Asthma prevalences in 1975 were consistent with those of previous studies in Finland and Sweden. The present study detected only a slight rise in the prevalence of asthma during 1975 to 1990, whereas a Finnish study on conscripts showed as high as a sixfold increase in recent decades. The age distribution of our study group differed from that of Haahtela et al, because our data included no young adults 30 years old in prevalence calculations. Thus, the greater rise in asthma prevalence of other studies is probably because of an increase among children and young adults. Moreover, our prevalence figures are based on subjects aged 30 to 59 years old at the time of each survey, and thus on different subjects from our incidence analysis. Canadian pharmacy viagra

Cumulative incidence provides an estimate of the probability, or risk, that an individual will develop a disease during a specified period of time. The probability of developing asthma during the 15-year period was approximately 2% for both men and women, but risk was dependent on age, even though all subjects were adults. Thus, on average, 1.6 new asthma diagnoses were made annually per 1,000 adults, which is consistent with the annual age and sex adjusted incidence for definite asthma (1.38/ 1,000) in the study of Yunginger et al and with the standardized incidence (2.10/1,000/yr) found by McWhorter et al. The probability of being diagnosed with hay fever during the same period was higher, with men having a risk of almost 10% and women, 13.6%, although age had no effect. This means that annually there is an average of six new hay fever diagnoses among 1,000 adult men and nine among 1,000 adult women.

The increase in asthma incidence between 1976 to 1981 and 1982 to 1990 was more obvious among men than women, although neither was statistically significant; at the same time the incidence of chronic bronchitis decreased. It is possible that these trends are partly because of changes in diagnostic criteria, especially among men, with a preference for an asthma diagnosis. Atopy is found to be a predisposing factor for chronic bronchitis, but allergic Kamagra Australia subjects with symptoms such as cough and phlegm are more likely to be considered as asthmatics than chronic bronchitis sufferers. One reason is that in Finland the costs of asthma medication have been better subsidized by the Social Insurance Institution of Finland throughout the whole study period, whereas medication costs for chronic bronchitis have been included in this higher subsidy category only since 1986.