Background
Gestational diabetes (GDM) is a well-established postpartum diabetes risk indicator. A systematic review indicates that GDM confers a 7-fold risk increase [
1], with 30–70% of women developing type 2 diabetes within 10 years of a GDM pregnancy [
2]. GDM is also associated with postpartum development of metabolic syndrome [
3], hypertension and cardiovascular disease [
4]. The American Diabetes Prevention Program trial demonstrated that an intervention strategy focusing on eating and physical activity habits can markedly reduce diabetes risk following GDM [
5], although attracting younger mothers is challenging. Studies to date have tailored interventions to mothers, but mothers themselves express a need for partner collaboration for health behaviour change [
6].
Collaboration by partners for diabetes prevention may not only be important for the mother’s health but also for the partner’s health. In a previous study, we demonstrated that GDM in mothers is associated with incident diabetes in fathers [
7]. Shared diabetes risk in partners is likely mediated by shared partner behaviours, as identified through analyses of the English Longitudinal Study of Ageing [
8] and the Framingham Heart Study [
9]. Shared risk and shared behaviours arguably constitute levers for collaboration between partners for diabetes prevention.
We have been developing a multimodal health behaviour change strategy following GDM, and testing it iteratively through a pre intervention/post intervention change design (The MoMM program: M
indful mO
vement, M
indful eating, Mi
ndful living). The aim is to optimize recruitment and engagement through these steps to ultimately launch a large randomized controlled trial. The key elements of this intervention are group sessions with preparation of healthy meals under a dietitian’s supervision and walks, games, and exercises with an exercise physiologist. Both components are coupled with discussion of how to realistically optimize eating and physical activity patterns at home. Sessions are held once per month over 4 to 6 months. On-site childcare is available. We previously reported effects in mothers [
10]. The present study enrolled and evaluated both mothers and their partners (MoMM-ii). The aim of this study was to adapt the previous program to more comprehensively include partners and to evaluate changes in health behaviors and cardiometabolic profiles in both mothers and partners following participation in the MoMM-ii program.
Discussion
This phase IIa trial in couples within 5 years of a GDM history demonstrates that a group based multimodal program (meal preparation, physical activity, on-site childcare, discussion, between-session contact) can engage not only mothers but also partners, and can help both achieve favourable changes in physical activity, dietary choices, and sleep measures. Among the 87% of participants who attended at least one session, three quarters of mothers and 64% of partners completed at least 3 of the 5 scheduled sessions. At baseline, physical activity and sleep duration were under recommended levels; both mothers and partners demonstrated clinically important increases in objective measures of step counts and moderated to vigorous physical activity and increases in sleep duration and quality. Baseline eating behaviours were good at baseline but there were nonetheless some favourable changes including a reduction in sodium-to-potassium intake ratio. However, similar to post GDM programs targeting mothers alone [
27], in this program recruitment of those at risk continues to be challenging. Baseline cardiometabolic measures were well within normal limits on average and eating behaviours were generally good. Consequently, ability to demonstrate impact on BMI and cardiometabolic profiles was limited.
Partners experienced conclusive increases in physical activity as assessed by objective measurement of both step counts (additional 1645 steps/day) and MVPA (additional 36 min/week), and this was corroborated through self-reported measures. Similar effects were observed in mothers. Pedometer-based programs that focus exclusively on step count changes demonstrated increases of 2000 steps/day [
28]. The step count increase level that we observed (1355 steps/day) was notable particularly given that the focus of the program was not strictly on steps. Perhaps even more importantly, we observed an objectively-assessed 30-min increase in MVPA, leading to a greater proportion of participants reaching the 150 min/week of MVPA. This may reflect the inclusion of a variety of physical activity options other than walking alone. Increasing MVPA improves cardiorespiratory fitness, reduces symptoms of depression and may help to reduce heart disease, stroke, high blood pressure and diabetes [
29].
We also observed a trend towards increased consumption in vegetables and fruit as well as a reduction in grain intake, consistent with a reduction in the sodium-to-potassium intake ratio [
30]. The effects on eating behaviours and dietary intake were less pronounced than effects on physical activity and there was no change in BMI. This is likely in part due to the fact that eating behaviours and dietary intakes were more adequate than physical activity at baseline.
The program also moved participants towards the recommended ≥7 h of sleep per night for adults [
26]. In a recent systematic review of prospective studies, Shan and colleagues demonstrated that individuals who sleep an average of 7–8 h per night have the lowest diabetes risk compared to those who sleep more or less than this [
31]. A 7 to 8 h sleep duration has also been associated with lower incidence of hypertension, stroke and coronary heart disease [
32]. The combined effects of higher physical activity levels, greater sleep duration, and lower sodium-to-potassium intake ratio may have contributed to the overall reduction in systolic blood pressure observed [
28,
30,
32]. The risk of cardiovascular disease rises with increasing blood pressure levels in a continuous manner [
33].
