Objective: To estimate the prevalence and factors associated with night sweats among adult primary care patients.
Study design: This was a cross-sectional study.
Population: Adult patients in 2 primary care practice-based research networks (PBRNs) during 1 week in the summer and 1 week in the winter in the years 2000 and 2001.
Outcome measures: We measured the prevalence of pure night sweats and night and day sweats in all patients and subgroups defined by age and sex, clinical variables associated with night sweats, and the frequency, severity, and rate of reporting.
Results: Of the 2267 patients who participated, 41% reported experiencing night sweats within the last month, including 23% with pure night sweats and an additional 18% with day and night sweats. The prevalence of night sweats in both men and women was highest in the group aged 41 years to 55 years. In multivariate analyses, factors associated with pure night sweats in women were hot flashes and panic attacks; in men, sleep problems. Variables associated with night and day sweats in women were increased weight, hot flashes, sleep disturbances, use of antihistamines, selective serotonin reuptake inhibitors (SSRIs), and other (non-SSRI, non-tricyclic) antidepressants; in men, increased weight, hot flashes, and greater alcohol use. A majority of patients had not reported their night sweats to their physicians, even when frequent and severe.
Conclusions: Night sweats are common and under-reported. Pure night sweats and night and day sweats may have different causes. With regard to the etiologies of pure night sweats, panic attacks and sleep disorders need further investigation.