Asthma, atopy and tuberculin responses in Chinese schoolchildren in Hong Kong

BACKGROUND: The prevalence rates of asthma and other atopic disorders have increased steadily in many developed countries over the past few decades. Recent epidemiological and animal studies have suggested that BCG vaccination might be beneficial in reducing the subsequent development of atopy. This study investigates the relationship between asthma, allergic symptoms, atopy, and tuberculin response in Chinese schoolchildren who received BCG vaccination at birth. METHODS: A total of 3110 schoolchildren aged 10 years were recruited for the Hong Kong arm of the phase II International Study of Asthma and Allergies in Childhood. Of the 2599 children born in Hong Kong and vaccinated with BCG after birth, 2201 had tuberculin testing performed at a mean (SD) age of 8.4 (1.4) years. A random subsample of 980 children was also recruited for skin prick testing. RESULTS: The prevalence rates of asthma ever, wheeze ever, current wheeze, current rhinoconjunctivitis, and current flexural eczema were not significantly different between tuberculin positive and negative subjects. The mean (SE) tuberculin response was 3.4 (0.2) mm in atopic subjects and 3.3 (0.2) mm in non-atopic subjects (difference not significant). Logistic regression analyses did not reveal any significant relationship between asthma ever, current wheeze, atopy, and positive tuberculin responses. CONCLUSIONS: This study did not find any relationship between asthma, allergic symptoms, atopy, and positive tuberculin reactivity in Chinese schoolchildren vaccinated with BCG at birth.     

Prevalence of atopy, asthma symptoms and diagnosis, and the management of asthma: comparison of an affluent and a non-affluent country

BACKGROUND: The prevalence of childhood asthma and of atopy varies widely between countries. However, few studies have compared the pattern of diagnosis and management of asthma, or the role of atopy in predisposing to asthma between a less affluent country and a more affluent country. The aim of this study was to compare the prevalence of symptoms, diagnosis, and management of asthma, and the prevalence of atopy as measured by skin prick tests in Nigeria and Australia using a standardised methodology. METHODS: Respiratory history was collected using a validated questionnaire administered to parents, and atopy was measured with skin prick tests in 654 Australian and 566 Nigerian children aged 8-11 years (70% consent rate in Australia, 60% in Nigeria). RESULTS: Wheeze and persistent cough were less prevalent in Nigeria (10.2% and 5.1%, respectively) than in Australia (21.9% and 9.6%, respectively), caused less morbidity, and were less likely to be labelled or treated as asthma than in Australia. There was no significant difference in the overall prevalence of atopy between the two countries (Australia 32. 5%, Nigeria 28.2%). Atopy was a strong risk for wheeze in both countries (odds ratio (OR) 3.4 (95% CI 2.3 to 5.1) in Australia, 1.8 (95% CI 1.0 to 3.3) in Nigeria), especially atopy to house dust mites (OR 3.1 (95% CI 2.1 to 4.7) in Australia, 2.4 (95% CI 1.3 to 4. 3) in Nigeria). CONCLUSION: Although there was a similar prevalence of atopy in both countries, Australian children had a higher prevalence of asthma symptoms. Further studies are needed to determine why atopic children in Australia are more at risk of developing asthma. Such studies will have important implications for the prevention of asthma.     

Prevalence of silent kidney disease in Hong Kong: the screening for Hong Kong Asymptomatic Renal Population and Evaluation (SHARE) program

