Diabetes during pregnancy increases MS risk in adult children: Norway study
People born unusually large also more likely to develop the disease
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- Maternal diabetes during pregnancy doubles the risk of MS in adult offspring.
- Large birth weight increases multiple sclerosis risk; small birth weight decreases it.
- More research is needed to understand these early-life factors and their mechanisms.
People whose biological mothers had diabetes during pregnancy are more likely to develop multiple sclerosis (MS) as adults, according to a new study from Norway.
The study also found that MS risk is heightened among people who were born unusually large, while babies who were abnormally small at birth have a lower risk of MS over the course of their lifetime.
“In this cohort study of national registry data, exposure to maternal diabetes and birth as [large for gestational age] were associated with a higher risk of adult-onset MS, whereas being born [small for gestational age] was associated with a lower risk compared to [appropriate for gestational age],” researchers wrote.
The study, “Maternal Pregnancy Outcomes and Offspring Risk of Adult-Onset Multiple Sclerosis,” was published in JAMA Neurology.
Data collected on more than 1.3 million pregnancies
MS is a chronic disorder marked by abnormal inflammation that damages healthy cells in the brain and spinal cord. Although several MS risk factors have been identified, the causes of MS are still incompletely understood.
Epidemiological studies have indicated that certain health issues occurring in a mother during pregnancy are associated with an increased lifelong risk of some metabolic disorders for the baby. But there hasn’t been much research into whether maternal issues during pregnancy are associated with lifelong MS risk for the baby.
To gain further insight into this matter, a team of scientists first used national databases to collect data on the pregnancies of more than 1.3 million babies born in Norway between 1967 and 1989. Using other national health databases from the 2000s and 2010s, the researchers then identified which of these individuals developed MS as adults and ran statistical tests to identify pregnancy factors significantly associated with the risk of MS in adulthood.
Results showed that babies whose biological mother had diabetes during pregnancy were more than twice as likely to develop MS. This included common preexisting forms of chronic diabetes like type 2, as well as gestational diabetes, a temporary form of diabetes that can develop during pregnancy.
Data also showed that babies who were above the 90th percentile for birth weight at their gestational age were approximately 13% more likely to develop MS as adults, compared with children who were between the 10th and 90th percentiles of birth weight. Conversely, children below the 10th percentile at birth were at significantly reduced risk of adulthood MS, by about 12%.
Maternal diabetes may cause lasting immune changes in babies
While the mechanisms for these associations remain unclear, the researchers said one hypothesis is that maternal diabetes may cause lasting immune changes in the baby that increase the susceptibility to MS. Alternatively, the high blood sugar from maternal diabetes may lead to a higher birth weight, which may increase the risk of MS by triggering chronic inflammation or lowering vitamin D levels.
Other pregnancy and birth-related factors, inlcuding being born preterm, having a mother with high blood pressure during pregnancy, or having the placenta separate from the uterus before birth, were not significantly associated with MS risk in the researchers’ models.
While it is well established that children with high [body mass index, a measure of body fat based on height and weight] and diabetes are more likely to develop MS in adulthood, our findings suggest that the roots may lie in the perinatal period.
Still, the findings overall suggest that at least some factors present at birth, and possibly even before, may influence adulthood MS risk. The scientists called for further studies to validate and expand on these findings.
“While it is well established that children with high [body mass index, a measure of body fat based on height and weight] and diabetes are more likely to develop MS in adulthood, our findings suggest that the roots may lie in the perinatal period,” the researchers wrote. “Early metabolic exposures may influence immune system programming and future growth trajectories. Future epidemiologic studies should examine markers of [fat composition in newborns] and growth to better understand how early-life factors shape MS risk.”
