Lifestyle interventions to reduce risk of diabetes among women with prior gestational diabetes mellitus

While lifestyle interventions involving exercise and a healthy diet in high-risk adults have been found to reduce progression to type 2 diabetes by >50%, little attention has been given to the potential benefits of such strategies in women with a history of gestational diabetes mellitus (GDM). We conducted a literature search of PubMed for English language studies of randomized controlled trials of lifestyle interventions among women with a history of GDM. In total, nine studies were identified which fulfilled the eligibility criteria. The majority of randomized trials of lifestyle interventions in women with GDM have been limited to pilot or feasibility studies. However, preliminary findings suggest that such interventions can improve diabetes risk factors in women with a history of GDM. Larger, well-designed controlled randomized trials are needed to assess the effects of lifestyle interventions on preventing subsequent progression to type 2 diabetes among women with GDM.

Background

Type 2 diabetes is a global epidemic. Worldwide, the total number of people with diabetes is projected to rise from 171 million in 2000 to 366 million in 2030 . At the same time, the age at onset for type 2 diabetes is decreasing highlighting the importance of identifying high-risk groups early, in order to implement prevention efforts. One such high-risk group is women who develop glucose intolerance during pregnancy. Both gestational diabetes mellitus (GDM) and milder glucose intolerance in pregnancy identify women who are at a high risk of subsequent glucose intolerance and type 2 diabetes.

GDM is one of the most common complications of pregnancy with a prevalence rate varying from 1% to 20% depending on the population studied and diagnostic criteria applied . With the recent adoption of the International Association of Diabetes and Pregnancy Study Groups Consensus Panel (IADPSG) diagnostic criteria, it is estimated that 18% of pregnant women will be diagnosed with GDM . Obesity is strongly associated with the risk of GDM , and it is expected that the incidence of GDM among women of reproductive age will further increase as the prevalence of obesity continues to rise among this age group.

GDM is related to short- and long-term adverse health outcomes for the mother. Compared with women with healthy pregnancies, women with histories of GDM have elevated cardiovascular disease (CVD) risk factors including higher blood pressure, triglyceride levels, and lower high-density lipoprotein (HDL) . Consistent with these findings, a meta-analysis found that GDM confers a sevenfold risk of future type 2 diabetes and up to one-third of women with type 2 diabetes have previously been diagnosed with GDM .

According to a systematic review, the highest risk period for the development of type 2 diabetes is within the first 5 years after a GDM pregnancy with 50% of Hispanic women developing type 2 diabetes within 5 years . Furthermore, a growing body of evidence shows a rapid postpartum change in CVD risk factors . For example, Retnakaran et al. found that by 12 months post partum, 17.1% of those with recent GDM and 10% of women with milder degrees of gestational glucose intolerance had progressed to prediabetes or diabetes .

Therefore, pregnancy can unveil a preexisting susceptibility for type 2 diabetes and offers the opportunity to implement interventions to decrease such a risk. However, while lifestyle interventions involving exercise and a healthy diet in high-risk adults have been found to reduce progression to type 2 diabetes by >50% , little attention has been given to the potential benefits of such strategies in women with a history of GDM. Indeed, studies of diabetes prevention among such high-risk pregnant and postpartum women are sparse. Collectively, the prior body of evidence suggests that such lifestyle interventions, if delivered to women with a history of GDM, would have the potential to delay or prevent one-sixth of type 2 diabetes cases in the female population .

Therefore, the goal of this review is to provide researchers and practitioners with a comprehensive overview of the randomized controlled trials of lifestyle interventions designed to reduce the risk of diabetes or diabetes risk factors among women with a history of GDM. To this end, the review first describes the impact of the lifestyle interventions on the incidence of type 2 diabetes and biomarkers of insulin resistance, weight change, and healthy behaviors such as physical activity, diet, and breast-feeding. The review then goes on to describe the study design and methods of new randomized trials which have been recently launched. The review concludes with a summary and recommendations for future research and practice.

Methods

We conducted a literature search of PubMed for English language studies of randomized controlled trials of lifestyle interventions among women with a history of GDM. Only published peer-reviewed journal articles of original research in the English language were included. Keyword searches included the following: lifestyle intervention, randomized controlled trial, type 2 diabetes, prevention, diet, physical activity, postpartum, pregnancy, weight retention, GDM, and health behaviors. Additional relevant articles cited in the reference lists of identified papers were retrieved manually.

