Prevalence of impaired glucose tolerance and diabetes after gestational diabetes mellitus comparing different cut-off criteria for abnormal glucose tolerance during pregnancy

Association of single nucleotide polymorphisms with insulin secretion, insulin sensitivity, and diabetes in women with a history of gestational diabetes mellitus

Background

This study investigated whether single nucleotide polymorphisms (SNPs) reported by previous genome-wide association studies (GWAS) to be associated with impaired insulin secretion, insulin resistance, and/or type 2 diabetes are associated with disposition index, the homeostasis model assessment of insulin resistance (HOMA-IR), and/or development of diabetes following a pregnancy complicated by gestational diabetes mellitus (GDM).

Methods

Seventy-two SNPs were genotyped in 374 women with previous GDM from Southern Sweden. An oral glucose tolerance test was performed 1–2 years postpartum, although data on the diagnosis of diabetes were accessible up to 5 years postpartum. HOMA-IR and disposition index were used to measure insulin resistance and secretion, respectively.

Results

The risk A-allele in the rs11708067 polymorphism of the adenylate cyclase 5 gene (ADCY5) was associated with decreased disposition index (beta = − 0.90, SE 0.38, p = 0.019). This polymorphism was an expression quantitative trait loci (eQTL) in islets for both ADCY5 and its antisense transcript. The risk C-allele in the rs2943641 polymorphism, near the insulin receptor substrate 1 gene (IRS1), showed a trend towards association with increased HOMA-IR (beta = 0.36, SE 0.18, p = 0.050), and the T-allele of the rs4607103 polymorphism, near the ADAM metallopeptidase with thrombospondin type 1 motif 9 gene (ADAMTS9), was associated with postpartum diabetes (OR = 2.12, SE 0.22, p = 0.00055). The genetic risk score (GRS) of the top four SNPs tested for association with the disposition index using equal weights was associated with the disposition index (beta = − 0.31, SE = 0.29, p = 0.00096). In addition, the GRS of the four SNPs studied for association with HOMA-IR using equal weights showed an association with HOMA-IR (beta = 1.13, SE = 0.48, p = 9.72874e−11). All analyses were adjusted for age, body mass index, and ethnicity.

Conclusions

This study demonstrated the genetic susceptibility of women with a history of GDM to impaired insulin secretion and sensitivity and, ultimately, to diabetes development.

Association between the rs1544410 polymorphism in the vitamin D receptor (VDR) gene and insulin secretion after gestational diabetes mellitus

Background and aims

Genetic variants involved in vitamin D metabolism have been associated with diabetes and related syndromes/diseases. We wanted to investigate possible associations of polymorphisms in genes involved in vitamin D metabolism with indices of insulin resistance and insulin secretion, and also with development of diabetes after gestational diabetes mellitus (GDM).

Materials and methods

We have studied 376 women with previous GDM. Eight single nucleotide polymorphisms (SNPs) in the genes for vitamin D receptor (VDR) [rs731236, rs7975232, rs10735810, and rs1544410], vitamin D binding protein (DBP) [rs7041 and rs4588], and cytochrome P450 family 27 subfamily B member 1 (CYP27B1) [rs10877012 and rs4646536] were genotyped by TaqMan Allelic Discrimination Assay using the Quantstudio 7 Flex system. A 75-g oral glucose tolerance test (OGTT) was performed 1–2 years postpartum. The homeostasis model assessment of insulin resistance (HOMA-IR) and the disposition index [(insulinogenic index: I30/G30)/HOMA-IR] were used to calculate insulin resistance and insulin secretion, respectively. Serum samples for determination of 25(OH)D3 were collected at the time of the OGTT. Manifestation of diabetes was followed up to five years postpartum.

Results

After adjustment for BMI, age, and ethnicity, the A-allele of the VDR rs1544410 polymorphism was found to be associated with increased disposition index (difference per allele = 3.56, 95% CI: 0.4567–6.674; p = 0.03). The A-allele of the DBP rs7041 polymorphism was found to be associated with 25(OH)D3 levels (difference [in nmol/L] per allele = −5.478, 95% CI: -8.315 to −2.641; p = 0.0002), as was the T-allele of the DBP rs4588 polymorphism (OR = −6.319, 95% CI: −9.466 to −3.171; p = 0.0001). None of the SNPs were significantly associated with HOMA-IR or postpartum diabetes.

