Chronic obstructive pulmonary disease in Welsh slate miners.

BACKGROUND: Exposure to respirable crystalline silica (RCS) causes emphysema, airflow limitation and chronic obstructive pulmonary disease (COPD). Slate miners are exposed to slate dust containing RCS but their COPD risk has not previously been studied. AIMS: To study the cumulative effect of mining on lung function and risk of COPD in a cohort of Welsh slate miners and whether these were independent of smoking and pneumoconiosis. METHODS: The study was based on a secondary analysis of Medical Research Council (MRC) survey data. COPD was defined as forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) ratio <0.7. We created multivariable models to assess the association between mining and lung function after adjusting for age and smoking status. We used linear regression models for FEV1 and FVC and logistic regression for COPD. RESULTS: In the original MRC study, 1255 men participated (726 slate miners, 529 unexposed non-miners). COPD was significantly more common in miners (n = 213, 33%) than non-miners (n = 120, 26%), P < 0.05. There was no statistically significant difference in risk of COPD between miners and non-miners when analysis was limited to non-smokers or those without radiographic evidence of pneumoconiosis. After adjustment for smoking, slate mining was associated with a reduction in %predicted FEV1 [ß coefficient = -3.97, 95% confidence interval (CI) -6.65, -1.29] and FVC (ß coefficient = -2.32, 95% CI -4.31, -0.33) and increased risk of COPD (odds ratio: 1.38, 95% CI 1.06, 1.81). CONCLUSIONS: Slate mining may reduce lung function and increase the incidence of COPD independently of smoking and pneumoconiosis.

Asthma and allergies: is the farming environment (still) protective in Poland? The GABRIEL Advanced Studies.

BACKGROUND: Evidence exists that a farming environment in childhood may provide protection against atopic respiratory disease. In the GABRIEL project based in Poland and Alpine regions of Germany, Austria and Switzerland, we aimed to assess whether a farming environment in childhood is protective against allergic diseases in Poland and whether specific exposures explain any protective effect. METHODS: In rural Poland, 23 331 families of schoolchildren completed a questionnaire enquiring into farming practices and allergic diseases (Phase I). A subsample (n = 2586) participated in Phase II involving a more detailed questionnaire on specific farm exposures with objective measures of atopy. RESULTS: Farming differed between Poland and the Alpine centres; in the latter, cattle farming was prevalent, whereas in Poland 18% of village farms kept ≥1 cow and 34% kept ≥1 pig. Polish children in villages had lower prevalences of asthma and hay fever than children from towns, and in the Phase II population, farm children had a reduced risk of atopy measured by IgE (aOR = 0.72, 95% CI 0.57, 0.91) and skin prick test (aOR = 0.65, 95% CI 0.50, 0.86). Early-life contact with grain was inversely related to the risk of atopy measured by IgE (aOR = 0.66, 95% CI 0.47, 0.92) and appeared to explain part of the farming effect. CONCLUSION: While farming in Poland differed from that in the Alpine areas as did the exposure-response associations, we found in communities engaged in small-scale, mixed farming, there was a protective farming effect against objective measures of atopy potentially related to contact with grain or associated farm activities.

Cystic fibrosis and survival to 40 years: a case-control study.

The clinical course of patients with cystic fibrosis (CF) is variable and probably determined by many interacting factors. We aimed to examine the influence of early social and clinical factors on long-term survival. A case-control study of adult CF patients was used to compare long-term survivors (aged ≥ 40 yrs) with patients who died before reaching 30 yrs of age. Each case (n = 78) was matched by birth date with at least one control (n = 152), after exclusion of "late diagnosis" patients. Probability-weighted logistic regression models were used to identify influences on survival. Factors resulting in increased probabilities of survival included high body mass index (OR 1.76, 95% CI 1.40-2.22), forced expiratory volume in 1 s (OR per 5% increase 1.54, 95% CI 1.32-1.80), and forced vital capacity (OR per 5% increase 1.54, 95% CI 1.33-1.78) at transfer to the adult clinic and the exclusive use of oral antibiotics (OR 8.31, 95% CI 3.02-22.88). Factors resulting in decreased probabilities of survival were Pseudomonas aeruginosa acquisition (OR 0.18, 95% 0.05-0.65) or pneumothorax before transfer to the adult clinic (OR 0.02, 95% CI 0.004-0.08) and referral from a paediatric clinic in a deprived area (OR 0.13, 95% CI 0.04-0.38). Long-term survival is associated with the clinical features present by the time of referral to an adult clinic. Even "early-diagnosis" disease appears to have different phenotypes, possibly independent of CF gene function, that have different survival patterns.

