Effect of community intervention to reduce heart disease risk - an analysis and interpretation of data obtained from two rural areas in Saskatchewan
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This study is a component of the Heart Health Intervention Evaluation project (HHIE), focusing on the rural intervention and control areas. The purpose of the HHIE project was to analyze and interpret the effectiveness of community intervention programs to bring about dietary change to reduce the risk of heart disease. The primary hypothesis of this study is that community intervention will result in reduced intake of total and saturated fat and increased intakes of carbohydrate (as per cent of total calories), dietary fibre and the antioxidant vitamins, namely, vitamins A, C and E. These nutrients are those documented in this report since they have been identified as having a relationship to heart disease. Dietary intakes assessed at the start of the program and at the end of the program were used to determine whether changes occurred as a result of the intervention program. The non-intervention region was similarly assessed to provide control data. According to a Statistics Canada protocol, subjects of both sexes in the age group 18-7 4 years were randomly selected from the Health Insurance Registration File (HIRF) of Saskatchewan Health. Dietary information was collected by a "mail-out/mail-back" procedure using a three day food diary and questionnaire. Nutrient intake was analyzed using the NUTS nutrient assessment system and Fibrefind, a program developed in the Division of Nutrition and Dietetics for dietary fibre analysis. Data was analyzed using the Minitab Program (Minitab for Windows, Release 11; 1996). Analysis involved the following: (1). For both areas, average intake of each of the nutrients was assessed in 1992- 1993 and again in 1995-1996. Differences in the intake of each of the nutrients between 1992-I993 and I995-I996 was calculated. A paired t-test was performed to see if there were significant changes between the two time periods. (2). Differences between the two regions after three years were then compared by performing an independent t-test. In short, within and between region comparisons were made. The test of significance is reported at p â‰¤ 0.05. No significant nutrient changes were observed in Coteau Hills. In Census District II, there were significant reductions in the absolute intakes of fat, carbohydrate and protein (in g/day) but not in the percentage of fat, protein and carbohydrate. NSP intakes did not change significantly in either region. Again, overall there were no significant increases in the intakes of any of the antioxidant vitamins in either region. Hence there were no significant changes observed with respect to the nutrients being analyzed in either region. There are several interpretations for the lack of change seen in the Coteau Hills. One factor to be considered is the low response in both phases. Of the original sample, only 20.8% in CD 11 and 16.7% in Coteau Hills responded both times. This raises the question of how representative the study sample was. Another factor to consider was the short time period between the Community Nutrition Advocate Program (CNAP) and the evaluation of this study. The CNAP initiated in January 1995, was a major initiative in the dietary intervention aspect in the Coteau Hills region. After initial training, the nutrition advocates went out to the communities in mid-March 1995. The evaluation for the present study was done between November 1995 to January 1996. A period of eight to ten months between the CNAP and the evaluation of the present study may not have been adequate to detect change in something as complex as dietary behavior. It was difficult to interpret the true effects of the intervention program. This is true of any intervention study where a number of factors are not under the control of the investigator. It brings to light that community studies cannot be done as in laboratory settings. It should be appreciated that various other conditions within the community namely, social and economic, and presence of various nutrition services all have an impact on the community. Additionally, the control area too is permitted to have 'natural' conditions; consequently unlike laboratory conditions, it is not possible to filter information into the control area. The community here is subjected to outside influences. These and other possible factors made it difficult to evaluate the success or failure of the intervention program.