Long-term protective effect of lactation on the development of type 2 diabetes in women with recent gestational diabetes mellitus

Prevention of Diabetes after Gestational Diabetes: Better Translation of Nutrition and Lifestyle Messages Needed

Type 2 Diabetes Mellitus (T2DM) and Gestational Diabetes (GDM) are important and escalating problems worldwide. GDM increases the risk of complications in pregnancy and birth, as well as a 1 in 2 chance of developing T2DM later in life. The burden of GDM extends to offspring, who have an increased risk of obesity and diabetes-further perpetuating the cycle of diabetes within families. Clinical trial evidence demonstrates T2DM incidence reduced by up to 50% for women with GDM with nutrition and physical activity changes and the economic modeling suggests cost effectiveness. The key diet-related changes to reduce T2DM risk are reviewed, in addition to breastfeeding. The difficulties associated with the delivery of dietary and lifestyle behaviour change to women after GDM are discussed and focus on: complex healthcare system interactions needed for care delivery; women finding postpartum self-care challenging; and low levels of awareness being present across the board. In addition, studies currently underway to improve care provision in this important area will be examined.

Gestational diabetes mellitus and cardiovascular risk after pregnancy

Gestational diabetes mellitus (GDM) affects many women in pregnancy and is enhanced by epidemic conditions of obesity, increasing age at the time of the first pregnancy, stressful life conditions, a sedentary lifestyle with less physical activity and unhealthy nutrition with highly processed, high-calorie food intake. GDM does not affect the mother and offspring in pregnancy alone, as there is compelling evidence of the long-term effects of the hyperglycemic state in pregnancy postpartum. Type 2 diabetes mellitus, cardiovascular disease and metabolic syndrome are more common in GDM women, and even the offspring of GDM women are reported to have higher obesity rates and a higher risk for noncommunicable diseases. Early prevention of risk factors seems to be key to overcoming the vicious cycle of cardiometabolic disease onset.

Lactation intensity and fasting plasma lipids, lipoproteins, non-esterified free fatty acids, leptin and adiponectin in postpartum women with recent gestational diabetes mellitus: the SWIFT cohort

OBJECTIVES

Lactation may influence future progression to type 2 diabetes after gestational diabetes mellitus (GDM). However, biomarkers associated with progression to glucose intolerance have not been examined in relation to lactation intensity among postpartum women with previous GDM. This study investigates whether higher lactation intensity is related to more favorable blood lipids, lipoproteins and adipokines after GDM pregnancy independent of obesity, socio-demographics and insulin resistance.

METHODS

The Study of Women, Infant Feeding, and Type 2 Diabetes (SWIFT) is a prospective cohort study that recruited 1035 women diagnosed with GDM by the 3-h 100g oral glucose tolerance tests (OGTTs) after delivery of a live birth in 2008-2011. Research staff conducted 2-h 75 g OGTTs, and assessed lactation intensity, anthropometry, lifestyle behaviors and socio-demographics at 6-9 weeks postpartum (baseline). We assayed fasting plasma lipids, lipoproteins, non-esterified free fatty acids, leptin and adiponectin from stored samples obtained at 6-9 weeks postpartum in 1007 of the SWIFT participants who were free of diabetes at baseline. Mean biomarker concentrations were compared among lactation intensity groups using multivariable linear regression models.

RESULTS

Increasing lactation intensity showed graded monotonic associations with fully adjusted mean biomarkers: 5%-8% higher high-density lipoprotein cholesterol (HDL-cholesterol), 20%-28% lower fasting triglycerides, 15%-21% lower leptin (all trend P-values < 0.01), and with 6% lower adiponectin, but only after adjustment for insulin resistance (trend P-value = 0.04).

CONCLUSION

Higher lactation intensity was associated with more favorable biomarkers for type 2 diabetes, except for lower plasma adiponectin, after GDM delivery. Long-term follow-up studies are needed to assess whether these effects of lactation persist to predict progression to glucose intolerance.

