Physical activity and nutrition intervention for Singaporean women aged 50 years and above: study protocol for a randomised controlled trial.

BACKGROUND: The majority of the older Singaporean women aged 50 years and above are physically inactive and have unhealthy dietary habits, placing them at 'high risk' of non-communicable diseases (NCDs). The adoption of regular physical activity (PA) and a healthy diet are essential lifestyle behaviours to reduce this risk. This randomised controlled trial (RCT) involves the development, implementation and evaluation of a PA and nutrition programme for community-dwelling Singaporean women who currently attend recreational centres (RCs are public facilities supporting social leisure activities) in their local area. The intervention will be developed after conducting formative evaluation with RC attendees and managers through focus group discussions and pilot testing of resources (i.e. surveys, accelerometers, and health booklets). Programme ambassadors (trained, certified fitness instructors and nutritionists) will deliver all sessions in English and Mandarin; implement classes to meet participants' varying needs; and conduct sessions at different times at convenient venues. Social Cognitive Theory (SCT) has been selected as the theoretical framework to inform intervention strategies as it explores the interactions of human behaviour with the environment and has been found to be valuable when developing behavioural change interventions particularly in older adults (J Gerontol B Psychol Sci Soc Sci 67B(1):18-26, 2012; Obesity Reviews 15(12):983-95, 2014). Its major construct, self-efficacy, is invaluable in achieving successful behaviour change, such as increasing levels of PA or improving dietary intake (Trials. 2017; https://doi.org/10.1186/s13063-016-1771-9 ; Psychol Health Med 18(6):714-24, 2013).

METHODS: The development and implementation of the PA and nutrition intervention strategies will be guided by SCT and Motivational interviewing (MI) and implemented by trained programme ambassadors at the RCs. Sixty RCs located in Singapore will be selected from five major geographical districts and randomly allocated to the intervention (n = 30) or control (n = 30) cluster. A sample of 600 (intervention n = 300; control n = 300) women aged 50 years and above will then be recruited from these 60 centres and only the intervention group will be enrolled into the PA and nutrition intervention. It is hypothesised that by the end of the intervention, the intervention group participants compared to the control group will show significantly greater improvements in the following outcome variables: PA and dietary behaviours, health-related quality of life, objective measures of PA, anthropometric, lipid and glucose profiles. Data will be collected at baseline and 6 months and analysed using mixed regression models.

DISCUSSION: It is anticipated that recruitment, retention and compliance of participants will be challenging due to the target group being unfamiliar with such community-based research programmes.

TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry, ACTRN12617001022358. Registered on 14 July 2017.  https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=372984&isReview=true.