Gestational diabetes linked to earlier type 2 diabetes — Study

Women who develop gestational diabetes during pregnancy may go on to develop type 2 diabetes nearly 13 years earlier than women without a history of the pregnancy-related condition, according to new research from Denmark.

The findings, to be presented at the Annual Meeting of the European Association for the Study of Diabetes (EASD) in Milan, Italy, suggest that a history of gestational diabetes may be associated not only with a greater risk of type 2 diabetes but also with an earlier and potentially more severe form of the disease.

The study was led by Dr Maria Houborg Petersen of Steno Diabetes Center Odense, Denmark, in collaboration with researchers from Steno Diabetes Centre Odense and Steno Diabetes Center Aarhus.

Gestational diabetes occurs when high blood sugar develops during pregnancy. Women who experience it are known to face an increased risk of developing type 2 diabetes later in life.

Previous research has suggested that almost half of women with gestational diabetes could develop type 2 diabetes within 10 years.

For the new study, researchers analysed data from the Danish Centre for Strategic Research in Type 2 Diabetes (DD2) cohort, involving 2,865 women who had previously been pregnant.

Of these, 173 women had a history of gestational diabetes, while 2,692 had not experienced the condition.

The difference in age at diagnosis was striking. Women with previous gestational diabetes were diagnosed with type 2 diabetes at a median age of 43.5 years, compared with 56.3 years among women without a history of gestational diabetes — a difference of almost 13 years.

The proportion diagnosed before the age of 40 was also substantially higher among women with previous gestational diabetes.

About 40 per cent of those with a history of gestational diabetes developed type 2 diabetes before the age of 40, compared with only 6 per cent of women without such a history.

Researchers also found evidence that women with previous gestational diabetes were more likely to require insulin treatment.

At enrolment in the DD2 study, 10.4 per cent of women with previous gestational diabetes were receiving insulin, compared with 5.2 per cent of those without the history.

Blood tests also indicated differences in insulin production. Median fasting serum C-peptide, a marker of the body’s insulin production, was 1,068 pmol/L among women with previous gestational diabetes, compared with 1,195 pmol/L among women without it.

However, the groups had similar body mass index and measures of blood glucose control, including HbA1c and fasting plasma glucose.

The researchers found no significant differences in surrogate measures of insulin production or insulin sensitivity.

Complications, including kidney disease, nerve damage and cardiovascular disease, were also broadly comparable between the groups.

There was a statistically significant difference in diabetic retinopathy, but the researchers cautioned that the numbers were too small to determine whether the finding had meaningful clinical implications.

The researchers said the findings highlight the importance of continued monitoring of women after gestational diabetes.

According to the study team, these women may face an earlier onset of type 2 diabetes and a greater likelihood of requiring insulin treatment once diabetes develops.

The findings do not establish that gestational diabetes itself directly causes earlier type 2 diabetes, but they reinforce the importance of long-term follow-up after a pregnancy affected by the condition.

For women with a history of gestational diabetes, the researchers said closer surveillance could help identify rising blood sugar levels earlier and support timely intervention before or soon after type 2 diabetes develops.