Stabilization of an increasing trend in physician-diagnosed asthma prevalence in Saskatchewan, 1991 to 1998

Abstract

Objectives: To determine the prevalence of asthma, bronchitis, and COPD using the physician services database of the Saskatchewan Health Department from 1991 to 1998.

Design: Descriptive population-based study.

Setting: The Province of Saskatchewan, Canada.

Participants: Residents of Saskatchewan covered by universal health care in the province.

Results: In all age groups, asthma prevalence increased between 1991 and 1995 and either was stable or declined between 1996 and 1998. Preschool children had the highest asthma prevalence during the study period, followed by children aged 5 to 14 years, young adults aged 15 to 34 years, and adults aged 35 to 64 years. Children aged 0 to 4 years and adults aged 35 to 64 years in the Registered Indian population had greater asthma prevalence than persons in other urban or rural populations during the study period. Asthma prevalence rates in rural populations were less than or similar to the rates of urban populations in all age groups during the study period. The prevalence of bronchitis was greater in the Registered Indian population than in urban and rural populations in all age groups throughout the study period. When persons who had visited a physician for bronchitis were excluded from the prevalence calculation, the original increases seen in asthma prevalence among very young children and older adults of Registered Indian origin disappeared, with the urban population having greater asthma prevalence in all age groups. In the Registered Indian population, adults aged 35 to 64 years had almost twofold increases in the prevalence of COPD in comparison to other Saskatchewan populations.

Conclusions: Asthma prevalence, which had been on the increase in the 1980s and early 1990s, was either stable or declining during the latter part of 1990s in Saskatchewan. Preschool children and older adults from the Registered Indian population had greater asthma prevalence than did those from other Saskatchewan populations. Asthma prevalence among the rural populations was either similar or lower in comparison to the rates for the urban populations in all age groups during the study period. Further research is required to elucidate the findings in this study.