Conclusions

This study provides evidence that the rs1544410 polymorphism of the VDR gene may be associated with increased insulin secretion in women after pregnancy complicated by GDM. Further studies in other populations are needed to confirm the results.

Changing diagnostic criteria for gestational diabetes in Sweden - a stepped wedge national cluster randomised controlled trial - the CDC4G study protocol

Background

The optimal criteria to diagnose gestational diabetes mellitus (GDM) remain contested. The Swedish National Board of Health introduced the 2013 WHO criteria in 2015 as a recommendation for initiation of treatment for hyperglycaemia during pregnancy. With variation in GDM screening and diagnostic practice across the country, it was agreed that the shift to new guidelines should be in a scientific and structured way. The aim of the Changing Diagnostic Criteria for Gestational Diabetes (CDC4G) in Sweden (www.cdc4g.se/en) is to evaluate the clinical and health economic impacts of changing diagnostic criteria for GDM in Sweden and to create a prospective cohort to compare the many long-term outcomes in mother and baby under the old and new diagnostic approaches.

Methods

This is a stepped wedge cluster randomised controlled trial, comparing pregnancy outcomes before and after the switch in GDM criteria across 11 centres in a randomised manner. The trial includes all pregnant women screened for GDM across the participating centres during January–December 2018, approximately two thirds of all pregnancies in Sweden in a year. Women with pre-existing diabetes will be excluded. Data will be collected through the national Swedish Pregnancy register and for follow up studies other health registers will be included.

Discussion

The stepped wedge RCT was chosen to be the best study design for evaluating the shift from old to new diagnostic criteria of GDM in Sweden. The national quality registers provide data on the whole pregnant population and gives a possibility for follow up studies of both mother and child. The health economic analysis from the study will give a solid evidence base for future changes in order to improve immediate pregnancy, as well as long term, outcomes for mother and child.

Trial registration

CDC4G is listed on the ISRCTN registry with study ID ISRCTN41918550 (15/12/2017)

The Risk for Glucose Intolerance after Gestational Diabetes Mellitus since the Introduction of the IADPSG Criteria: A Systematic Review and Meta-Analysis

The aim of the study was to assess the postpartum risk for glucose intolerance since the introduction of the ‘International Association of Diabetes and Pregnancy Study Groups’ (IADPSG) criteria for gestational diabetes mellitus (GDM). Studies published since 2010 were included, which evaluated the risk for type 2 diabetes mellitus (T2DM), impaired glucose tolerance (IGT), and cardiovascular (CV) events in women with previous GDM compared to normal glucose tolerant women. We included forty-three studies, evaluating 4,923,571 pregnant women of which 5.8% (284,312) had a history of GDM. Five studies used IADPSG criteria (n = 6174 women, 1314 with GDM). The overall pooled relative risk (RR) for postpartum T2DM was 7.42 (95% CI: 5.99–9.19) and the RR for postpartum T2DM with IADPSG criteria was 6.45 (95% CI: 4.74–8.77) compared to the RR of 9.08 (95% CI: 6.96–11.85; p = 0.17) for postpartum T2DM based on other diagnostic criteria. The RR for postpartum IGT was 2.45 (95% CI: 1.92–3.13), independent of the criteria used. None of the available studies with IADPSG criteria evaluated the risk for CV events. Women with a history of GDM based on the IADPSG criteria have a similarly increased risk for postpartum glucose intolerance compared to GDM based on other diagnostic criteria. More studies with GDM based on the IADPSG criteria are needed to increase the quality of evidence concerning the long-term metabolic risk.

Long-term risk of diabetes in women at varying durations after gestational diabetes: a systematic review and meta-analysis with more than 2 million women

This study aims to investigate the impact of gestational diabetes mellitus (GDM) on the long-term risks of diabetes in women with prior GDM, including the effect at different time periods after GDM. We searched PubMed and other databases to retrieve articles which were published prior to February 28, 2017. Cohort studies which evaluated the risk and time of onset of diabetes postpartum in women with and without GDM were included. Meta-analysis with random effects models was used to obtain pooled relative risks and 95% confidence intervals for the risk of diabetes. Subgroup analyses were performed to check for different effect sizes as well as consistency across groups. Multivariable logistic regression was used to adjust for confounders. Thirty cohort studies with 2,626,905 pregnant women were included. Women with prior GDM had 7.76-fold (95% confidence intervals: 5.10-11.81) unadjusted pooled risk of diabetes as compared with women without GDM, whilst the adjusted risk was 17.92-fold (16.96-18.94). The adjusted ORs of GDM for diabetes among women at <3, ≥3 - <6 and ≥6 - <10 years after GDM were 5.37 (3.51-9.34), 16.55 (16.08-17.04) and 8.20 (4.53-14.86), respectively. Women with prior GDM had substantially increased risk of diabetes, with the risk highest during the 3-6 years after GDM.

