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Biomedical subjects

D Strachan

Publications and source records attributed to D Strachan.

At least 19 recordsLinked to original sources
PubMed2005

Maternal age of menarche is not associated with asthma or atopy in prepubertal children.

BACKGROUND: Maternal sex hormones in pregnancy can theoretically influence the developing fetal immune system and modulate the subsequent development of atopic disorders. Early onset of menarche has been linked to increased oestrogen levels in adult women. A study was undertaken to examine the association between early onset menarche in pregnant women and asthma and atopic status of their children at 7 years of age. METHODS: The Avon Longitudinal Study of Parents and Children (ALSPAC) is a longitudinal birth cohort study in which pregnant women, resident in Avon (UK), were recruited on the basis of an expected date of delivery between 1 April 1991 and 31 December 1992. Maternal age at menarche was assessed from prenatal questionnaires administered to the women. Clinical outcomes in the children were based on mothers' responses to self-completion questionnaires and included asthma, eczema, and hay fever. The atopic status of the child was objectively assessed by skin prick tests to a panel of common aeroallergens at the age of 7 years. Analyses used multivariable logistic regression with a diverse range of possible confounders. RESULTS: Complete data were available on 5765 woman and child pairs. The prevalence of ever reported asthma to 7 years was 20.4%, eczema 58.6%, hay fever 12.1%, and atopy (defined as any positive (>2 mm weal) response) was present in 20.6%. There were no significant differences in mean age of menarche between mothers of children with and without each of the primary outcomes. Adjusted odds ratios (95% CI) for the latest age of menarche (16+ years) compared with the lowest (<12 years) reference group were 1.41 (1.00 to 1.99) for asthma, 0.98 (0.73 to 1.91) for eczema, 0.95 (0.62 to 1.44) for hay fever, and 0.98 (0.68 to 1.42) for atopy. CONCLUSION: No consistent association was found between maternal age at menarche and asthma, eczema, hay fever or atopy in their children during early childhood.

Adolescent↗
PubMed2005

Relationship between aeroallergen and food allergen sensitization in childhood.

BACKGROUND: Previous studies measuring the prevalence of allergen sensitization have been relatively small and used small numbers of allergens. To effectively evaluate children with atopic disease, we need an accurate knowledge of which allergens are important. OBJECTIVE: To measure the prevalence of sensitization within a large unselected birth cohort, to examine the associations between sensitization to different allergens and determine whether atopy can be defined by a small panel of allergens. METHODS: The Avon Longitudinal Study of Parents and Children is a population-based birth cohort of 13,638 singletons surviving to 4 weeks of age. The cohort was skin tested at 7 years of age to house dust mite (Dermatophagoides pteronyssinus), grass pollens, cat, peanuts, mixed tree nuts and egg and one of three other panels: animal danders, foods or aeroallergens. Sensitization was defined as a weal diameter of > or =3 mm. The strength of associations between sensitization to different allergens was tested by calculating the odds ratio adjusted for sensitization to D. pteronyssinus and grass pollen and gender. RESULTS: Valid data were obtained from 6412 singletons. Sensitization was most common to aeroallergens: grass pollens (8.5%), D. pteronyssinus (7.8%), cat (4.9%), D. farinae (3.6%), dog (2.7%), horse (1.4%), rabbit (1.4%). Of the foods tested, the most common sensitization was to peanut (1.4%) and mixed tree nuts (1.0%). More than 95% of subjects with sensitization to any of the 29 allergens tested were sensitized to one of grass, D. pteronyssinus or cat allergen. There were strong associations of multiple sensitizations both within and between different allergen classes (pollens, animals, foods, peanut and tree nuts). CONCLUSIONS: Seven-year-old children in the UK are primarily sensitized to aeroallergens, but also to peanuts and tree nuts. There are strong associations between sensitization within allergen groups as well as between allergen groups. Further studies are required to observe whether similar associations are seen with clinical allergy to these allergens.

Air Pollution↗
PubMed2004

Mode of delivery is not associated with asthma or atopy in childhood.

