermatitis were significantly more common in Hong Kong than in Beijing or Guangzhou. The atopy rate was also higher in Hong Kong (41.2%) than in Beijing (23.9%) or Guangzhou (30.8%). Atopy was strongly correlated with current wheeze (OR 7.74; 95% CI = 5.70-10.51). Subgroup analyses of children from Hong Kong revealed that children born in mainland China who had subsequently migrated to Hong Kong had a significantly lower rate of allergic symptoms and atopy than those children born in Hong Kong. CONCLUSION: Using a standardized written questionnaire along with a skin prick test and skin examination, we confirmed that the prevalence of asthma, allergic diseases and atopy was highest in schoolchildren from Hong Kong. Atopic sensitization is an important factor associated with asthma in Chinese children.

Asian People↗

PubMed2001

Macrophages, neutrophils and tumour necrosis factor-alpha expression in bronchiectatic airways in vivo.

Bronchiectasis is increasingly being recognized as an inflammatory condition of the airways in which pathological permanent dilation occurs. We have obtained endobronchial biopsies in 14 patients with stable bronchiectasis and 15 control subjects. Airway neutrophils, macrophages and tumour necrosis factor-alpha (TNFalpha)-positive cells were stained with monoclonal antibodies and the densities of positive cells in the lamina propria were determined by using a computer image analyser. There was significantly higher neutrophil, macrophage and TNFalpha-positive cell densities in the lamina propria of bronchiectatic than control airways (P < 0.001, P < 0.001 and P=0.0002, respectively). Airway neutrophil density in bronchiectasis but not in controls, correlated with TNFalpha-positive cell density (r=0.71, P=0.004). A significant correlation between airway macrophage and TNFalpha-positive cell densities was demonstrated in both control and bronchiectatic airways (r=0.63, P=0.016 and r=0.60, P=0.02 respectively). Neutrophil density negatively correlated with per cent forced vital capacity (FVC%) predicted among patients with bronchiectasis (r=-0.53, P=0.04). Bronchiectasis patients who were regular sputum producers had a significantly higher macrophage, but not neutrophil density than their counterparts (P=0.02 and P=0.48 respectively). Our original findings suggest that airway macrophages could contribute to neutrophil influx into airway walls through their production of TNFalpha and therefore play an important role in the pathogenesis of bronchiectasis.

Aged↗

PubMed2001

Increase in plasma adrenomedullin in patients with heart failure characterised by diastolic dysfunction.

OBJECTIVE: To investigate the relation between plasma adrenomedullin and the severity of diastolic dysfunction in patients with heart failure. DESIGN: Prospective study. SETTING: University teaching hospital. PATIENTS: 77 patients (mean (SEM) age 66.3 (1.2) years; 75% male) who were being followed in the outpatient clinic after admission to hospital for acute heart failure. INTERVENTIONS: Same day echocardiography with Doppler studies; determination of venous adrenomedullin concentration by radioimmunoassay. MAIN OUTCOME MEASURES: Plasma adrenomedullin concentration and its correlation with systolic and diastolic function. RESULTS: 31 patients (40%) had isolated diastolic dysfunction (ejection fraction > 50%), and the remaining 46 had a depressed ejection fraction (< 50%). Of the patients with diastolic dysfunction, 17 had a restrictive filling pattern. In all but one of these there was coexisting systolic failure (chi(2) = 10.7, p = 0.001). Patients with systolic heart failure and a restrictive filling pattern (group 1, n = 16) had a higher plasma adrenomedullin than those with systolic failure and a non-restrictive filling pattern (group 2, n = 30) or with isolated diastolic heart failure and a non-restrictive filling pattern (group 3, n = 30) (mean (SEM): 91.7 (21.1) v 38.4 (8.8) v 34.0 (6.5) pmol/l, both p < 0.05). All heart failure values were higher (p < 0.01) than the control value (6.9 (1.2) pmol/l). Ejection fraction and left ventricular dimensions were similar in groups 1 and 2. Plasma adrenomedullin did not correlate with ejection fraction or New York Heart Association functional class. Stepwise multiple regression analysis showed that the presence of a restrictive filling pattern was the only independent variable associated with a high plasma adrenomedullin. CONCLUSIONS: Plasma adrenomedullin concentrations in patients with heart failure are determined by the presence of diastolic dysfunction, and are especially raised in the presence of a restrictive filling pattern. There appears to be no correlation with systolic dysfunction.