BACKGROUND: End-stage renal disease (ESRD) is epidemic worldwide. In Hong Kong, the annual incidence of ESRD has risen from 100 pmp (per million population) in 1996 to 140 pmp in 2003. SHARE (Screening for Hong Kong Asymptomatic Renal Population and Evaluation program) is a population-based screening program aimed at identifying the prevalence of unrecognized renal disease in asymptomatic individuals, allowing further evaluation and disease-modifying interventions. METHODS: From November to December 2003, SHARE was conducted in several large residential communities in Hong Kong. The screening tool included a questionnaire documenting demographics and history or family history of diabetes mellitus (DM), hypertension (HT), and chronic kidney disease (CKD), together with on-site measurements of blood pressure (BP) and urine dipstick for protein, blood, and glucose. RESULTS: There were a total of 1811 participants. One thousand two hundred and one subjects were entered into the final analysis. Among the 1201 who were apparently "healthy" (asymptomatic and without history of DM, HT, or CKD), the prevalence of positive (> or =1+) urine dipstick for protein, glucose, blood, protein or blood, any urine abnormality, and HT (BP> or =140/90) was 3.2%, 1.7%, 13.8%, 16%, 17.4%, and 8.7%, respectively. Thirty three percent of the age over 60 years old group had either hypertension or urine abnormalities, compared with 24.0% in the 41- to 60-year-old group and 9.7% in the 20- to 40-year-old group. Having a family history of diabetes or hypertension increases the risk of having urine abnormalities, while a family history of hypertension also increases the risk of high blood pressure. CONCLUSION: It is concluded that subclinical abnormalities in urinalysis or BP readings are prevalent across all age groups in the adult population. An effective screening program at the primary care level that identifies these subjects for further evaluation is warranted, and the public in Hong Kong should be educated toward the significance of such findings in order to have regular health check for asymptomatic renal diseases.     

No increase in the prevalence of asthma, allergies, and atopic sensitisation among children in Germany: 1992-2001

BACKGROUND: From 1970 to 1990 increasing rates of asthma and allergic sensitisation were observed in several countries. The aim of this study was to investigate time trends in the prevalence of asthma and allergic sensitisation among school children in Germany between 1992 and 2001. METHODS: Parental reports of asthma, hay fever, and wheezing and measurements of specific serum IgE antibodies were investigated in six serial cross sectional surveys of 9-11 year old school children in three study areas in south west Germany. RESULTS: A total of 6762 school children of mean age 10 years (mean participation rate 77.9%) took part in the investigation in the three study areas. Over the 9 year study period no increase in the prevalence of current wheezing and asthma was observed. In addition, the prevalence of atopic sensitisation remained unchanged during the observation period. CONCLUSIONS: These data, using parental reports and objective measures of allergy, suggest that there has been no further increase in the prevalence of asthma and atopy since 1992. The epidemic may thus have reached a plateau.     

Allergic comorbidities in bronchial asthma, in children

Bronchial asthma is the most frequent chronic disease of childhood. The association of this disease with allergic rhinitis increases the prevalence and severity of bronchial asthma to 60% compared with 2% in subjects without allergic rhinitis. Food allergy can be expressed in a variety of respiratory symptoms, especially when IgE mediated immune responses are involved. In children, the prevalence of bronchial asthma associated with food induced atopic eczema is 2-8% and respiratory clinical picture can be a component of the multisystem anaphylactic reaction or of chronic respiratory disease like bronchial asthma, serous otitis. The association of other allergic comorbidities, like sinusitis, ocular allergies, lymphoid hypertrophy, sleep obstructive apnoea, leads to the conclusion that allergic bronchial asthma (extrinsic) is a systemic disease, with onset at any age, and the dominant clinical feature depends on the child's genetic pattern.     

The CD14 C-159T polymorphism is not associated with asthma or asthma severity in an Australian adult population

BACKGROUND: CD14 functions as a multifunctional receptor for bacterial cell wall components including endotoxin and lipopolysaccharide and is likely to play a role in the polarisation of T lymphocytes into Th1 and Th2 subsets, thereby influencing the cytokine profile and subsequent IgE production in response to antigen/allergen contact in allergic phenotypes. A functional C-159T polymorphism has been described in the promoter region of the gene and has been associated with increased gene expression, atopy, and non-atopic asthma in different ethnic populations. A study was undertaken to examine the association between the C-159T polymorphism and asthma, asthma severity, and atopy in a large Australian white population. METHODS: PCR-RFLP analysis was used to characterise the C-159T polymorphism in mild (n = 264), moderate (n = 225) and severe (n = 79) asthmatic patients and non-asthmatic controls (n = 443), including atopic (n = 688) and non-atopic (n = 323) individuals. Association analyses were performed using chi(2) tests. RESULTS: There was no association between the polymorphism and asthma (p = 0.468) or asthma severity (p = 0.727), and only a very weak association with atopy (p = 0.084). A meta-analysis of all studies conducted to date revealed similar genotypic frequencies in white ethnic populations and confirmed that there was no overall association with atopy (p = 0.52) or asthma (p = 0.23), although there was significant between study heterogeneity (p = 0.01). CONCLUSIONS: This study confirms that there is no association between the CD14 C-159T polymorphism and asthma or asthma severity and a weak association between this polymorphism and atopy in an adult population.     

