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Is It Hot in Here, or Is This Insomnia?

Insomnia symptoms increased significantly with severity of hot flashes.

Several studies have found that being female is a risk factor for insomnia, possibly because women are more likely to develop depression and anxiety disorders (both commonly associated with sleep disturbances) and because sleep problems might emerge secondary to reproductive cycle–related changes. Among other factors, the association between menopause and insomnia has been attributed to the occurrence and severity of nocturnal hot flashes because they may interrupt sleep. However, studies of this association have yielded conflicting results.

To determine whether hot flashes (occurring at least 3 days per week in the prior month) are associated with insomnia symptoms (occurring at least 3 days per week for the past 6 months), researchers of this study (supported by a manufacturer of hormone therapy) interviewed a random sample of 3243 California adults by telephone; 982 met the eligibility criteria (women aged 35 to 65). Investigators used Sleep-EVAL computer software to interview participants about items such as sleep habits/disturbances, medical problems, sociodemographic information, menopausal status, and presence and severity of hot flashes.

Using World Health Organization definitions, 562 women were premenopausal, 219 were perimenopausal, and 201 were postmenopausal. One third reported having hot flashes, with the highest prevalence among perimenopausal women (79.0%), followed by postmenopausal (39.3%) and premenopausal women (12.5%).

After adjusting for variables such as marital status, occupation, race/ethnicity, perceived health quality, BMI, chronic pain, and depressive symptoms, chronic insomnia was significantly associated with increased severity of hot flashes; more than 80% of midlife women with severe hot flashes reported insomnia. Other factors such as chronic pain, sleep apnea, and perception of poor health were also associated with sleep problems.

Comment: Despite the limitations of self-reported data, this study clearly contributes to a better understanding of the role of hot flashes in chronic insomnia — a condition that significantly affects quality of life and overall functioning. The authors acknowledge the other factors that contribute to altered sleep in midlife women, but the association with hot flashes is unequivocal. Careful assessment and, if appropriate, pharmacologic management of hot flashes should become routine when midlife women present with sleep complaints.

— Claudio N. Soares, MD, PhD

Published in Journal Watch Women's Health October 12, 2006

Citation(s):

Ohayon MM. Severe hot flashes are associated with chronic insomnia. Arch Intern Med 2006 Jun 26; 166:1262-8.

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