Glucose homeostasis, beta cell function, and insulin resistance in relation to vitamin D status after gestational diabetes mellitus

INTRODUCTION

We wanted to determine vitamin D status after gestational diabetes mellitus (GDM) and to evaluate whether levels of 25-hydroxyvitamin D₃ (25OHD₃ ) are associated with beta cell function, insulin resistance or a diagnosis of diabetes after GDM.

MATERIAL AND METHODS

Glucose homeostasis was assessed during a 75-g oral glucose tolerance test one to two years after delivery in 376 women with previous GDM (287 European and 78 non-European, including 33 Arab and 35 Asian women). Insulin resistance was estimated using homeostasis model assessment of insulin resistance (HOMA-IR). The insulinogenic index (I/G30) and the disposition index [(I/G30)/HOMA-IR] were used to calculate insulin secretion. Concentrations of serum 25OHD₃ were determined.

RESULTS

Mean (±SD) 25OHD₃ concentration was 50.0 ± 22.3 nmol/L and differed significantly among subgroups of body mass index, ethnicity, and glucose tolerance status; 53% had 25OHD₃ levels <50 nmol/L and 87% had 25OHD₃ levels <75 nmol/L. There was a negative correlation between 25OHD₃ concentration and HOMA-IR (p < 0.001) and a positive correlation between 25OHD₃ and disposition index (p = 0.002) in univariable regression analysis. Correlations attenuated after adjustment for body mass index. In univariable regression analysis, 25OHD₃ concentrations were significantly associated with diabetes after GDM (p = 0.004). However, in a multivariable model, non-European origin, HOMA-IR and insulinogenic index were significantly associated with postpartum diabetes, whereas 25OHD₃ concentrations were not.

CONCLUSION

Vitamin D deficiency/insufficiency in previous GDM cases appears to be associated with beta cell dysfunction and insulin resistance, but not with postpartum diabetes when factors well known to influence type-2 diabetes were adjusted for.

HbA1c as a predictor of diabetes after gestational diabetes mellitus

AIM

We wanted to investigate third-trimester HbA1c as a predictor of diabetes after gestational diabetes mellitus (GDM).

METHODS

Women with GDM were followed up prospectively for five years from pregnancy to detect the development of diabetes. The ability of HbA1c to predict diabetes was evaluated with receiver-operating characteristic (ROC) curves and logistic regression analysis.

RESULTS

By five years, 73 of 196 women had been diagnosed with diabetes. An optimal cut-off point for HbA1c of 36mmol/mol (5.4%) could predict diabetes with 45% sensitivity and 92% specificity. For HbA1c ≥39mmol/mol (≥5.7%), sensitivity, specificity, and positive predictive value were 30%, 97%, and 91%, respectively. In logistic regression analysis, adjusting for the diagnostic glucose concentration during pregnancy, HbA1c levels in the upper quartile (≥36mmol/mol) were associated with a 5.5-fold increased risk of diabetes.

CONCLUSION

Third-trimester HbA1c levels in the pre-diabetes range revealed women with post-partum diabetes with high specificity and high positive predictive value. HbA1c testing could be used as a strategy to select high-risk women for lifestyle interventions aimed at prevention of diabetes starting during pregnancy. The results should encourage further validation in other populations using new diagnostic criteria for GDM.

Early diabetes screening in women with previous gestational diabetes: a new insight

BACKGROUND

Gestational diabetes mellitus (GDM) is a risk factor for the development of diabetes mellitus (DM). However, there is a low return rate for this screening, so it is important to search for earlier methods for evaluation after delivery, to increase the number of pregnant women screened, so you can start the treatment or prevention of these early comorbidities. To determine the accuracy of the 75 g 2-h oral glucose tolerance test (OGTT) performed between 48-72 h after delivery for the diagnosis of DM using the OGTT after 6 weeks as the gold standard criterion, and to identify the optimal cutoff points for this exam for diabetes screening after a pregnancy complicated by GDM.

METHODS

82 women with previous GDM underwent an OGTT between 48-72 h postpartum and repeated the test 6 weeks after delivery.

