Independent predictors for bone loss included lower body mass index ( regression coefficient : hip , -0.18 % and spine , -0.26 % per 1 kg/m ) , longer tenofovir exposure ( hip , -0.74 % and spine , -1.0 % per year ) , greater change in CD4 to week 12 ( hip , -5.11 % per 10-fold higher ) , and higher baseline HIV-RNA ( spine , -0.7 % per 10-fold higher ) .