Epidemiological studies of congenital heart defects in the Southeast region of Sweden

• In the most recent analysis of Swedish data on congenital malformations, it appeared that in the county of Östergötland, the prevalence of infants with a diagnosed congenital malformation was higher than in the rest of the country. This observation initiated an effort to make a more complete identification of all infants born with a congenital malformation in that county and to compare it with the other two counties in the Southeast region of Sweden (Jönköping and Kalmar), utilising all the relevant Swedish medical health registers available. A total of 10,171 infants with a congenital malformation of any type were identified in the region: 4,698 infants in Östergötland county (6.2%), and 5,473 in the reference counties (5.4%). A 15% excess malformation risk in Östergötland compared with the two reference counties. Various validations of the register data were undertaken and different types of error were detected. Limb reduction defects seemed to occur more often in Östergötland county and there was an increased risk of cardiovascular malformations in Östergötland county (22%).The next step comprised an exploration of putative risk factors for cardiac defects in the area. Maternal body mass index (BMI) >29 was found to be a significant risk factor for cardiac defects. Maternal diabetes mellitus and maternal use of antiepileptics were associated with an increased risk of cardiac defects in the offspring.To explore if the pregnant women in Östergötland county differed from the women in the reference counties, a comparative analysis of potential risk factors was performed. The only single putative risk factor that could contribute to the excess risk of cardiac defects in Östergötland county was matemal residency in a rural district. Notably, nearly all the potential risk factors studied i.e. spontaneous abortions, involuntary childlessness, maternal disease, high maternal body mass index, matemal medical during use and alcohol use in early pregnancy, parental employment and paternal age were stronger in Östergötland county compared to the reference area. A conceivable explantation is that one or more unidentified factors could activate prevalent and weak teratogenic risk factors for cardiac defects.Drinking water could be such a factor. By using a geographical infmmation system (GIS) it was possible to obtain individual data on drinking water characteristics. An increased tisk of a congenital cardiac defect seemed to be associated with the chlorination procedure, in particular the use of chlorine dioxide, and with increasing total trihalomethane concentration.

Nyckelord

MEDICINE

MEDICIN

Publikations- och innehållstyp

vet (ämneskategori)

dok (ämneskategori)