Healthy eating and active living after gestational diabetes mellitus (HEALD-GDM): Rationale, design, and proposed evaluation of a randomized controlled trial.

BACKGROUND: Gestational diabetes mellitus (GDM) is a common complication in pregnancy and a significant risk factor for type 2 diabetes (T2D). Most women who have had GDM are not engaging in health behaviours known to reduce their risk for developing future T2D. The objective of this study is to evaluate the effectiveness of a lifestyle modification program targeting healthy eating and active living behaviours after a GDM pregnancy. METHOD: This trial will randomize 100 women to either a lifestyle modification program or a control condition. Those allocated to the Healthy Eating and Active Living for Diabetes and Gestational Diabetes Mellitus (HEALD-GDM), program will receive a previously developed and tested 24-week program led by an Exercise Specialist at a local recreational facility. The original HEALD program will be tailored for women with GDM through the provision of complementary childcare at HEALD-GDM sessions and theory-guided peer-led telephone support. Our primary outcome is the 6-month change in objectively derived average daily moderate and vigorous physical activity. DISCUSSION: Programs to increase physical activity in women with GDM should carefully consider and find ways to address known barriers specific to this population. We believe that our modified program may be successfully translated to women who have had GDM. CLINICAL TRIALS REGISTRATION: NCT02483949.

Testing social-cognitive mediators for objective estimates of physical activity from the Healthy Eating and Active Living for Diabetes in Primary Care Networks (HEALD-PCN) study.

OBJECTIVE: More evidence from prospective studies is needed to determine 'if' and 'how' social cognitive constructs mediate behaviour change. In a longitudinal study, we aimed to examine potential social cognitive mediators of objectively measured physical activity (PA) behaviour among people with type 2 diabetes (T2D) who participated in a six-month PA intervention. METHODS: All participants from the proven effective Healthy Eating and Active Living for Diabetes in Primary Care Networks trial were included for this secondary analysis. Change in pedometer-derived daily step counts (baseline to six months) was the outcome of interest. Primary constructs of interest were from Social Cognitive Theory, however constructs from and Theory of Planned Behaviour were also tested in a mediating variable framework using a product-of-coefficients test. RESULTS: The sample (N = 198) had a mean age of 59.5 (SD 8.3) years, haemoglobin A1c 6.8% (SD 1.1), 50% women, BMI 33.6 kg/m(2) (SD 6.5), systolic pressure 125.6 mmHg (SD 16.2) and average daily steps were 5879 (SD 3130). Daily pedometer-determined steps increased for the intervention group compared to usual care control at six-months (1481 [SD 2631] vs. 336 [SD 2712]; adjusted p = .002). There was a significant action theory test effect for 'planning' (A = .21, SE = .10, p = .037), and significant conceptual theory test results for 'subjective norms' (B = 657, SE = 312, p = .037) and 'cons' (B = -664, SE = 270, p = .015). None of the constructs satisfied the criteria for mediation. CONCLUSIONS: We were unable to account for the effect of a pedometer-based PA intervention for people with T2D through our examination of mediators. Our findings are inconsistent with some literature concerning PA interventions in diabetes; this may be due to variability in measures used or in study populations.