Prevalence and persistence of sleep complaints in a rural older community sample: the MoVIES project.

Abstract

To determine the prevalence and 2-year persistence of subjective sleep complaints in a rural older population. A prospective epidemiological study of an age-stratified random community sample. The mid-Monongahela Valley, a rural area of Southwestern Pennsylvania. A total of 1050 individuals with a mean age of 74.4 years (range, 66-97; SD = 5.5); 57.2% were women. Subjective responses to questions about sleep complaints, classified as "never" experienced versus "sometimes" or "usually"; these questions reflected difficulty falling asleep (DFA), sleep continuity disturbance (SCD), early morning awakening (EMA), and uncontrollable daytime somnolence (DaSom). Subjects were also asked about snoring. Frequencies of these complaints were used to calculate their prevalence; those who remained in the study 2 years later were asked the same questions again to determine the persistence of sleep complaints. On the first occasions, subjects were also asked for "usual" estimates of how long they took to fall asleep, how many times they wakened during the night, and how many hours of sleep they obtained per night. With regard to prevalence, 385 (36.7%) subjects reported DFA, 301 (28.7%) reported SCD, 201 (19.1%) reported EMA, and 198 individuals (18.9%) reported DaSom. Of those who knew whether they snored, 334 (40.0%) reported snoring loudly during sleep. Within the age range of this group, age was not associated with complaints of insomnia or somnolence; however, older age was associated with a significantly lower prevalence of snoring (P < .001). All three insomnia complaints were significantly more common among women (P < .001). Snoring was significantly more common among men (P < .005), but there was no gender difference in DaSom. With regard to subjective estimates, of those reporting DFA, 49.2% reported that sleep latency exceeded an hour; of those reporting SCD, 26.2% reported waking three or more times per night; and of the entire sample, 11.8% reported 5 hours or less, whereas 12.7% reported 9 to 12 hours, of sleep per night. Approximately 2 years later, among those who had reported insomnia previously and participated in the follow-up wave, the persistence of DFA was 74.9%, that of SCD 68.9%, that of EMA 47.3%, and that of known snoring was 59.6%. The persistence of DaSom, however, was only 5.7%; only DaSom was significantly (P = .049) associated with mortality. Sleep complaints were common among these older individuals. Because these data were collected prospectively, they also provide objective evidence that insomnia is relatively persistent or chronic among older adults. This finding has implications for the diagnosis and long-term management of sleep disorders in older people. Derivation from a random community-based sample rather than from samples of patients or volunteers makes these data more generalizable to the general older population. Finally, these data describe a rural older populations, a group which, in general, is medically underserved and understudied.