Gestational diabetes and risk of subsequent development of type 2 diabetes

There is a significant risk that women who develop gestational diabetes will subsequently develop Type 2 diabetes.

A study in Sweden involved the long term follow up women with gestational diabetes mellitus (GDM)

• case-control study
• study population: Women earlier identified as having gestational diabetes mellitus
• method: Twenty-eight women diagnosed with GDM in 1984-1985, and a control group (n = 52) who gave birth at the same time performed a 2-h oral glucose tolerance test 15 years later
• results: Ten women (35%) in the GDM group were diagnosed with type 2 diabetes mellitus and none in the control group (P < 0.001). Mean BMI in the diabetic group was 27.4 kg/m2 and in the non-diabetic GDM group 24.6 kg/m2 (P < 0.05)
• the study authors concluded that women who are diagnosed with GDM have a considerably higher risk of developing type 2 diabetes mellitus later in life - in this study 35% of women with a history of GDM were shown to have developed Type 2 diabetes at 15 years post GDM (1)

Risk factors for developing type 2 diabetes if history of gestational diabetes (2):

• evidence that the risk of type 2 diabetes was significantly higher in women having increased anthropometric characteristics with relative measures of association ranging from 0.8 to 8.7 and women who used insulin during pregnancy with relative measures of association ranging between 2.8 and 4.7. A later gestational age at diagnosis of gestational diabetes, >24 weeks gestation on average, was associated with a reduction in risk of development of type 2 diabetes with relative measures of association ranging between 0.35 and 0.99
• authors concluded that there is substantial evidence for 3 risk factors associated with the risk of type 2 diabetes in women having gestational diabetes

NICE have stated risk factors for gestational diabetes (3):

Risk factors for gestational diabetes:

• BMI above 30 kg/m2
• previous macrosomic baby weighing 4.5 kg or above
• previous gestational diabetes
• family history of diabetes (first-degree relative with diabetes)
• minority ethnic family origin with a high prevalence of diabetes

Assessment of insulin sensitivity/resistance and their relations with leptin concentrations and anthropometric measures in a pregnant population with and without gestational diabetes mellitus (4)

• both groups were comparable for gestational age, height, weight, and body mass index
• insulin resistance assessed by homeostasis model assessment for insulin resistance (HOMA-IR) method was significantly higher in gestational diabetes mellitus (GDM) patients compared to their normal glucose tolerance (NGT) weight-matched control group
• insulin sensitivity calculated from quantitative insulin sensitivity check index (QUICKI-IS) equation was significantly lower in GDM group
• calculated lean body mass was found to be similar in between both groups
• body fat percentage derived from skinfold thickness (SFT) parameters was significantly higher in women with GDM
• women with GDM had significantly higher levels of serum insulin and leptin concentrations when compared with the NGT group
• all SFT measurements were higher in GDM group when compared to those in NGT women
• the study found no correlation between leptin levels and insulin resistance; also the study found negative correlation between leptin levels and insulin sensitivity

Reference:

1. BJOG. 2002 Nov;109(11):1227-31.
2. Baptiste-Roberts K et al.Risk factors for type 2 diabetes among women with gestational diabetes: a systematic review. Am J Med. 2009 Mar;122(3):207-214
3. NICE (February 2015). Diabetes in pregnancy: management of diabetes and its complications from preconception to the postnatal period
4. Yilmaz O et al. Assessment of insulin sensitivity/resistance and their relations with leptin concentrations and anthropometric measures in a pregnant population with and without gestational diabetes mellitus.J Diabetes Complications. 2009.