In total, nine randomized controlled trials of lifestyle interventions conducted among women with a history of GDM were identified to fulfill the eligibility criteria ( Tables 1 and 2 ) .

Table 1
Randomized trials of lifestyle interventions to reduce risk of type 2 diabetes among women with gestational diabetes mellitus (GDM); study designs.
Author (year) Name Design Pilot Population Intervention Mode Goals
Cheung et al.; 2011 RCT; FU: 12 months Pilot 43 women with previous GDM <4 years previously; Australia Exercise intervention vs. usual care control individualized in-person; telephone; mailings PA: 150 min/week or 10,000 steps/day for 5 days/week.
Ferrara et al.; 2011 DEBI (Diet, Exercise and Breastfeeding Intervention) RCT; FU: 12 months Pilot 197 women with current GDM; California Lifestyle intervention (diet, exercise, breast-feeding) versus usual care control individualized in-person; telephone Weight: return to prepregnancy weight if normal, lose 5% of prepregnancy weight if overweight; PA: 150 min/week of moderate-intensity or harder; Diet: ≤25% calories from fat; Breast-feeding: exclusively for 6 months
Hu et al.; 2012 Tianjin Gestational Diabetes Mellitus Prevention Program (TGDMPP) RCT; 1 year Preliminary results 404 women with previous GDM from 05 to 09; China Lifestyle intervention (diet and exercise) versus usual care control individualized in-person Weight: no weight loss if normal weight, lose 5–10% of prepregnancy weight if BMI≥24 kg/m 2 through reduction of ≥10% total calories; PA: 150 of moderate-intensity or harder; Diet: TF <30%; fiber 20–30 g/day; % calories from fat
Kim et al.; 2012 RCT; FU: 13 weeks Pilot 49 women with previous GDM within past 3 years; Michigan Exercise intervention versus usual care control web based Steps: up to 10,000 steps/day
McIntyre et al.; 2012 RCT; FU: 12 weeks Pilot 28 women with previous GDM 6 weeks post partum; Australia Exercise intervention versus usual care control individualized in-person; telephone PA: 150 min/week
Ratner et al.; 2008 Diabetes Prevention Project (DPP) RCT; FU: 2.8 years. 350 women with previous GDM and current elevated glucose levels from the DPP; US Lifestyle intervention (diet and exercise) versus placebo individualized in person; group sessions Weight: Reduction ≥7% of initial body weight; Diet: low-calorie, low-fat; PA: moderate intensity ≥150 min/wk.
Reinhardt et al.; 2012 RCT; FU: 6 months Pilot 38 women following GDM diagnosis; Australia Lifestyle intervention (diet and exercise) versus usual care control telephone; mailings Healthy eating and physical activity
Shyam et al.; 2013 RCT; FU: 6 months 77 women with previous GDM within 2 months; Malaysia Low GI diet versus usual care control in-person; text messaging, emails Weight: 5–7% reduction in body weight if BMI >23 and maintain if normal; PA: moderate intensity 30 min/day for 5 times/week
Wein et al.; 1999 RCT; FU: 796 person-years (median 51 months) 200 women with previous GDM from 89 to 91 and subsequent IGT Diet intervention versus control telephone; mailings Diet: healthy eating; PA: exercise (30 min for 3 times/week)
RCT = randomized clinical trial; FU = follow-up; GDM = gestational diabetes mellitus; IGT = impaired glucose tolerance; PA=physical activity; FG = fasting glucose; GI = glycemic index; PA = physical activity, LTPA = leisure time physical activity, BMI = body mass index.
