SAHARA - South Asian HeArt Risk Assessment


Overview


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The South Asian HeArt Risk Assessment (SAHARA) randomized trial will compare the effectiveness of a one-year interactive multimedia health behaviour intervention to usual care in reducing MI (myocardial infarction) risk factors among South Asians living in two regions of Canada: Ontario and BC. SAHARA will also investigate whether knowledge of genetic risk for MI influences behaviour change. Information generated from SAHARA will directly inform health policy and programming aimed at preventing MI incidences, and will increase our understanding of the influence of genetic risk as a motivator for behavioural change.


Background


South Asians demonstrate increased plasma glucose, apolipoprotein B and systolic blood pressure and lower apolipoprotein A as their BMI increases above 21, compared to white Caucasians who are able to "defend" their overweight and avoid these changes until their BMI increases above 30. As indicated by previous studies, the likely pathophysiology of South Asians' heightened sensitivity to weight gain is their increased tendency to develop visceral and ectopic fat (which are associated with negative health outcomes) when in a state of energy excess. While certain genetic variants may interact with environmental factors to explain this ethnic phenomenon, the prevention of weight gain, weight maintenance, and weight loss may be the single most important strategy to reduce MI risk factors among South Asians.


Objectives


Among South Asian men and women 30 or more years of age who live in the Greater Toronto and Vancouver areas, we propose:

1. To determine if a multimedia-based health behaviour intervention designed to improve health behaviours, including dietary habits and physical activity, improves the MI risk factor score.

2. To determine if knowledge of genetic risk for the 9p21 variant associated with MI influences behavior change and the MI risk factor score.


Methodology


SAHARA is a single-blinded randomized trial comparing intervention to usual care for changes in INTERHEART risk score following 1 year in the study. The INTERHEART risk score is a simple and valid risk factor scoring system that was developed by the Public Health Research Institute (PHRI) based on data from the INTERHEART case-control study.

Eligible participants are South Asians 30 years of age or older, and they are recruited from community meeting places including places of worship and cultural centres. Participants are invited for an assessment where socio-demographic information, and dietary, physical activity and past medical history are used to calculate the INTERHEART risk score. Physical measures, including blood pressure, body weight and height (to calculate BMI), and waist and hip circumference, are also collected. A brief set of 3 questions regarding health-behaviour changes are administered, and a 30 mL non-fasting blood sample is collected from all participants.

Subjects randomized to the control group are encouraged to access the SAHARA website for South Asian-specific heart disease prevention advice. For the intervention group, we are using a strategy of goal setting, self-monitoring, and continual re-enforcement using readiness-for-change-oriented messages that support motivation and confidence for behaviour change. Brief messages are sent by email or text message once per week (method and time of message delivery are chosen by the participant) and are geared to motivate subjects to make changes. They include advice and support regarding reduction of energy-dense, nutrient poor foods (i.e. fried, fast foods, sugary beverages, and desserts), and promote increased consumption of fruits and vegetables. Physical activity messages are geared towards decreasing sedentary behaviours and increasing regular physical activity. All health messages are culturally relevant and will be tailored for the duration of the study to the participant's current stage of change.

All subjects receive a telephone call at 3 and 9 months to monitor their success at meeting their goals, and to reassess their readiness for change. For the intervention group, this enables us to tailor the type of messages sent in the subsequent three months. All data required to calculate the INTERHEART risk score are collected from all subjects at 6 months and 1 year. Each participant receives a summary of their risk factor profile after each clinic visit.


Progress to Date


The study is complete and in the analysis phase.