Daily symptom rates in patients with chronic obstructive pulmonary disease and in other subjects with presumed high sensitivity to air pollution who lived near a coal-fired plant were compared with 24-hr ambient air concentrations of nitrogen dioxide, sulfur dioxide, soot, and suspended particles as well as with emissions from the plant. The mean concentrations of each of the pollutants during the 4-month study period were below 30 micrograms/m3, and no single 24-hr concentration exceeded 100 micrograms/m3. There were no consistent associations between plant emissions and pollutant levels or between these two variables and daily symptom rates. The results indicate that the coal-fired plant was not of major importance for the occurrence of acute respiratory symptoms in the surrounding population.
BACKGROUND: A population-based case-control study was performed in Stockholm to assess the influence of air pollution on the occurrence of severe wheezing bronchitis in children. METHODS: The study included 197 children aged 4 months to 4 years, who were hospitalized because of breathing difficulties with wheezing, and 350 population controls. Information on potential risk factors for childhood wheezing and a residential history was obtained at home interview with parents. Outdoor nitrogen dioxide (NO2) concentrations at home addresses and day care centres from birth on were estimated from validated models, mainly using data on traffic intensity from municipal registers. RESULTS: The risk of wheezing bronchitis was related to time-weighted mean outdoor NO2 exposure in girls (P = 0.02), but not in boys. A gas stove in the home appeared to be a risk factor primarily for girls. All analyses controlled for parental asthma and maternal smoking, which were independent risk factors for wheezing bronchitis. CONCLUSIONS: The results suggest that exposure to combustion products containing NO2 may be of particular importance for the development of wheezing bronchitis in girls.
BACKGROUND: The prevalence of allergic diseases has increased rapidly in recent decades, particularly in children. For adequate prevention it is important not only to identify risk factors, but also possible protective factors. The aim of this study was to compare the prevalence of allergic diseases and sensitization between farm children, children in anthroposophic families, and reference children, with the aim to identify factors that may protect against allergic disease. METHODS: The study was of cross-sectional design and included 14,893 children, aged 5-13 years, from farm families, anthroposophic families (recruited from Steiner schools) and reference children in Austria, Germany, The Netherlands, Sweden and Switzerland. A detailed questionnaire was completed and allergen-specific IgE was measured in blood. RESULTS: Growing up on a farm was found to have a protective effect against all outcomes studied, both self-reported, such as rhinoconjunctivitis, wheezing, atopic eczema and asthma and sensitization (allergen specific IgE > or = 0.35 kU/l). The adjusted odds ratio (OR) for current rhinoconjunctivitis symptoms was 0.50 (95% confidence interval (CI) 0.38-0.65) and for atopic sensitization 0.53 (95% CI 0.42-0.67) for the farm children compared to their references. The prevalence of allergic symptoms and sensitization was also lower among Steiner school children compared to reference children, but the difference was less pronounced and not as consistent between countries, adjusted OR for current rhinoconjunctivitis symptoms was 0.69 (95% CI 0.56-0.86) and for atopic sensitization 0.73 (95% CI 0.58-0.92). CONCLUSIONS: This study indicates that growing up on a farm, and to a lesser extent leading an anthroposophic life style may confer protection from both sensitization and allergic diseases in childhood.
Antioxidant intake may reduce the risk of allergic disease by protecting against oxidative tissue damage. Major sources of antioxidants in the Western world are fruits, vegetables (vitamin C, ß-carotene, a-tocopherol), meat and milk (selenium, magnesium, zinc). Children may exclude or eat less of some fruits and vegetables due to cross-reactivity between pollen and these foods, complicating assessment of causal relationships.
To investigate the association between dietary antioxidant intake and allergic disease, taking potential reverse causation into account.
Data on 2442 8-year-old children from the Swedish birth cohort study BAMSE were analysed. Children with completed parental questionnaires on exposures and health, including a food-frequency questionnaire and who provided a blood sample were included. Associations between antioxidant intake during the past year and current allergic disease were analysed using logistic regression.
An inverse association was observed between intake of ß-carotene and rhinitis (OR(adj), highest vs. lowest quartile, 0.67, 95% CI 0.49-0.93). Magnesium intake was inversely related to asthma (OR(adj), 0.65, 95% CI 0.42-1.00) and atopic sensitisation (OR(adj), 0.78, 95% CI 0.61-1.00). Following exclusion of children who avoided certain fruits, vegetables or milk due to allergic symptoms (n = 285), the inverse association remained between magnesium intake and asthma (OR(adj), 0.58, 95% CI 0.35-0.98), whereas all other associations became non-significant.
Diet modifications due to allergy may affect the antioxidant intake and needs to be considered when investigating the relationship between diet and allergic disease. Magnesium intake seems to have a protective effect on childhood asthma.
This study examines sex differences in the relative risks of lung cancer and other smoking-related cancers (i.e. cancers of the upper respiratory tract, oesophagus, pancreas, bladder, and renal pelvis). Data on smoking habits in 1963 from a random sample of 56,000 men and women were linked with information on new cases of cancer for 1964-89. Compared with people who have never smoked, the relative risks of lung cancer at different levels of pack-years completed in 1963 (>5, 6-15, 16-25 and 25 + pack-years) were 1.6, 4.4, 14.2, and 17.9 for men, and 2.1, 6.3, 10.3, and 16.5 for women. The corresponding relative risks of other smoking-related cancers were 1.8, 3.0 5.4, and 6.4 for men, and 2.0, 3.1, 5.0, and 6.5 for women. These results suggest that men and women have similar relative risks of smoking-related cancers at different levels of smoking.
