08/13/2013 06:48 EDT | Updated 10/13/2013 05:12 EDT

Children of obese mothers face heart risk in midlife

Children of obese and overweight women have a higher risk of premature death from heart attacks and other cardiovascular events, a new study suggests.

Maternal obesity is known to be associated with harmful outcomes for the child at birth, such as fetal distress and increased risk of obesity, hypertension and metabolic disorders later in life.

Now Scottish researchers say maternal obesity also increases the risk of premature death and hospital admission for cardiovascular events such as heart attack, stroke and angina, based on a study of 37,709 people who were followed since their birth in Aberdeen in 1950 to now.

Of the mothers in the study, 21 per cent were overweight and four per cent were obese. About 20 per cent of Canadian women of childbearing age are obese, according to Health Canada.

The researchers found that the risk of dying from any cause was 35 per cent higher in those born to obese mothers compared with those whose mothers were normal weight, after accounting for factors such as the mother's age at delivery, number of previous pregnancies, the mother and father's social class, and infant sex, birth weight and gestation at delivery.

"Our results are important, indicating that the offspring of obese mothers are a high-risk group who should be assessed for cardiovascular risk, and actively encouraged to maintain a healthy lifestyle," Rebecca Reynolds, a professor of metabolic medicine at the University of Edinburgh and her co-authors concluded.

"This could avoid perpetuation of an intergenerational cycle of obesity."

The researchers noted that they couldn't separate out the direct effects of maternal obesity on the developing child from the shared genetic and lifestyle influences after birth, such as clustering of unhealthy diets and lack of exercise in families.

Both the researchers and a journal commentator said the findings point to an urgent need for strategies to prevent obesity in women of childbearing age.

The study is the first to describe associations between maternal obesity and risk of cardiovascular illness and death in mid-life, Pam Factor-Litvak, a professor of epidemiology at Columbia University in New York said in the commentary.

Factor-Litvak said two open questions remain: what is the role of the early postnatal environment and what is the role of parental obesity?

As for biological explanations of how maternal overnutrition might contribute, Factor-Litvak pointed to changes in metabolic programming in offspring from increased exposure to glucose, lipid and inflammatory molecules in the womb.

The study's authors did not have information on paternal obesity, which another British study suggests could also matter. The researchers called for more work in animal models to understand how prenatal effects of maternal obesity differ from environmental effects after birth.

The research was funded by grants from Scotland's Chief Scientist Office, Chest, Heart & Stroke Scotland, Tommy's and the British Heart Foundation.