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Aug. 10, 2000 -- A woman having a child after age 35 faces an increased risk for a number of potentially serious problems, including Down's syndrome and other genetic disorders. Now, researchers say having a baby at a later age may also increase the risk of your child developing diabetes.
In a study published in the Aug. 12 issue of the British Medical Journal, researchers from the University of Bristol found that children whose mothers were age 45 or older when they gave birth had more than triple the risk of developing type 1 (insulin-dependent) diabetes compared with babies whose mothers were age 20 or younger at the time of their birth.
Children of mothers who were younger than 45 also had their share of increased risks. Other studies have hinted before at a connection between older age of the mother and the child's risk of diabetes, but the new study goes one step further by showing a 25% increase in risk for every five years after age 20 that a woman gives birth. Men fathering children later in life were also more likely to have a child who developed diabetes, and the risk for men was increased 9% for every five-year increase in age.
"The difference between our study and others is that we've actually seen a continuous increase in risk all the way up from age 20," lead author Polly J. Bingley, MD, tells WebMD. "We haven't just found that it's the very old mothers that are at risk."
Bingley's study involved 1,375 families in which one or more children had type 1 diabetes. The average age at diagnosis was 10.5, but some were diagnosed as young as approximately 5 months or as late as 28 years old.
In families with multiple children, the firstborn had the highest risk of diabetes. The risk decreased about 15% per child for each subsequent brother or sister. Boys had a significantly greater risk than girls -- about 21% higher risk overall.
As for the risk associated with the father's age, Bingley says that finding is intriguing because it suggests that the risk may be highest for children of couples where both the mother and father are older.
Along with the already known increase in women having children later in life than ever before, the findings may offer a possible explanation for the rise in rates of type 1 diabetes. In some countries, the rate of insulin-dependent diabetes is four times higher than it was in the 1950s.
According to the Juvenile Diabetes Foundation, 35 children are diagnosed with type 1 diabetes each day. Signs and symptoms may include excessive thirst, constant hunger, and excessive urination; sudden unexplained weight loss; rapid, hard breathing; sudden vision changes or blurry vision, drowsiness or exhaustion; or a fruity odor to the breath.
Bingley says the mother's immune system may play a role in increasing her child's risk.
"We know that the interaction between the unborn child and the mother's immune system is very complex and so we would speculate that that is one possible reason," she says. "It's obviously something that is not genetically determined that we're seeing, something that's happening while the baby is in the uterus."
But a diabetes expert who commented on the study for WebMD cautions against making too much of the findings.
"To some extent, it raises interesting questions, but doesn't necessarily provide the final answer," says Robert Goldstein, MD, PhD, chief of scientific affairs for the Juvenile Diabetes Foundation.
"It's not the first time this has been alleged, and they have not answered the question of why that is."
Goldstein says that while the immune system may play a role, the British team did not actually evaluate the immune systems of mothers and babies in the study, so it is difficult to draw strong conclusions or to rule out other factors that could be involved, such as genetics and the environment. He says further studies are needed to determine if older moms have age-related abnormalities of their immune system that may get passed on to their child.