Table 2
Randomized trials of lifestyle interventions to reduce risk of type 2 diabetes among women with gestational diabetes mellitus (GDM); findings.
Author (year) Name Impact on type 2 diabetes Impact on biomarkers of insulin resistance Impact on weight Impact on PA Impact on diet Impact on breast-feeding
Cheung et al.; 2011 NA NA BMI (kg/m 2 ): 28 (95% CI: 23.9, 34.3) versus 25.5 (95% CI: 22.5, 28.7), p = 0.14 Steps (% achieving goal): 30.8 versus 17.6 p = 0.34; PA (% achieving goal): 70.0 versus 57.9, p = 0.51 NA
Ferrara et al.; 2011 DEBI (Diet, Exercise and Breastfeeding Intervention) NA NA Weight (% achieving goal): 37.5% versus 21.4%, p = 0.07 PA (difference in mean change in min/week): 25.3, p = 0.91 Fat (% difference in mean change) −3.6, p = 0.002 Breastfeeding (difference in % partially or exclusively breast-feeding): 15%, p = 0.09
Hu et al.; 2012 Tianjin Gestational Diabetes Mellitus Prevention Program (TGDMPP) NA FG (change in mmol/l): −0.09 ± 0.52 versus −0.09 ± 0.6, p = 0.97; Insulin (change in pmol/l): −11.8 ± 27.4 versus −3.2 ± 31.2, p = 0.004 Weight change: −1.4 ± 3.44 kg versus −0.21 ± 3.52 kg (0.3%), p = 0.001; BMI change: −0.50 ± 1.41 kg/m 2 versus −0.09 ± 1.37 kg/m2, p = 0.004 LTPA (% increased): 59.4% versus 26.9%, p < 0.001 Fat (% decrease): 77.1 versus 68.9, p = 0.064; Fiber (% increase) 59.5 versus 47.4, p = 0.012 NA
Kim et al.; 2012 NA FG (change in mmol/l): −0.046 versus 0.038, p = 0.65; 2-h glucose on 75-g OGTT (change in mmol/l): −0.48 versus −0.42, p = 0.91 Weight (change in kg): -0.14 kg versus −1.5 kg, p = 0.13 PA (% moderate-intensity): 58 versus 47, p = 0.51 NA NA
McIntyre et al.; 2012 NA FG (change in mmol/L): 0.25 + 0.56 versus 0.12 + 0.42, NS; Insulin (change in μU/mL): 1.49 + 4.23 versus 0.06 + 3.89, NS Change in weight (kg): 0.97 + 3.7 versus 0.22 + 4.2 NS PA (median (range) increase in planned PA min/week): 60 (0−540) versus 0 (0−580); p = 0.234; walking: NS NA NA
Ratner et al.,; 2008 Diabetes Prevention Project (DPP) Diabetes: 53% risk reduction versus placebo, p = 0.002 NA Weight (change in kg): −5.13 ± 0.43 versus approx. 0 in placebo at 6 months; 1.6 ± 0.80 versus approx. 0 in placebo at 3 years PA (change in h/week): 1.5 h/week versus NA in year 1; <0.5 versus NA in year 3. NA NA
Reinhardt et al.; 2012 NA NA BMI (difference in change in kg/m2): −1.5 (95% CI: −2.8, −0.1); Weight (difference in change in kg): −4.0 (95% CI: −7.6, −0.5) LTPA (change in min/day): 11 (95% CI: 1, 22) Total fat (change in g/day): −19 (95%CI: −37, −1); GL (unit change) −26 (95% CI −48, −4) NA
Shyam et al.; 2013 NA Glucose: 2-h post 75 g OGTT (median mmol/l, IQR): −0.2 (2.8) versus 0.8 (2.0), p = 0.025; Insulin (<2 μU/L): 61.5% versus 52.6%, p = 0.228 Weight (% achieving goal): 33% versus 8%, p = 0.01 PA (median MET-min/week, IQR): 933 (1403) versus 965 (857), p = 0.908 Fat (g): 58 ± 18 versus 53 ± 16, p = 0.695 for difference in change; Fiber (g): 17 ± 4 versus 13 ± 4, p = 0.02 for difference in change; GI: 57 ± 5 versus 64 ± 6, p = 0.033 for difference in change
Wein et al.; 1999 Diabetes (annual IR): 6.1% versus 7.3% (IRR = 0.83, 95% CI: 0.47, 1.48) NA NA NA NA
RCT = randomized clinical trial; FU = follow-up; GDM = gestational diabetes mellitus; IGT = impaired glucose tolerance; PA = physical activity; FG = fasting glucose; GI = glycemic index; PA = physical activity, LTPA = leisure-time physical activity.