Acute Disease↗

PubMed2001

The effect of aging on nasal mucociliary clearance, beat frequency, and ultrastructure of respiratory cilia.

The increased susceptibility of the elderly to lower respiratory tract infection cannot be fully explained. Although mucociliary clearance, which is affected by ciliary beating and ultrastructure, plays a crucial role in the defense of the airways against inhaled microbes, little is known of the effects of aging on these parameters. We studied the nasal mucociliary clearance (NMCC) time, ciliary beat frequency, and ultrastructure of respiratory cilia in a cohort of healthy volunteers (age range 11 to 90 yr). Ciliary beat frequency of ciliated nasal epithelial cells was obtained via an established photometric method, and NMCC time was measured with the saccharine test. There was a correlation of ciliary beat frequency (r = -0.48, p = 0.0001) and NMCC time r = 0.64, p < 0.001) with increasing age. Transmission electron microscopy revealed an increase in the percent of subjects exhibiting microtubular disarrangement and single central microtubules with aging (p = 0.002 and p = 0.005, respectively). Subjects older than 40 yr of age had significantly slower ciliary beat frequency, higher percent of ciliary cross-sections displaying single tubules, and longer NMCC time than their younger counterparts (p < 0.05). These findings may help explain the frequent occurrence of respiratory infection in the elderly.

Adolescent↗

PubMed2000

Endothelin-1 in stable bronchiectasis.

Endothelin (ET)-1 has been suggested to promote neutrophil adhesion to endothelium, migration to inflamed areas, and release of elastase. ET-1 might therefore play a role in the pathogenesis of bronchiectasis, a chronic inflammatory and infective airway disease which is still poorly understood. Thirty five patients with stable bronchiectasis (20 females, mean age+/-SD 49.1+/-15.0 yrs) and 18 control subjects (8 females, 49.4+/-11.3 yrs) were recruited prospectively. The ET-1 levels in serum and sputum were measured by commercially available enzyme linked immunosorbent assay (ELISA) kits. Patients with Pseudomonas aeruginosa in their sputum had a significantly higher serum level of ET-1 (median 25.8, interquartile range 13-43.9 pg x mL(-1)) than patients without P. aeruginosa (0, 0-10.5 pg x mL(-1); p=0.0004) and healthy control subjects (4.6, 0-16.3 pg x mL(-1); p=0.002). However, patients with and without P. aeruginosa infection had no significant difference in sputum ET-1 level (p=0.15). There was no correlation between serum or sputum ET-1 levels with the serum and sputum levels of the interleukin (IL)-1beta, IL-8 and tumour necrosis factor (TNF)-alpha; the number of bronchiectasis lung lobes; and spirometry. Serum ET-1 level correlated with 24 h sputum volume for the bronchiectasis patients (r=0.51, p=0.002). The results, therefore, suggest a significant pathogenic role for endothelin-1 among Pseudomonas aeruginosa-infected patients with bronchiectasis. Further studies should be performed to evaluate the clinico-pathological correlation and expression of endothelin-1 in bronchiectasis.

Bronchiectasis↗

PubMed2000

Validation of prediction equations for basal metabolic rate in chinese subjects.