Asthma in Late Adolescents of Western Mexico: Prevalence and Associated Factors

IntroductionGiven the number of changes that occur during late adolescence, it is possible that the behavior of asthma may also be different. The aim of our paper is to determine the prevalence of asthma in a population of late adolescents and its possible association with obesity, tobacco smoke exposure and family history of allergic disease.Methods and subjectsIn a cross-sectional, population-based analytical study design, we selected a stratified random sample of subjects aged 15–18. By modeling risk through logistic regression, we assessed the relationship between asthma and the following covariables: gender, obesity, excess weight, family history of allergic disease and tobacco smoke exposure.Results1600 subjects were included, and the following prevalences were identified: asthma 7.8%, obesity 9.6%, active smoking in the father 2 9.8%, active smoking in the mother 18.6% and active smoking habit in the study subjects 15.1%. In the final model, a significant association was found between asthma and the following variables: (1) asthma in the mother (adjusted OR [aOR]=2.95, 95% CI, 1.55–5.6), (2) history of allergic rhinitis (aOR=4.66, 95% CI, 2.63–8.25), and (3) male sex (aOR=1.48, 95% CI, 1.02–2.15). No association was seen with obesity or tobacco smoking of the parents.ConclusionOur results suggest that maternal history of asthma, personal history of allergic rhinitis and male sex are related with asthma late adolescence, while smoking and being overweight are not.     

Siblings, multiple births, and the incidence of allergic disease: a birth cohort study using the West Midlands general practice research database

BACKGROUND: The presence of older siblings reduces the risk of developing hay fever, eczema and atopy, but findings for asthma have been inconsistent. Whether twins have a reduced risk of allergic disease is also unclear. We have investigated these questions in a birth cohort analysis of the West Midlands General Practice Research Database (GPRD). METHODS: Our birth cohort included 29,238 children. The incidence of allergic disease was examined according to the number of siblings, multiple births, and parental allergic disease and smoking habit using Cox regression. RESULTS: There was a dose related decrease in the incidence of eczema and hay fever with increasing number of older siblings (hazard ratio for children with three or more older siblings compared with none 0.70 (95% CI 0.64 to 0.76) for eczema and 0.67 (95% CI 0.52 to 0.86) for hay fever). In contrast, the presence of older siblings increased the incidence of asthma (HR 1.17, 95% CI 1.06 to 1.29), although this effect was strongly dependent on age of diagnosis. For children diagnosed over the age of 2 years the presence of older siblings was protective (HR 0.66, 95% CI 0.52 to 0.82), while below this age the reverse was true (HR 1.38, 95% CI 1.24 to 1.54). Members of a multiple birth had a reduced incidence of all three allergic diseases. Birth order and multiple birth effects were independent of sex, maternal age, consulting behaviour, and parental allergy and smoking habit. CONCLUSIONS: The presence of older siblings and being a member of a multiple birth appears to protect against the development of eczema, hay fever, and asthma diagnosed after the age of 2. In contrast, the presence of older siblings increases the incidence of early asthma.     

Diet and childhood asthma in a society in transition: a study in urban and rural Saudi Arabia

