medwireNews: The significantly increased risk for type 2 diabetes after a diagnosis of gestational diabetes mellitus (GDM) persists for over 35 years, suggests a study published in Diabetes Care.
Claire Weinberg (National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA) and co-authors say their findings “should be a call to action that motivates women who were ever diagnosed with GDM to be screened regularly” and “should alert health professionals to extend screening programs to target this population.”
The team gathered data for 47,471 women who participated in the Sister Study and were free from type 2 diabetes at time of enrollment in 2003–2009.
At baseline, 1414 women had received at least one diagnosis of GDM and these patients were younger than those without a GDM diagnosis, with a higher BMI.
Over an average 10.2 years of follow-up, 13.4% of women with a history of GDM were diagnosed with type 2 diabetes compared with 6.9% of those without GDM.
After adjusting for a raft of confounding factors, including race/ethnicity, baseline BMI, education, and time since GDM, women with GDM at the start of follow-up were 2.5 times more likely to be diagnosed with type 2 diabetes than those without.
And although this association weakened by approximately 24% after each decade of follow-up, the elevated risk for type 2 diabetes in women with a history of GDM remained significant in the long-term, the researchers say.
Specifically, the hazard ratio (HR) for type 2 diabetes diagnosis was 3.87 after 6–15 years of follow-up, 3.50 after 16–25 years, 1.95 after 26–35 years, and 1.62 after 35 years.
Further analysis showed that women with one, two, or three or more pregnancies affected by GDM were a respective 3.46, 4.77, and 7.15 times more likely to develop type 2 diabetes in the following 6–15 years than those without GDM.
The increased risks in each of these patient groups remained significant after at least 35 years of follow-up, with corresponding HRs of 1.49, 2.06, and 3.08.
The researchers hypothesized that baseline BMI might act as a “mediator” in the relationship between GDM and type 2 diabetes if the GDM led to weight gain.
But switching to self-reported BMI at ages 30–39, as a proxy for pregestational BMI, made “little difference” to their risk for type 2 diabetes in women with GDM, say Weinberg et al.
“Personalized lifestyle interventions that target women with both a BMI in the overweight or obese category and a history of GDM may be effective in reducing their burden of type 2 diabetes,” the researchers suggest.
“Additionally, women with a history of GDM, especially those with a history of multiple pregnancies with GDM who also have a BMI in the overweight or obese category, should be screened regularly for type 2 diabetes, even late in life,” they recommend.
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