The role of lactation in GDM women

Lactating women exhibit more favorable blood glucose and insulin profiles, as well as increased insulin sensitivity than nonlactating women. Yet, much less is known about whether these favorable effects on metabolic risk factors persist long-term among women with gestational diabetes mellitus (GDM). The evidence that lactation reduces incident type 2 diabetes after GDM pregnancy is limited and inconsistent. Well-controlled, prospective studies that measure lactation intensity and duration, and comprehensively screen for postpartum glucose tolerance are needed to conclusively determine whether lactation can lead to reduced risk of type 2 diabetes after GDM pregnancy.

Differences in breast-feeding initiation and continuation by maternal diabetes status

Objective

To examine (i) the prevalence of and associations between breast-feeding initiation and continuation by maternal diabetes status and (ii) the reasons for not initiating and/or continuing breast-feeding by maternal diabetes status.

Design

Secondary data analyses of a population-based cross-sectional study were conducting using data from the US Centers for Disease Control and Prevention’s Pregnancy Risk Assessment Monitoring System (PRAMS), 2009–2011. Multivariable logistic regression was used to investigate the associations between breast-feeding initiation and continuation by diabetes status.

Setting

Thirty states and New York City, USA.

Subjects

Mothers of recently live-born infants, selected by birth certificate sampling.

Results

Among 72755 women, 8·8 % had gestational diabetes mellitus (GDM) and 1·7 % had pregestational diabetes mellitus (PDM). Breast-feeding initiation was similar among GDM and no diabetes mellitus (NDM) women (80·8 % v. 82·2 %, respectively, P=0·2), but continuation was lower among GDM (65·7 % v. 68·8 %, respectively, P=0·01). PDM women had lower initiation and continuation compared with NDM (78·2 %, P=0·03 and 60·4 %, P<0·01, respectively). In adjusted analyses, current smoking status was a significant effect modifier for initiation, but not for continuation.

Conclusions

Differences in breast-feeding initiation and continuation prevalence by maternal diabetes status may reflect differences in prenatal education, indicating the need for increased efforts among PDM women. Additionally, non-smoking women with PDM or GDM would benefit from additional breast-feeding education.

Impact of gestational hyperglycemia on maternal and child health

PURPOSE OF REVIEW

To address the recent evidence regarding the association between hyperglycemia during pregnancy and adverse short-term and long-term outcome for both mothers and offspring.

RECENT FINDINGS

Recent data suggest a relationship between hyperglycemia during pregnancy and adverse short-term fetal outcomes, mainly those associated with excessive fetal growth. The degree of hyperglycemia plays an important role in risk stratification. Moreover, the long-term effect of hyperglycemia during pregnancy is expressed mainly as cardiometabolic morbidity and increased risk for the development of metabolic syndrome both maternal and in early adolescence. Alternation in DNA methylation and gene expression of metabolic pathways were found in association with hyperglycemia in utero, supporting the 'developmental origins of disease' hypothesis.

SUMMARY

The effect of hyperglycemia on the early life metabolic environment may contribute to the subsequent risk of cardiovascular or metabolic morbidity later in life. It is also a sign of future maternal metabolic alternation. Several future randomized trials, hopefully will help to determine if early intervention could decrease the risk for gestational diabetes and whether long term adverse outcome are preventable and importantly the association with degree of maternal hyperglycemia in pregnancy and future morbidity.

Maternal outcomes and follow-up after gestational diabetes mellitus

Gestational diabetes mellitus reflects impaired maternal insulin secretion relative to demand prior to pregnancy, as well as temporary metabolic stressors imposed by the placenta and fetus. Thus, after delivery, women with gestational diabetes have increased risk of diabetes and recurrent gestational diabetes because of their underlying impairment, which may be further exacerbated by fat accretion during pregnancy and post-partum deterioration in lifestyle behaviours. This hypothetical model is discussed in greater detail, particularly the uncertainty regarding pregnancy as an accelerator of β-cell decline and the role of gestational weight gain. This report also presents risk estimates for future glucose intolerance and diabetes and reviews modifiable risk factors, particularly body mass and lifestyle alterations, including weight loss and breastfeeding. Non-modifiable risk factors such as race/ethnicity and insulin use during pregnancy are also discussed. The review concludes with current literature on lifestyle modification, recommendations for post-partum glucose screening, and future directions for research to prevent maternal disease.

