Of 496 children , 49 % were male , 299 ( median age 2.5 years [ IQR 1.5-4 .0 ] ) were ART-naive , 109 ( median age 6 years [ IQR 5.5-7 .0 ] ) were ART-experienced and 88 ( median age 2.2 years [ IQR 1.5-3 .0 ] ) were control children .