Babies born to obese mothers may face an increased risk of dying early from heart problems in their adult life, according to research published last night that paints an alarming picture of the future as obesity-related disease is handed down from one generation to the next.
The comprehensive study looked at nearly 30,000 women who gave birth in Aberdeen, Scotland, between 1950 and 1976 and who were weighed and measured in early pregnancy. When the researchers then searched for death certificates among the nearly 38,000 children - by then aged 34 to 61 - they found that those whose mothers had been obese had a 35 per cent higher chance of dying as a result of cardiovascular disease than the children of normal-weight mothers. Health records showed that they also had a 42 per cent higher risk of being treated in hospital for heart problems.
Experts called for more effort to educate young women who might become pregnant about good eating habits and exercise as the implications of the study became clear. One in five pregnant women in Britain today is obese. If the researchers are right, the UK and other developed nations could face a huge rise in heart disease and early deaths as the children of these obese mothers hit middle age.
Obesity often runs in families and the researchers accept it is hard to separate the effects of growing up in a household where overweight is the norm, an excess of fattening food is available and no one is playing sport.
But, they say, it is well known that premature, undernourished, severely underweight babies run a higher risk of heart problems and cancer. They theorise that babies may also suffer long-term health problems if they receive too much nutrition in the womb. Animal studies show that developmental over-nutrition can cause permanent changes in appetite control and energy metabolism.
At the time that the mothers in the study gave birth, only 21 per cent were overweight and 4 per cent were obese. Now 20 per cent are obese.
"With the rising rates of excess weight among pregnant women, our findings of an association between maternal overweight and obesity and premature death in the adult offspring is a major public health concern," write the authors, Rebecca Reynolds, professor of metabolic medicine at Edinburgh University and colleagues in the British Medical Journal.
Prof Reynolds stressed that their findings should not be used to blame women.
“We don’t want to be blaming anybody at all, just highlighting that we have found an association,” she told said. “Ideally we’d like to understand more about the mechanisms. We want to see whether it is possible to help women planning a pregnancy to be a healthy weight.” She would like greater public awareness that starting pregnancy at a healthy weight was best both for mother and child, she added.
In a BMJ editorial on the study, Dr Pam Factor-Litvak from the department of epidemiology at Columbia University in New York says that the paper leaves open two questions - the effect of the child's environment while growing up and the influence of a father's obesity.
At the moment, she adds, US guidelines recommend that overweight women should not put on more than 5-9kg (11-20lbs) during pregnancy, which is less than the 7-11kg recommended for normal-weight women, but if the study is correct, there needs to be action to help women before they get pregnant.
Dr Tim Chico, consultant cardiologist at Sheffield Teaching Hospitals, said it was a worrying finding.
“It suggests the current obesity epidemic will lead to an increased risk of heart disease even in babies born in the future,” he said. It was unclear whether pregnancy, genes or the environment in early childhood were the issue, but either way, the study emphasised the importance of trying to maintain a healthy weight.
“No parent wants to think that their actions might affect the health of their children, and this is often a powerful motivation to change our behaviour. The message of this study is clear; if a mother is overweight, it may be her children that pay the price.”
Guardian