Daily vasomotor symptoms, sleep problems, and mood: using daily data to evaluate the domino hypothesis in middle-aged women.

OBJECTIVE: The aim of this study was to investigate the relationships among daily reports of vasomotor symptoms (hot flashes and/or sweats), same-day sleep problems, and next-day mood reports in middle-aged women.
METHODS: Fifty-five healthy middle-aged women were recruited to keep daily records for up to 5 years or until menopause. For each participant, the first 252 days of contiguous data with the highest weekly frequency of vasomotor symptoms was selected for the current analyses. Multilevel structural equation modeling was used to test whether changes in daily vasomotor symptom occurrence predicted changes in occurrence of same-day sleep problems and changes in next-day positive and negative mood ratings and whether sleep problems mediated any predictive effect of symptoms on next-day mood.
RESULTS: Controlling for initial depression, daily vasomotor symptoms predicted same-day sleep problems (b = 0.59, P < 0.001) and next-day positive mood (b = -0.07, P < 0.01), although significant direct relationships between vasomotor symptoms and mood were found primarily in women with initial depression scores in the low to moderate range. Sleep problems predicted next-day positive (b = -0.08, P < 0.01) and negative (b = 0.10, P < 0.001) mood more robustly than vasomotor symptoms did.
CONCLUSIONS: Sleep problems predicted worse mood on the following day and accounted for only a small portion of the relationship between vasomotor symptoms and mood. These findings suggest that any effect of vasomotor symptoms on mood may occur largely through a mechanism other than sleep disruption.