Atopy in people aged 40 years and over: Relation to airflow limitation.

BACKGROUND: Previous studies have reached conflicting conclusions about the role of atopy as a risk factor for COPD. In part, this is attributable to variation in the definitions of airflow limitation and the treatment of people with asthma. OBJECTIVE: To establish whether there is any independent association between atopy and post-bronchodilator airflow limitation in the general population aged 40 years and over. METHODS: A cross-sectional survey was conducted in a general population sample of 2415 people aged 40 years and over in Australia. A history of ever being diagnosed with asthma was elicited by questionnaire. Atopy was defined as any skin prick test weal to common aeroallergens ≥4 mm. Airflow limitation was defined as post-bronchodilator spirometric (FEV1 /FVC) ratio

Prevalence of chronic airflow limitation in Kashmir, North India: results from the BOLD study.

BACKGROUND: Data on spirometrically defined chronic airflow limitation (CAL) are scarce in developing countries. OBJECTIVE: To estimate the prevalence of spirometrically defined CAL in Kashmir, North India. METHODS: Using Burden of Obstructive Lung Disease survey methods, we administered questionnaires to randomly selected adults aged ⩾40 years. Post-bronchodilator spirometry was performed to estimate the prevalence of CAL and its relation to potential risk factors. RESULTS: Of 1100 participants initially recruited, 953 (86.9%) responded and 757 completed acceptable spirometry and questionnaires. The prevalence of a forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) ratio less than the lower limit of normal was 17.3% (4.5) in males and 14.8% (2.1) in females. Risk factors for CAL included higher age, cooking with wood and lower educational status. The prevalence of current smoking was 61% in males and 22% in females; most smoked hookahs. CAL was found equally in non-smoking males and females, and was independently associated with the use of the hookah, family history of respiratory disease and poor education. A self-reported doctor's diagnosis of chronic obstructive pulmonary disease was reported in 8.4/1000 (0.9% of females and 0.8% of males). CONCLUSION: Spirometrically confirmed CAL is highly prevalent in Indian Kashmir, and seems to be related to the high prevalence of smoking, predominantly in the form of hookah smoking.

Gaps in using bronchodilators, inhaled corticosteroids and influenza vaccine among 23 high- and low-income sites.

BACKGROUND: Increasing access to essential respiratory medicines and influenza vaccination has been a priority for over three decades. Their use remains low in low- and middle-income countries (LMICs), where little is known about factors influencing use, or about the use of influenza vaccination for preventing respiratory exacerbations. METHODS: We estimated rates of regular use of bronchodilators, inhaled corticosteroids and influenza vaccine, and predictors for use among 19 000 adults in 23 high-income countries (HICs) and LMIC sites. RESULTS: Bronchodilators, inhaled corticosteroids and influenza vaccine were used significantly more in HICs than in LMICs, after adjusting for similar clinical needs. Although they are used more commonly by people with symptomatic or severe respiratory disease, the gap between HICs and LMICs is not explained by the prevalence of chronic obstructive pulmonary disease or doctor-diagnosed asthma. Site-specific factors are likely to influence use differently. The gross national income per capita for the country is a strong predictor for use of these treatments, suggesting that economics influence under-treatment. CONCLUSION: We still need a better understanding of determinants for the low use of essential respiratory medicines and influenza vaccine in low-income settings. Identifying and addressing these more systematically could improve the access and use of effective treatments.

Geographical variation in the prevalence of sensitization to common aeroallergens in adults: the GA(2) LEN survey.

BACKGROUND: Geographical variation in the prevalence of sensitization to aeroallergens may reflect differences in exposure to risk factors such as having older siblings, being raised on a farm or other unidentified exposures. OBJECTIVE: We wanted to measure geographical variation in skin prick test positivity and assess whether it was explained by differences in family size and/or farm exposure. We also compared prevalence in younger and older subjects. METHODS: Within the Global Allergy and Asthma European Network (GA(2) LEN) survey, we measured the prevalence of skin prick positivity to a panel of allergens, and geometric mean serum total immunoglobulin E (IgE), in 3451 participants aged 18-75 years in 13 areas of Europe. Estimated prevalence was standardized to account for study design. We compared prevalence estimates in younger and older subjects and further adjusted for age, gender, smoking history, farm exposure, number of older siblings and body mass index (BMI). RESULTS: Skin prick test positivity to any one of the measured allergens varied within Europe from 31.4% to 52.9%. Prevalence of sensitization to single allergens also varied. Variation in serum total IgE was less marked. Younger participants had higher skin prick sensitivity prevalence, but not total IgE, than older participants. Geographical variation remained even after adjustment for confounders. CONCLUSION: Geographical variation in the prevalence of skin prick test positivity in Europe is unlikely to be explained by geographical variation in gender, age, smoking history, farm exposure, family size and BMI. Higher prevalence in younger, compared to older, adults may reflect cohort-associated increases in sensitization or the influence of ageing on immune or tissue responses.

The prevalence and distribution of food sensitization in European adults.