OBJECTIVES: To examine the validity of existing prediction equations for basal metabolic rate (BMR) and two generated regression equations in healthy Chinese subjects and patients with chronic diseases. SUBJECTS: One-hundred and thirty-four healthy Chinese volunteers of aged 16-88 among staff working in Shatin Hospital and their relatives, and 30 elderly patients with heart disease, stroke and chronic obstructive airway disease (COAD) were recruited. INTERVENTIONS: Height, weight, biceps and triceps skinfold thickness, body fat percentage, and BMR were measured in the healthy subjects and patients. Two regression equations were derived from 70 healthy Chinese subjects. Three existing equations (WHO, Liu and Jia equations) and two derived equations were then cross-validated in 64 subjects and 30 patients. RESULTS: For the healthy Chinese subjects, as well as patients, the BMR calculated by Liu was the closest to the measured BMR among all the equations, although there was slight underestimation for patients. CONCLUSION: This study confirms that the Liu equation is the most appropriate for predicting BMR in healthy Chinese subjects, but it underestimates the BMR in those with chronic diseases. Fat-free mass is the best predictor of measured BMR. SPONSORSHIP: Unrestricted research grant in nutrition from the Bristol-Myers Squibb Foundation.

Adolescent↗

PubMed1999

HpaII polymorphism in the atrial natriuretic peptide gene and hypertension.

This was an association study of genetic polymorphisms to compare the distribution of the genotypes and alleles of the HpaII polymorphism of the atrial natriuretic peptide (ANP) gene in hypertensive patients and normotensive controls. The setting was an outpatient clinic run by a University Department handling referrals from primary care. The patient cohort was composed of 217 subjects, consisting of 109 healthy controls and 108 patients with newly diagnosed or documented hypertension. The genomic DNA was extracted from peripheral blood leukocytes, amplified by polymerase chain reaction, and digested with the restriction enzyme HpaII. H1 and H2 alleles were identified after electrophoresis. The main outcome measures were to identify the frequencies of ANP genotypes and alleles in hypertensive patients and normotensive controls. The H1H1, H1H2, and H2H2 genotypes occurred in 1%, 19%, and 80% of controls and 3%, 18%, and 80% of hypertensive patients, respectively. The frequencies of the H1 and H2 alleles were 0.11 and 0.89 in controls and 0.12 and 0.88 in hypertensive patients. The frequencies of the ANP genotypes and alleles did not differ significantly between controls and hypertensive patients. Our findings differed from previous reports and suggested that this polymorphism is not associated with hypertension in this population.

Adult↗

PubMed1999

Evaluation of the efficacy of a hospital-based asthma education programme in patients of low socioeconomic status in Hong Kong.

BACKGROUND: Good asthma control requires optimal medical treatment in conjunction with appropriate self-management. In the West, the effectiveness of patient education on improving self-management has been well documented. However, data amongst Asian populations are lacking. We performed a pilot study to evaluate the efficacy of a hospital based education programme aimed at improving self-management skills and reducing morbidity in a Chinese population with low socioeconomic status and education level. METHODS: Our asthma education programme was a low-cost programme conducted in essence by specialist respiratory nurses. Patients attending our asthma clinic were instructed during a two-hour educational session on the pathophysiology of asthma, its potential triggers, the appropriate use of medications including proper inhaler techniques, and the self-management of their disease. These instructions were reinforced by video sessions at subsequent outpatient clinic attendance when patients' inhaler and peak flow techniques were checked by the same nurses and their self-management plan re-examined by the attending physicians. Asthma knowledge, inhaler technique, FEV1 and peak expiratory flow (PEF), and patients' self-rating of their asthma were determined at baseline, 6 months and 1 year after the intervention. Morbidity was assessed by the numbers of hospitalizations, unscheduled visits to family physicians and accident and emergency department attendance, courses of oral steroid used and days off work or school at baseline and 1 year. RESULTS: Two hundred and thirty patients were recruited for the study, 83% completing the entire assessment period. The group demonstrated significant improvements in lung function: the mean FEV1 +/- SD increased from 63.6 +/- 20.6% of predicted values at baseline to 68.5 +/- 22.3% at 6 months and 68.6 +/- 22.8% at 1 year (P < 0.05), and the mean PEF +/- SD increased from 64.6 +/- 23.0% of predicted values at baseline to 75.4 +/- 27.0% at 6 months and 76.8 +/- 24.5% at 1 year(P < 0.001). There were also significant improvements in inhaler technique (P < 0.01), asthma knowledge (P < 0.001), patients' self-rating of their asthma (P < 0.05), and reductions in the numbers of hospitalizations (P < 0.01), visits to family physicians (P < 0.001) and accident and emergency department attendance (P < 0.001) during the study period. Patients with moderate to severe asthma as defined by an FEV1 of < 80% of predicted values were most likely to benefit from the programme. CONCLUSIONS: We conclude that patient education is likely to be an essential component in the holistic approach to the management of asthma even amongst Asian populations of low socioeconomic status and education level. Further studies using randomised controlled trials are necessary to consolidate our findings.