Impact of breastfeeding on maternal metabolism: implications for women with gestational diabetes

Lactating compared with nonlactating women display more favorable metabolic parameters, including less atherogenic blood lipids, lower fasting and postprandial blood glucose as well as insulin, and greater insulin sensitivity in the first 4 months postpartum. However, direct evidence demonstrating that these metabolic changes persist from delivery to postweaning is much less available. Studies have reported that longer lactation duration may reduce long-term risk of cardiometabolic disease, including type 2 diabetes, but findings from most studies are limited by self-report of disease outcomes, absence of longitudinal biochemical data, or no assessment of maternal lifestyle behaviors. Studies of women with a history gestational diabetes mellitus (GDM) also reported associations between lactation duration and lower the incidence of type 2 diabetes and the metabolic syndrome. The mechanisms are not understood, but hormonal regulation of pancreatic β-cell proliferation and function or other metabolic pathways may mediate the lactation association with cardiometabolic disease in women.

Breastfeeding and the maternal risk of type 2 diabetes: a systematic review and dose-response meta-analysis of cohort studies

BACKGROUND AND AIMS

Breastfeeding has been associated with reduced risk of maternal type 2 diabetes in some cohort studies, but the evidence from published studies have differed with regard to the strength of the association. To clarify this association we conducted a systematic review and dose-response meta-analysis of breastfeeding and maternal risk of type 2 diabetes.

METHODS AND RESULTS

We conducted a systematic review and dose-response meta-analysis of prospective studies of breastfeeding and maternal risk of type 2 diabetes. We searched the PubMed, Embase and Ovid databases up to September 19th 2013. Summary relative risks were estimated using a random effects model. Six cohort studies including 10,842 cases among 273,961 participants were included in the meta-analysis. The summary RR for the highest duration of breastfeeding vs. the lowest was 0.68 (95% CI: 0.57-0.82, I(2) = 75%, p heterogeneity = 0.001, n = 6). The summary RR for a three month increase in the duration of breastfeeding per child was 0.89 (95% CI: 0.77-1.04, I(2) = 93%, p heterogeneity < 0.0001, n = 3) and the summary RR for a one year increase in the total duration of breastfeeding was 0.91 (95% CI: 0.86-0.96, I(2) = 81%, p heterogeneity = 0.001, n = 4). There was little difference in the summary estimates whether or not BMI had been adjusted for. The inverse associations appeared to be nonlinear, p nonlinearity < 0.0001 for both analyses, and in both analyses the reduction in risk was steeper when increasing breastfeeding from low levels.

CONCLUSION

This meta-analysis suggests that there is a statistically significant inverse association between breastfeeding and maternal risk of type 2 diabetes.

Gestational diabetes mellitus in korean women: similarities and differences from other racial/ethnic groups

Gestational diabetes mellitus (GDM) reflects defects in insulin secretion in response to the metabolic demands of pregnancy. While GDM is increasingly common worldwide due in large part to the obesity epidemic, its frequency is relatively low in Korean women. In this report, the prevalence and risk factors for GDM, perinatal outcomes, and postpartum course are compared in non-Korean and Korean women. While Koreans and non-Koreans with GDM share pathophysiology and complications, there may be differences in the role of obesity and thus the effectiveness of interventions targeting obesity in GDM women. Further investigations of the effectiveness of weight loss interventions and pharmacotherapy specifically among Korean women are needed. Dietary and other lifestyle data from Korean populations could inform prevention and treatment strategies in other countries which suffer from significantly higher prevalences of GDM.