BACKGROUND: Complaints of 'food allergy' are increasing. Standardized surveys of IgE sensitization to foods are still uncommon and multicountry surveys are rare. We have assessed IgE sensitization to food-associated allergens in different regions of Europe using a common protocol. METHODS: Participants from general populations aged 20-54 years in eight European centres (Zurich, Madrid, Utrecht, Lodz, Sophia, Athens, Reykjavik and Vilnius) were asked whether they had allergic symptoms associated with specific foods. Weighted samples of those with and without allergic symptoms then completed a longer questionnaire and donated serum for IgE analysis by ImmunoCAP for 24 foods, 6 aeroallergens and, by allergen microarray, for 48 individual food proteins. RESULTS: The prevalence of IgE sensitization to foods ranged from 23.6% to 6.6%. The least common IgE sensitizations were to fish (0.2%), milk (0.8%) and egg (0.9%), and the most common were to hazelnut (9.3%), peach (7.9%) and apple (6.5%). The order of prevalence of IgE sensitization against different foods was similar in each centre and correlated with the prevalence of the pollen-associated allergens Bet v 1 and Bet v 2 (r = 0.86). IgE sensitization to plant allergen components unrelated to pollen allergens was more evenly distributed and independent of pollen IgE sensitization (r = -0.10). The most common foods containing allergens not cross-reacting with pollens were sesame, shrimp and hazelnut. DISCUSSION: IgE sensitization to foods is common, but varies widely and is predominantly related to IgE sensitization to pollen allergens. IgE sensitization to food allergens not cross-reacting with pollens is rare and more evenly distributed.

The use of ethnically specific norms for ventilatory function in African-American and white populations.

BACKGROUND: In the USA, different standards are usually set for spirometric values in African-American and white populations. It is unclear to what extent the lower lung function found in African-Americans is 'normal' in the sense of having no adverse consequences. METHODS: African-American and white participants in the Atherosclerosis Risk in Communities (ARIC) limited access data set, from four communities in the USA had spirometric testing at baseline beginning in 1986 and were followed up to assess survival to the end of 2002. RESULTS: Forced Expiratory Volume in 1 s (FEV(1)) and Forced Vital Capacity (FVC) were lower in the African-American than the white sample both for men and women and adjustment for potential confounders had little effect on the estimated difference {difference in FVC after adjustment: men, -0.68 l [95% confidence interval (95% CI) -0.75 to -0.61]; women, -0.41 l (95%CI -0.45 to -0.36)}. The FEV(1)/FVC ratio was slightly greater among African-American than white participants [difference: men, 1.5% (95%CI 0.7-2.1); women, 1.7% (95%CI 1.1-2.2)]. After adjustment for age and height, survival was similar in each ethnic group for any given level of FVC before and after adjustment for potential confounders. The hazard ratio for African-American compared with white participants was 1.24 for men (95% CI 0.91-1.69) and 0.96 for women (95% CI 0.66-1.38). CONCLUSIONS: A given FVC has the same prognostic significance for 'normal' African-American and white participants. It is inappropriate to use ethnic norms when assessing prognosis.

Forced vital capacity, airway obstruction and survival in a general population sample from the USA.

BACKGROUND: Many studies show a link between forced expiratory volume in 1 s (FEV(1)) and survival in the general population and this has been interpreted as a link between airway obstruction and survival. However, the observation that vital capacity is also associated with survival weakens this interpretation. METHODS: Data on spirometry and survival were taken from the Atherosclerosis Risk in Communities (ARIC) limited access dataset. Survival among 7489 participants with usable spirometry and complete data was regressed against measures of ventilatory function after controlling for many other factors likely to be associated with survival. RESULTS: Survival was strongly associated with forced vital capacity (FVC) after adjustment for FEV(1), but not the other way round. The fully adjusted hazard ratio (HR) associated with high FVC was 0.90 in men (95% CI 0.80 to 1.00; p=0.049) and 0.82 in women (95% CI 0.70 to 0.95; p=0.01). This compares with 0.98 for FEV(1) in men (95% CI 0.90 to 1.07; p.0.72) and 1.01 in women (95% CI 0.89 to 1.15; p=0.84). There was no association between survival and airway obstruction as measured by the FEV(1)/FVC ratio. CONCLUSIONS: FVC but not airway obstruction predicts survival in asymptomatic adults without chronic respiratory diagnoses or persistent respiratory symptoms. The association is not explained by age, anthropometry, smoking, income occupation or blood pressure. As FVC later in life, cardiovascular risk, type II diabetes mellitus and low-grade systemic inflammation are all associated with poor fetal growth, these other conditions may be partly responsible for the poor survival in those with low FVC.

The effects of allergens in outdoor air on both atopic and nonatopic subjects with airway disease.

