Search PubMed⌕ Search

Biomedical subjects

A J Newman Taylor

Publications and source records attributed to A J Newman Taylor.

At least 19 recordsLinked to original sources
PubMed2006

The effects of farming and birth order on asthma and allergies.

A farm childhood is apparently protective in allergic disease, but studies of this issue in Europe have been confined to particular types of farming practice. This study addressed whether or not this effect was generalisable. A cross-sectional survey of 800 schoolchildren living in rural Crete was undertaken. Standard questions relating to allergic disease were included and atopy was measured through skin-prick tests involving 10 local aeroallergens. The prevalence of atopy was 24%, but associated symptoms were far less common. At all ages, children from farming families had more frequent contact with farm animals (mainly goats), but were no less likely to be atopic. Atopy and seasonal rhinitis were significantly and independently more common among first-born children. This community has an intermediate prevalence of atopy but a very low frequency of allergic disease; farming does not seem to be an important determinant, possibly because it is of the wrong sort. Thus farming effects may be specific to local practices. First-born children in this community also appear to be at increased risk of allergic disease.

Adolescent↗
PubMed2005

Childhood atopy and allergic disease and skin test responses to environmental mycobacteria in rural Crete: a cross-sectional survey.

BACKGROUND: Through its powerful immunoregulatory effects, infection with atypical mycobacteria may exert a protective effect on the development of childhood allergic disease. OBJECTIVE: To examine the relationship between childhood atopy or allergic disease and previous infection with four species of atypical mycobacteria. METHODS: Eight hundred and six children aged 8-18 years and living in rural Crete--most of whom had had previous BCG immunization--underwent skin prick testing with 10 aeroallergens; their parents completed a standardized questionnaire relating to allergic disease. No less than 8 weeks later each child underwent intradermal skin tests with 0.1 mL solutions of four selected mycobacterial reagents (Aviumin C, Gordonin, Chelonin and Ranin I). RESULTS: Twenty-three percent of children were atopic on skin prick testing; far fewer had symptoms of asthma (5%) or hayfever in conjunction with a positive prick test to pollens (2%). Eighty percent of children had positive skin responses to one or more mycobacterial species. Among all children--and those with a BCG scar--there was no association between atopy or allergic symptoms and mycobacterial skin responses; among the few children without a BCG scar however those with positive mycobacterial responses were less likely to be atopic or to report allergic symptoms; these differences were not statistically significant. CONCLUSIONS: Our findings, in a population of BCG-immunized children, do not lend support to the suggestion that infection with atypical mycobacteria is protective against childhood allergic disease.

Adolescent↗
PubMed2005

Supermarket baker's asthma: how accurate is routine health surveillance?

BACKGROUND: Regular health surveillance is commonly recommended for workers exposed to occupational antigens but little is known about how effective it is in identifying cases. AIMS: To report one large company's surveillance and compare its findings with those of a standard cross-sectional survey in the same workforce. METHODS: A supermarket company with 324 in-store bakeries producing bread from raw ingredients conducted a three-stage health surveillance programme in around 3000 bakery employees. The first stage involved the administration of a simple respiratory questionnaire. If chest symptoms were present a second questionnaire focusing on their work relationship was administered. If positive a blood sample was requested for the measurement of specific IgE to flour and fungal alpha-amylase. The results were compared to an independent cross-sectional survey of employees in 20 of the company's stores. RESULTS: Two hundred and ninety nine (92%) of the company's bakeries took part in surveillance. The overall employee response for the first stage was 77%; a quarter of those with respiratory symptoms reported that they were work related. Seventy four (61%) of those with work related chest symptoms had a measurement of specific IgE to either flour or fungal alpha-amylase, of whom 30 (41%) had a positive result. Surveillance estimated that 1% of bakery employees (1% bakers, 2% managers, 0.6% confectioners) had work related symptoms with specific IgE. This compared with 4% (7.5% bakers, 3.3% managers, 0% confectioners) in the cross-sectional survey (n = 166, 93% response). CONCLUSION: Comparison with a standard cross-sectional survey suggests that routine surveillance can underestimate the workplace burden of disease. The reasons may include technical or resource issues and uncertainties over confidentiality or the perceived consequences of participation. More research needs to be done looking into the design and efficacy of surveillance in occupational asthma.

Asthma↗
PubMed2005

Evidence based guidelines for the prevention, identification, and management of occupational asthma.