Beneficial effects of breastfeeding in women with gestational diabetes mellitus

Gestational diabetes mellitus (GDM) increases the future risk of developing type 2 diabetes mellitus (T2DM). There is now a growing evidence that breastfeeding has short- and long-term health benefits for mothers with GDM. Mothers with GDM who breastfeed have improved lipid and glucose metabolic profiles for the first 3 months after birth. However, women with GDM are less likely to breastfeed and, if they do, breastfeeding is usually continued for a shorter duration compared with women without GDM. One long-term prospective study followed women with GDM from delivery for up to 19 years postpartum, and found that breastfeeding for ≥3 months reduced the risk of T2DM and delayed the development of T2DM by a further 10 years compared with breastfeeding for <3 months. However, the physiological mechanisms underlying the protective effects of breastfeeding are still unknown, even though it is important to gain a full understanding of the pathways involved in these effects. Therefore, the purpose of this review is to provide a comprehensive analysis of the recent developments in the field of GDM and breastfeeding. We reviewed data from animal experiments and human studies. We also provide insight into the molecular pathways and describe promising topics for future research.

Postpartum outcomes in women with gestational diabetes and their offspring: POGO study design and first-year results

BACKGROUND

Gestational diabetes mellitus (GDM) is a risk factor for mothers to develop type 2 diabetes (T2D) postpartum, and for their children to develop obesity. The aim of the ongoing POGO study is to identify long-lasting changes in the maternal and fetal metabolism and microbiome, after GDM, which contribute to subsequent development of T2D and obesity.

METHODS

Women screened for GDM are asked to attend a postpartum study visit together with their offspring. At the visit, demographic, nutritional, and anthropometric data are recorded. Additionally, data about physical activity, metabolism, and genetic susceptibility are collected using accelerometers, breath gas analyses, 75g oral glucose tolerance tests (OGTT), and bio-samples such as blood and stool.

RESULTS

To date, 121 women (median follow-up time postpartum: 5.5 years) have been enrolled together with 133 index children. GDM has been diagnosed using OGTT in 105 women (and 117 children). It showed that 47 mothers had abnormal glucose tolerance, including 19 cases of impaired glucose tolerance, 19 of impaired fasting glucose, eight with T2D, and one with type 1 diabetes (T1D). The prevalence of obesity in the offspring of GDM mothers was 5.1%. Of 61 children tested by OGTT, three were diagnosed with impaired glucose tolerance, another three with impaired fasting glucose, and none with T1D or T2D.

CONCLUSIONS

The POGO study will contribute to the understanding of the pathogenesis of T2D and obesity after GDM, and will thus help to develop appropriate prevention and intervention strategies. This article presents the first results of the ongoing study, which are looking promising.

Relationship between lactation duration and insulin and glucose response among women with prior gestational diabetes

BACKGROUND

Few studies have investigated whether favorable effects of lactation persist after weaning and protect women with prior gestational diabetes mellitus (GDM) against later development of insulin resistance and insulin secretion defects.

OBJECTIVE

To investigate the impact of lactation duration on insulin and glucose response among women with prior GDM.

DESIGN/METHODS

The study group comprised 144 women with a history of GDM between 2003 and 2010. Plasma insulin and glucose concentrations were obtained from a 75 g oral glucose tolerance test (OGTT). Total lactation duration (exclusive breastfeeding and breast and bottle-feeding) for all infants was self-reported in months.

RESULTS

Mean age was 36.5±5.0 years. Time between delivery and metabolic testing was 4.0±1.9 years. Women breastfed for an average of 13.9±16.8 months. Most women (80.6%) reported a history of lactation. Women who lactated had higher homeostasis model assessment for insulin sensitivity (HOMA-IS) and Matsuda indices and lower fasting and 2-h post-OGTT insulin concentrations as well as area under the curve (AUC) for insulin (P≤0.01 for all). Compared with women who lactated for <10 months, women who lactated for ≥10 months had improved insulin sensitivity-secretion index, higher HOMA-IS and Matsuda indices, lower fasting and 2-h post-OGTT insulin concentrations as well as AUC for insulin, and lower incidence of impaired glucose intolerance (P≤0.05 for all). In multiple linear regression analyses, lactation duration emerged as an independent predictor of fasting insulin concentrations (β=-0.02) and insulin sensitivity indices (β=0.02) (P≤0.05 for all).

CONCLUSIONS

These results suggest that longer duration of lactation is associated with improved insulin and glucose response among women with prior GDM.