Asthma deaths in Washington State, 1980-1989: Geographic and demographic distributions

Background: Asthma prevalence and mortality rates have been increasing for the past two decades for reasons that are not definitively known. Few studies of asthma mortality rates have concentrated on subnational regions, such as individual states. Objective: To determine geographic and demographic patterns of asthma mortality in Washington State during 1980 through 1989 and to compare aggregated data with patterns of chronic bronchitis mortality. Methods: Age-adjusted mortality rates for asthma and chronic bronchitis were calculated from 1480 through 1989 for all age groups. Rates were then disaggregated by county,gender, age, and race. Rates were calculated from death certificates listed by the Washington State Center for Health Statistics as either asthma (ICD9-493) or chronic bronchitis (ICD9-490 and 491) and census data. Results: During the period 1980-1989, age-adjusted mortality rates for asthma increased by 15% while those for bronchitis decreased by 43%. There was no consistent geographic pattern in the increase, though one county with a very small population had the highest rate of increase. Female asthma mortality rates increased during the decade, while male asthma mortality rates and both male and female bronchitis rates decreased. Two populations demonstrated pronounced increases in asthma mortality rates: females between ages 40 and 69 years and non-whites. Conclusions: While increased asthma mortality rates have been noted elsewhere for non-whites, this is the first study to demonstrate elevated mortality rates for middle aged women. The explanation for this remains a mystery.