Abstract
Background: Metabolic syndrome (MetS) is a cluster of interrelated risk factors, including central obesity, dyslipidaemia, hypertension, and impaired glucose regulation, that increase the risk of cardiovascular disease, type 2 diabetes, and other chronic conditions. Its prevalence among adults of reproductive age is rising, with implications for both individual and intergenerational health. Evidence shows that both maternal and paternal preconception health influence offspring metabolic risk via genetic, epigenetic, and behavioural pathways. Despite this, preconception lifestyle interventions have predominantly targeted women, with minimal attention given to couples as a unit of change. Couples-based approaches may improve adherence and sustainability of healthy lifestyle behaviours through shared goals, mutual support, and accountability. This thesis aimed to investigate the feasibility and value of a True Couples-Based Intervention (TCBI) for preconception health through an exploratory sequential mixed methods design.Methods: The research was underpinned by a postpositivist pragmatic approach and comprised three interlinked studies within a sequential mixed methods design. Phase 1 was a systematic review of couples-based behaviour change interventions targeting diet and/or physical activity for MetS prevention. The review synthesised peer-reviewed studies to determine effectiveness, theoretical underpinnings, and integration of relational dynamics. Phase 2 was a qualitative study involving semi-structured interviews with heterosexual, nulliparous women and their partners of reproductive age, conducted individually with each partner. Thematic analysis explored perceived barriers, facilitators, and preferences for joint participation in a lifestyle program, with emphasis on relational influences on health behaviours. Phase 3 was a 10-week feasibility study of an online TCBI, incorporating dietary and physical activity advice, self-monitoring, and feedback at set intervals. Quantitative data included anthropometry, dietary intake, and sedentary time, analysed descriptively at baseline and completion. Qualitative dyadic interviews captured participants’ experiences of the intervention, and thematic analysis identified factors influencing engagement and adherence. Findings were integrated across all phases to identify convergent, complementary, and unique insights.
Results: Phase 1 identified a limited number of couples-based interventions relevant to MetS prevention, with few conducted in the preconception context. Most lacked explicit use of behavioural theory and gave limited attention to spousal concordance or relational mechanisms of change. This evidence gap provided the rationale and design considerations for the subsequent qualitative and feasibility studies. Phase 2 revealed that couples valued joint participation, mutual encouragement, and shared accountability, while also anticipating challenges such as time constraints, environmental barriers, and differences in motivation. Participants expressed a preference for flexible, personalised interventions that could be integrated into daily life. These insights informed the content, delivery mode, and support strategies used in the feasibility study.
In Phase 3, retention and completion rates were high, and most couples reported making positive dietary changes, including increased vegetable intake and reduced discretionary foods. Several couples achieved measurable improvements in anthropometric indicators, even if they did not reach healthy ranges within the short intervention period. However, sedentary behaviour remained high for many participants. Qualitative findings indicated that couple support and engagement were central to adherence, with joint goal-setting and shared responsibility fostering motivation. Barriers included competing priorities, limited access to resources, and differences in readiness for change. The intervention was acceptable and relevant to participants, who recommended greater personalisation, interactive components, and integration with community or healthcare services.
Conclusions: The systematic review provided foundational evidence on the scarcity and limitations of existing couples-based interventions for MetS prevention, guiding the development of a preconception-focused approach. The qualitative study offered rich insight into relational, motivational, and contextual factors shaping couples’ engagement with lifestyle change, which directly informed intervention design. The feasibility study demonstrated that a TCBI is acceptable, implementable, and capable of achieving positive dietary and anthropometric changes within a short timeframe, though addressing sedentary behaviour may require additional strategies. Collectively, these findings offer novel, multi-phase evidence that targeting both partners in the preconception period is a promising strategy to improve adherence, foster sustainable behaviour change, and reduce intergenerational risk of MetS. Future research should test this approach in larger, more diverse samples, over longer durations, using objective measures, and assess cost-effectiveness and integration into existing preconception and primary care frameworks.
| Date of Award | 2026 |
|---|---|
| Original language | English |
| Supervisor | Ro McFarlane (Supervisor) & Cathy KNIGHT-AGARWAL (Supervisor) |
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