BACKGROUND: The causes of the worldwide increases in asthma and allergic diseases in childhood, which seem to relate to increasing prosperity, are unknown. We have previously hypothesised that a reduction in the antioxidant component of the diet is an important factor. An investigation was undertaken of dietary and other risk factors for asthma in Saudi Arabia where major lifestyle differences and prevalences of allergic disease are found in different communities. METHODS: From a cross sectional study of 1444 children with a mean age of 12 (SD 1) years in Jeddah and a group of rural Saudi villages, we selected 114 cases with a history of asthma and wheeze in the last 12 months and 202 controls who had never complained of wheeze or asthma, as recorded on the ISAAC questionnaire. Risk factors for asthma and allergies (family history, social class, infections, immunisations, family size, and diet) were ascertained by questionnaire. Atopy was assessed by skin prick testing. RESULTS: In univariate analyses, family history, atopy, and eating at fast food outlets were significant risk factors for wheezy illness, as were the lowest intakes of milk and vegetables and of fibre, vitamin E, calcium, magnesium, sodium, and potassium. These differences were present also in the urban children considered separately. Sex, family size, social class, infections, and parental smoking showed no relationship to risk. In multiple logistic regression analysis, urban residence, positive skin tests, family history of allergic disease, and the lowest intakes of vitamin E, magnesium and sodium related significantly and independently to risk. The lowest tertile of intake of vitamin E was associated with a threefold (95% CI 1.38 to 6.50) increase in risk when adjusted for the other factors. Intake of milk and vegetables both showed inverse linear relationships to being a case. CONCLUSIONS: This study suggests that dietary factors during childhood are an important influence in determining the expression of wheezy illness, after allowing for urban/rural residence, sex, family history, and atopy. The findings are consistent with previous studies in adults and with the hypothesis that change in diet has been a determinant of the worldwide increases in asthma and allergies.     

Homocysteine,endothelial dysfunction,and coronary artery disease: emerging strategy for secondary prevention

Atherosclerosis is an important medical problem of the 21st century, but traditional risk factors could only account for 50% of the problem. Hyperhomocysteinemia is emerging as an independent atherosclerosis risk factor, associated with folate deficiency, renal failure, and relative deficiency of MTHFR (C677T polymorphism) or other enzymes depending on gender, age, and smoking status. Hyperhomocysteinemia has been reported to occur in 11-22% of western people, in 3-5% of normal asymptomatic Chinese subjects aged 18-70 years in Hong Kong, Macau, Sydney, and San Francisco, 23-36% of Chinese in Hong Kong with premature coronary artery disease, and 29% of a nonselective series of coronary subjects in Hong Kong. Evidence is accumulating that documents its associations with atherosclerosis disease in both case-control observations and prospective cohort studies, in vitro experiments, and in vivo experimental models in both animals and human subjects, as well as the successful improvement by homocysteine-lowering of endothelial function as surrogate atherosclerosis endpoints in asymptomatic human and coronary patients (secondary prevention). A number of large scale homocysteine-lowering trials are currently underway for stroke and heart attacks prevention. Collectively these trials will include more than 65,000 patients at high-risk for cardiovascular and stroke events, and should provide a reliable evidence-base for prevention.     

Relation of body mass index to asthma and atopy in children: the National Health and Nutrition Examination Study III

BACKGROUND: An increase in the prevalence of obesity and asthma over recent decades has been reported in affluent societies. Both overweight and obesity have been shown to be inversely related to having been breastfed, which is also a potential protective factor against childhood atopic diseases. The aim of this analysis was to explore the relation of body mass index (BMI) to asthma and atopy in a large representative sample of the United States population. METHODS: Children aged 4-17 years were included in the NHANES III survey. Prevalences of atopic diseases and potential confounding factors such as exposure to environmental tobacco smoke, birth weight, breast feeding, and household size were assessed using structured interviews with parents. Height and weight were measured, and BMI was calculated as kg/m(2) and transformed into Z scores. Children underwent skin prick tests for atopy to a battery of food and inhalant allergens. RESULTS: The prevalence of asthma (8.7% v 9.3% v 10.3% v 14.9%, p=0.0001) and atopy (48.6% v 50.5% v 53.0% v 53.2%, p=0.05) rose significantly with increasing quartiles of BMI. After adjustment for confounders, a significant positive association between BMI and asthma remained (adjusted OR 1.77, 95% confidence interval 1.44 to 2.19 between the highest and lowest quartiles of BMI), whereas no independent relation between BMI and atopy was evident. No effect modification by sex or ethnic group was seen. CONCLUSIONS: The effects of increased BMI on asthma may be mediated by mechanical properties of the respiratory system associated with obesity or by upregulation of inflammatory mechanisms rather than by allergic eosinophilic inflammation of the airway epithelium.     

Bronchial hyperresponsiveness in young students of southern China: relation to respiratory symptoms, diagnosed asthma, and risk factors.

