THE NATURAL-HISTORY OF INSOMNIA AND ITS RELATIONSHIP TO RESPIRATORY SYMPTOMS

Background: Although insomnia is a frequent complaint among patients, epidemiologic study has been limited. Researchers have reported a wide range in the prevalence of this complaint in a variety of selected po pulations. Other parameters, such as incidence and remission rates, ha ve not been reported. Methods: Subjects of the Tucson (Ariz) Epidemiol ogic Study of Obstructive Lung Disease were asked questions about trou ble sleeping in the 1984-1985 (survey I) and 1990-1992 (survey II) sur veys. Answers were analyzed along with responses to questions about ag e, sex, respiratory symptoms, and drug and alcohol use for sleep. Resu lts: The prevalence of insomnia was similar in both surveys, 34.4% in survey I and 34.1% in survey II. Women had a higher prevalence of inso mnia than men in both surveys, and insomnia was more common among olde r subjects (50.6% of the women aged 65 years or older had insomnia in survey II). In addition, the incidence of new insomnia in survey II wa s higher in the same groups. Grouping subjects by respiratory symptoms , we found that the prevalence of insomnia was significantly related t o cough, dyspnea, or wheeze. Furthermore, subjects with persistent or new respiratory symptoms at survey II were less likely to have remissi on of insomnia by that survey (31.6% vs 51.5%; P < .05; odds ratio, 0. 43) and more likely to develop new insomnia (28.6% vs 14.5%; P < 05; o dds ratio, 2.36) than subjects with either no symptoms or disappearanc e of their symptoms by survey II. Conclusions: In our population, inso mnia is a common dynamic complaint whose frequency waxes and wanes in association with respiratory symptoms.