A cohort of 3,916 Swedish copper smelter workers employed for at least 3 months between 1928 and 1967 was followed up through 1981. Arsenic exposure was estimated for different time periods at each workplace within the smelter. Detailed job records were linked to the exposure matrix, thus forming individual cumulative arsenic exposure measures for each smelter worker. Smoking history was collected for 107 lung cancer cases and 214 controls from the cohort. Lung cancer risks were positively related to cumulative arsenic exposure with smoking standardized relative risks ranging from 0.7 to 8.7 in different exposure groups. A negative confounding by smoking was suggested in the higher exposure categories. The interaction between arsenic and smoking for the risk of developing lung cancer was intermediate between additive and multiplicative and appeared less pronounced among heavy smokers.
Exposure to elevated levels of ambient air pollutants can lead to adverse cardiovascular effects. Potential mechanisms include systemic inflammation and perturbation of the coagulation balance.
To investigate long- and short-term effects of air pollution exposure on serum levels of inflammatory (IL-6, TNF-alpha and CRP) and coagulation (fibrinogen and PAI-1) markers relevant for cardiovascular pathology.
The study group consisted of a population sample of 1028 men and 508 women aged 45-70 years from Stockholm. Long-term air pollution exposure was assessed using spatial modelling of traffic-related NO(2) and heating-related SO(2) emissions at each subject's residential addresses over retrospective periods of 1, 5 and 30 years. Short-term exposure was assessed as averages of rooftop measurements over 12-120 h before blood sampling.
Long-term exposures to both traffic-NO(2) and heating-SO(2) emissions showed consistent associations with IL-6 levels. 30-year average traffic-NO(2) exposure was associated with a 64.5% (95% CI 6.7% to 153.8%) increase in serum IL-6 per 28.8 microg/m(3) (corresponding to the difference between the 5th and 95th percentile exposure value), and 30-year exposure to heating-SO(2) with a 67.6% (95% CI 7.1% to 162.2%) increase per 39.4 microg/m(3) (5th-95th percentile value difference). The association appeared stronger in non-smokers, physically active people and hypertensive subjects. We observed positive non-significant associations of inflammatory markers with NO(2) and PM(10) during 24 h before blood sampling. Short-term exposure to O(3) was associated with increased, and SO(2) with decreased, fibrinogen levels.
Our results suggest that exposure to moderate levels of air pollution may influence serum levels of inflammatory markers.
BACKGROUND: Increased prevalence of atopic disorders in children may be associated with changes in types of childhood infections, vaccination programmes, and intestinal microflora. People who follow an anthroposophic way of life use antibiotics restrictively, have few vaccinations, and their diet usually contains live lactobacilli, which may affect the intestinal microflora. We aimed to study the prevalence of atopy in children from anthroposophic families and the influence of an anthroposophic lifestyle on atopy prevalence. METHODS: In a cross-sectional study, 295 children aged 5-13 years at two anthroposophic (Steiner) schools near Stockholm, Sweden, were compared with 380 children of the same age at two neighbouring schools in terms of history of atopic and infectious diseases, use of antibiotics and vaccinations, and social and environmental variables. Skin-prick tests were done for 13 common allergens, and we took blood samples from children and their parents for analysis of allergen-specific serum IgE-antibodies. FINDINGS: At the Steiner schools, 52% of the children had had antibiotics in the past, compared with 90% in the control schools. 18% and 93% of children, respectively, had had combined immunisation against measles, mumps, and rubella, and 61% of the children at the Steiner schools had had measles. Fermented vegetables, containing live lactobacilli, were consumed by 63% of the children at Steiner schools, compared with 4.5% at the control schools. Skin-prick tests and blood tests showed that the children from Steiner schools had lower prevalence of atopy than controls (odds ratio 0.62 [95% CI 0.43-0.91]). There was an inverse relation between the number of characteristic features of an anthroposophic lifestyle and risk of atopy (p for trend=0.01). INTERPRETATION: Prevalence of atopy is lower in children from anthroposophic families than in children from other families. Lifestyle factors associated with anthroposophy may lessen the risk of atopy in childhood.
Comment In: Lancet. 1999 May 1;353(9163):1457-810232306
AIMS: To investigate the effect of breast feeding on allergic disease in infants up to 2 years of age. METHODS: A birth cohort of 4089 infants was followed prospectively in Stockholm, Sweden. Information about various exposures was obtained by parental questionnaires when the infants were 2 months old, and about allergic symptoms and feeding at 1 and 2 years of age. Duration of exclusive and partial breast feeding was assessed separately. Symptom related definitions of various allergic diseases were used. Odds ratios (OR) and 95% confidence intervals (CI) were estimated in a multiple logistic regression model. Adjustments were made for potential confounders. RESULTS: Children exclusively breast fed during four months or more exhibited less asthma (7.7% v 12%, OR(adj) = 0.7, 95% CI 0.5 to 0.8), less atopic dermatitis (24% v 27%, OR(adj) = 0.8, 95% CI 0.7 to 1.0), and less suspected allergic rhinitis (6.5% v 9%, OR(adj) = 0.7, 95% CI 0.5 to 1.0) by 2 years of age. There was a significant risk reduction for asthma related to partial breast feeding during six months or more (OR(adj) = 0.7, 95% CI 0.5 to 0.9). Three or more of five possible allergic disorders-asthma, suspected allergic rhinitis, atopic dermatitis, food allergy related symptoms, and suspected allergic respiratory symptoms after exposure to pets or pollen-were found in 6.5% of the children. Exclusive breast feeding prevented children from having multiple allergic disease (OR(adj) = 0.7, 95% CI 0.5 to 0.9) during the first two years of life. CONCLUSION: Exclusive breast feeding seems to have a preventive effect on the early development of allergic disease-that is, asthma, atopic dermatitis, and suspected allergic rhinitis, up to 2 years of age. This protective effect was also evident for multiple allergic disease.