RESULTS

The prevalence of DM and prediabetes based on the first OGTT was 3.7 and 32.9 %, respectively, and 8.5 and 20.7 %, respectively, at the second OGTT. For those with DM, the area under the curve (AUC) based on the fasting plasma glucose (FPG) was 0.77 (95 % CI 0.61-0.92), and based on 2-h OGTT was 0.82 (95 % CI 0.66-0.97). For patients with prediabetes, the AUC based on the FPG was 0.73 (95 % CI 0.59-0.86) and based on the 2-h OGTT was 0.74 (95 % CI 0.61-0.87). Using a FPG cutoff value of 78 mg/dl (4.3 mmol/L) and a 2-h OGTT cutoff value of 130 mg/dl (7.2 mmol/L) for DM, the specificity was 58.7 and 60 %, the sensitivity was 71.4 and 85.7 %, the positive predictive value was 13.9 and 16.7 and the negative predictive value was 95.7 and 97.9 %, respectively.

CONCLUSIONS

OGTT performed early in postpartum is a useful tool for identifying women with previous GDM who must perform an OGTT 6 weeks after delivery.

Gestational diabetes: Glycaemic predictors for fetal macrosomia and maternal risk of future diabetes

AIMS

To investigate how glucose levels at diagnosis of gestational diabetes (GDM) are associated with infant birth weight and long-term risk of manifest diabetes mellitus in the mother.

METHODS

In a case control study GDM pregnancies (n=2085) were compared with non-GDM pregnancies matched for day of delivery and obstetric unit (n=3792). GDM was defined as capillary blood glucose (cB-glucose) ≥9.0mmol/l (plasma glucose ≥10.0mmol/l) after a 75g oral glucose tolerance test (OGTT). The GDM cohort were followed up 8.5-13.5yrs after initial diagnosis with a questionnaire, answered by 1324 GDM women (65%).

RESULTS

GDM women had higher mean infant birth-weight compared with controls (3682g vs. 3541g, P<0.001). In multiple linear regression analysis, birth weight was positively correlated to fasting cB-glucose at GDM diagnosis (P<0.001), increased week of gestation (P<0.001) and BMI before pregnancy (P<0.003), while 2h OGTT cB-glucose values ≥9.0mmol/l were not related. Infants born to mothers with fasting cB-glucose ≤4.5mmol/l had no increased mean birth-weight or macrosomia (≥4500g) compared to controls. In the follow up 334/1324 women (25%) of the GDM women had developed diabetes, 215 type 2 diabetes, 46 type 1 diabetes and 72 unclassified diabetes. In logistic regression fasting cB-glucose and 2h OGTT cB-glucose at diagnosis of GDM as well as BMI >25 and origin outside Europe were risk factors for manifest diabetes.

CONCLUSIONS

Fasting blood glucose at diagnosis of GDM gives important information besides 2h OGTT glucose about pregnancy outcome and future risk for maternal diabetes.

Model for individual prediction of diabetes up to 5 years after gestational diabetes mellitus

Aims

To identify predictors of diabetes development up to 5 years after gestational diabetes mellitus (GDM) and to develop a prediction model for individual use.

Methods

Five years after GDM, a 75-g oral glucose tolerance test (OGTT) was performed in 362 women, excluding women already diagnosed with diabetes at 1- to 2-year follow-up or later (n = 45). All but 21 women had results from follow-up at 1–2 years, while 84 women were lost from that point. Predictive variables were identified by logistic regression analysis.

Results

Five years after GDM, 28/362 women (8 %) were diagnosed with diabetes whereas 187/362 (52 %) had normal glucose tolerance (NGT). Of the latter, 139/187 (74 %) also had NGT at 1- to 2-year follow-up. In simple regression analysis, using NGT at 1–2 years and at 5 years as the reference, diabetes at 1- to 2-year follow-up or later was clearly associated with easily assessable clinical variables, such as BMI at 1- to 2-year follow-up, 2-h OGTT glucose concentration during pregnancy, and non-European origin (P < 0.0001). A prediction model based on these variables resulting in 86 % correct classifications, with an area under the receiver-operating characteristic curve of 0.91 (95 % CI 0.86–0.95), was applied in a function-sheet line diagram illustrating the individual effect of weight on diabetes risk.

Conclusions

The results highlight the importance of BMI as a potentially modifiable risk factor for diabetes after GDM. Our proposed prediction model performed well, and should encourage validation in other populations in future studies.