BACKGROUND: Occupational asthma is the most frequently reported work related respiratory disease in many countries. This work was commissioned by the British Occupational Health Research Foundation to assist the Health and Safety Executive in achieving its target of reducing the incidence of occupational asthma in Great Britain by 30% by 2010. AIM: The guidelines aim to improve the prevention, identification, and management of occupational asthma by providing evidence based recommendations on which future practice can be based. METHODS: The literature was searched systematically using Medline and Embase for articles published in all languages up to the end of June 2004. Evidence based statements and recommendations were graded according to the Royal College of General Practitioner's star system and the revised Scottish Intercollegiate Guidelines Network grading system. RESULTS: A total of 474 original studies were selected for appraisal from over 2500 abstracts. The systematic review produced 52 graded evidence statements and 22 recommendations based on 223 studies. DISCUSSION: Evidence based guidelines have become benchmarks for practice in healthcare and the process used to prepare them is well established. This evidence review and its recommendations focus on interventions and outcomes to provide a robust approach to the prevention, identification, and management of occupational asthma, based on and using the best available medical evidence. The most important action to prevent cases of occupational asthma is to reduce exposure at source. Thereafter surveillance should be performed for the early identification of symptoms, including occupational rhinitis, with additional functional and immunological tests where appropriate. Effective management of workers suspected to have occupational asthma involves the identification and investigation of symptoms suggestive of asthma immediately they occur. Those workers who are confirmed to have occupational asthma should be advised to avoid further exposure completely and early in the course of their disease to offer the best chance of recovery.

Adult↗
PubMed2004

New pregnancies and loss of allergy.

BACKGROUND: Inverse associations between allergic disease and sibship have been consistently described and are frequently explained by purported lower rates of early infection among children from small families. Alternative explanations include the possibility that pregnancy itself determines maternal atopic status. OBJECTIVE: To test the hypothesis that atopy defined by skin prick test (SPT) declines with increasing numbers of pregnancies. METHODS: At enrollment to a birth cohort, mothers were skin prick tested to three common allergens. Seven years later these women underwent a second SPT and provided information on their reproductive histories. At both visits, information on allergic disease was also sought. RESULTS: Twenty five (15%) women who were initially atopic were no longer so at the second visit; loss of hayfever symptoms was reported by 33 (29%) women. Women with higher numbers of intervening pregnancies were more likely to 'lose' their atopy (P=0.05) and symptoms of hayfever (P=0.02); this was not true for asthma. The findings could not be accounted for by maternal age. CONCLUSION: Successive pregnancies may in part determine a mother's atopic state. Since maternal atopy is a risk factor for childhood atopic disease, this process may affect the atopic state of successive children. These findings suggest an alternative explanation for the sibship effect in allergic disease.

Adult↗
PubMed2004

Early allergen exposure, skin prick responses, and atopic wheeze at age 5 in English children: a cohort study.

BACKGROUND: For many years it has been assumed that the risk of childhood respiratory allergies is related to allergen exposures in early life. There are, however, few prospective data in support. We aimed to examine this relationship in a representative cohort of children born in Ashford, Kent (UK). METHODS: 625 children (94% of those eligible) were followed from birth to the age of 5.5 years at which time 552 underwent skin prick testing to extracts of house dust mite and cat fur allergens. Maternal reports of wheeze in the last year were collected by interview. These outcomes were related to individual domestic concentrations of Der p 1 and Fel d I allergens estimated from dust collection at the age of 8 weeks. RESULTS: 10% of children were sensitised to house dust mite or cat at age 5.5 years; 7% had atopic wheeze. No significant relationships between allergen exposure and either sensitisation or wheeze were found but, on examination, the exposure-response relationships for both allergens and for each outcome rose steeply at low levels of exposure and were attenuated at high levels of exposure. These patterns were modified by paternal atopy and by birth order. CONCLUSIONS: There are no linear relationships between early allergen exposure and the induction of childhood respiratory allergy; rather, the risks of IgE sensitisation and asthma rise at very low levels of exposure and are attenuated thereafter. These patterns are influenced by parental atopy and birth order. These findings suggest important gene-environment interactions in the development of atopy and asthma and imply that reductions in domestic allergen exposure alone are unlikely to have a major impact in decreasing the incidence of these diseases in childhood.

Allergens↗
PubMed2004

Early prescriptions of antibiotics and the risk of allergic disease in adults: a cohort study.