Administration, Oral↗

PubMed1999

Effects of theophylline, dexamethasone and salbutamol on cytokine gene expression in human peripheral blood CD4+ T-cells.

CD4+ T-cells are considered as pivotal in orchestrating the airway inflammation in asthma through the actions of their cytokines. Current hypothesis suggests that the anti-asthma effect of theophylline may be due to its anti-inflammatory actions, although the exact mechanisms remain unclear. The in vitro effect of theophylline on cytokine gene expression in peripheral blood CD4+ T-cells in normal subjects was compared with that of dexamethasone and salbutamol. CD4+ T-cells were cultured with phytohaemagglutin and phorbol myristate acetate in the presence of different concentrations of theophylline (10(-8)-10(-3) M or 0.0018-180 microg x mL(-1)) in one group of subjects (n=8), dexamethasone (10(-9)-10(-6) M or 0.39-390 ng x mL(-1)) in a second group (n=8) and salbutamol (10(-9)-10(-4) M or 0.00058-58 microg x mL(-1)) in a third group (n=8). Gene expression of interleukin (IL)-3, IL-4, IL-5, granulocyte-macrophage colony-stimulating factor (GM-CSF) and interferon (IFN)-gamma was semiquantified by reverse transcription-polymerase chain reaction. Suppressed expression of IL-3 (36.9%), IL4 (38.8%), GM-CSF (24.6%) and IFN-gamma (37.7%), but not of IL-5, was only seen with theophylline at a concentration of 10(-3) M (180 microg x mL(-1)) (p<0.05) and not at lower concentrations. In contrast, dexamethasone caused a dose-dependent suppression of transcription of all cytokines, with 39.5% for IL-3, 84.4% for IL-4, 40.6% for IL-5, 50.9% for GM-CSF and 31.8% for IFN-gamma at 10(-6) M (390 ng x mL(-1)) (p<0.05-0.001). Salbutamol did not suppress gene expression of any of the cytokines at the concentrations examined. These data suggest that cytokine gene expression of CD4+ T-cells is not affected at therapeutic concentrations of theophylline and salbutamol, but its suppression is likely to be an important mechanism underlying the therapeutic effect of corticosteroids in asthma.

Adrenergic beta-Agonists↗

PubMed1998

Indoor environment of residential homes in Hong Kong--relevance to asthma and allergic disease.

