Increased risk of learning disabilities in low birth weight boys at age 11 years.
BACKGROUND
Few studies have examined learning disabilities among low birth weight (< or =2500 g) children, and those that have, have focused on very low birth weight children (<1500 g). We tested the hypothesis that low birth weight increases the risk of reading and math disabilities, examined possible sex differences in the effect of low birth weight, and assessed risk across the entire range of low birth weight.


METHODS
Low birth weight and normal birth weight children were randomly selected from the 1983-1985 newborn lists of an urban and a suburban hospital in southeast Michigan. Children with neurological impairments were excluded. Children were evaluated at age 6 years and at age 11 years. Of the 823 children in the initial assessment, 717 (87.1%) participated in the second assessment. The Wechsler Intelligence Scale for Children--Revised and the Woodcock-Johnson Psycho-Educational Battery--Revised were used to identify children with learning disabilities. Learning disabilities were estimated in 574 children with IQs of > or =85.


RESULTS
Low birth weight was associated with increased risk for reading and math disability in male children (odds ratio = 3.3 and odds ratio = 6.5, respectively) but not in female children. The increased risk of learning disabilities among male children applied to the entire range of low birth weight and was observed in both the urban and suburban communities.


CONCLUSIONS
The effect of low birth weight on learning disabilities appears to be specific to male children. Although this sex-specific effect is consistent with previous findings of a greater vulnerability of male children to pregnancy and birth complications, it remains to be replicated and clarified.
Johnson
E O
EO
Department of Psychiatry, Henry Ford Health Sciences Center, Detroit, Michigan 48202, USA.
Breslau
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N
D001034:Apgar Score; D002391:Catchment Area, Health; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007859:Learning Disabilities / Q000175:diagnosis* / Q000453:epidemiology; D008297:Male; D008433:Mathematics; D008824:Michigan / Q000453:epidemiology; D011247:Pregnancy; D015995:Prevalence; D011932:Reading; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors