A causal relationship between sleep behaviour and osteoporosis: a two-sample reverse-mediated Mendelian randomisation study

Abstract

Abstract Background In recent years, there have been more and more clinical observational studies on sleep behaviour and osteoporosis, but the causal relationship between sleep behaviour and osteoporosis at the genetic level, and whether there are mediating factors between the two is still unclear. Methods From the published GWAS data, seven sleep behaviours were selected as exposure factors: insomnia, sleep time, getting up in the morning, napping during the day, sleep type (early/late rise), narcolepsy and snoring. Bone mineral density of heel (H-BMD), forearm (FA-BMD), lumbar vertebra (LS-BMD) and femoral neck (FN-BMD) were the outcome factors. The causal relationship between low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) was analyzed through Mendelian randomization. Results The results of a two-sample Mendelian randomization study showed that snoring was positively correlated with lumbar bone density (OR = 1.555, 95%CI: 1.189–2.032, P = 0.001). The results of reverse Mendelian randomization showed that lumbar bone density was not the cause of snoring (P = 0.466). Mediating Mendelian randomization studies showed that both LDL cholesterol and triglycerides had mediating effects on sleep behaviour and bone density (OR = 0.92, 95%CI: 0.87–0.98, P = 5.56e-3) (OR = 1.17, 95%CI: 1.09–01.26, P = 3.72e-5). Conclusions Our study shows that snoring is a factor affecting lumbar bone density, and low-density lipoprotein cholesterol and triglyceride play an intermediary role in it. Therefore, correcting snoring and controlling low-density lipoprotein cholesterol and triglyceride index should be included in the clinical regimen for preventing and treating bone mineral density decline.