A clinical trial is testing the effectiveness and usefulness of a preventive health action centred on physical activity and dietetics among people who have been living as a couple for less than two years. An Australian randomized controlled trial by Dzator and colleagues, published in the Journal of Clinical Epidemiology in 2004, evaluates over 12 months the effectiveness and cost-effectiveness of a primary prevention program combining physical activity and healthy eating on the fitness, diet and cholesterol levels of people living in a couple for less than 2 years. The results show a healthier diet, improved fitness and cholesterol levels for up to 12 months in the program participants compared to the control group.

The rationale of the study

Marriage or cohabitation can have a negative impact on people's health. People living in a couple for the first time tend to increase their energy intake and decrease their physical activity leading to weight gain. This lifestyle increases health risk factors such as cardiovascular disease and chronic diabetes. Cardiovascular disease is the leading cause of death in many countries. In Australia, 39% of deaths in 2000 were associated with cardiovascular disease. They also represent a significant economic and social cost. 12% of health expenditure in Australia in 1993 and 1994 was spent on CVD care, amounting to $3.7 billion. The level of physical activity is insufficient to provide health benefits for half of Australians. Lack of physical activity has significant costs in terms of morbidity and mortality. Between 1989 and 2000, overweight and obesity rates increased from 48 to 67% for men and 34 to 52% for women. Weight gain also increases the risk of type 2 diabetes. The question asked Is a preventive health program based on education for healthier eating and regular physical activity cost-effective?

The method

The randomized controlled trial by Dzator et al. compares the cost-effectiveness of two health prevention actions based on physical activity and diet and the adoption of a healthier lifestyle. The study involved 81 couples living together for the first time for less than 2 years. The participants were randomly placed in 3 distinct groups: one group benefited from the physical activity and nutrition program (high intensity), another group benefited from the same program but less intense (low intensity) and a control group. The biological measures were systolic and diastolic pressure and heart rate. Anthropometric measurements included weight, height, waist and hip circumference. Fasting blood was taken to determine total cholesterol and high-density lipoprotein (HDL) levels. Measurements were made on the 3-day diet (Xyris Diet/1 Software and Short Fat Questionnaire), the level of physical activity (7-day recall questionnaire and 14-day activity recall) and the economic cost of the programs. The measures were taken at the beginning of the intervention, at the end of the intervention at 16 weeks and at 12 months of follow-up.

The non-drug intervention (NMI) tested

The physical activity and diet program lasted 4 months. The program consisted of a series of 6 modules covering nutrition, physical activity and the benefits of adopting a healthy lifestyle. A physical activity professional and a dietician trained in primary prevention explained the objective of the program to the couples during the first visit. Intensive program: Sessions were mailed out and alternated with supervised sessions. Each group consisted of 8 couples. Low-intensity program: Participants attended an initial group session. Then the modules were mailed out every 2-3 weeks. The physical activity program was designed to encourage participants to engage in at least 30 minutes of moderate physical activity on most days of the week. Health education themes included the health benefits of exercise, healthy eating, how to start an exercise program, how to prevent injuries, how to recognize signs of overuse, and how to maintain physical activity over time even as a couple. The nutrition program was designed to encourage healthy eating habits that are high in fruits, vegetables, fibre and low in fat and salt. Educational modules covered the healthy diet pyramid, types and sources of dietary fat, healthy eating on a budget, specific nutritional needs and guidelines for healthy menu choices in restaurants.

The main results

The results show that both health prevention programs are effective in improving the physical and nutritional health of participants compared to the control group. The results also show a greater improvement in cholesterol levels, blood pressure, fat intake, and level of physical activity in the intensive program group compared to the low-intensity program group. The high-intensity program is more cost-effective than the low-intensity program at the end of the intervention and after one year.