The health impact of undiagnosed airflow obstruction in a national sample of United States adults

To determine the health and functional impact of undiagnosed airflow obstru ction for subjects in the general population, we used data obtained as part of the Third National Health and Nutrition Examination Survey (NHANES III) . Categories of diagnosed and undiagnosed airflow obstruction were defined using questionnaire responses and spirometric results. Health and functiona l impact of airflow obstruction was assessed from responses to questions ab out general health status, walking 1/4 mile, lifting or carrying something as heavy as 10 lb, or needing help with personal care. Undiagnosed airflow obstruction (12.0%) was more common than doctor-diagnosed chronic obstructi ve pulmonary disease (COPD) (3.1%) or asthma (2.7%). Although undiagnosed a irflow obstruction was usually very mild, approximately 5% of the entire sa mple had an FEV, less than 75% predicted. After adjusting for smoking, obes ity, and comorbid conditions, the risk of impaired health and functional st atus with undiagnosed airflow obstruction was independently associated with severity of FEV, impairment. For males and females, ever smoking was stron gly associated with all types of airflow obstruction, diagnosed or not. How ever, among females with airflow obstruction, 12.2% to 35.2% never smoked. Undiagnosed airflow obstruction is common in the general population of the United States and is associated with impaired health and functional status.