BACKGROUND: The prevalence of asthma and allergic disease has been increasing in Hong Kong and environmental factors are thought to play a major role. AIM: To define the distribution of common inhaled allergens and air pollutants inside residential homes in Hong Kong. METHODS: Forty randomly selected residential homes were visited and surveyed. Dust samples were collected from mattress, bedroom floor, lounge room floor and kitchen floor for assays of Der p 1, Fel d 1, and Bla g 2. Nitrogen dioxide (NO2) levels were measured by stationary samplers left in the bedroom, lounge room and kitchen over a 1-week period. RESULT: All 40 homes were apartments in high-rise buildings and the mean age of the homes was 7.6 +/- 4.8 years. Visible dampness and mould patches were present in 27.5% of homes and the main fuel for cooking was gas (97.5%). Der p 1, Fel d 1 and Bla g 2 were detectable in at least 1 niche in over 85% of homes. In particular, all dust samples from mattress and bedroom floor contained Der p 1, and over 50% had levels > or = 2 microg/g. The (geometric) mean Der p 1 level in mattress dust was 8.8 (0.3-157.8) microg/g. Fel d 1 and Bla g 2 were present in low levels throughout the homes with respective (geometric) means of 0.3 (0-3.7) microg/g and 0.1 (0-1.1) Unit/g in mattress dust. NO2 was readily detected in all niches but the highest level was in the kitchen with mean exposure of 48.7 ppb which was 1.5 times higher than that in the bedroom and lounge room. CONCLUSION: Major allergens of mite, cat and cockroach, and NO2 are present in varying quantities in residential homes in Hong Kong. Exposure to these environmental factors could be important in the development of asthma and allergic diseases in susceptible individuals.

Air Pollution, Indoor↗

PubMed1998

M235T polymorphism of the angiotensinogen gene and hypertension in Chinese.

OBJECTIVES: To compare the distributions of the genotypes and alleles of the M235T polymorphism of the angiotensinogen gene for hypertensive patients and normotensive controls. DESIGN: A study of association of genetic polymorphisms. SETTING: An outpatient clinic run by a university department handling referrals from primary care. PATIENTS: Two hundred and four subjects, 103 normal controls and 101 patients with newly diagnosed or documented hypertension. METHOD: Genomic DNA was extracted from peripheral blood leucocytes, amplified by polymerase chain reaction and digested with the restriction enzyme Tth 111 I. Methionine (M) and threonine (T) alleles were identified after electrophoresis. MAIN OUTCOME MEASURES: Prevalences of angiotensinogen genotypes and alleles for hypertensive patients and controls. RESULTS: MM, TM and TT genotypes occurred in 3, 24 and 73% of controls and 1, 22 and 77% of hypertensive patients, respectively. The prevalences of the M and T alleles were 0.15 and 0.85 among controls and 0.12 and 0.88 among hypertensive patients. The prevalences of the angiotensinogen genotypes and alleles for controls and hypertensive patients did not differ significantly. CONCLUSIONS: Our findings differed from previous reports and suggested that this polymorphism is not associated with hypertension in this population.

Adult↗

PubMed1998

Deep vein thrombosis and pulmonary embolism in the Chinese population.

Deep vein thrombosis and pulmonary embolism is a well-recognised major health problem in the West. There is a deep-rooted belief among clinicians that deep vein thrombosis is rare in Asians, particularly in the Chinese population. However, it appears that the incidence of venous thrombosis and pulmonary embolism is increasing in Chinese patients. Prophylaxis reduces the incidence of venous thrombosis by 66% and of pulmonary embolism by 50%--- prophylaxis should therefore be considered for Chinese patients who have a high risk of developing postoperative deep vein thrombosis. This report reviews the current literature on this subject.

Journal Article↗

PubMed1998

Sarcoidosis in a Hong Kong Chinese woman.

Sarcoidosis is rare in the Chinese population and most patients with sarcoidosis present with asymptomatic mediastinal lymphadenopathy. We report on a 31-year-old woman who presented with bilateral hilar lymphadenopathy and pulmonary infiltration that spontaneously resolved without treatment, and we present a review of the literature on sarcoidosis among the Hong Kong Chinese population.

Journal Article↗

PubMed1998

Marked difference between angiotensin-converting enzyme and neutral endopeptidase inhibition in vivo by a dual inhibitor of both enzymes.