A cross sectional study was carried out to determine the prevalence of bronchial hyperresponsiveness and asthma in 3067 students aged 11-17 years in an urban and a rural area of Guangzhou (Canton), China. The methods used included a self administered questionnaire, a histamine bronchial provocation test, and allergen skinprick tests. Bronchial hyperresponsiveness was defined as a 20% fall in FEV1 and peak expiratory flow at a provoking dose of histamine (PD20) less than 7.8 mumol on two occasions four weeks apart. The response rate was 98.0% and 99.2% in the two areas. The prevalence of bronchial hyperresponsiveness was 4.1% and of diagnosed asthma 2.4% in the total population. There were no significant differences in prevalence between the urban and the rural area or between boys and girls. The 11-12 year group had a higher prevalence of bronchial hyperresponsiveness (7.6%) than the older groups. Of the 125 with bronchial hyperresponsiveness, 12.0% were defined as having severe or moderate (PD20 less than 0.8 mumol), 26% mild (0.9-3.2 mumol), and 62% slight bronchial hyperresponsiveness (3.3-7.8 mumol). The severity of bronchial hyperresponsiveness was closely related to diagnosed asthma, wheezing, and cough, though half the students with bronchial hyperresponsiveness were symptom free. The most common allergens were house dust and house dust mite in the city, and hay dust, pollen, and feathers in the rural area. The odds ratios for having respectively slight, mild or moderate, and severe bronchial hyperresponsiveness were 5.9, 21.0, and 30.4 for atopy; 1.9, 1.9, and 7.3 for early respiratory infection; and 3.1, 2.5, and 5.6 for a history of parental asthma.     

Prevalence of asthma and risk factors among Chinese, Malay, and Indian adults in Singapore.

BACKGROUND--The prevalence and morbidity of asthma vary greatly among different ethnic communities and geographical locations, but the roles of environmental and genetic factors are not fully understood. The differences in prevalence of adult asthma among Chinese, Malay, and Indian ethnic groups in Singapore were examined, and the extent to which these could be explained by personal and environmental factors were investigated. METHODS--A stratified disproportionate random sample (n = 2868) of Chinese (n = 1018), Malays (n = 967), and Indians (n = 883) of both sexes was drawn from households in five public housing estates, and an interviewer administered questionnaire was used to determine cumulative and current prevalence of "physician diagnosed asthma" (symptoms with a physician diagnosis of asthma). RESULTS--Lifetime cumulative prevalence (standardised to the general population) of "physician diagnosed asthma" was 4.7% in men and 4.3% in women; 12 month period prevalences were 2.4% and 2.0%, respectively. Cumulative prevalence of asthma was significantly higher in Indians (6.6%) and Malays (6.0%) than in Chinese (3.0%); period prevalences of asthma were 4.5% in Indians, 3.3% in Malays, and 0.9% in Chinese. Ownership of cats or dogs was more frequent in Malays (15.4%) and Indians (11.2%) than in Chinese (8.8%). Rugs and carpets were also more frequently used by Malays (52.2%) and Indians (40.7%) than by Chinese (8.9%). Current smoking prevalences were higher in Malays (27.3%) than in Indians (19.4%) and Chinese (23.0%). Malays and Indians did not have higher rates of atopy (11.1% and 15.2%, respectively) than Chinese (15.4%). Adjustment for these factors in multivariate analyses reduced the greater odds of asthma in Malays and Indians, but not to a significant extent. CONCLUSIONS--There are ethnic differences in the prevalence of asthma in Singapore which are not entirely explained by differences in smoking, atopy, or other risk factors. Other unmeasured environmental factors or genetic influences are likely to account for residual differences in the prevalence of asthma.     

Respiratory symptoms, asthma, exercise test spirometry, and atopy in schoolchildren from a Lima shanty town

