Utility of an alternative bicycle commute route of lower proximity to motorised traffic in decreasing exposure to ultra-fine particles, respiratory symptoms and airway inflammation - a structured exposure experiment

Background: Bicycle commuting in an urban environment of high air pollution is known as a potential health risk, especially for susceptible individuals. While risk management strategies aimed to reduce motorised traffic emissions exposure have been suggested, limited studies have assessed the utility of such strategies in real-world circumstances. Objectives: The potential of reducing exposure to ultrafine particles (UFP; < 0.1 µm) during bicycle commuting by lowering interaction with motorised traffic was investigated with real-time air pollution and acute inflammatory measurements in healthy individuals using their typical, and an alternative to their typical, bicycle commute route. Methods: Thirty-five healthy adults (mean ± SD: age = 39 ± 11 yr; 29% female) each completed two return trips of their typical route (HIGH) and a pre-determined altered route of lower interaction with motorised traffic (LOW; determined by the proportion of on-road cycle paths). Particle number concentration (PNC) and diameter (PD) were monitored in real-time in-commute. Acute inflammatory indices of respiratory symptom incidence, lung function and spontaneous sputum (for inflammatory cell analyses) were collected immediately pre-commute, and one and three hours post-commute. Results: LOW resulted in a significant reduction in mean PNC (1.91 x e4 ± 0.93 x e4 ppcc vs. 2.95 x e4 ± 1.50 x e4 ppcc; p ≤ 0.001). Besides incidence of in-commute offensive odour detection (42 vs. 56 %; p = 0.019), incidence of dust and soot observation (33 vs. 47 %; p = 0.038) and nasopharyngeal irritation (31 vs. 41 %; p = 0.007), acute inflammatory indices were not significantly associated to in-commute PNC, nor were these indices reduced with LOW compared to HIGH. Conclusions: Exposure to PNC, and the incidence of offensive odour and nasopharyngeal irritation, can be significantly reduced when utilising a strategy of lowering interaction with motorised traffic whilst bicycle commuting, which may bring important benefits for both healthy and susceptible individuals.

Prevalence and determinants of respiratory symptoms, asthma, chronic bronchitis and allergic sensitization in Helsinki : A comparison between Finland, Sweden and Estonia. The FinEsS studies - Helsinki I

Objectives: To assess the prevalence and risk factor profiles of respiratory symptoms, asthma and chronic bronchitis in Helsinki, and to compare these results with those for Sweden and Estonia. Other important aims were to evaluate the prevalence and determinants of type 1 sensitization in Helsinki. Materials and methods: This presentation is a part of a large epidemiological study in Finland, Estonia and Sweden (FinEsS). The first part of the study consisted of a postal questionnaire in 1995-1996 distributed to subjects in eight study centres. The study population in each centre was a population-based random sample designed to be representative of the general population. The original study sample in Helsinki consisted of 8000 subjects aged 20-69 years, 6062 (76%) of whom participated. Comparisons between countries were based on a narrower age group, 20-64 years, since 64 years was the upper age limit used in the original study in Estonia. Thus, altogether 58 661 subjects aged 20-64 years were invited to participate in Finland, Sweden and Estonia, and 44 483 (76%) did so. The second part of the study was a clinical study with a structured interview, lung function measurements and skin-prick tests with 15 common allergens. This thesis reports only the results of the prick tests in Helsinki. Of the 1200 subjects invited to participate in Helsinki, 643 (54%) consented. Skin-prick tests were performed on subjects ≤ 60 years of age; thus, a total of 498 tests were done. Results: In Helsinki, the prevalence of physician-diagnosed asthma was 6.6% and of physician-diagnosed chronic bronchitis 3.7% among subjects aged 20-69 years. Comparison of the results between Finland, Sweden and Estonia in subjects 20-64 years of age revealed the highest prevalence of physician-diagnosed asthma in Sweden, 7.8%, while the prevalence in Finland was 5.9% and in Estonia 2.0% (p<0.001). The prevalence of physician-diagnosed asthma among those aged 20-29 years was 7.9% in Stockholm, 6.3% in Helsinki and 2.8% in Tallinn. Asthma-related symptoms were most common in Estonia, and among those with typical asthma symptoms the diagnosis of asthma was least likely in Estonia. Physician-diagnosed chronic bronchitis was reported to be 10.7% in Estonia, 3.1% in Sweden and 2.9% in Finland among subjects aged 20-64 years (p<0.001). Among those aged 20-29 years, 7.6% in Tallinn reported physician-diagnosed chronic bronchitis, while the prevalence estimates were 1.4% in Stockholm and 1.3% in Helsinki. The prevalence of smoking was similar for women in all three countries, around 30%, but large differences in smoking habits were present among men; 60% of Estonian, 39% of Finnish and 28% of Swedish men smoked. Skin-prick tests in Helsinki revealed a high prevalence of sensitization, 46.9%. For subjects aged 26-39 years, the prevalence was highest, 56.8%, and 23.7% were sensitized to at least four allergens. The most common sensitizing allergen was the dog. Sensitization to multiple allergens was associated with a high prevalence of asthma and allergic rhinitis. Conclusions: Compared with earlier Finnish studies, a higher prevalence of asthma and a lower prevalence of chronic bronchitis were found in Helsinki. The prevalence of physician-diagnosed chronic bronchitis was low in Helsinki, with only one-fifth of subjects fulfilling the symptom criteria for chronic bronchitis reporting having a diagnosis of chronic bronchitis. The prevalences of asthma and chronic bronchitis were similar in Finland and Sweden, but in Estonia physician-diagnosed asthma was less common and physician-diagnosed chronic bronchitis more common, particularly among young subjects. Further analyses revealed that the diagnosis of asthma was favoured in Finland and Sweden, while the diagnosis of chronic bronchitis was more likely in Estonia for subjects with the same symptoms. Allergic sensitization was common in Helsinki. Our findings of multiple sensitization also speak in favour of evaluating the degree of sensitization when assessing allergies.