BACKGROUND: It is frequently asserted that antibiotic prescriptions in childhood are associated with the development of allergic disease, especially asthma. A study was undertaken to establish the direction of this relationship. METHODS: A retrospective cohort study of 746 adults was performed in three general practices. Antibiotic prescriptions in the first 5 years of life, collected from contemporary medical records, were related to self-reports of asthma and hay fever and the results of skin prick testing with common aeroallergens. RESULTS: There was no relationship between early antibiotic prescription and atopy, either for all antibiotic use (OR 1.01) or for antibiotics prescribed at different ages. The significant associations between prescriptions at ages 4 and 5 and hay fever (OR 1.23 and 1.16, respectively) were explained by coexisting asthma. Relationships between antibiotic use and asthma (allergic or otherwise) were statistically significant and strengthened with increasing age of prescription, but were largely confined to antibiotics prescribed for lower respiratory symptoms. CONCLUSIONS: The reported associations between childhood antibiotic use and asthma are most plausibly explained by "reverse causation"--the tendency for prescriptions to be written for the early manifestations of pre-existing asthma.

Adult↗
PubMed2003

HLA phenotype and exposure in development of occupational asthma.

OBJECTIVE: To review relevant scientific literature to understand the contribution of exposure to the risk of developing occupational asthma and whether HLA class 2 molecules contribute to individual susceptibility to sensitization and asthma caused by low-molecular-weight chemicals. STUDY SELECTION: The author's expert opinion was used to select relevant articles based on systematic reviews of relevant literature. RESULTS: Studies during the past decade have shown that intensity of exposure is an important determinant of asthma induced by inhaled respiratory sensitizers, both proteins and low-molecular-weight chemicals. There is evidence that HLA class 2 alleles contribute to the risk of sensitization and asthma caused by low-molecular-weight chemical sensitizers. HLA-DR3 is associated with an increased risk of developing specific IgE to trimellic anhydride (TMA) and complex platinum salts such as ammonium hexachloroplate (ACP). In those exposed to ACP and possibly also to TMA, risk is greater in those who have experienced lower intensity of exposure. CONCLUSIONS: Exposure intensity is an important determinant of sensitization and asthma caused by respiratory sensitizers. HLA class 2 alleles contribute to individual susceptibility to low-molecular-weight chemicals. For some chemicals, the contribution of HLA class 2 alleles is greater in those less exposed at work to the relevant chemical.

Animals↗
PubMed2003

Can early infection explain the sibling effect in adult atopy?

Atopy is strongly and inversely related to family size, a pattern which is plausibly assumed to reflect a protective effect of early infection. The current study tested this hypothesis by case-referent analysis of an adult cohort in the UK. The study established that atopy, defined by prick tests to common aeroallergens, was less common among those from larger families after adjustment for potentially confounding factors. In particular, a higher number of brothers appeared to offer protection. The current authors attempted to explain this distribution by examining contemporary family-doctor records of early childhood infections; and by a number of other indirect indices of early-life "hygiene". The sibling effect was unexplained by evidence of infection with either hepatitis A or Helicobacter pylori, or by counts of infections or antibiotic prescriptions in early life. There was a significant and independent negative association between the number of gastrointestinal infections before the age of 5 yrs and the odds of atopy. Dog ownership and home moving in early life also displayed potentially protective associations. Although the current study replicates the finding that atopy is inversely associated with family size this could not be explained by documentary or serological evidence of early infection. The findings support the suggestion that the "sibling effect" in atopy may not simply reflect protection by early infection.

Adult↗
PubMed2001

Allergen and dust exposure as determinants of work-related symptoms and sensitization in a cohort of flour-exposed workers; a case-control analysis.

