Postmenopausal women who report sleeping less than 5 hours per night are more likely to develop low bone mineral density at all major sites and are at increased risk for osteoporosis at the hip and spine, according to findings published in the Journal of Bone and Mineral Research.
“Our study suggests that sleep may negatively impact bone health, adding to the list of the negative health impacts of poor sleep,” Heather Ochs-Balcom, PhD, associate professor in the department of epidemiology and environmental health at the University at Buffalo School of Public Health and Health Professions at the State University of New York, said in a press release. “I hope that it can also serve as a reminder to strive for the recommended 7 or more hours of sleep per night for our physical and mental health.”
In a cross-sectional study, Ochs-Balcom and colleagues analyzed data from 11,084 postmenopausal women aged 50 to 79 years at baseline who participated in the Women’s Health Initiative and underwent DXA measurements at one of three clinical centers (mean age, 63 years; 78% white). Women underwent hip, spine and whole-body DX scans and completed sleep questionnaires (WHI Insomnia Rating Scale) at baseline. Researchers used adjusted linear regression models to examine the associations between usual sleep duration and sleep quality with site-specific BMD measures, and also used multinomial regression models to assess the association between sleep duration and quality with low bone mass, defined as a T-score between –2.5 to –1, and osteoporosis.
Within the cohort, 10% of women reported sleeping 5 hours or less per night and 4.5% reported sleeping 9 hours or more per night. Approximately 33% met the threshold for insomnia.
Postmenopausal women who report sleeping less than 5 hours per night are more likely to develop low bone mineral density at all major sites and are at increased risk for osteoporosis at the hip and spine.
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In adjusted linear regression models, women who reported sleeping 5 hours or less per night had on average 0.012 g/cm2 to 0.018 g/cm2 lower BMD at all four sites compared with women who reported sleeping 7 hours per night. Spine and whole-body BMD values were also on average 0.01 g/cm2 lower for women who reported sleeping 6 hours per night when compared with women who slept 7 hours per night.
In the adjusted multinomial models, women who reported sleeping 5 hours or less per night were more likely to have low bone mass (OR = 1.22; 95% CI, 1.03-1.45) and osteoporosis of the hip (HR = 1.63; 95% CI, 1.15-2.31) compared with women who slept 7 hours per night. Researchers also observed a similar pattern for spine BMD, noting women who slept less than 5 hours per night had higher odds for osteoporosis (adjusted OR = 1.28; 95% CI 1.02-1.6) compared with women who slept 7 hours per night.
Associations between sleep quality and BMD did not reach statistical significance, according to the researchers.
“The associations we identified are modest in terms of the continuous BMD measures when comparing across the different sleep duration categories,” the researchers wrote. “The difference we observed between the 5 hour per night group compared with the reference group was approximately –0.012 to –0.017 g/cm2, which is roughly equivalent to 1 year of aging.”
The researchers noted that the findings provide epidemiologic evidence of sleep as a partially modifiable risk factor for BMD that deserves further replication.
“Prospective studies are needed to evaluate whether sleep duration is associated with BMD loss and the short- and long-term effects of unhealthy sleep patterns on bone health. If studies show that sleep duration has a causal link with bone density, sleep promotion interventions may serve as a way to mitigate bone loss in individuals at high risk of osteoporosis,” they wrote. – by Regina Schaffer
Disclosures: One of the authors reports she has received a grant from Merck.
