Birth defects affect one in 17, study finds
Doctor says simple public health measures could prevent 70 per cent of conditionsJan 31, 2006 | www.theglobeandmail.com One in every 17 babies born in the world has a serious birth defect, a hidden epidemic of global proportions, according to a revealing new study.
Almost eight million children annually suffer from a birth defect, including 3.3 million who die and another 3.2 million who live with severe mental and physical disabilities that often condemn them to a life of poverty and suffering.
"This is a serious, vastly unappreciated and underfunded public health problem," said Jennifer Howse, president of the March of Dimes, which commissioned the report.
Birth defects principally involve deformities of the heart and spine, and blood disorders, but as many as 70 per cent of the conditions are preventable with simple public-health measures and basic medical technologies, Dr. Howse said.
While the vast majority of children being born with birth defects are in the developing world, the problem also exists in wealthy, developed countries.
The new report is the first to catalogue the extent of birth defects on a country-to-country basis, and shows that the prevalence ranges from a low of 39.7 per 1,000 live births in France to a high of 82 per 1,000 in Sudan.
Canada ranked 14th among 193 countries, with a prevalence of 45.5 birth defects per 1,000 live births.
Arnold Christianson of the University of Witwatersrand in Johannesburg, South Africa, said the research team identified a staggering 7,000 types of birth defects, though there were five of genetic (or partially genetic) origin that accounted for a large number of the total, including: congenital heart defects; neural-tube defects such as spina bifida; blood disorders such as thalassemia and sickle-cell anemia; Down syndrome and glucose-6 phosphate dehydrogenase deficiency (G6PD).
Dr. Christianson said there are social and environmental factors that also explain why a significant proportion of birth defects occur.
For example, most neural-tube defects are due to dietary deficiencies. Canada has virtually eliminated conditions like spina bifida by fortifying flour with folic acid. Similarly, adding iodine to salt can slash the rate of hyperthyroidism, a leading cause of mental retardation.
Dr. Christianson said consanguineous (blood-relative) marriages greatly increase the risk of birth defects. For example, in the malaria belt, a higher proportion of the population carries one copy of a gene that confers protection against malaria, but also increases the risk of sickle-cell, thalassemia and G6PD. That problem could be curbed with basic genetic counselling, he said.
The risk of having a child with Down syndrome increases with maternal age, and that can be addressed by improving access to birth control, Dr. Christianson said. Even basic vaccinations against conditions like rubella could eliminate grave conditions like congenital rubella syndrome.
The report notes that only about 50 per cent of birth defects are accurately diagnosed, even in wealthy countries.
The new data focus largely on genetic and dietary factors known to cause specific birth defects, because they are easiest to track. But Dr. Christianson noted that there are other social factors like smoking and alcohol use during pregnancy that are taking an enormous toll.