Topical tacrolimus in atopic dermatitis : Effects of long-term treatment on skin and respiratory symptoms

Objective: Patients with atopic dermatitis often have a poor long-term response to conventional topical or systemic treatments. Staphylococcal superinfections, skin atrophy due to corticosteroid use, and asthma and allergic rhinitis are common. Only a few, usually short-term, studies have addressed the effects of different treatments on these problems. Tacrolimus ointment is the first topical compound suitable for long-term treatment. The aim of this thesis was to evaluate the effects of long-term topical tacrolimus treatment on cutaneous staphylococcal colonization, collagen synthesis, and symptoms and signs of asthma and allergic rhinitis. Methods: Patients with moderate-to-severe atopic dermatitis were treated with intermittent 0.1% tacrolimus ointment in prospective, open studies lasting for 6 to 48 months. In Study I, cutaneous staphylococcal colonization was followed for 6 to 12 months. In Study II, skin thickness and collagen synthesis were followed by skin ultrasound and procollagen I and III propeptide concentrations of suction blister fluid samples for 12 to 24 months and compared with a group of corticosteroid-treated atopic dermatitis patients and with a group of healthy subjects. Study III was a cross-sectional study of the occurrence of respiratory symptoms, bronchial hyper-responsiveness, and sputum eosinophilia in atopic dermatitis patients and healthy controls. In Study V, the same parameters as in Study III were assessed in atopic dermatitis patients before and after 12 to 48 months of topical tacrolimus treatment. Study IV was a retrospective follow-up of the effect of tacrolimus 0.03% ointment on severe atopic blepharoconjunctivitis and conjunctival cytology. Results: The clinical response to topical tacrolimus was very good in all studies (p≤0.008). Staphylococcal colonization decreased significantly, and the effect was sustained throughout the study (p=0.01). Skin thickness (p<0.001) and markers of collagen synthesis (p<0.001) increased in the tacrolimus-treated patients significantly, whereas they decreased or remained unchanged in the corticosteroid-treated controls. Symptoms of asthma and allergic rhinitis (p<0.0001), bronchial hyper-responsiveness (p<0.0001), and sputum eosinophilia (p<0.0001) were significantly more common in patients with atopic dermatitis than in healthy controls, especially in subjects with positive skin prick tests or elevated serum immunoglobulin E. During topical tacrolimus treatment the asthma and rhinitis (p=0.005 and p=0.002) symptoms and bronchial hyper-responsiveness (p=0.02) decreased significantly, and serum immunoglobulin E and sputum eosinophils showed a decreasing trend in patients with the best treatment response. Treatment of atopic blepharoconjunctivitis resulted in a marked clinical response and a significant decrease in eosinophils, lymphocytes, and neutrophils in the conjunctival cytology samples. No significant adverse effects or increase in skin infections occurred in any study. Conclusions: The studies included in this thesis, except the study showing an increase in skin collagen synthesis in tacrolimus-treated patients, were uncontrolled, warranting certain reservations. The results suggest, however, that tacrolimus ointment has several beneficial effects in the long-term intermittent treatment of atopic dermatitis. Tacrolimus ointment efficiently suppresses the T cell-induced inflammation of atopic dermatitis. It has a normalizing effect on the function of the skin measured by the decrease in staphylococcal colonization. It does not cause skin atrophy as do corticosteroids but restores the skin collagen synthesis in patients who have used corticosteroids. Tacrolimus ointment has no marked systemic effect, as the absorption of the drug is minimal and decreases along with skin improvement. The effects on the airway: decrease in bronchial hyper-responsiveness and respiratory symptoms, can be speculated to be caused by the decrease in T cell trafficking from the skin to the respiratory tissues as the skin inflammation resolves, as well as inhibition of epicutaneous invasion of various antigens causing systemic sensitization when the skin barrier is disrupted as in atopic dermatitis. Patients with moderate-to-severe atopic dermatitis seem to benefit from efficient long-term treatment with topical tacrolimus.

