Risk factors for cardiovascular malformations in Finland

Abstract

The possible effects of genetic and environmental risk factors during pregnancy on the occurrence of cardiovascular malformations in the offspring was studied in 408 cases and 756 controls. The cases represented all registered cardiovascular malformations reported in Finland during 1982-1983. The controls were randomly selected from all babies born during the same period. Both the case and control mothers were interviewed by midwives approximately three months after delivery using a structured questionnaire. The parents of cases had more cardiovascular malformations than parents of the controls. Maternal alcohol consumption seemed to double the risk of atrial septal defect (OR = 1.9, CI95 1.0-3.4). Maternal exposure to dyes, lacquers or paints was a significant risk factor for conal septal defects (OR = 2.9, CI95 = 1.2-7.5). Maternal upper respiratory infection was twice as common among the hypoplastic left ventricle group as among the controls. Maternal smoking, coffee, tea and cola consumption and intake of acetylsalicylic acid were equally prevalent in both groups. Maternal exposure to anesthetic gases, wood preservatives or pesticides was not associated with the risk of cardiovascular malformations. The study confirms that very little is known of the etiology of congenital heart disease.

Association Between Maternal Chronic Conditions and Congenital Heart Defects

“…Our findings of associations between maternal chronic illnesses such as congenital heart disease and systemic connective tissue disorders and CHD were also in line with previous studies. 8,14,15,29,38 In addition, we observed that preexisting hypertension among mothers posed an elevated risk of certain subtypes of CHD. We also observed an association between maternal cigarette smoking and CHDs as in previous studies, 39,40 and the association was specific to particular subtypes of CHD.…”

“…An even smaller portion can be attributable to known environmental factors such as maternal rubella infection, although a few studies suggest that the fraction of cases attributable to identifiable factors may be as high as 30% for some types of heart defects. [12][13][14] Nevertheless, CHD prevention has been hampered by a limited understanding of modifiable risk factors.…”

Noninherited Risk Factors and Congenital Cardiovascular Defects: Current Knowledge

“…6 The National Public Health Institute in Helsinki retrospectively conducted a study in Finland of cases and controls born during 1982 to 1984. 7 In both of these casecontrol studies, information on potential exposures early in pregnancy was obtained by interview of the parents after the child was born. There were no available reliability or validation studies of the parental reports.…”

“…Reports of exposure to degreasing or other solvents have been associated with an increased risk of hypoplastic left heart syndrome, coarctation of the aorta, pulmonic stenosis, transposition of the great arteries with intact ventricular septum, tetralogy of Fallot, total anomalous pulmonary venous return, nonchromosomal atrioventricular septal defects, and Ebstein's anomaly. 6 Maternal reports of occupational exposure to organic solvents have been associated with an increased risk of VSDs 119,175 ; dyes, lacquers, and paints with conotruncal malformations 150 ; and mineral oil products with coarctation of the aorta. 176 Herbicides, Pesticides, and Rodenticides A study suggesting an association of maternal employment in the agricultural industry with an increased risk of conotruncal defects 36 suggested a possible association with chemicals used in agriculture.…”

“…In this review, most of the findings on risk factors come from case-control studies, and the best available information comes from 2 large population-based case-control studies specifically designed to investigate risk factors for congenital heart disease in an exploratory manner: the BWIS conducted in the Baltimore-Washington area between 1981 and 1989 6 and the study conducted in Finland by the National Public Heath Institute in Helsinki of cases and controls born during 1982 to 1984. 7 Although these larger, population-based studies used standardized methods for ascertaining and classifying cardiac defects, control selection, and methods to minimize potential biases and confounding, the above methodological issues may still be present. Therefore, the consistency of the findings from among multiple well-designed studies is particularly important.…”