OBJECTIVES: To estimate the incidence of specific IgE sensitization and allergic respiratory symptoms among UK bakery and flour mill workers; and to examine the roles of flour aeroallergen and total dust exposures in determining these outcomes. METHODS: A cohort of 300 new employees, without previous occupational exposure to flour, were followed prospectively for a median (range) of 40 (1-91) months. Cases-defined as those developing work-related symptoms or a positive skin prick test to flour or alpha-amylase during follow up--were compared with controls, matched for duration of employment. Exposures to flour aeroallergen and total inhalable dust were estimated using a questionnaire and personal sampling techniques. RESULTS: Incidence rates for work-related eye/nose and chest symptoms were 11.8 and 4.1 cases per 100 person years (py), respectively. Fewer employees developed positive skin prick tests to flour (2.2 cases per 100 py) or alpha-amylase (2.5 cases per 100 py). Positive skin tests to occupational allergens were more common among those with new work-related symptoms. There were clear relationships between the risks of developing work-related symptoms or a positive skin prick test and three categories of estimated exposure to total dust or flour aeroallergen. Atopic employees were more likely to develop a positive skin prick test-but not work-related symptoms. These findings were unaffected by age, sex or cigarette smoking. CONCLUSIONS: In this population, many work-related symptoms which develop after first employment in modern UK bakeries or flour mills were not accompanied by evidence of IgE sensitization to flour or alpha-amylase. Although average dust exposures were within current occupational standards, the risks of development of upper and lower respiratory symptoms and of specific sensitization were clearly related to total dust and/or flour aeroallergen exposure. The incidence of work-related chest symptoms in the presence of a positive skin test to flour or alpha-amylase in this setting was approximately 1 case per 100 py.

Adult↗
PubMed2001

Analysis of allergens in rat fur and saliva.

BACKGROUND: The fur is an important source of allergens in many mammal species, but this source has not been extensively studied in rats. Rat room dust contains high-molecular-weight allergens that have been found to cross-react with fur and its presumed salivary contaminants. The role of rat fur and saliva as a source of respiratory allergens merits further investigation. The objective was to describe the allergens present in the fur and saliva of male rats. METHODS: Allergen extracts were prepared from the saliva and fur of the pelts from adult male rats. Immunoblotting was used to describe the allergens present in rat fur and saliva with serum from 76 and 25 individuals, respectively. RESULTS: There was considerable variation between the individuals in the binding of IgE to the separated fur and saliva allergens. Immunoblot analysis identified 23 allergens in rat fur. "Major" allergens were found at the "origin", and at 55, 51, 19, and 17 kDa, and "intermediate" allergens at 74, 67 (probably albumin), and 21.5 (diffuse) kDa. Seventeen salivary allergens were described with "major" allergens at 21.5, 19.5, 19, 18, and 17.5 kDa. Many subjects had IgE to the 67 kDa (56%) and 43 kDa (64%) allergens but the density of staining was weak. CONCLUSION: Rat fur and saliva are the sources of many allergens. Fur contained five "major" allergens and was a complex source of allergens of relatively high molecular weight (>22 kDa). The most important salivary allergens have molecular weights of less than 22 kDa. Fur is the most probable source of the high-molecular-weight allergens found in rat room dust.

Allergens↗
PubMed2001

Environmental associations with eczema in early life.

BACKGROUND: Although atopic eczema (AE) is a common disease, little is known about its causes. OBJECTIVES: To investigate the role of dietary and environmental factors associated with the development of AE by the age of 2 years. METHODS: A cohort of children was recruited before birth from a consecutive series of newly pregnant mothers presenting for antenatal care at three general practices in Ashford, Kent, U.K. Data up to the age of 2 years were available for 624 (97%) of the original cohort. AE was defined using components of the U.K. diagnostic criteria for AE, maternal report of doctor-diagnosed eczema and maternally reported eczema. Exposures of interest were family history of allergic disease, dietary and breastfeeding patterns, family size and exposure to indoor domestic allergens. RESULTS: The cumulative prevalence of AE using the U.K. diagnostic criteria was 14% (95% confidence interval, CI 11-17%). The prevalence of maternally reported doctor-diagnosed eczema was much higher (31%, 95% CI 27-35%) and almost half (45%) the mothers reported that their child had ever had eczema (95% CI 41-49%). The relationship between parental atopy, parental history of allergic disease and the child's eczema was consistently stronger for the mothers than the fathers. There was a marked increase in the prevalence of eczema with increasing maternal education and in less crowded homes, associations that remained significant after controlling for other factors. CONCLUSIONS: The associations with environmental factors are consistent with the hypothesis that more crowded houses, increased family size and birth order, which may possibly increase early exposure to infections, may offer protection from subsequent development of eczema.

Adult↗
PubMed2001

Crete: does farming explain urban and rural differences in atopy?

