A CROSS-SECTIONAL SURVEY OF CARDIOMETABOLIC RISK FACTORS IN PRIMARY CARE PATIENTS WITH ABDOMINAL OBESITY IN CANADA

Abstract

BACKGROUND: The Mediterranean diet has been shown to reduce all-cause and cardiovascular mortality as well as improve cardiometabolic risk profile, endothelial function and reduce markers of vascular inflammation. Since cardiovascular disease is the second cause of death in Canada, randomized clinical trials evaluating the efficacy of the Mediterranean diet in high-risk primary and secondary prevention are warranted. In order to conduct such studies, validated dietary assessment Methods specific to population and food habits are needed. Therefore, the aim of our study was to assess the reproducibility and the relative validity of a quantitative food frequency questionnaire (FFQ) focused on the Mediterranean diet to be used in clinical trials at the Montreal Heart Institute’s Prevention Center. METHODS: Fifty (50) participants (54% (27 of 50) women) aged 19 to 86 years with and without coronary disease were recruited, and randomized in 3 groups in a crossover design where the sequence of administration of questionnaires differed in each group. The FFQ includes 157 food items and was designed to measure food intake over one month. It was administered twice 3 to 5 weeks apart to assess reproducibility and was compared to a 12-day dietary record carried out over a 1-month period to assess validity. Participants were asked not to modify their diet for the duration of the study. FFQs were self-administered and reviewed by a registered dietician. All questionnaires were analyzed using The Food Processor software. RESULTS: For reproducibility (n 1⁄4 47), intraclass correlation coefficients (ICC) for energy and 25 nutrients ranged from 0.38 (95% confidence interval (CI), > 0.15) for folate to 0.91 (95% CI, > 0.85) for alcohol (mean 0.63). For validity (n 1⁄4 48), ICCs ranged from 0.36 (95% CI, > 0.14) for potassium to 0.85 (95% CI, > 0.77) for alcohol (mean 0.57). Gross misclassification of subjects in extreme quartiles of energy and nutrient intake revealed to be between 2% and 6% for energy and each nutrient assessed. CONCLUSION: The FFQ demonstrates good reproducibility and validity for energy and most key nutrients of the Mediterranean diet as well as low gross misclassification of subjects into quartiles of intake. Moreover, the validity of the FFQ reveals to be comparable to other largely used FFQs. Therefore, these results support the eventual use of the FFQ in clinical trials on the Mediterranean diet.