Heart birth defects linked to neighbourhood poverty, pollution

By Marie McCullough

PHILADELPHIA — While the causes of congenital heart defects are often unclear, a new California study shows that poverty and pollution are risk factors.

The findings bolster previous research, and have implications for Philadelphia, the nation’s poorest big city, where many neighbourhoods carry the toxic legacy of their industrial pasts.

Preliminary data from the California study will be presented on Monday at the American Heart Association’s annual meeting, being held in Philadelphia November 16-19.

Congenital heart defects — the most common birth defects — are structural abnormalities that arise in the heart or nearby blood vessels as a foetus is developing. Among newborns, the incidence of these defects has been reported in studies to range between 4 and 10 per 1,000 births.

After troubled breathing sent her to the ER, she discovered a lifelong heart condition she didn’t know she had. Although some abnormalities are minor and others can be surgically corrected, an estimated 1.3 million Americans are living with chronic cardiovascular problems stemming from the defects.

Mother of baby born with congenital heart defect to others: “You are not alone.”

The new study, led by scientists from University of California, San Francisco, mined a large California population database to get six years of health and demographic data for more than 2.4 million newborns and their mothers. The overall incidence of serious heart defects was relatively low — 3.2 per 1,000 births.

The team used census and state data to drill down to the neighbourhood level, assessing socioeconomics — occupation, education, and wealth — and exposure to pollutants.

In the poorest neighbourhoods with the worst environmental pollution — where 10 per cent of state residents live — the odds of a baby being born with a heart defect were almost 40 per cent higher than in the wealthiest, cleanest neighbourhoods. Even in the least polluted neighbourhoods, low socioeconomic status was linked to about a 23 per cent increase in heart birth defects.

Genetics plays a role in congenital heart defects, but so do mothers’ health problems and habits. Previous studies have found that diabetes, hypertension, smoking and drinking during pregnancy increase the risk of such defects. Economically disadvantaged children are also at higher risk of dying of problems related to heart birth defects, a study published earlier this year found.

“Basically, it’s not social deprivation itself that increases the risk of congenital heart defects, but other factors that occur as a result of social deprivation,” said lead researcher Shabnam Peyvandicq, a UCSF professor of paediatrics, epidemiology and statistics.