The Scottish Heart Health Study. Dietary intake by food frequency questionnaire and odds ratios for coronary heart disease risk. I. The macronutrients.

Identification of the risk of coronary heart disease (CHD) from nutrients in the diet is of importance to both primary and secondary disease prevention. This paper reports the mean intakes and odds ratios for the macronutrients in groups of CHD-diagnosed, -undiagnosed and CHD-free men and women, aged 40-59 years, who participated in the Scottish Heart Health Study (n = 10,359). Diet was assessed by food frequency questionnaire and odds ratios were determined relative to the lowest quintile and adjusted for the classical CHD risk factors (+/- social class). Six per cent of the study population were CHD-diagnosed and 14.5% were identified as possible cases of undiagnosed CHD. The results suggest that change in diet as a result of diagnosis does occur, and is more pronounced in men. The effect is to give odds ratios, for diagnosed CHD, opposite to those which may be expected on the basis of current knowledge of nutrition and CHD risk. According to the intake data from the undiagnosed group, a relatively low energy intake, a high percentage of energy from protein and a moderate percentage of energy from alcohol diet are favourable factors with respect to CHD risk for men. For women, only alcohol significantly altered risk of undiagnosed CHD, and surprisingly, no measure of dietary fat showed a modifying effect on risk of undiagnosed CHD for men or for women. The implications, and influence of measurement error and variance on these results are discussed.