Adjusting for pre-ART level , lower 6-month gain in CD4 % was associated with later walking ( 0.18 months earlier per unit increase in CD4 % ; P = 0.004 ) and speech ( 0.12 months earlier per unit increase in CD4 % ; P = 0.05 ) , and lower 6-month gains in weight-for-age ( P = 0.009 ) , height-for-age ( P = 0.03 ) and weight-for-height ( P = 0.02 ) were associated with later walking .