Childhood peak flow and the Oxford Transport Strategy.

BACKGROUND: Studies of the health effects of traffic interventions are rare. The Oxford Transport Strategy (OTS), implemented in June 1999, involved a wide range of permanent changes designed to reduce congestion in the city centre of Oxford, UK. The impact of the OTS on peak expiratory flow (PEF) and respiratory symptoms among schoolchildren in the city is reported. METHODS: A dynamic cohort of 1389 children aged 6-10 years attending first schools in Oxford was studied. Schools were visited 2-3 times a year for 5-day periods between 1998 and 2000. On each day of each visit children had their PEF measured and were asked about their respiratory symptoms. RESULTS: Changes in traffic varied across the city. In the whole population, regression analysis of daily PEF adjusting for potential confounders showed statistically significant improvements post-OTS (beta = 5.52 l/min, 95% CI 3.08 to 7.97), but there was no consistent evidence that these improvements varied by changes in traffic exposure. In post-hoc analyses, children currently receiving treatment for asthma tended to experience a greater increase in PEF post-OTS as did children from less affluent homes, although these differences did not reach statistical significance. In each of these groups, greater benefits were observed among those living near roads where traffic levels fell post-OTS. CONCLUSIONS: These findings suggest that traffic management may lead to small localised improvements in childhood respiratory health and that such benefits are limited to children with pre-existing respiratory problems and those from less affluent backgrounds.

Atopy and asthma in rural Poland: a paradigm for the emergence of childhood respiratory allergies in Europe.

BACKGROUND: We hypothesized that, in south-west Poland, a 'rural' protective effect on atopy and respiratory allergies would be most pronounced among children but that at all ages would be stronger among those with a rural background. METHODS: A cross-sectional survey of the inhabitants (age >5 years, n = 1657) of Sobotka, a town of 4000 people in south-west Poland: and seven neighbouring villages. We measured and analysed responses to skin prick tests (atopy) and to a standard questionnaire (asthma and hayfever). RESULTS: Atopy was very uncommon (7%) among villagers at all ages but not among townspeople (20%, P < 0.001); the differences were most marked among those aged under 40 years. Asthma and hayfever were similarly distributed, both being very rare among villagers. The differences appear to be explained by the cohort effect of a communal move away from rural life. This interpretation is supported by an ecological correlation (rho = -0.59) between rural populations and childhood wheeze in 22 European countries. CONCLUSION: The very striking differences in the prevalence of allergy between these two neighbouring communities of central Europe reflect the pan-continental population movements that may have been responsible for the emergence of childhood allergies in Europe.

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.

Effect of lung-volume-reduction surgery in patients with severe emphysema.

BACKGROUND: Although many patients with severe emphysema have undergone lung-volume-reduction surgery, the benefits are uncertain. We conducted a randomized, controlled trial of the surgery in patients with emphysema. Patients with isolated bullae were excluded because such patients are known to improve after bullectomy. METHODS: Potentially eligible patients were given intensive medical treatment and completed a smoking-cessation program and a six-week outpatient rehabilitation program before random assignment to surgery or continued medical treatment. After 15 patients had been randomized, the entry criteria were modified to exclude patients with a carbon monoxide gas-transfer value less than 30 percent of the predicted value or a shuttle-walking distance of less than 150 m, because of the deaths of 5 such patients (3 treated surgically and 2 treated medically). RESULTS: Of the 174 subjects who were initially assessed, 24 were randomly assigned to continued medical treatment and 24 to surgery. At base line in both groups, the median forced expiratory volume in one second (FEV1) was 0.75 liter, and the median shuttle-walking distance was 215 m. Five patients in the surgical group (21 percent) and three patients in the medical group (12 percent) died (P=0.43). After six months, the median FEV1 had increased by 70 ml in the surgical group and decreased by 80 ml in the medical group (P=0.02). The median shuttle-walking distance increased by 50 m in the surgical group and decreased by 20 m in the medical group (P=0.02). There were similar changes on a quality-of-life scale and similar changes at 12 months of follow-up. Five of the 19 surviving patients in the surgical group had no benefit from the treatment. CONCLUSIONS: In selected patients with severe emphysema, lung-volume-reduction surgery can improve FEV1, walking distance, and quality of life. Whether it reduces mortality is uncertain.