Annette Kainu

FEV1 Response to Bronchodilation in an Adult Urban Population

BACKGROUND Most studies evaluating bronchodilation in flow-volume spirometry have been conducted in patients with obstructive airways diseases, but less is known about bronchodilation responses in the general population or in healthy subjects. METHODS We evaluated an urban population sample of 628 adults (260 men, 368 women) aged 25 to 74 years with flow-volume spirometry using inhalation of 0.4 mg of a salbutamol aerosol with a spacer device for bronchodilation. On the basis of a structured interview, a subgroup of 219 healthy, asymptomatic nonsmokers was selected. RESULTS In the population sample, the average increase in FEV(1) from baseline after salbutamol inhalation was 77.2 mL (SD, 109.7 mL) or 2.5% (SD, 3.9%). In healthy asymptomatic nonsmokers, the mean change in FEV(1) was 62.0 mL (SD, 89.7 mL) or 1.8% (SD, 2.6%). In the whole population, the 95th percentile limit of the increase in FEV(1) was 8.5%, while it was 5.9% among healthy asymptomatic nonsmokers. The absolute change in FEV(1) correlated significantly with baseline FVC (p < 0.01). The FEV(1)/FVC ratio at baseline was the strongest influencing factor for the bronchodilation response. CONCLUSIONS The results indicate that a significant increase in FEV(1) from baseline in a bronchodilation test is around 9% in an urban population. The level of the significant absolute increase in FEV(1) seems to depend on FVC. Low baseline FEV(1)/FVC ratio, reflecting airflow limitation, is the strongest determinant for FEV(1) response to bronchodilation.

COPD in Helsinki, Finland: socioeconomic status based on occupation has an important impact on prevalence

Objectives: Chronic obstructive pulmonary disease (COPD) is globally a major, but often undiagnosed, cause of morbidity and mortality. The aims of this study were to assess the prevalence of COPD in Helsinki, Finland, with international diagnostic criteria and to analyse risk factors including socioeconomic status, and disease severity. Methods: A general population sample of 628 adults (368 women) completed flow-volume spirometry with bronchodilation test and a structured interview. Post-bronchodilation spirometry was assessed both using the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria and relative to the fifth percentile of the reference value (lower limit of normal, LLN). Results: According to GOLD criteria, 37 (5.9%), and by using the LLN criteria, 43 subjects (6.8%) had airway obstruction consistent with COPD. Using the GOLD criteria, four subjects or 0.6% of the population had severe, 3.0% moderate, and 2.2% mild COPD. Of those with post-bronchodilator obstruction, 49% had no previous diagnosis of obstructive airways disease and did not use medication for any respiratory disease. The prevalence of undiagnosed COPD defined by GOLD was 2.9% (LLN 3.3%). In addition to age, smoking history, and prior history of asthma, socioeconomic status based on occupation was significantly related to COPD in the population. Manual workers in industry (GOLD 10.0%, LLN 11.7%) and non-manual assistant employees (10.2%, 10.2%) had a significantly higher prevalence of COPD than professionals (2.8%, 2.3%). Conclusions: Although smoking is the main modifiable risk factor for COPD, the disease was significantly related to manual workers and non-manual assistant employees, i.e. socioeconomic groups reflecting occupation.

Reference values of spirometry for Finnish adults

Diagnostic assessment of lung function necessitates up‐to‐date reference values. The aim of this study was to estimate reference values for spirometry for the Finnish population between 18 and 80 years and to compare them with the existing Finnish, European and the recently published global GLI2012 reference values.

Increase in prevalence of physician-diagnosed asthma in Helsinki during the Finnish Asthma Programme: improved recognition of asthma in primary care? A cross-sectional cohort study

Background: The continuing rise in asthma prevalence has been questioned, with recent reports suggesting a plateau. Aims: To assess a 10-year trend in the age-adjusted prevalence of physician-diagnosed asthma, respiratory and allergic symptoms, and use of asthma medication in the adult population of Helsinki during the Finnish Asthma Programme from 1994 to 2004. Methods: Two cross-sectional postal surveys were conducted among random Finnish National Population Registry samples 10 years apart using the same protocol. A total of 6,062 subjects (75.9%) and 2,449 subjects (61.9%) participated in 1996 and 2006, respectively. Results: The prevalence of physician-diagnosed asthma increased from 6.5% in 1996 to 10.0% in 2006 (p<0.001). This was evident in both genders aged <60 years, but particularly in women aged <40 years, paralleling an increased use of asthma medication. Concurrently, the prevalence of allergic rhinoconjunctivitis increased from 37.2% to 44.4% (p<0.001). The prevalence of physician-diagnosed chronic obstructive pulmonary disease remained unchanged (3.7%), while current smoking abated. Subjects with a smoking history had more respiratory symptoms (p<0.001). Among subjects without physician-diagnosed asthma, those reporting allergic rhinoconjunctivitis had a higher prevalence of lower respiratory tract symptoms. Conclusions: The prevalence of allergic rhinoconjunctivitis and physician-diagnosed asthma has increased in Helsinki during 10 years in adults, especially in women aged <40 years. Concomitantly, the use of asthma medication increased and subjects with physiciandiagnosed asthma were less symptomatic. The increase in the prevalence of physician-diagnosed asthma may partly be due to improved diagnostic recognition of asthma in primary care during the Finnish Asthma Programme, but the concurrent rise in allergic rhinoconjunctivitis may reflect a true rise in prevalence.

Atopic sensitization to common allergens without symptoms or signs of airway disorders does not increase exhaled nitric oxide

Background:  Elevated fractional exhaled nitric oxide (FENO) associates positively with symptomatic atopy among asthmatics and in the general population. It is, however, unclear whether sensitization to common allergens per se– as verified with positive skin prick tests – affects FENO in healthy individuals.