Despite the favourable effects on health behaviours, reductions in glucose levels or insulin resistance were not observed, in contrast to our previous study in mothers alone [
10]. In comparison to mothers in that study, those in the current study were younger (mean 38 years, SD 5 vs. 40 years, SD 5) with more recent pregnancy (1.9 years ago SD 1.1 vs. 3.5 years ago SD 2.0) and lower postpartum weight retention (1.9 kg SD 5.4 vs. 4.4 kg SD 5.4). Prediabetes (impaired glucose tolerance and/or impaired fasting glucose) was substantially less prevalent (15% vs. 37%). These differences are likely important in terms of ability to demonstrate effects on glucose handling. O’Reilly and colleagues [
27] conducted a large diabetes prevention program randomized controlled trial among women within 1 year of a GDM pregnancy (MAGDA-DPP). The intervention included 1 individual session, 5 group sessions, and 2 telephone contacts. The overall prevalence of prediabetes was 12%, similar to our current study. At the 1-year assessment, no between group conclusive differences were observed for fasting glucose, oral glucose tolerance testing values, or blood pressure measures. This raises the possibility that even though postpartum diabetes risk is highest during the first 5 years postpartum [
2], prediabetes and insulin resistance may be more apparent beyond 2 years postpartum and thus impact on these measures may be more evident later in life.
The findings in our Canadian study and those of O’Reilly and colleagues in Australia illustrate the challenges of recruitment. The MAGDA investigators enrolled and randomized 7% of potentially eligible participants; we enrolled 6% of potentially eligible participants (Fig.
1). Higher recruitment rates may be achievable in other settings; for example, in an ongoing trial in China (Tianjin trial) [
34], 25% of potentially eligible women were enrolled. Insulin resistance was not measured in the trial by O’Reilly and colleagues but in our single arm intervention trial, the baseline HOMA-IR was normal at 1.2 while in the Tianjin trial it was close to 2. There appears to be a need in some settings to develop better strategies to attract at-risk individuals into diabetes prevention programs. Although we did recruit participants from various ethnicities, including those at high risk for diabetes, their socio-economic status was arguably high (e.g., two thirds had completed a university degree). Moreover, baseline cardiometabolic measures were within normal limits.
Our program focused on the couple rather than on the mother alone. To attract couples at risk, however, may require more focused and effective motivational strategies and knowledge sharing directed at both parents during pregnancy, given the variety of barriers to postpartum participation that have been described [
35]. An alternative is to build a postpartum diabetes prevention program into the structure of care. This approach was tested through a cluster randomized pragmatic trial conducted among 44 Kaiser Permanente clinics in mothers [
36]. However, with such an approach, engagement and attendance is not guaranteed. While 13 telephone coaching sessions were offered to active arm participants in that trial, half did not participate in even one conversation. In the MAGDA trial, 52% received the ‘minimum’ intervention of 1 individualized session and 1 group session; interestingly, greater engagement was achieved in a telephone coaching strategy examined by the MAGDA investigators in a single arm intervention study [
37]. In our single arm intervention study, 87% of those enrolled attended at least one session; moreover, more than 60% of fathers and 75% of mothers attended at least 3 of the 5 scheduled sessions. The active nature of the sessions (e.g., cooking, exercising) may have enhanced their attractiveness.
We have demonstrated that it is possible to engage both partners and mothers in a health behavior change program and that both will derive benefit in terms of improvement in these behaviors. The blood pressure lowering observed also signal a cardiometabolic impact of these behavioural changes. There are several limitations to our study. First, it is not a randomized controlled trial but rather a single-arm intervention study; thus there is no control arm with which to compare our findings. However, this design was deliberately chosen as part of a process of iterative refinement. We ultimately seek to develop an intervention that merits the large investment that a randomized controlled trial requires [
38]. Importantly, although we have demonstrated engagement and impact on health behaviors, we have also determined that recruitment strategies must be further refined to attract those most at risk and in whom metabolic benefit can be corroborated. Finally, the ideal randomized controlled trial will include not only health behaviour, engagement, and cardiometabolic outcomes, but also clinical outcomes such as recurrent GDM and incident type 2 diabetes.
Acknowledgements
We thank Deborah Chan, Rani Cruz and Cindy Ibberson (research assistants) for their help with recruitment, assessments, coaching and coordinating the in-person sessions and Andrea Blotsky and Alexandra Cooke (graduate students) for their help with assessments. We thank Thea Demmers, MSc, RD who led the nutrition sessions (PERFORM Centre, Concordia University). She was assisted by Nasim Saberi RD and Shawna Birman RD and by trainees (Kate Sinclair, Angela Pacey, Alison Walker, Ailee Shinoki, Julia Burt, Chantal Bourrassa). We also thank Christina Weiss MSc, Kinesiologist who led the physical activity sessions. She was assisted by Tanja Trost, Pierre Tobjian and Kyle Van Der Vlist.