Lifestyle and health status in a sample of Swedish women four years after pregnancy: a comparison of women with a history of normal pregnancy and women with a history of gestational diabetes mellitus

Background

Despite the recommendations to continue the regime of healthy food and physical activity (PA) postpartum for women with previous gestational diabetes mellitus (GDM), the scientific evidence reveals that these recommendations may not be complied to. This study compared lifestyle and health status in women whose pregnancy was complicated by GDM with women who had a normal pregnancy and delivery.

Methods

The inclusion criteria were women with GDM (ICD-10: O24.4 A and O24.4B) and women with uncomplicated pregnancy and delivery in 2005 (ICD-10: O80.0). A random sample of women fulfilling the criteria (n = 882) were identified from the Swedish Medical Birth Register. A questionnaire was sent by mail to eligible women approximately four years after the pregnancy. A total of 444 women (50.8%) agreed to participate, 111 diagnosed with GDM in their pregnancy and 333 with normal pregnancy/delivery.

Results

Women with previous GDM were significantly older, reported higher body weight and less PA before the index pregnancy. No major differences between the groups were noticed regarding lifestyle at the follow-up. Overall, few participants fulfilled the national recommendations of PA and diet. At the follow-up, 19 participants had developed diabetes, all with previous GDM. Women with previous GDM reported significantly poorer self-rated health (SRH), higher level of sick-leave and more often using medication on regular basis. However, a history of GDM or having overt diabetes mellitus showed no association with poorer SRH in the multivariate analysis. Irregular eating habits, no regular PA, overweight/obesity, and regular use of medication were associated with poorer SRH in all participants.

Conclusions

Suboptimal levels of PA, and fruit and vegetable consumption were found in a sample of women with a history of GDM as well as for women with normal pregnancy approximately four years after index pregnancy. Women with previous GDM seem to increase their PA after childbirth, but still they perform their PA at lower intensity than women with a history of normal pregnancy. Having GDM at index pregnancy or being diagnosed with overt diabetes mellitus at follow-up did not demonstrate associations with poorer SRH four years after delivery.

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-015-0487-2) contains supplementary material, which is available to authorized users.

Role of HbA1c in post-partum screening of women with gestational diabetes mellitus

Aim

To compare the performance of HbA1c with established glucose criteria during an oral glucose tolerance test (OGTT) and to assess HbA1c as a screening test for undiagnosed diabetes and pre-diabetes after gestational diabetes mellitus (GDM).

Methods

Glucose homeostasis was re-evaluated 1–5 years after delivery in 140 women with previous GDM, by means of OGTT and simultaneous HbA1c measurement. Glucose tolerance was defined according to World Health Organisation criteria. HbA1c ≥6.5% (≥48 mmol/mol) was used for diabetes diagnosis and HbA1c ≥5.7% (≥39 mmol/mol) to define abnormal glucose homeostasis.

Results

HbA1c had low sensitivity (14.3%) and high specificity (99.1%) in diabetes diagnosis. Sensitivity and specificity of HbA1c to detect abnormal glucose tolerance were 29.5% and 95.2%, respectively. The consistency in classifying abnormal glucose tolerance between HbA1c and OGTT criteria was 59% (κ = 0.227) and the area under the receiver operating characteristic curve was 0.708. The combined use of HbA1c and fasting glucose criteria showed similar performance to that of fasting glucose criteria alone. The latter identified 63% of the women with pre-diabetes or diabetes in the study cohort. However, by lowering the cut-point of HbA1c to ≥5.0% (≥31 mmol/mol), an additional proportion (27%) with isolated post-glucose load hyperglycaemia was identified.

Conclusion

Proposed thresholds of HbA1c had low diagnostic sensitivity. Combined with a fasting glucose test, the performance was no better than with using a fasting glucose test alone. Combining a fasting glucose test with a lower HbA1c cut-point may be an alternative approach for selection of women for an OGTT.

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We compare the performance of HbA1c with established glucose criteria during an oral glucose tolerance test (OGTT).

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We also assess HbA1c as a screening test for undiagnosed diabetes and pre-diabetes after gestational diabetes mellitus.

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Proposed thresholds of HbA1c had low diagnostic sensitivity relative to OGTT.

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Combining HbA1c with a fasting glucose test the performance was no better than using a fasting glucose test alone.

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Combining a fasting glucose test with a lower HbA1c cut-point may be an option for selection of women for an OGTT.

