tokens: Bronchopulmonary dysplasia ( BPD ) and an exclusive formula feeding showed a 2.8 - 4.6 - fold higher risk ( 95 % Confidence Interval : Mental Developmental Index 1.73 - 7.58 ; Psychomotor Developmental Index 1.44 - 14.54 ; body length 1.20 - 6.41 ) for developmental deficits ( mental and psychomotor developmental index ; body length ) .