Spirometric and anthropometric determinants of forced expiratory time in a general population

Background:  Forced expiratory time (FET) has gained new interest in the joint recommendation of the American Thoracic Society (ATS) and the European Respiratory Society (ERS) for the assessment of spirometry. Interpretation of FET is, however, difficult as limited information is available on spirometric and anthropometric determinants of FET in populations.

Combined effect of smoking and occupational exposure to dusts, gases or fumes on the incidence of COPD.

Abstract To assess risk factors related to the development of chronic obstructive pulmonary disease (COPD) including smoking and occupational exposure (OE) to dusts, gases or fumes, we performed a longitudinal 11-year follow-up postal survey. The original study population was a random population sample of 8000 inhabitants of Helsinki aged 20 to 69 years in 1996. Participants of the first postal questionnaire were invited to this follow-up survey in 2007 with 4302 (78%) answers obtained. Cumulative incidence of COPD in 11 years was 3.43% corresponding to an incidence rate of 3.17/1000/year after exclusion of those with self-reported physician-diagnosed COPD and ever COPD in 1996. Smoking and age, but not gender, were associated with incident COPD. Reported family history of COPD increased the cumulative incidence to 8.55% vs 3.04% among those without a family history (p < 0.001). In multivariate analysis, significant independent risk factors for incident COPD were: current smoking in 1996 (OR 4.40 [95% CI 2.89–6.71]), age over 50 (OR 3.42 [95% CI 2.22–5.26]), family history of COPD (OR 2.08 [1.27–3.43]), ever asthma (OR 2.28 [1.35–3.86]), and self-reported OE (OR 2.14 [1.50–3.05]). Occupational exposure to dusts, gases or fumes, assessed both based on self-reported exposure and a job exposure matrix using reported professions, was an independent risk factor for incident COPD. Smoking and OE together yielded an additive effect on incidence of COPD.

Repeatability of exhaled nitric oxide measurements in patients with COPD.

The assessment of the presence of eosinophilic airway inflammation may help in predicting the steroid response in subjects with respiratory symptoms. Unlike patients with asthma, only a subset of patients with chronic obstructive pulmonary disease (COPD) benefits from steroid treatment. Fractional exhaled nitric oxide (FENO) is a useful surrogate marker for eosinophilic airway inflammation, but data on the repeatability of FENO measurements in COPD needed for the assessment of significant change are insufficient. The aim of this study was to assess the short‐term repeatability of FENO measurement in subjects with moderate to very severe chronic airway obstruction compared to that in healthy subjects. We studied 20 patients with stable COPD and 20 healthy subjects, and determined FENO (flow rate 50 ml s−1) three times: at baseline, 10 min and 24 h after baseline. Spirometry was performed on the first study day after the FENO measurements. The median FENO concentration in patients with COPD was 15·6 ppb, and in healthy subjects, 15·2 ppb. The coefficient of variation (CoV) for 24‐h measurements was 12·4% in COPD patients, and 15·9% in healthy subjects. Among COPD patients with global initiative for chronic obstructive lung disease stage 2 disease, the CoV was 13·7%, and among those with stage 3–4 disease, 10·5%. The findings indicate that the short‐term repeatability of FENO measurement in patients with moderate to very severe COPD is equally good as in healthy subjects. A change in FENO exceeding 24% is likely to reflect a minimum measurable change in COPD.

Reference values for spirometry - report from the Obstructive Lung Disease in Northern Sweden studies

Background Abnormal lung function is commonly identified by comparing observed spirometric values to corresponding reference values. It is recommended that such reference values for spirometry are evaluated and updated frequently. The aim of this study was to estimate new reference values for Swedish adults by fitting a multivariable regression model to a healthy non-smoking general population sample from northern Sweden. Further aims were to evaluate the external validity of the obtained reference values on a contemporary sample from south-western Sweden, and to compare them to the Global Lung Function Initiative (GLI) reference values. Method Sex-specific multivariable linear regression models were fitted to the spirometric data of n=501 healthy non-smoking adults aged 22–91 years, with age and height as predictors. The models were extended to allow the scatter around the outcome variable to depend on age, and age-dependent spline functions were incorporated into the models to provide a smooth fit over the entire age range. Mean values and lower limits of normal, defined as the lower 5th percentiles, were derived. Result This modelling approach resulted in unbiased estimates of the spirometric outcomes, and the obtained estimates were appropriate not only for the northern Sweden sample but also for the south-western Sweden sample. On average, the GLI reference values for forced expiratory volume in one second (FEV1) and, in particular, forced expiratory vital capacity (FVC) were lower than both the observed values and the new reference values, but higher for the FEV1/FVC ratio. Conclusion The evaluation based on the sample of healthy non-smokers from northern Sweden show that the Obstructive Lung Disease in Northern Sweden reference values are valid. Furthermore, the evaluation based on the south-western Sweden sample indicates a high external validity. The comparison with GLI brought further evidence to the consensus that, when available, appropriate local population-specific reference values may be preferred.

Intra-session repeatability of FET and FEV6 in the general population

Background:  The recent American Thoracic Society/European Respiratory Society spirometry guidelines harmonized quality criteria and included assessment of forced expiratory time (FET) in bronchodilation testing when an isolated significant forced vital capacity (FVC) bronchodilation effect is observed. No consensus exists on the criteria of accepted variability of FET. Forced expiratory volume in 6 s (FEV6) has been suggested to replace FVC, especially in primary care. We examined the variability of FET and FEV6 and its determinants in the general population.