BACKGROUND: Little is known about the associations between symptoms of asthma, pulmonary function tests, and atopy in developing countries. While asthma in children is often associated with atopy, some studies of wheezing illness have found little or no association, leading to suggestions that there are subgroups of wheezing illness. The ISAAC study recently reported that the prevalence of reported asthma symptoms in Lima, Peru was among the highest in the world, but did not report on the atopic status of the subjects. METHODS: A cross sectional survey was conducted of children aged 8-10 years who had previously participated in a cohort study of respiratory and diarrhoeal illnesses in infancy. Questionnaires were administered asking about respiratory symptoms and asthma diagnoses, pulmonary function tests were performed before and after exercise on a treadmill, and atopy was determined from skin prick tests and specific serum IgE levels. RESULTS: A total of 793 children participated in the survey. The prevalence of asthma related symptoms in the last 12 months was 23.2%, but only 3.8% of children reported a recent asthma attack. The mean differences in pretest percentage predicted forced expiratory volume in one second (FEV(1)) were 8.1% (95% CI 2.4 to 13.8) between children who did and did not report an asthma attack in the last 12 months, and 5.3% (95% CI 2.8 to 7.9) in children who did and did not report respiratory symptoms. The corresponding differences in mean percentage fall in FEV(1) after exercise were 3.1% (95% CI -1 to 7.1) and 5.1% (95% CI 3.4 to 6.8). Recent asthma or respiratory symptoms were not associated with atopy in this population (odds ratios 1.29 (95% CI 0.56 to 2.97) and 0.91 (95% CI 0.61 to 1.37), respectively). CONCLUSIONS: Most asthma in these children was unrecognised and mild. Asthma and asthma symptoms in this population do not seem to be related to atopy.     

Factors influencing the prevalence of asthma among first degree relatives of extrinsic and intrinsic asthmatics.

The prevalence of asthma, hay fever, and eczema was examined in first degree relatives of extrinsic (atopic) and intrinsic (non-atopic) asthmatics attending the asthma clinics of the Brompton Hospital and the Doncaster Royal Infirmary. In both the Doncaster and Brompton populations the prevalence of asthma, hay fever, and eczema was significantly higher among relatives of extrinsic than among relatives of intrinsic asthmatics. Furthermore, the prevalence of these traits tended to be higher among siblings of extrinsic probands with one or both parents affected than among siblings of probands with neither parent affected. Most importantly, the prevalence of asthma among first degree relatives was positively correlated with the prevalence of hay fever or eczema or both among relatives and with the degree of atopy in the probands. These findings are consistent with the results of previous investigations in which the expression of asthma was shown to depend on a genetic predisposition to the trait as well as exposure to environmental provoking agents. We further suggest that the presence of atopy in genetically predisposed individuals increases the risk of developing asthma.     

Candidate gene loci in asthmatic and allergic inflammation.

New techniques for scanning the human genome promise great advances in tracking the origins of disorders caused by multiple genes. However, it is clear from the studies presented in this overview that we are far from understanding the genetic basis of asthma and atopy and their interaction with the environment. It is also clear that agreement must be reached on definition of the phenotype and methods of ascertainment in order to carry out large multicentre collaborative studies. Positive findings need to be validated in different populations selected for the presence of the disease and then confirmed in a random population where the prevalence of asthma and atopy will also be expected to be significant.     

The prevalence of aspirin intolerant asthma (AIA) in Australian asthmatic patients

BACKGROUND: Aspirin intolerant asthma (AIA) is a clinically distinct syndrome characterised by the precipitation of asthma attacks following the ingestion of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs). The prevalence of AIA among Australian asthmatic patients has not previously been reported. METHODS: Three populations were surveyed to establish the prevalence of AIA among Australian asthmatics. Two surveys were completed in patients recruited from the metropolitan area in Perth, Western Australia, one comprising 150 recruited from hospital based sources (hospital cohort) and the second comprising 366 from the membership of the Asthma Foundation of Western Australia (Asthma Foundation cohort). In a third study 1298 individuals were randomly selected from the rural community of Busselton in Western Australia. RESULTS: The prevalence of AIA in the hospital and Asthma Foundation cohorts was found to be 10.7% and 10.4%, respectively. Univariate analyses in the Asthma Foundation cohort indicated that AIA was associated with more severe asthma (OR = 2.4, 95% CI 1.18 to 4.86), nasal polyposis (OR=3.19, 95% CI 1.52 to 6.68), atopy (OR=2.96, 95% CI 1.48 to 5.89), sulfite sensitivity (OR=3.97, 95% CI 1.87 to 8.41), and sensitivity to wine (OR=3.27, 95% CI 1.65 to 6.47). Multivariate analyses indicated that atopy (OR=2.80, 95% CI 1.38 to 5.70), nasal polyposis (OR=3.39, 95% CI 1.57 to 7.29), and the number of asthma attacks in the previous 12 months (OR=1.20, 95% CI 1.02 to 1.42) were independent predictors for AIA, as was wine sensitivity (OR=2.20, 95% CI 1.02 to 4.72). The prevalence of AIA among asthmatic patients in the Busselton cohort was 10.9%. In addition, 2.5% of non-diagnosed asthmatics in this cohort reported asthma symptoms following aspirin ingestion. CONCLUSION: The prevalence of respiratory symptoms triggered by aspirin/NSAID use was found to be 10-11% in patients with asthma and 2.5% in non-asthmatics. Aspirin sensitivity appears to be a significant problem in the community and further investigations of the mechanisms of these responses and the possible link between this syndrome and other food and chemical sensitivities are required.     

