Impact of switching from zidovudine to tenofovir disoproxil fumarate on bone mineral density and markers of bone metabolism in virologically suppressed HIV-1 infected patients; a substudy of the PREPARE study - Cotter, A G; Vrouenraets, S M; Brady, J J; Wit, F W; Fux, C A; Furrer, H; Brinkman, K; Sabin, C A; Reiss, P; Mallon, P W (J Clin Endocrinol Metab, 2013)