Of these studies, two examined the impact of the lifestyle intervention on the subsequent incidence of diabetes , and four examined the impact on postpartum biomarkers of insulin resistance .

In terms of other risk factors for diabetes, all with the exception of one study examined the impact of the lifestyle intervention on weight change and physical activity. Four of the trials examined the impact on diet . Only one study to date reported the impact on breast-feeding .

Methods

We conducted a literature search of PubMed for English language studies of randomized controlled trials of lifestyle interventions among women with a history of GDM. Only published peer-reviewed journal articles of original research in the English language were included. Keyword searches included the following: lifestyle intervention, randomized controlled trial, type 2 diabetes, prevention, diet, physical activity, postpartum, pregnancy, weight retention, GDM, and health behaviors. Additional relevant articles cited in the reference lists of identified papers were retrieved manually.

In total, nine randomized controlled trials of lifestyle interventions conducted among women with a history of GDM were identified to fulfill the eligibility criteria ( Tables 1 and 2 ) .

Table 1
Randomized trials of lifestyle interventions to reduce risk of type 2 diabetes among women with gestational diabetes mellitus (GDM); study designs.
Author (year) Name Design Pilot Population Intervention Mode Goals
Cheung et al.; 2011 RCT; FU: 12 months Pilot 43 women with previous GDM <4 years previously; Australia Exercise intervention vs. usual care control individualized in-person; telephone; mailings PA: 150 min/week or 10,000 steps/day for 5 days/week.
Ferrara et al.; 2011 DEBI (Diet, Exercise and Breastfeeding Intervention) RCT; FU: 12 months Pilot 197 women with current GDM; California Lifestyle intervention (diet, exercise, breast-feeding) versus usual care control individualized in-person; telephone Weight: return to prepregnancy weight if normal, lose 5% of prepregnancy weight if overweight; PA: 150 min/week of moderate-intensity or harder; Diet: ≤25% calories from fat; Breast-feeding: exclusively for 6 months
Hu et al.; 2012 Tianjin Gestational Diabetes Mellitus Prevention Program (TGDMPP) RCT; 1 year Preliminary results 404 women with previous GDM from 05 to 09; China Lifestyle intervention (diet and exercise) versus usual care control individualized in-person Weight: no weight loss if normal weight, lose 5–10% of prepregnancy weight if BMI≥24 kg/m 2 through reduction of ≥10% total calories; PA: 150 of moderate-intensity or harder; Diet: TF <30%; fiber 20–30 g/day; % calories from fat
Kim et al.; 2012 RCT; FU: 13 weeks Pilot 49 women with previous GDM within past 3 years; Michigan Exercise intervention versus usual care control web based Steps: up to 10,000 steps/day
McIntyre et al.; 2012 RCT; FU: 12 weeks Pilot 28 women with previous GDM 6 weeks post partum; Australia Exercise intervention versus usual care control individualized in-person; telephone PA: 150 min/week
Ratner et al.; 2008 Diabetes Prevention Project (DPP) RCT; FU: 2.8 years. 350 women with previous GDM and current elevated glucose levels from the DPP; US Lifestyle intervention (diet and exercise) versus placebo individualized in person; group sessions Weight: Reduction ≥7% of initial body weight; Diet: low-calorie, low-fat; PA: moderate intensity ≥150 min/wk.
Reinhardt et al.; 2012 RCT; FU: 6 months Pilot 38 women following GDM diagnosis; Australia Lifestyle intervention (diet and exercise) versus usual care control telephone; mailings Healthy eating and physical activity
Shyam et al.; 2013 RCT; FU: 6 months 77 women with previous GDM within 2 months; Malaysia Low GI diet versus usual care control in-person; text messaging, emails Weight: 5–7% reduction in body weight if BMI >23 and maintain if normal; PA: moderate intensity 30 min/day for 5 times/week
Wein et al.; 1999 RCT; FU: 796 person-years (median 51 months) 200 women with previous GDM from 89 to 91 and subsequent IGT Diet intervention versus control telephone; mailings Diet: healthy eating; PA: exercise (30 min for 3 times/week)

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Nov 6, 2017 | Posted by in OBSTETRICS | Comments Off on Lifestyle interventions to reduce risk of diabetes among women with prior gestational diabetes mellitus

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