Osteoporosis in China

Summary  

Based on related studies published between 1980 and May 2008, we examine the prevalence of osteoporoses in mainland China, Hong Kong, and Taiwan. Overall, the prevalence of osteoporosis among these Chinese populations remains low compared to other Caucasian populations; in the mainland, it was approximately 13%.     

Primary prevention of asthma and atopy during childhood by allergen avoidance in infancy: a randomised controlled study

BACKGROUND: Recent increases in the prevalence of asthma and atopy emphasise the need for devising effective methods for primary prevention in children at high risk of atopy. METHOD: A birth cohort of genetically at risk infants was recruited in 1990 to a randomised controlled study. Allergen avoidance measures were instituted from birth in the prophylactic group (n=58). Infants were either breast fed with mother on a low allergen diet or given an extensively hydrolysed formula. Exposure to house dust mite was reduced by the use of an acaricide and mattress covers. The control group (n=62) followed standard advice as normally given by the health visitors. At age 8, all 120 children completed a questionnaire and 110 (92%) had all assessments (skin prick test, spirometry, and bronchial challenges). RESULTS: In the prophylactic group eight children (13.8%) had current wheeze compared with 17 (27.4%) in the control group (p=0.08). Respective figures were eight (13.8%) and 20 (32.3%) for nocturnal cough (p=0.02) and 11 of 55 (20.0%) and 29 of 62 (46.8%) for atopy (p=0.003). After adjusting for confounding variables, the prophylactic group was found to be at a significantly reduced risk for current wheeze (odds ratio (OR) 0.26 (95% confidence interval (CI) 0.07 to 0.96)), nocturnal cough (OR 0.22 (95% CI 0.06 to 0.83)), asthma as defined by wheeze and bronchial hyperresponsiveness (OR 0.11 (95% CI 0.01 to 1.02)), and atopy (OR 0.21 (95% CI 0.07 to 0.62)). CONCLUSION: Strict allergen avoidance in infancy in high risk children reduces the development of allergic sensitisation to house dust mite. Our results suggest that this may prevent some cases of childhood asthma.     

FIRST INTERNATIONAL SYMPOSIUM ON CARDIOVASCULAR SCIENCE—FROM BENCH TO BEDSIDE

Abstract Atherosclerosis is an important medical problem of the 21^st century, but traditional risk factors could only account for 50% of the problem. Hyperhomocysteinemia is emerging as an independent atherosclerosis risk factor, associated with folate deficiency, renal failure, and relative deficiency of MTHFR (C677T polymorphism) or other enzymes depending on gender, age, and smoking status. Hyperhomocysteinemia has been reported to occur in 11–22% of western people, in 3–5% of normal asymptomatic Chinese subjects aged 18–70 years in Hong Kong, Macau, Sydney, and San Francisco, 23–36% of Chinese in Hong Kong with premature coronary artery disease, and 29% of a nonselective series of coronary subjects in Hong Kong. Evidence is accumulating that documents its associations with atherosclerosis disease in both case‐control observations and prospective cohort studies, in vitro experiments, and in vivo experimental models in both animals and human subjects, as well as the successful improvement by homocysteine‐lowering of endothelial function as surrogate atherosclerosis endpoints in asymptomatic human and coronary patients (secondary prevention). A number of large scale homocysteine‐lowering trials are currently underway for stroke and heart attacks prevention. Collectively these trials will include more than 65,000 patients at high‐risk for cardiovascular and stroke events, and should provide a reliable evidence‐base for prevention.