Dual inhibition of neutral endopeptidase 24.11 (NEP) and angiotensin-converting enzyme (ACE) offers the potential for improved therapy of hypertension and cardiac failure. S 21402-1 [(2S)-2-[(2S,3R)-2-thiomethyl-3-phenylbutanamido] propionic acid] is a sulfhydryl-containing potent inhibitor of both NEP (Ki = 1.7 nM) and ACE (Ki = 4.5 nM). S 21402-1 and the sulfhydryl-containing ACE inhibitor captopril were administered to rats by intraperitoneal injection (0, 0.3, 3, 30, 300 mg/kg). Urine was collected for 4 h; then plasma and kidneys were collected. The difference in NEP and ACE inhibition by S 21402-1 in vivo was greater than 1000-fold. All doses of S 21402-1 inhibited NEP, as indicated by plasma NEP activity, radioinhibitor binding to kidney sections, urinary sodium excretion and bradykinin-(1-7)/bradykinin-(1-9) ratio. However, only 300 mg/kg S 21402-1 inhibited ACE, as indicated by plasma angiotensin II/angiotensin I ratio, renin and angiotensinogen levels. Although S 21402-1 (30 and 300 mg/kg) inhibited renal NEP, as indicated by the bradykinin-(1-7)/bradykinin-(1-9) ratio in kidney, S 21402-1 had no effect on renal ACE, as indicated by the angiotensin II/angiotensin I ratio in kidney. Moreover, captopril was greater than 10-fold more potent than S 21402-1 as an ACE inhibitor in vivo. In separate experiments, the pressor response of anesthetized rats to angiotensin I showed more rapid decay in ACE inhibition by S 21402-1 than by captopril. These studies indicated that in vivo modification of S 21402-1 caused a much greater decrease in potency of ACE inhibition than NEP inhibition. Consequently, effective ACE inhibition by S 21402-1 required doses much higher than those required for NEP inhibition.

Angiotensin II↗

PubMed1997

Sensitization to inhaled allergens as a risk factor for asthma and allergic diseases in Chinese population.

BACKGROUND: Allergen sensitization is associated with asthma and allergic disease in children, but such a relationship has not been confirmed in Chinese populations. OBJECTIVES: The objective of this study was to evaluate the effects of allergen sensitization and family history of atopy on asthma and allergic disease in Chinese schoolchildren from three southeast Asian populations. METHODS: Written questionnaires on respiratory and allergic symptoms were completed by parents of children of secondary-school age (age range 12 to 18 years) in Hong Kong (n = 1062), Kota Kinabalu in eastern Malaysia (n = 409), and San Bu in southern China (n = 737). A subsample of school-children underwent skin prick testing to common inhalant allergens (Hong Kong 471 children, Kota Kinabalu 321, San Bu 647). RESULTS: The prevalence of asthma and allergic disease in schoolchildren was highest in Hong Kong, intermediate in Kota Kinabalu, and lowest in San Bu. However, the overall rate of atopic sensitization was similar in the three populations (49% to 63%). House dust mite and cockroach were the two most common allergens causing sensitization and these gave rise to more than 95% of the positive skin test results in all three populations. By regression analysis, mite allergy was associated with rhinitis and asthma in all three populations, and a family history of asthma, rhinitis, or eczema was strongly associated with respective symptoms in the subjects. After adjusting for age, sex, atopic status, and family history of allergic disease, the place of residence remained a significant independent factor for asthma (odds ratio [OR] = 1.0 for Hong Kong, 0.57 for Kota Kinabalu, 0.15 for San Bu, p < 0.001), rhinitis (OR = 1.0 for Hong Kong, 0.59 for Kota Kinabalu, 0.15 for San Bu, p < 0.001), or eczema (OR = 1.0 for Hong Kong, 0.35 for Kota Kinabalu, 1.01 for San Bu, p < 0.001). CONCLUSION: Sensitization to indoor allergens was a significant risk factor for asthma and allergic disease, and familial clustering of disease was common in the region. However, the marked difference in disease prevalence in the three southeast Asian populations of Chinese schoolchildren cannot be explained by atopic sensitization and family history alone, and the place of residence was an independent risk factor for asthma and allergies, which suggests an important environmental role in disease pathogenesis.

Adolescent↗