BACKGROUND: Urban-rural differences in the prevalence of atopy and associated allergic diseases have been reported in several non-European countries. Within Europe, where such variations are less striking, a farm childhood has been postulated to be protective. OBJECTIVE: We aimed to compare the prevalence of atopy in urban and rural children living in Crete and to examine the role of early exposure to a farming environment in explaining any measured differences. METHODS: A cross-sectional survey of children attending secondary schools in Iraklion, the capital city, and five villages 100 km to the south. Atopy was determined by the responses to skin prick tests with seven common aeroallergens. RESULTS: Nine-hundred and ninety-seven children participated in the survey. 19.6% of those living in Iraklion, but only 9.6% of those from the villages, had a positive response to one or more skin prick tests. Among urban children there were significant gradients in the prevalence of atopy across several categories of animal contact and consumption of farm (unpasteurized) milk products--before the age of 5 years. These differences, however, were not apparent among the rural children.

Adolescent↗
PubMed2001

Current best practice for the health surveillance of enzyme workers in the soap and detergent industry.

This study defines current best practice for the health surveillance of workers who are potentially exposed to enzymes in the manufacture of enzymatic detergent products. It is recommended that health surveillance is performed 6-monthly for the first 2 years and annually thereafter. The health surveillance programme should include a respiratory questionnaire to detect symptoms, assessment of lung function to detect pre-symptomatic changes and an immunological test to detect specific immunoglobulin E (IgE) to enzymes. The International Union Against Tuberculosis and Lung Disease respiratory questionnaire should be used since it has been validated extensively for detecting asthma. Operators should observe the American Thoracic Society performance criteria for spirometers and standardized procedures for conducting spirometry. Since current airborne monitoring techniques for enzymes do not detect short-duration peak exposures, the incidence of employee sensitizations remains the most reliable measure of the integrity of environmental control. The Pepys skin prick test has been validated as a sensitive, specific and practical test for detecting specific IgE to many inhalant allergens including enzymes. For newly sensitized workers, a multi-cause investigation should be conducted to identify potential sources of exposure. Group results of immunological test results assist in the evaluation of workplace control measures, and should be used to monitor the effectiveness of hygiene and engineering programmes and to help prioritize areas for improvement. Positive responses to a questionnaire or abnormal spirometry should be assessed further. Occupational asthma should be excluded in any case of adult-onset asthma that starts or deteriorates during working life. This is particularly important because an accurate diagnosis of occupational asthma with early avoidance of exposure to its cause can result in remission of symptoms and restoration of lung function.

Asthma↗
PubMed2000

An outbreak of asthma in a modern detergent factory.

The striking decrease in the occurrence of protease-induced occupational asthma in the detergent Industry has been attributed to enzyme encapsulation. We report an outbreak of asthma, at least equal in size to those reported in the 1960s, in a modem European factory which has exclusively used encapsulated enzymes. A survey revealed that enzyme sensitisation and work-related respiratory symptoms were positively correlated with airborne enzyme exposure. We suggest that encapsulation alone is insufficient to prevent enzyme-Induced allergy and asthma.

Adolescent↗
PubMed2000

Risk factors for bronchial hyperresponsiveness in workers exposed to acid anhydrides.

Risk factors for bronchial hyperresponsiveness have previously been established in the general community. In settings where occupational asthma is a risk, it has not been established whether occupational sensitization or measures of exposure are important. Bronchial responsiveness to histamine was measured in a cohort of 506 workers exposed to acid anhydrides. Skin-prick tests were performed with conjugates of phthalic, maleic and trimellitic anhydride with human serum albumin and with common inhalant allergens. Employment and smoking histories were recorded. Occupational exposure was measured using personal air samplers and estimates of past exposure made by retrospective exposure assessment. Three hundred and seventy workers (73%) had bronchial responsiveness measured (median age 39 yrs, range 18-77) and 46 (12%) of these were hyperresponsive (provocative dose causing a 20% fall in forced expiratory volume in one second (FEV1; PD20) < or = 8 micromol). Twelve (3%) of these responsive workers had a skin-prick test reaction to an acid anhydride conjugate, 124 (34%) to a common inhalant allergen, and 148 (40%) were current smokers. Multivariate analysis showed that occupational sensitization, sensitization to a common inhalant allergen, age, and pack-years of smoking were independent risk factors for bronchial hyperresponsiveness. Of these only occupational sensitization was completely independent of baseline FEV1. It is concluded that sensitization to acid anhydrides is a significant risk factor for bronchial hyperresponsiveness. However, measures of personal acid anhydride exposure were not associated with bronchial hyperresponsiveness.

Adolescent↗