Adjusting for pre-ART level , lower @-month gain in CD@ % was associated with later walking ( @ months earlier per unit increase in CD@ % ; P = @ ) and speech ( @ months earlier per unit increase in CD@ % ; P = @ ) , and lower @-month gains in weight-for-age ( P = @ ) , height-for-age ( P = @ ) and weight-for-height ( P = @ ) were associated with later walking .