BACKGROUND: Caesarean-section delivery has been associated with the subsequent development of atopy and wheezing in childhood. OBJECTIVE: To examine the association between mode of delivery (vaginal vs. caesarean section) and development of atopy, asthma and wheezing disorders in a population-based cohort of children. METHODS: The Avon Longitudinal Study of Parents and Children is a longitudinal birth cohort of children born 1 April 1991 to 31 December 1992. Mode of delivery was categorized as vaginal (including forceps and ventouse extractions) or caesarean section (elective and emergency). Primary outcomes were parental report of asthma or wheezing between 69 and 81 months of age, physician-diagnosed asthma (PDA) at 91 months of age and atopy at 7 years by skin prick testing. Possible confounding factors were considered in a multivariable logistic regression model. RESULTS: Total livebirths were 14,062, from which were selected 12 367 born to mothers resident in a defined area and delivered in one of two major obstetric hospitals. Of these infants, 10,980 (88.8%) were delivered vaginally and 1387 (11.2%) by caesarean section. Outcome data were available for 7495 (61%) subjects (asthma 69-81 months); 7389 (60%) (wheeze 69-81 months); 7196 (58%) (PDA 91 months) and 5916 (48%) (atopy 7 years). Adjusted odds ratios [95%confidence interval] for caesarean section compared with vaginal delivery were not statistically significant for any outcome we considered: asthma 69-81 months 1.16 [0.9, 1.5]; wheeze 69-81 months 0.95 [0.7, 1.3]; PDA 1.14 [0.9, 1.4]; atopy 1.04 [0.8, 1.3]. CONCLUSION: Delivery by caesarean section was not associated with the subsequent development of asthma, wheezing or atopy in later childhood in this population.

Adult↗
PubMed2003

Novel association suggests multiple independent QTLs within chromosome 5q21-33 region control variation in total humans IgE levels.

Asthma is a common, heterogeneous, complex disease accompanied by raised total and specific immunoglobulin-E (IgE) antibody levels. Despite numerous previous reports of linkage and association of asthma, atopy and serum IgE levels to genes within the 5q21-33 region, definitive, replicable results are still not available. We used the classical twin design to (i) estimate the relative contributions of genes and environment to variation in total IgE levels, (ii) assess genetic linkage, and (iii) examine allelic association of 11 microsatellite markers spanning the 5q21-33 region to total IgE. Variation in total IgE level was shown to be highly heritable (65%). Although evidence for linkage of the 11 microsatellites to IgE was not observed, the omnibus test of association, not confounded by population substructure, showed positive association of D5S393 and D5S673 to IgE. Genes in the vicinity of D5S673 include hepatitis A virus receptor (HAVCR-1) and IL-12B. Recently, the mouse orthologue of HAVCR-1, the T-cell membrane family of proteins, have been shown to be in strong association with expression of airway hyperactivity in a mouse model of human asthma and atopy. IL-12B subserves many proinflammatory functions and also induces B cells proliferation.

Adolescent↗
PubMed2003

Is oral azithromycin effective for the treatment of cyclosporine-induced gingival hyperplasia in cardiac transplant recipients?

Anecdotal evidence suggests that azithromycin is effective for the treatment of cyclosporine-induced gingival hyperplasia in solid-organ transplant recipients. We present the cases of two heart transplant patients who insidiously developed gingival hyperplasia, likely because of immunosuppression with cyclosporine, which was treated with azithromycin. Evidence supporting the efficacy of azithromycin in the treatment of cyclosporine-induced gingival hyperplasia in solid organ transplant recipients was searched for, identified, and then critically assessed. While no data were found specifically evaluating azithromycin in cardiac transplant patients, there were nine pertinent papers identified that evaluated the clinical question of interest in the renal transplant population [Wahlstrom et al. (1995) The New England Journal of Medicine 332, 753; Boran et al. (1996) Transplantation Proceedings 28, 2316; Gomez et al. (1997) Nephrology Dialysis Transplantation 12, 2694; Ljutic (1997) Dialysis & Transplantation 26, 787; Puig et al. (1997) Transplantation Proceedings 29, 2379; Nash et al. (1998) Transplantation 65, 1611; Nowicki et al. (1998) Annals of Transplantation 3, 25; Wirnsberger et al. (1998) Transplantation Proceedings 30, 2117; Citterio et al. (2001) Transplantation Proceedings 33, 2134]. These studies and case reports are summarized. While more evidence is required to support routine use of azithromycin for the treatment of cyclosporine-induced gingival hyperplasia in cardiac transplant recipients, preliminary published evidence from renal transplant patients is certainly favourable.

Administration, Oral↗
PubMed2003

Validity and interpretation of mortality, health service and survey data on COPD and asthma in England.

