Reference values of spirometry for Finnish adults.

BACKGROUND: 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. METHODS: Spirometry was performed for 1380 adults in the population-based FinEsS studies and for 662 healthy non-smoking volunteer adults. Detailed predefined questionnaire screening of diseases and symptoms, and quality control of spirometry yielded a sample of 1000 native Finns (387 men) healthy non-smokers aged 18-83 years. Sex-specific reference values, which are estimated using the GAMLSS method and adjusted for age and height, are provided. RESULTS: The predicted values for lung volumes are larger than those obtained by GLI2012 prediction for the Caucasian subgroup for forced vital capacity (FVC) by an average 6·2% and 5·1% and forced expiratory volume in 1 s (FEV1) by an average 4·2% and 3·0% in men and women, respectively. GLI2012 slightly overestimated the ratio FEV1/FVC with an age-dependent trend. Most reference equations from other European countries, with the exception of the Swiss SAPALDIA study, showed an underestimation of FVC and FEV1 to varying degrees, and a slight overestimation of FEV1/FVC. CONCLUSION: This study offers up-to-date reference values of spirometry for native Finns with a wide age range. The GLI2012 predictions seem not to be suitable for clinical use for native Finns due to underestimation of lung volumes.

Increase of asthma in adults in northern Finland?--a report from the FinEsS study.

BACKGROUND: According to previous studies, the prevalence of asthma has been lower in Finland than in other Nordic countries. In the present study, we assessed the prevalence of asthma and respiratory symptoms in northern Finland and calculated risk factors for these conditions. METHODS: In November 1995, 7937 randomly selected subjects, 20-69 years of age, in northern Finland were invited to participate in a postal questionnaire survey. Complete answers were received from 6633 subjects (83.6%). RESULTS: Asthma diagnosed by a physician was reported by 6.0%, while 6.3% were using asthma medicines. Asthma was most common in young adults and the elderly. The prevalence of wheezing during the previous 12 months was reported by 19.7%, while wheezing with shortness of breath apart form colds during the previous 12 months was reported by 7.1%. Only small differences between the sexes were found in prevalence of asthma and respiratory symptoms. All symptoms were strongly smoking-dependent. Sixty-three percent of men and 42% of women were current or ex-smokers. Family history of obstructive airway disease was the strongest risk factor for asthma (OR 2.9), while increasing age, smoking, and family history of obstructive airway disease were the most important risk factors for frequent wheeze. CONCLUSIONS: The results indicate that the prevalence of asthma and symptoms associated with asthma in adults in northern Finland is now similar to that observed in Sweden and the other Nordic countries.

Does non-responder bias have a significant effect on the results in a postal questionnaire study?

BACKGROUND AND AIM: In epidemiological questionnaire studies results can be influenced by non-responder bias. However, in respiratory epidemiology this has been analysed in very few recently published papers. The aim of our paper is to assess if the results found in our previous postal questionnaire study in an adult population in Northern Finland were biased by non-response. METHODS: A random sample of 385 persons from the 1,284 non-responders in a previous postal questionnaire study was examined. The same questionnaire as in the original study was again mailed to these persons, and those still not answering were contacted by phone. RESULTS: Totally 183 complete answers (48%) were collected. Lack of interest (56%) and forgetting to mail the response letter (22%) were the most common reasons to non-response. Typical non-responders were young men and current smokers who less frequently reported respiratory symptoms in exercise and asthma than the responders in the original study. Answers collected by phone gave for some questions higher prevalence rates than postal answers. CONCLUSION: Firstly, in this population the response rate (83.6%) in the original study was high enough to provide reliable results for respiratory symptoms and diseases, only the prevalence of current smoking was biased by non-response. Secondly, the methods used for collecting responses in a non-response study may influence the results.

Dependence of cold-related coronary and respiratory symptoms on age and exposure to cold.

Cold causes cardiopulmonary stress often perceived as shortness of breath or chest pain, and causes exacerbation of these symptoms in persons suffering heart or lung disease. We investigated the prevalence of these symptoms and their association with sex, age and cold exposure in a population-based sample of 1,785 persons who lived in three areas of Finland. The exposure to cold was measured by the annual number cold days (mean daily temperature below 0 degree C) in the resident locality and weekly hours spent in the cold in winter. Shortness of breath was 25% and chest pain 52% more common in females than in males, and their prevalence increased by 24% and 77%, respectively, for every 10 years of age. The prevalence of shortness of breath increased by 5% and chest pain by 6% for every 10 cold days in the resident locality, and by 6% and 7% for every 10 hours spent in the cold, respectively. We suggest that environmental cold, measured by the number of cold days throughout the year and weekly hours spent in the cold, may provoke cardiopulmonary symptoms independent of sex and age.