Causal roles of educational duration in bone mineral density and risk factors for osteoporosis: a Mendelian randomization study.

ABSTRACT

BACKGROUND: Educational duration might play a vital role in preventing the occurrence and development of osteoporosis(OP). PURPOSE: To assess the causal effect of educational duration on bone mineral density(BMD) and risk factors for OP by Mendelian randomization(MR) study. METHODS: The causal relationship was analyzed using data from genome-wide association study(GWAS). Inverse variance weighting (IVW) was used as the main analysis method. Horizontal pleiotropy was identified by MR-Egger intercept test, MR pleiotropy residual sum and outlier (MR-PRESSO) test. The leave-one-out method was used as a sensitivity analysis. RESULTS: The IVW results indicated that there was a positive causal relationship between educational duration and BMD (OR = 1.012, 95%CI1.003-1.022), physical activity(PA) (OR = 1.156, 95%CI1.032-1.295), calcium consumption (OR = 1.004, 95%CI1.002-1.005), and coffee intake (OR = 1.019, 95%CI1.014-1.024). There was a negative association between whole body fat mass (OR = 0.950, 95%CI0.939-0.961), time for vigorous PA (OR = 0.955, 95%CI0.939-0.972), sunbath (OR = 0.987, 95%CI0.986-0.989), salt consumption (OR = 0.965, 95%CI0.959-0.971), fizzy drink intake (OR = 0.985, 95%CI0.978-0.992), smoking (OR = 0.969, 95%CI0.964-0.975), and falling risk (OR = 0.976, 95%CI0.965-0.987). There was no significant association between educational duration and lean mass, time for light-to-moderate PA, milk intake, and alcohol intake. Horizontal pleiotropy was absent in this study. The results were robust under sensitivity analyses. CONCLUSION: A longer educational duration was causally linked with increased BMD. No causal relationship had been found between educational duration and lean mass, time for light-to-moderate PA, milk intake, and alcohol consumption as risk factors for osteoporosis.