Hot flashes, insomnia, and the reproductive stages: a cross-sectional observation of women from the EPISONO study

Abstract

Study Objectives: To investigate the association of hot flashes and insomnia in women in premenopause and postmenopause. Methods: The study was performed using data from the São Paulo Epidemiological Sleep Study. Women in premenopause were classified as having regular menstrual cycles, being anovulatory, or using hormonal contraceptives. Women in menopause were classified as being in perimenopause, early postmenopause, or late postmenopause. Women reporting frequent insomnia symptoms and relevant daytime complaints were classified as having insomnia disorder. Polysomnography alterations suggestive of insomnia were also identified. Results: The frequency of hot flashes was 42% among women in postmenopause (mainly in early postmenopause) and 9% among women in premenopause (mainly anovulatory; P < .01). Approximately 18.7% had insomnia disorder, 48% had isolated insomnia symptoms, and 32.4% had polysomnography alterations. Comparing women in menopause with those in premenopause, the diagnosis of insomnia was similar (premenopause: 18.9% vs menopause: 17.5%), but women in menopause had more frequent isolated insomnia symptoms (premenopause: 43.9% vs menopause: 55.9%; P = .02) and polysomnography correlates of insomnia (premenopause: 26.5% vs menopause: 42.6%; P < .01). Hot flashes were more frequent among women with insomnia disorders (25.5%) and with isolated insomnia symptoms (23.0%) when compared with good sleepers (12.6%) in the entire sample (P = .01). Among women in late menopause, the prevalence of hot flashes was higher in both women with insomnia disorders (42.1%) and with isolated insomnia symptoms (37.5%) when compared with women who were good sleepers (14.3%; P = .05). Conclusions: Hot flashes are associated with insomnia and polysomnography alterations suggestive of insomnia. The prevalence of hot flashes among women with insomnia disorder is especially high among women in late postmenopause.