Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research
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J. Bone Miner. Res. · Nov 2021
Association of Sleep Traits and Heel Bone Mineral Density: Observational and Mendelian Randomization Studies.
Observational studies have suggested that sleep and circadian disturbances are potentially modifiable risk factors for low bone mineral density (BMD), but the causal relationship is unclear. This study aimed to (i) replicate the findings by examining observational association of sleep traits with low estimated BMD); (ii) examine whether these associations were causal by using Mendelian randomization (MR) analyses; and (iii) investigate potential modulation effects of sex and menopause. A total of 398,137 White British subjects (aged 39 to 73 years) with valid BMD estimated by quantitative ultrasound of the heel (eBMD) at baseline were included. ⋯ Subgroup analyses suggested associations of short/long sleep and definite eveningness with low eBMD among men, short sleep with low eBMD among premenopausal women, and short sleep, eveningness, and daytime sleepiness among postmenopausal women. In bidirectional MR analyses, there was no causal relationship between sleep traits and eBMD in either overall sample or subgroup analyses. In summary, although observational analysis showed a robust association of low eBMD with sleep duration, chronotype, and insomnia, there was no evidence of causal relationship as suggested by MR analysis. © 2021 American Society for Bone and Mineral Research (ASBMR).