Identifying individuals with high fat levels and low P:S ratios, in their diets, for intensive dietary intervention.

Abstract

OBJECTIVES: To assess whether simple scores from a dietary questionnaire could identify those with high dietary fat or low P:S ratio intakes, for intensive dietary intervention. DESIGN: Cross-sectional and longitudinal studies. SETTING: Community setting in the Hunter Region of New South Wales, Australia. SUBJECTS: Two random samples of adults 35-69 years from the electoral roll. In the cross-sectional study 287/322 (86%) subjects completed the diet questionnaire and a reference standard questionnaire. In the longitudinal study 546/653 (84%) of subjects completed the diet questionnaire, and had blood cholesterol measured on two occasions, 3 months apart. MAIN OUTCOME MEASURES: In the cross-sectional study, the simple scores of total fat intake (Fat Intake Score) and P:S ratio (Unsaturated Score) were compared with the daily intakes of total fat and P:S ratio obtained from the standard questionnaire. In the longitudinal study, changes in the scores were compared with changes in blood total cholesterol. RESULTS: A Fat Intake Score of greater than 125 had the best receiver operator characteristics for identifying high total fat intake (> 100 g/day: sensitivity = 67%, specificity = 70%). An Unsaturated Score of less than 0.3 had the best characteristics for identifying a low P:S ratio (< 0.5: sensitivity = 63%, specificity = 60%). Subjects who decreased Fat Intake Score by one category, had a fall in blood cholesterol of 0.14 mmol L-1 (95% confidence interval (CI) = 0.01-0.26 mmol L-1), while those decreasing by two categories decreased their blood cholesterol by 0.56 mmol L-1 (95% CI = 0.30-0.86 mmol L-1). Subjects increasing their Unsaturated Score category had a fall in blood cholesterol of 0.17 mmol L-1 (95% CI = 0.02-0.32 mmol L-1). CONCLUSION: Simple dietary scores can identify those with high fat intakes, and monitor changes related to changes in blood cholesterol levels.