Autism and associated medical and familial factors: A case control study

To systematically review medical and familial conditions in autistic subjects (AU) as compared to other developmentally disabled controls (DD). Data was gathered prospectively for 102 AUs and 106 DDs who were comparable for age, sex, and nonverbal intelligence. Chi-square and t test analyses were used to evaluate the data collected for AUs and DDs. Demographic data for AUs and DDs was similar for age, sex, and nonverbal IQ scores. The only statistically significant demographic differences were higher educational levels in mothers of AUs and increased number of firstborn AUs. Family history data revealed a greater number of reported maternal learning disabilities for DDs and increased paternal mental retardation for AUs but no differences in familial medical or psychiatric disorders. No prenatal or perinatal risk factors were identified in the AU group although increased alcohol use during pregnancy and decreased gestational age was found in the DD group. Review of developmental and behavioral issues revealed delayed toileting, tantrums, strong food preferences, and preoccupations to be significantly increased in AUs as compared to DDs. No significant differences were noted between the two groups in health problems or doctor visits. However, AUs had significantly larger mean head size than DDs. This study confirmed several previously established findings in autism including 4 to 1 male prevalence, increased head size, strong food preferences, and lack of prenatal/perinatal findings specifically associated with autism. However, the data suggested no increased prevalence of health problems among AUs or their family members compared to DDs. Several biologic interventions and etiologic theories of autism have been based on the assumption of medical differences in this population, an assumption called into question by current data.