Occupational exposure to particulate matter and respiratory symptoms in Portuguese swine barn workers

Certain environmental conditions in animal and plant production have been associated with increased frequency in respiratory illnesses, including asthma, chronic bronchitis, and hypersensitivity pneumonitis, in farmers occupationally exposed in swine production. The aim of this study was to characterize particulate matter (PM) contamination in seven Portuguese swine farms and determine the existence of clinical symptoms associated with asthma and other allergy diseases, utilizing the European Community Respiratory Health Survey questionnaire. Environmental assessments were performed with portable direct-reading equipment, and PM contamination including five different sizes (PM0.5, PM1.0, PM2.5, PM5.0, PM10) was determined. The distribution of particle size showed the same trend in all swine farms, with high concentrations of particles with PM5 and PM10. Results from the questionnaire indicated a trend such that subjects with diagnosis of asthma were exposed to higher concentrations of PM with larger size (PM2.5, PM5, and PM10) while subjects with sneezing, runny nose, or stuffy nose without a cold or flu were exposed to higher concentrations of PM with smaller size (PM0.5 and PM1). Data indicate that inhalation of PM in swine farm workers is associated with increased frequency of respiratory illnesses.

Respiratory symptoms in preterm infants: burden of disease in the first year of life

Objective While respiratory symptoms in the first year of life are relatively well described for term infants, data for preterm infants are scarce. We aimed to describe the burden of respiratory disease in a group of preterm infants with and without bronchopulmonary dysplasia (BPD) and to assess the association of respiratory symptoms with perinatal, genetic and environmental risk factors. Methods Single centre birth cohort study: prospective recording of perinatal risk factors and retrospective assessment of respiratory symptoms during the first year of life by standardised questionnaires. Main outcome measures: Cough and wheeze (common symptoms), re-hospitalisation and need for inhalation therapy (severe outcomes). Patients: 126 preterms (median gestational age 28.7 weeks; 78 with, 48 without BPD) hospitalised at the University Children's Hospital of Bern, Switzerland 1999-2006. Results Cough occurred in 80%, wheeze in 44%, rehospitalisation in 25% and long term inhalation therapy in wheezers in 13% of the preterm infants. Using logistic regression, the main risk factor for common symptoms was frequent contact with other children. Severe outcomes were associated with maximal peak inspiratory pressure, arterial cord blood pH, APGAR and CRIB-Score. Conclusions Cough in preterm infants is as common as in term infants, whereas wheeze, inhalation therapy and re-hospitalisations occur more often. Severe outcomes are associated with perinatal risk factors. Preterm infants who did not qualify for BPD according to latest guidelines also showed a significant burden of respiratory disease in the first year of life.

A prospective study of the impact of air pollution on respiratory symptoms and infections in infants

Rationale: There is increasing evidence that short-term exposure to air pollution has a detrimental effect on respiratory health, but data from healthy populations, particularly infants, are scarce. Objectives: To assess the association of air pollution with frequency and severity of respiratory symptoms and infections measured weekly in healthy infants. Methods: In a prospective birth cohort of 366 infants of unselected mothers, respiratory health was assessed weekly by telephone interviews during the first year of life (19,106 total observations). Daily mean levels of particulate matter (PM10), nitrogen dioxide (NO2), and ozone (O3) were obtained from local monitoring stations. We determined the association of the preceding week's pollutant levels with symptom scores and respiratory tract infections using a generalized additive mixed model with an autoregressive component. In addition, we assessed whether neonatal lung function influences this association and whether duration of infectious episodes differed between weeks with normal PM10 and weeks with elevated levels. Measurements and Main Results: We found a significant association between air pollution and respiratory symptoms, particularly in the week after respiratory tract infections (risk ratio, 1.13 [1.02-1.24] per 10 μg/m(3) PM10 levels) and in infants with premorbid lung function. During times of elevated PM10 (>33.3 μg/m(3)), duration of respiratory tract infections increased by 20% (95% confidence interval, 2-42%). Conclusions: Exposure to even moderate levels of air pollution was associated with increased respiratory symptoms in healthy infants. Particularly in infants with premorbid lung function and inflammation, air pollution contributed to longer duration of infectious episodes with a potentially large socioeconomic impact.

Elevated exhaled nitric oxide in newborns of atopic mothers precedes respiratory symptoms

RATIONALE: Exhaled nitric oxide (NO) is a well-known marker of established airway inflammation in asthma. Its role in the disease process before the onset of respiratory symptoms remains unclear. Objectives: To examine whether elevated NO in newborns with clinically naive airways is associated with subsequent respiratory symptoms in infancy. METHODS: We measured exhaled NO concentration and output after birth and prospectively assessed respiratory symptoms during infancy in a birth cohort of 164 unselected healthy neonates. We examined a possible association between NO and respiratory symptoms using Poisson regression analysis. RESULTS: In infants of atopic mothers, elevated NO levels after birth were associated with increased risk of subsequent respiratory symptoms (risk ratio [RR], 7.5; 95% confidence interval [CI], 1.7-32.4 for each nl/s increase in NO output; p = 0.007). Similarly, a positive association between NO and symptoms was seen in infants of smoking mothers (RR, 6.6; 95% CI, 2.3-19.3; p = 0.001), with the strongest association in infants whose mothers had both risk factors (RR, 21.8; 95% CI, 5.8-81.3; p < 0.001). CONCLUSIONS: The interaction of NO with maternal atopy and smoking on subsequent respiratory symptoms is present early in life. Clinically, noninvasive NO measurements in newborns may prove useful as a new means to identify high-risk infants. Future confirmation of a role for NO metabolism in the evolution of respiratory disease may provide an avenue for preventative strategies.

Association between reported exposure to road traffic and respiratory symptoms in children: evidence of bias

BACKGROUND: Many studies showing effects of traffic-related air pollution on health rely on self-reported exposure, which may be inaccurate. We estimated the association between self-reported exposure to road traffic and respiratory symptoms in preschool children, and investigated whether the effect could have been caused by reporting bias. METHODS: In a random sample of 8700 preschool children in Leicestershire, UK, exposure to road traffic and respiratory symptoms were assessed by a postal questionnaire (response rate 80%). The association between traffic exposure and respiratory outcomes was assessed using unconditional logistic regression and conditional regression models (matching by postcode). RESULTS: Prevalence odds ratios (95% confidence intervals) for self-reported road traffic exposure, comparing the categories 'moderate' and 'dense', respectively, with 'little or no' were for current wheezing: 1.26 (1.13-1.42) and 1.30 (1.09-1.55); chronic rhinitis: 1.18 (1.05-1.31) and 1.31 (1.11-1.56); night cough: 1.17 (1.04-1.32) and 1.36 (1.14-1.62); and bronchodilator use: 1.20 (1.04-1.38) and 1.18 (0.95-1.46). Matched analysis only comparing symptomatic and asymptomatic children living at the same postcode (thus exposed to similar road traffic) showed similar ORs, suggesting that parents of children with respiratory symptoms reported more road traffic than parents of asymptomatic children. CONCLUSIONS: Our study suggests that reporting bias could explain some or even all the association between reported exposure to road traffic and disease. Over-reporting of exposure by only 10% of parents of symptomatic children would be sufficient to produce the effect sizes shown in this study. Future research should be based only on objective measurements of traffic exposure.