The comparability of asthma and chronic obstructive pulmonary disease (COPD) epidemiology in different English routine data sources was examined to explore their use and validity in investigating environmental influences on respiratory health. National data were obtained for mortality, emergency hospital admissions, general practitioner contacts and symptoms in the early 1990s. Age/sex patterns, seasonal variations and regional and urban/rural age/sex standardised event ratios were examined. Spearman rank correlations were used to describe consistency of regional rankings across data sets. Asthma showed inconsistent disease patterns in different data sources and weak correlations for regional rankings but COPD was notably consistent. Unmeasured confounders may partly explain the findings, but individual level adjustment for social class and smoking (possible for symptoms) only partially attenuated the higher COPD rates in northern and urban areas and did not affect findings for asthma. When epidemiological patterns are consistent across data sources as with chronic obstructive pulmonary disease in England, healthcare use is likely to reflect the underlying prevalence and severity of disease and can be used to study environmental influences. When patterns vary, as with asthma, the validity of the data in relation to its intended use must be carefully considered.

Adolescent↗
PubMed2003

Increasing prevalence of asthma in UK primary care during the 1990s.

OBJECTIVE: To estimate recent prevalence trends of physician-diagnosed asthma in primary care in the UK, and to test the hypothesis that the asthma epidemic in the UK peaked in the mid-1990s and is currently declining. METHODS: A retrospective cohort of asthma patients was obtained from the General Practice Research Database (GPRD). From January 1990 to February 1999, asthmatics were followed up to death, censoring or mention of chronic obstructive pulmonary disease (COPD) in their clinical record. Prevalence rates of ever and managed asthma were obtained by sex, age and calendar year. RESULTS AND CONCLUSION: From 1990 to 1998, annual prevalence rates of managed physician-diagnosed asthma in women rose from 3.01% (95%CI 2.99-3.03) to 5.14% (95%CI 5.10-5.18), and in men from 3.44% (95%CI 3.41-3.46) to 5.06% (95 %CI 5.02-5.10) (P for trend <0.01 in both). In 1998, prevalence rates of managed asthma in children aged 5-14 affected 7.86% (95%CI 7.71-8.00) of girls and 10.30% (95%CI 10.15-10.47) of boys. Increasing prevalence rates in adult asthma (maximum 4.11% in 1998, 95%CI 4.03-4.19) and elderly asthma (maximum 3.37% in 1998, 95%CI 3.29-3.46) were observed as well in 1998. The study shows that the burden of asthma in UK primary care during the 1990s was still increasing.

Adult↗
PubMed2002

Molecular epidemiology of tuberculosis in London 1995-7 showing low rate of active transmission.

BACKGROUND: Tuberculosis notification rates for London have risen dramatically in recent years. Molecular typing of Mycobacterium tuberculosis has contributed to our understanding of the epidemiology of tuberculosis throughout the world. This study aimed to assess the degree of recent transmission of M tuberculosis in London and subpopulations of the community with high rates of recent transmission. METHODS: M tuberculosis isolates from all persons from Greater London diagnosed with culture positive tuberculosis between 1 July 1995 and 31 December 1997 were genetically fingerprinted using IS6110 restriction fragment length polymorphism (RFLP) typing. A structured proforma was used during record review of cases of culture confirmed tuberculosis. Cluster analysis was performed and risk factors for clustering were examined in a univariate analysis followed by a logistic regression analysis with membership of a cluster as the outcome variable. RESULTS: RFLP patterns were obtained for 2042 isolates with more than four copies of IS6110; 463 (22.7%) belonged to 169 molecular clusters, which ranged in size from two (65% of clusters) to 12 persons. The estimated rate of recent transmission was 14.4%. Young age (0-19 years) (odds ratio (OR) 2.65, 95% confidence interval (CI) 1.59 to 4.44), birth in the UK (OR 1.55, 95% CI 1.04 to 2.03), black Caribbean ethnic group (OR 2.19, 95% CI 1.15 to 4.16), alcohol dependence (OR 2.33, 95% CI 1.46 to 3.72), and streptomycin resistance (OR 1.82, 95% CI 1.15 to 2.88) were independently associated with an increased risk of clustering. CONCLUSIONS: Tuberculosis in London is largely caused by reactivation or importation of infection by recent immigrants. Newly acquired infection is also common among people with recognised risk factors. Preventative interventions and early diagnosis of immigrants from areas with a high incidence of tuberculosis, together with thorough contact tracing and monitoring of treatment outcome among all cases of tuberculosis (especially in groups at higher risk of recent infection), remains most important.

Adolescent↗
PubMed2001

Asthma and allergy in Albania and the UK.

In the first phase of the International Study of Asthma and Allergies in Childhood, a large difference in occurrence of asthma symptoms was seen between children in Albania and the UK. We did skin-prick tests with various allergens and measured peak expiratory flow rate in about 1000 children from each country. A large difference in the proportion of exercise-induced bronchial reactivity was evident between children from Albania and the UK (0.8% vs 5.4%, respectively). However, the frequency of allergic sensitisation was closely similar (15.0% vs 17.8%, respectively). These results suggest that large geographical variations in asthma prevalence can arise without differences in frequency of atopy.

