Jessica M Harris

The introduction of solids in relation to asthma and eczema

Background: Despite scarce scientific evidence, current feeding guidelines recommend delayed introduction of solids for the prevention of asthma and allergy. Aims: To explore whether late introduction of solids is protective against the development of asthma, eczema, and atopy. Methods: A total of 642 children were recruited before birth and followed to the age of 5½ years. Main outcome measures were: doctor’s diagnosis of eczema ever, atopy according to skin prick test results against inhalant allergens, preschool wheezing, transient wheezing, all defined at age 5–5½ years. Introduction of solids as main exposure measure was assessed retrospectively at age 1 year. Results: There was no evidence for a protective effect of late introduction of solids for the development of preschool wheezing, transient wheezing, atopy, or eczema. On the contrary, there was a statistically significant increased risk of eczema in relation to late introduction of egg (aOR 1.6, 95% CI 1.1 to 2.4) and milk (aOR 1.7, 95% CI 1.1 to 2.5). Late introduction of egg was furthermore associated with a non-significant increased risk of preschool wheezing (aOR 1.5, 95% CI 0.92 to 2.4). There was no statistical evidence of feeding practices playing a different role in the development of asthma and eczema after stratification for parental asthma and atopy status. Conclusions: Results do not support the recommendations given by present feeding guidelines stating that a delayed introduction of solids is protective against the development of asthma and allergy.

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

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.

Mortality in a cohort of vermiculite miners exposed to fibrous amphibole in Libby, Montana

Background: Fibrous tremolite is a widespread amphibole asbestiform mineral, airborne fibres of which constitute an environmental hazard in Libby, Montana, northern California, and elsewhere. Aims: To determine excess risk from lung cancer, mesothelioma, and all-cause mortality in a cohort of men exposed to tremolite, but no other form of asbestos. Methods: Mortality by certified cause and various measures of exposure to tremolite and related amphibole fibres was assessed in a cohort of 406 vermiculite mineworkers in Libby, Montana, employed before 1963 and followed until 1999. Results: Total deaths were: lung cancer 44 (SMR 2.40), non-malignant respiratory disease (NMRD) 51 (SMR 3.09), all causes 285 (SMR 1.27); included among the total were 12 deaths ascribed to mesothelioma (4.21% of all deaths). Adjusted linear increments in relative risks (per 100 f/ml.y), estimated by Poisson regression, were: lung cancer (0.36, 95% CI 0.03 to 1.20), NMRD (0.38, 95% CI 0.12 to 0.96), and all deaths (0.14, 95% CI 0.05 to 0.26). Conclusions: The all-cause linear model would imply a 14% increase in mortality for mine workers exposed occupationally to 100 f/ml.y or about 3.2% for a general population exposed for 50 years to an ambient concentration of 0.1 f/ml. Amphibole fibres, tremolite in particular, are likely to be disproportionately responsible for cancer mortality in persons exposed to commercial chrysotile, but to what extent cannot be readily assessed.

A prospective study of wound infection in coronary artery surgery

OBJECTIVE The incidence of wound infection in coronary artery surgery is low, but there is an appreciable mortality associated with sternal infection. In other fields of surgery there is evidence that an all disposable paper gown and drape system has protective advantages over a fabric system. Using an established wound scoring system (ASEPSIS), we investigated this in a prospective, randomised trial of patients undergoing cardiac surgery. METHODS 505 patients undergoing isolated coronary artery surgery in a single hospital over an 18 month period were randomised to either a disposable, paper drape system or re-usable fabric drapes. Allocation was stratified according to whether or not the patient had had previous coronary artery surgery. Patients were followed for 3 months. Total infection scores for each wound were calculated from daily scores collected in hospital together with the scores at six weeks and three months. RESULTS The two randomised groups were otherwise well matched. Full follow-up information was available for 464 (92%) patients. There was no evidence of any difference in rates of sternal or leg wound infection between the two groups (P = 0.87 and 0.62, respectively). Women were more likely to have infected sternal wounds (P = 0.17) and significantly more likely to have infected leg wounds (P = 0.04). Patients with sternal wound infections had a significantly higher body mass index (P = 0.001). High Parsonnet scores and increased time on ventilation were significantly associated with leg wound but not sternal infections. For both wound sites, patients with infections had spent longer in the operating theatre. CONCLUSION In a randomised controlled study of patients undergoing coronary artery surgery we found that the use of paper drapes and gowns conferred no benefit over a reusable fabric in terms of post-operative wound infection. Although females and diabetics are more likely to experience this complication, an important additional risk factor is an extended operating time.

Maternal atopy and parity

Background Family size and high birth order were related to the prevalence of hayfever and positive skin prick test. However, this association may be explained by maternal atopy. We examined the relationship between maternal atopy and the number of offspring in three European cohorts of pregnant women.

Cryptogenic fibrosing alveolitis and lung cancer: the BTS study

Background: The risk of lung cancer is often reported to be increased for patients with cryptogenic fibrosing alveolitis (CFA). Methods: Vital status was sought for all 588 members of the British Thoracic Society (BTS) cryptogenic fibrosing alveolitis (CFA) study 11 years after entry to the cohort. Observed deaths due to lung cancer were compared with expected deaths using age-, sex- and period-adjusted national rates. The roles of reported asbestos exposure and smoking were also investigated. Results: 488 cohort members (83%) had died; 46 (9%) were certified to lung cancer (ICD9 162). The standardised mortality ratio (SMR) was 7.4 (95% CI 5.4 to 9.9). Stratified analysis showed increased lung cancer mortality among younger subjects, men and ever smokers. Using an independent expert panel, 25 cohort members (4%) were considered to have at least moderate exposure to asbestos; the risk of lung cancer was increased for these subjects (SMR 13.1 (95% CI 3.6 to 33.6)) vs 7.2 (95% CI 5.2 to 9.7) for those with less or no asbestos exposure). Ever smoking was reported by 448 (73%) of the cohort and was considerably higher in men than in women (92% vs 49%; p<0.001). Most persons who died from lung cancer were male (87%), and all but two (96%) had ever smoked. Ever smokers presented at a younger age (mean 67 vs 70 years; p<0.001) and with less breathlessness (12% smokers reported no breathlessness vs 5% never smokers; p = 0.02). Conclusions: These findings confirm an association between CFA and lung cancer although this relationship may not be causal. The high rate of smoking and evidence that smokers present for medical attention earlier than non-smokers suggest that smoking could be confounding this association.

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.

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.

Early allergen exposure and atopic eczema.

Background  The relationship between exposure to indoor aeroallergens in early life and subsequent eczema is unclear. We have previously failed to show any significant associations between early life exposure to house dust mite and cat fur allergens and either sensitization to these allergens or wheeze. We have also previously reported a lower prevalence of parent‐reported, doctor‐diagnosed eczema by age 2 years for children exposed to higher concentrations of house dust mite, but no other associations with other definitions of eczema or for exposure to cat allergen.