Dietary intervention for age-related macular degeneration patients

This two-year project will implement and evaluate a telephone-delivered dietary behaviour intervention for AMD patients, aiming to promote a diet that is rich in vegetables, fruits, fish, low-glycaemic index foods and the appropriate use of antioxidant supplements. It will have a two-pronged approach: (1) ensures the correct information on diet and AMD is passed onto the patient; and (2) an accredited practicing dietitian (APD) provides telephone coaching and support to facilitate and enhance the patients’ adoption of dietary recommendations. Participants will be randomised to one of two groups - intervention or wait-list control Participants in the intervention group will be mailed a workbook that contains information on dietary behaviours promoting optimal macula health; information on goal setting; problem-solving; self-rewards; positive self-talk; relapse, and action plans. They will be scheduled to receive weekly phone calls over 4 months from the counsellor (accredited practicing dietitian, APD). The initial consultation over the phone will be about 30-45 mins in duration and subsequent weekly follow up phone calls will be about 15-20 minutes in duration. Content of calls will be tailored to participants’ stage of change. For all stages, there will be a discussion of the diet-disease relationship, as well identification of appropriate goals, and arrangement of follow up calls. Participants in a ‘pre-contemplative’ or contemplative’ stage, will participate in calls that focus on self-reevaluation, environmental re-evaluation, and general dietary advice e.g. key food groups, and recommended serves. Participants in the ‘preparation’, and ‘action’ stages, will be engaged in calls that focus on goal setting, strategies to achieving goals, and discussion of barriers to change. A prospective, randomised trial design will be used to determine pre- and post-intervention changes in dietary intakes and behaviours. Intakes will be assessed using a validated 145-item Food Frequency Questionnaire (FFQ) and a Dietary Behaviour Questionnaire (DBQ). The FFQ and DBQ will be used at baseline, and 6 months post-intervention, while the DBQ alone will be used at the end of the 4-month intervention, and at 3 months. The intervention and controls group will be compared based on post-intervention intake levels and behaviour change. All participant contacts will be systematically tracked to allow for reporting on: the number of call attempts, completed calls (or ‘dose’ of intervention received), number of calls completed at the scheduled time (versus via call back), reasons for missed calls, and call duration. The call content will be tracked via checklists completed after each call allowing for reporting on the extent to which the intervention content is delivered per protocol, and the percentage of participants setting goals for dietary behaviours. At the end of the intervention, participants will be asked a set of questions that will help us understand their experience of the telephone coaching, including if they found it useful and whether they would recommend this to a friend. Using a Likert scale ranging from 0-5, they will be able to rate their satisfaction with the overall intervention content and the dietary messages provided, as well as their adherence to the dietary advice provided by the dietitian. Finally, they will be able to detail any suggestions on how this intervention could be improved. We will carry out ‘within trial’ cost-effectiveness analysis in which outcomes will be measured as clinically relevant improvements as per the FFQ and DBQ. The perspective taken will be that of health provider. We will collect data prospectively on the costs to deliver the intervention program (telephone calls, staff time, training, mail-outs, and any other intervention resources).