Using multivariable mendelian randomization to estimate the bmi-independent causal effect of bone mineral density on osteoarthritis. Issue 1 (April 2020) - Hartley, A.; Sanderson, E.; Granell, R.; Paternoster, L.; Zheng, J.; Southam, L.; Zeggini, E.; Gregson, C.L.; Tobias, J.H.