Smoking ‘robs babies of heart disease protection’

WOMEN who smoke during pregnancy rob their children of a key protection against heart disease, research has shown.

Babies of smoking mothers undergo changes in the womb that lead them to have lower levels of “good” cholesterol.

Known as high-density lipoprotein (HDL), “good” cholesterol helps prevent damage to arteries, and heart disease.

The better-known “bad” cholesterol, low-density lipoprotein (LDL), has the opposite effect.

Scientists found that smoking during pregnancy reduced blood levels of HDL in eight-year-old children by about 0.15 millimoles per litre (mmol/L).

It is a large enough drop to have a significant effect, resulting in a 10%-15% greater risk of heart disease, the researchers believe.

The study involved examining the arteries and cholesterol levels of 405 healthy eight-year-olds who had been part of a trial that looked at asthma and allergies.

Researchers collected data before the children were born and as they grew up, including information about mothers’ smoking habits before and after pregnancy.

They discovered that mothers’ smoking had an effect that remained significant after adjusting for a range of factors that might have influenced the results.

These included exposure to tobacco smoke after birth, duration of breastfeeding, sedentary lifestyle and body weight.

The findings were published in the European Heart Journal.

Study leader Professor David Celermajer, from the University of Sydney, Australia, said: “Cholesterol levels tend to track from childhood to adulthood, and studies have shown that for every 0.025mmol/L increase in HDL levels, there is an approximately 2%-3% reduction in the risk of coronary heart disease.

“If we extrapolate this, we can suggest that the difference of 0.15mmol/L between children of smoking mothers versus non-smoking mothers might result in a 10%-15% higher risk for coronary disease in the children of smoking mothers. This is an approximation only, but the best one we have.”

The scientists pointed out that about 15% of women in many Western countries still ignored the health warnings about smoking while pregnant.

The findings were important since HDL played a vital role in protecting against atherosclerosis, the build-up of hard fatty deposits on artery walls.

Prof Celermajer said: “Children born to mothers who have smoked during pregnancy will need to be watched particularly carefully for other coronary risk factors, like high blood pressure, high LDL ‘bad’ cholesterol levels, and especially cigarette smoking themselves.

“The only ways to increase HDL levels are regular exercise and with the use of certain medications such as niacin. We will have to do long-term follow-up to see if these particular children continue to have lower HDL cholesterol levels than normal, but one should presume that this risk factor might indeed be persistent.”

Senior cardiac nurse Amy Thompson said: “This Australian study found that the children of women who smoked during pregnancy had lower levels of HDL, the ‘good’ type of cholesterol. But it’s not clear why.

“More research is needed to reveal the biological mechanics behind this link.

“However, mothers-to-be should not wait for this. Smoking during pregnancy poses many other well-established risks to women and their unborn babies, and this study adds to that evidence. Stopping smoking has huge health benefits, so if you smoke and are pregnant, or plan to be, contact your GP for advice and support to help you quit.”