Editor—We agree with Epstein that the association between serum cholesterol concentration and the various subtypes of ischaemic stroke may differ. Unfortunately, we do not have enough data to allow us further to study the subtypes of ischaemic stroke in this cohort.
Any possible association between dietary fat and stroke could be attenuated if participants with high dietary fat intake were taking cholesterol lowering drugs. However, error from this source is likely to be modest because our results were virtually unchanged after exclusion of 4474 (10.23%) participants who reported history of hypercholesterolemia at baseline (data not shown).
Ravnskov questioned our statement that the types of fat were more important than total fat in predicting risk of coronary heart disease. Findings from early studies on dietary fat and coronary heart disease were inconsistent, in part, because of the inadequate dietary assessment, incomplete adjustment for total energy intake, and failure to account for other components of diet. On the basis of metabolic studies, epidemiological observations, and randomised trials, the quality of fat rather than the amount of total fat is clearly important in determining risk of coronary heart disease.1,2
Hu et al, which we cited, found that after adjustment for other risk factors, replacement of 5% of energy from saturated fat with the same amount of polyunsaturated fat was associated with a 50% lower risk of coronary heart disease.3 A protective effect of polyunsaturated fat is also supported by the results of randomised clinical trials.4
Competing interests: None declared.
References
- 1.Hu FB, Manson JE, Willett WC. Types of dietary fat and risk of coronary heart disease: a critical review. J Am Coll Nutr 2001;20: 5-19. [DOI] [PubMed] [Google Scholar]
- 2.Ascherio A. Epidemiologic studies on dietary fats and coronary heart disease. Am J Med 2002;113(suppl 9B): s9-12. [DOI] [PubMed] [Google Scholar]
- 3.Hu FB, Stampfer MJ, Manson JE, Rimm E, Colditz GA, Rosner BA, et al. Dietary fat intake and the risk of coronary heart disease in women. N Engl J Med 1997;337: 1491-9. [DOI] [PubMed] [Google Scholar]
- 4.Sacks FM, Katan M. Randomized clinical trials on the effects of dietary fat and carbohydrate on plasma lipoproteins and cardiovascular disease. Am J Med 2002;113(suppl 9B): s13-24. [DOI] [PubMed] [Google Scholar]