Background: This study was performed to evaluate the time trends in prevalence of asthma and related factors in Denizli, Turkey.
Methods: Two cross-sectional surveys were performed, 6 years apart (2002 and 2008) using the ISAAC protocol, in the 13-14 age groups and comparisons were made between the results.
Results: Lifetime prevalence of wheeze, 12 month prevalence of wheeze, and the prevalence of wheeze after exercise in the previous 12 months were significantly increased respectively from 10.2% to 13.4% (POR = 1.37, 95%CI = 1.18-1.58, p < 0.001), from 5.0% to 6.2% (POR = 1.26, 95%CI = 1.02-1.55, p = 0.016) and from 9% to 10.2% (POR = 1.15, 95%CI = 0.98-1.35, p = 0.046) in 2008 study. Doctor diagnosed asthma prevalence also increased significantly from 2.1% to 12.9 (POR = 6.80, 95%CI = 5.22-8.85, p < 0.001). Prevalence of sleep disturbed by wheeze in the last 12 months; but, never woken with wheezing (POR = 1.62, 95%CI = 1.26-2.09, p = < 0.001) and less than one night per week (POR = 1.58, 95%CI = 1.06-2.36, p = 0.013) were significantly increased in 2008 study. Severe attacks of wheeze limiting speech in the last year was increased from 1.3% to 2.2% (POR = 1.67, 95%CI = 1.14-2.43, p = 0.004). The number of wheeze attacks in the previous 12 months was increased significantly for 4-to-12 attacks (POR = 1.54, 95%CI = 1.03-2.32, p = 0.02) in 2008 study. However, prevalence of waking with cough in the last 12 months did not change. While history of family atopy and domestic animal at home were found as significant risk factors for asthma in 2002 study, male gender, history of family atopy and stuffed toys were found significant in 2008.
Conclusions: The prevalence of asthma symptoms were increased in Denizli. History of family atopy, male gender and stuffed toys were important risk factors for asthma in 2008.