BACKGROUND: Reports on air pollution and asthma exacerbations have been inconsistent, although effects of airborne allergen can be spectacular. With no generalized test for allergen in air, it is not known how far allergen is responsible for nonepidemic exacerbations of the disease. METHODS: Two hundred and ninety-seven patients using bronchodilators aged 18-64 years attending a London practice provided serum samples and were asked to report any acute respiratory events over the coming months. Small particles with a mean aerodynamic diameter <10 microm (PM(10)) were collected using a high volume sampler on the roof of the practice. The ability of airborne particles to bind IgE from the patients was compared for particles sampled on the weekend before their reported exacerbation with particles sampled on the weekend 2 weeks before or after. RESULTS: Exacerbations were associated with a 25% increase in IgE binding to particles collected on the previous weekend compared with the control weekends (95% confidence interval: 10-43%; P = 0.00089). This increase was not higher in patients with positive skin tests or in those sensitized to grass or tree pollens. CONCLUSIONS: Airborne allergen is an important cause of exacerbations even in those with 'intrinsic' asthma. It is important to identify the allergens responsible, as some of these may be controllable. Interpretation of associations of asthma exacerbations with other air pollutants is difficult in the light of these findings.

Maternal testosterone in pregnancy and atopic outcomes in childhood.

BACKGROUND: In mice, androgens downregulate Th2 cytokine responses, but whether androgen levels during pregnancy might influence the development of allergy in the offspring has not been studied. METHODS: In the Avon Longitudinal Study of Parents and Children (ALSPAC), a population-based birth cohort of 14 541 pregnancies, we related maternal blood total testosterone during pregnancy, measured in a subset of the cohort, to allergic outcomes in the offspring, including asthma, hayfever, eczema (n=543) and wheezing (n=532) at 69-81 months, and atopy (positive skin prick test to Dermatophagoides pteronyssinus, cat or grass, n=386) and blood total immunoglobulin E (IgE; n=314) at 7 years. We used logistic and linear regression to analyse binary outcomes and log-transformed IgE, respectively, controlling for potential confounders. RESULTS: Maternal testosterone was negatively associated with total IgE in boys [adjusted geometric mean ratio (GMR), per doubling of testosterone, 0.33 (0.20-0.55), P=0.000038 (n=168)], but not in girls [GMR 1.04 (0.53-2.06), P=0.91 (n=146)], P-value interaction 0.0086. The effect in boys was even stronger in the absence of maternal atopic disease. Testosterone was not associated with skin test positivity or atopic disease in either sex. CONCLUSIONS: Higher testosterone levels in pregnancy are associated with lower IgE production in boys.

Paracetamol use in pregnancy and wheezing in early childhood.

BACKGROUND: We recently reported links between frequent paracetamol (acetaminophen) use and wheezing and asthma in adults and children, but data are lacking on possible effects of prenatal exposure on wheezing in early childhood. METHODS: In the population based Avon Longitudinal Study of Parents and Children (ALSPAC) women were asked twice during pregnancy (at 18-20 weeks and 32 weeks) about their usage of paracetamol and aspirin. Six months after birth, and at yearly intervals thereafter, mothers were asked about wheezing and eczema symptoms in their child. The effects of paracetamol and aspirin use in pregnancy on the risk in the offspring of wheezing at 30-42 months (n=9,400) and eczema at 18-30 months (n=10,216) and on their risk of different wheezing patterns (defined by presence or absence of wheezing at <6 months and at 30-42 months) were examined. RESULTS: Paracetamol was taken frequently (most days/daily) by only 1% of women. After controlling for potential confounders, frequent paracetamol use in late pregnancy (20-32 weeks), but not in early pregnancy (<18-20 weeks), was associated with an increased risk of wheezing in the offspring at 30-42 months (adjusted odds ratio (OR) compared with no use 2.10 (95% CI 1.30 to 3.41); p=0.003), particularly if wheezing started before 6 months (OR 2.34 (95% CI 1.24 to 4.40); p=0.008). Assuming a causal relation, only about 1% of wheezing at 30-42 months was attributable to this exposure. Frequent paracetamol use in pregnancy was not associated with an increased risk of eczema. Frequent aspirin use in pregnancy was associated with an increased risk of wheezing only at <6 months. CONCLUSIONS: Frequent use of paracetamol in late pregnancy may increase the risk of wheezing in the offspring, although such an effect could explain only about 1% of the population prevalence of wheezing in early childhood.

London-born black Caribbean children are at increased risk of atopic dermatitis

BACKGROUND: Previous reports suggest that atopic dermatitis is more common in black Caribbean children born in the United Kingdom than in white children. It is unclear whether these differences are caused by selection bias or variations in the use of the word "eczema" in the groups studied. OBJECTIVE: Our objective was to explore ethnic group differences in the prevalence of atopic dermatitis in London schoolchildren. METHOD: A cross-sectional prevalence survey of 693 junior school children in three schools was performed. Atopic dermatitis was defined in three ways: (1) by a dermatologist, (2) by visible flexural dermatitis as recorded by an independent observer, and (3) by a history of flexural dermatitis according to the child's parents. RESULTS: The prevalence of atopic dermatitis according to examination by a dermatologist was 16.3 percent in black Caribbean children and 8.7 percent in white children. This increased risk was present for different methods of defining of atopic dermatitis and persisted after adjustment for potential confounders. CONCLUSION: London-born black Caribbean children appear to be at an increased risk of having atopic dermatitis. (AU)