At 28 months , obesity prevalence in boys was decreased -2.36 % in the intervention group ( from 9.59 % to 7.23 % ) and increased 2.03 % ( from 7.40 % to 9.43 % ) in the control group ; the difference was 4.39 % ( 95 % CI 3.48 to 5.30 ; P = 0.01 ) .