Albania↗
PubMed2001

A case-control study of food poisoning seen at an accident and emergency department.

We investigated the hypothesis that sporadic food poisoning is a result of the consumption of food cooked or prepared outside the home. We did a case-control study, set in an urban emergency department, to find out the odds ratios for the risk of food poisoning associated with various patterns of consumption. We found that recent eating out (exposure on the day of or day before presentation) was associated with an odds ratio of 2.41 (95% CI 1.29-4.50) for presenting with food poisoning.

Adult↗
PubMed2001

In utero and perinatal complications preceding asthma.

BACKGROUND: It has been suggested that pregnancy and early life may influence the development of asthma in the offspring, but published studies have not carefully controlled for potential biases. METHODS: In a large British birth cohort of 4065 natural children of 2583 mothers, we investigated whether in utero and perinatal influences contribute to the development and the severity of asthma in childhood, allowing for possible confounders of the relationship, and considering the nonindependence of familial data. RESULTS: Child asthma (10.1%) was more frequently reported by mothers when there had been health complications during pregnancy (prevalence =14.3%; adjusted odds ratio [ORadj] =2.01; 95% confidence interval, 1.52-2.67), labor, or delivery (19.3%, ORadj =1.35, 1.01-1.81); child illness or health complications during the first week of life (22.6%, ORadj =1.35, 1.01-1.82); and birth weight of < 2.5 kg (7.0%, ORadj =1.57, 1.10-2.25). Specific causes of health complications during pregnancy which significantly related to asthma were early or threatened labor (ICD: 644) (4.8%, ORadj =1.58, 1.03-2.40) and the malposition or malpresentation of the fetus (ICD: 652) (1.6%, ORadj =3.63, 1.47-8.91). CONCLUSION: The results provide further evidence that in utero and perinatal factors may increase the risk of developing asthma.

Adolescent↗
PubMed2001

Risk factor associations with wheezing patterns in children followed longitudinally from birth to 3(1/2) years.

BACKGROUND: There is a paucity of detailed longitudinal data on wheeze in early childhood. Not all children who wheeze in early infancy will continue to wheeze into childhood and beyond. This study aims to investigate possible risk factors for different patterns of wheeze in the pre-school years. SUBJECTS AND METHODS: Study participants were part of the Avon Longitudinal Study of Parents and Children (ALSPAC). Maternal reports of child wheeze between birth and 6 months and again between 30 and 42 months were gathered prospectively. Children were categorized into early wheeze, persistent wheeze or late onset wheeze. A large number of risk factors were assessed for each wheezing phenotype using multivariable logistic regression models. RESULTS: Over 70% of children who wheezed in the first 6 months did not wheeze 3 years later. Wheezing between 0-6 months was independently associated with the presence of older siblings, male sex, delivery between April and December, bottle feeding, young maternal age, prenatal tobacco smoke exposure, atopy and parental history of asthma. From within this group of early wheezers, risk factors for wheeze that persisted beyond 6 months included pre-term delivery, young maternal age, living in rented local authority housing, atopy and a maternal (not paternal) history of asthma. Atopy and a family history of asthma emerged as the main predictors of wheeze that developed after 6 months of age. CONCLUSION: It is clear that a number of wheezing syndromes exist by 3(1/2) years, albeit with some degree of overlap. Detailed follow-up of this cohort is underway to determine whether risk factor associations determined in the first 3(1/2) years have long-term significance for the clinical entity termed 'asthma'.

Child, Preschool↗
PubMed2001

Pharyngeal pouch (Zenker's diverticulum).

Pharyngeal pouches occur most commonly in elderly patients (over 70 years) and typical symptoms include dysphagia, regurgitation, chronic cough, aspiration, and weight loss. The aetiology remains unknown but theories centre upon a structural or physiological abnormality of the cricopharyngeus. A diagnosis is easily established on barium studies. Treatment is surgical via an endoscopic or external cervical approach and should include a cricopharyngeal myotomy. Unfortunately pharyngeal pouch surgery has long been associated with significant morbidity, partly due to the surgery itself and also to the fact that the majority of patients are elderly and often have general medical problems. External approaches are associated with higher complication rates than endoscopic procedures. Recently, treatment by endoscopic stapling diverticulotomy has becoming increasingly popular as it has distinct advantages, although long term results are not yet available. The small risk of developing carcinoma within a pouch that is not excised remains a contentious issue and is an argument for long term follow up or treating the condition by external excision, particularly in younger patients.