The impact of ethnicity on glucose homeostasis after gestational diabetes mellitus

The objective of this study was to examine measures of insulin resistance and beta cell function in relation to ethnicity and the development of diabetes after gestational diabetes mellitus (GDM). Glucose homeostasis was assessed during a 75 g oral glucose tolerance test 1-2 years after delivery in 456 women with previous GDM (362 European, 94 non-European; including 41 Arab and 43 Asian women) and 133 control women. Insulin resistance was estimated using homeostasis model assessment of insulin resistance (HOMA-IR). The insulinogenic index (I/G30) and the disposition index [(I/G30)/HOMA-IR] were used to quantify insulin secretion. Women developing diabetes after GDM were characterized by increased HOMA-IR [p = 0.010, adjusted for body mass index (BMI)], whereas the disposition index was decreased in all women with previous GDM irrespective of glucose tolerance, most pronounced in the presence of diabetes (BMI-adjusted p = 1 × 10(-5)). Non-European origin was associated with increased HOMA-IR (p = 0.001 vs. European), strengthened by adjustment for BMI in Asian women (p = 0.046 vs. p = 0.016), but eradicated among Arab women (p = 0.004 vs. p = 0.65). Non-European women exhibited an increased frequency of diabetes after GDM (17 % vs. European 4 %, p = 2 × 10(-5)). In addition to BMI, non-European and Asian origin was associated with the development of diabetes after GDM in a multivariate logistic regression analysis, whereas Arab origin was not. Our results highlight the importance of preventive measures to ensure a healthy lifestyle in women with GDM, particularly in high-risk ethnic groups.

Original research: postpartum testing rates among women with a history of gestational diabetes--systematic review

AIMS

Gestational diabetes mellitus (GDM) is increasing and 30% have persistent postpartum dysglycemia. Reported compliance with recommended postpartum testing ranges 9-95% without a clear explanation for this wide variation. Small and conflicting differences in testing rates are associated with some demographics (race, use of insulin), but system factors likely play a larger role. A systematic literature review was performed to identify system based factors that could explain the broad variation in postpartum GDM testing rates.

METHODS

Original articles reporting postpartum testing rates among women with GDM were identified within PubMed, OVID, EMBASE, and the Cochrane Database of systematic reviews. Articles that did not report rates for the entire GDM cohort were excluded.

RESULTS

54/307 citations met inclusion criteria. The use of proactive patient contact programs increased postpartum testing rates from an average of 33% (range 9-71%) up to 60% (range 14-95%).

CONCLUSIONS

Proactively contacting patients via phone calls, education programs, or postal reminders was associated with higher postpartum testing rates. Rather than working to identifying individual demographic factors, systems based approaches were associated with a larger potential impact, and appear easily generalizable. Clinicians should think beyond individual habits and consider systematic approaches to improving testing rates.

Genetic prediction of postpartum diabetes in women with gestational diabetes mellitus

AIMS

To examine whether genetic variants that predispose individuals to type 2 diabetes (T2D) could predict the development of diabetes after gestational diabetes mellitus (GDM).

METHODS

13 SNPs (FTO rs8050136, CDKAL1 rs7754840 and rs7756992, CDKN2A/2B rs10811661, HHEX rs1111875, IGF2BP2 rs1470579 and rs4402960, SLC30A8 rs13266634, TCF7L2 rs7903146, PPARG rs1801282, GCK rs1799884, HNF1A rs1169288, and KCNJ11 rs5219) were genotyped in 793 women with GDM after a median follow-up of 57 months.

RESULTS

After adjustment for age and ethnicity, the TCF7L2 rs7903146 and the FTO rs8050136 variants significantly predicted postpartum diabetes; hazard ratio (95% confidence interval 1.29 (1.01-1.66) and 1.36 (1.06-1.74), respectively (additive model) versus 1.45 (1.01-2.08) and 1.56 (1.06-2.29) (dominant model)). Adjusting for BMI attenuated the effect of the FTO variant, suggesting that the effect was mediated through its effect on BMI. Combining all risk alleles to a weighted risk score was significantly associated with the risk of postpartum diabetes (hazard ratio 1.11, 95% confidence interval 1.05-1.18, p=0.00016 after adjustment for age and ethnicity).

CONCLUSIONS

The TCF7L2 rs7903146 and FTO rs8050136 polymorphisms, and particularly a weighted risk score of T2D risk alleles, predict diabetes after GDM. Further studies in other populations are needed to confirm our results.