The children of mothers who had diabetes before or during pregnancy have a significantly greater risk of needing lifelong vision correction. A new study in Denmark shows that the children of mothers who have diabetes-related complications have more severe vision problems.
Research in Denmark provides new evidence that prenatal exposure to maternal diabetes may be associated with an increased risk of impaired vision in childhood and young adulthood. The risk of needing corrective lenses doubles if the mother has diabetes-related complications.
The discovery links two of the greatest global health problems – diabetes and impaired vision – and intervening early can have major benefits according to a researcher behind the study.
“Globally, there is a high and rising incidence of impaired vision, including nearsightedness or farsightedness. Further, more and more people are developing diabetes – also during pregnancy. In this study, we found that they are linked, and this provides considerable potential for mitigating a mother’s diabetes and thus her child’s risk of impaired vision. Reducing this risk slightly will mean a great deal in absolute numbers to millions of people around the world,” explains an author behind the study, Yongfu Yu, Postdoctoral Fellow, Department of Clinical Medicine, Aarhus University.
The research has been published in Diabetologia.
Colleagues call the study noteworthy
Jakob Grauslund, Head of Research and Clinical Professor at Steno Diabetes Center Odense, says that the study is important and noteworthy because the children of mothers who had developed diabetic complications had the greatest risk of impaired vision by far.
Jakob Grauslund was not involved in the study, but he is performing research on diabetic eye diseases and has read the study with interest.
“Although diabetes is most often associated with retinopathy, the study shows that diabetes can also cause other – and in this case inherited – eye diseases. Although the study has many strengths – such as including data from all of Denmark with long follow-up – it also has limitations. One is the fact that Denmark’s registries only record a few people with eye diseases, since most people who need corrective lenses only consult opticians and general practitioners. Future studies should therefore also focus on this larger group to get a better impression of whether the results apply to all people with impaired vision or only the few followed up in a hospital,” says Jakob Grauslund.
Nearly 2.5 million births in Denmark included
Yongfu Yu and colleagues examined the Danish Medical Birth Registry. Like other registries in Denmark, it is unique in containing health data on the entire population far back in time. Denmark is one of very few countries that offers researchers access to such complete data on an entire population.
The researchers identified data on 2,470,580 births in Denmark from 1977 to 2016. They then identified how many mothers had type 1, type 2 or gestational diabetes either before or during pregnancy.
They then examined whether the children had refractive error, which means that the shape of the eye or cornea makes vision blurred, resulting in nearsightedness, farsightedness or astigmatism. The follow-up period was until age 25 years or the end of the study.
“A 25-year follow-up period is the longest for this type of study and provides a really good basis for examining the long-term effect of maternal diabetes before and during pregnancy,” explains Yongfu Yu.
Diabetes-related complications especially predispose children to impaired vision
The researchers found that 56,419 children (2.3%) had mothers with diabetes: 0.9% type 1 diabetes, 0.3% type 2 diabetes and 1.1% gestational diabetes.
The researchers also found that the proportion of children born to mothers with diabetes increased from 0.4% in 1977 to 6.5% in 2016.
During the follow-up period of up to 25 years, 553 children of mothers with diabetes were diagnosed with severe vision impairment (high refractive error). This indicates that children of mothers with diabetes had a 39% increased risk of severe vision impairment versus the children of mothers without diabetes.
Complications increase risk
The researchers also found that a child’s individual risk of severe vision impairment increased by 32% for mothers with type 1 diabetes and 68% for mothers with type 2 diabetes.
In addition, the researchers investigated how diabetes-related complications affected the risk of the child being diagnosed with severe vision impairment later in life.
The risk was 105% higher than for the children of mothers without diabetes. The children of mothers with diabetes but without complications only had an 18% increased risk of severe vision impairment.
“Before this study, we did not know whether a mother’s diabetes is associated with her child’s risk of impaired vision, so we were surprised that the association is so clear – especially if the mother has diabetes-related complications. The risk is also increased more than we expected,” says Yongfu Yu.
Maternal diabetes associated with many diseases among children
Yongfu Yu has no validated explanation for why the children of mothers with diabetes have an increased risk of developing nearsightedness or farsightedness, but he speculates that this may be related to the mother’s blood glucose during pregnancy.
If the mother has diabetes and her blood glucose is high, this may affect fetal blood glucose, which can harm the retina and thus lead to developing severe vision impairment later in life.
The researcher says that impaired vision among children is just one disorder associated with maternal diabetes.
The same research group from Aarhus University previously found that maternal diabetes can increase a child’s risk of cardiovascular disease, mental disorders and obesity.
“Maternal diabetes is currently a very hot field. More and more women of reproductive age have diabetes, and more and more children are developing various diseases and disorders such as nearsightedness, obesity and mental disorders. Mitigating this risk by helping mothers to control their blood glucose optimally during pregnancy could also reduce the incidence of many diseases in absolute numbers. This is especially true if mothers also have diabetes-related complications. They should then be monitored at a diabetes clinic to enable her to give birth to a child with as few risk factors as possible,” concludes Yongfu Yu.