Aged↗
PubMed2000

Linewidth collapse in three-photon exciton-polariton spectra of CsI under pressure

Unusual phenomena occurring under hydrostatic compression in the near-band-edge structure of CsI crystals were examined using the nonlinear optical technique of three-photon excitation. The lowest one-photon allowed transition to the exciton-polariton A of gamma-4 symmetry redshifts, while the one-photon forbidden paraexciton C of gamma-5 symmetry blueshifts to a crossing of energies at 4.4 kbar. During this process, the A level exhibits strong spectral line narrowing by more than a factor of 10, while the C level intensity increases by about the same factor. We believe this is the first reported observation of pressure induced line narrowing of deep UV electronic states in solids.

Journal Article↗
PubMed2000

Fungal and other spore counts as predictors of admissions for asthma in the Trent region.

OBJECTIVES: The importance of airborne fungal and other spores in provoking asthma attacks is uncertain. Panel studies have generated evidence that suggests a link between outdoor spore counts and severity of asthma. There have been no population based time series studies relating outdoor exposure to spores with incidence of attacks of asthma. METHODS: Outcomes were hospital admissions for asthma on 2002 days during 1987-94, for children and adults in the Trent region of England. Predictors were daily counts of 25 spore taxa from volumetric traps in Derby on the same and previous day. Admissions for asthma were adjusted for weekly, seasonal, and longer term trends by log linear autoregressive models. Spore counts on 6 days of asthma epidemics were also examined. RESULTS: When spore counts for individual taxa were analysed as quantitative variables, two positive and two negative correlations (out of a possible 100) were significant at the 5% level. When spore counts were dichotomised at the 90th percentile, one negative and eight positive correlations (out of 100) were significant at the 5% level. All significantly positive associations related to admissions among children, but none involved the total spore count. However, total spores were above the 90th percentile on four of the six epidemic days (odds ratio (OR) 9.92, 95% confidence interval (95% CI) 1.41 to 109.84), but epidemics occurred on only four of 343 days with high total moulds. CONCLUSIONS: There was some evidence that exceptional rates of admission for asthma tend to occur on days with high total mould spore counts, but no specific taxon was consistently implicated. The predictive power was insufficient to support a public warning system.

Adolescent↗
PubMed2000

Epidemiology of pneumothorax in England.

BACKGROUND: Little is known of the epidemiology of pneumothorax. Routinely available data on pneumothorax in England are described. METHODS: Patients consulting in primary care with a diagnosis of pneumothorax in each year from 1991 to 1995 inclusive were identified from the General Practice Research Database (GPRD). Emergency hospital admissions for pneumothorax were identified for the years 1991-4 from the Hospital Episode Statistics (HES) data. Mortality data for England & Wales were obtained for 1950-97. Analyses of pneumothorax rates by age and sex were performed for all data sources. Seasonal and geographical analyses were carried out for the HES data. RESULTS: The overall person consulting rate for pneumothorax (primary and secondary combined) in the GPRD was 24. 0/100 000 each year for men and 9.8/100 000 each year for women. Hospital admissions for pneumothorax as a primary diagnosis occurred at an overall incidence of 16.7/100 000 per year and 5.8/100 000 per year for men and women, respectively. Mortality rates were 1. 26/million per year for men and 0.62/million per year for women. The age distribution in both men and women showed a biphasic distribution for both GP consultations and hospital admissions. Deaths showed a single peak with highest rates in the elderly. There was an urban-rural trend observed for hospital admissions in the older age group (55+ years) with admission rates in the conurbations significantly higher than in the rural areas. Analysis for trends in mortality data for 1950-97 showed a striking increase in the death rate for pneumothorax in those aged 55+ years between 1960 and 1990, with a steep decline in the 1990s. Mortality in the younger age group (15-34 years) remained low and constant. CONCLUSION: There is evidence of two epidemiologically distinct forms of spontaneous pneumothorax in England. The explanation for the rise and fall in mortality for secondary pneumothorax is obscure.

Adolescent↗
PubMed2000

The effectiveness of topical treatment in discharging ears with in-dwelling ventilation tubes.

The efficacy and tolerability of topical treatment (both drops and spray) in the treatment of otorrhoea in those ears with ventilation tubes in-situ was studied. Sixty patients were randomised into two treatment groups. One group used an antibacterial/anti-inflammatory ear drop preparation (Otosporin) and the other group a similar preparation administered as an ear spray (Otomize). A 'blind' clinical assessment was made one and three weeks after commencing treatment. Both treatments (drops and spray) significantly improved patients' symptoms and signs after one week (p < 0.001). The spray was significantly easier to administer (p < 0.01) and caused less discomfort on application (p < 0.02).

Administration, Topical↗