This amazes me. How do they tell if people are lying on their food intake on the study questionaires? Well, they do a blood test on their triglycerides. If their triglycerides are low, then they are eating a lot of fat.

American Journal of Epidemiology Vol. 154, No. 12 : 1107-1112
2001 by The Johns Hopkins University School of Hygiene and Public Health

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NUTRITIONAL EPIDEMIOLOGY

Assessment of Questionnaire Validity for Measuring Total Fat Intake using Plasma Lipid Levels as Criteria
Walter Willett1,2,3, Meir Stampfer1,2,3, Nain-Feng Chu3, Donna Spiegelman3,4, Michelle Holmes2 and Eric Rimm1,2,3
1 Department of Nutrition, Harvard School of Public Health, Boston, MA.
2 Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.
3 Department of Epidemiology, Harvard School of Public Health, Boston, MA.
4 Department of Biostatistics, Harvard School of Public Health, Boston, MA.

ABSTRACT

The validation of dietary total fat measurements has been elusive because no specific biomarker exists. In metabolic studies with controlled diets, plasma fasting triglyceride levels are reduced with higher fat intake and can thus serve as an "alloyed gold" standard. Participants in this cross-sectional analysis were 269 men aged 47–83 years from the Health Professionals Follow-up Study who completed a semiquantitative food frequency questionnaire and provided fasting blood specimens in 1994. In a multiple regression analysis adjusted for age; smoking; alcohol consumption; physical activity; body mass index; and intakes of protein, dietary fiber, and total energy, total fat intake was inversely associated with fasting triglycerides (for a fat increase of 1% of energy, triglyceride levels were lower by 2.5% (95% confidence interval: -3.7 to -1.3%, p = 0.0002)). For reported fat intakes of 20% or less of energy, the geometric mean fasting triglyceride level was 179, and for more than 40% of energy, it was 102 mg/dl. In addition, as predicted by metabolic studies, the inverse association between dietary fat and fasting triglyceride level was much stronger among overweight men than among men with a BMI of less than 25. These data provide additional evidence that informative measurements of dietary fat can be obtained by carefully constructed food frequency questionnaires.

Acta Med Scand 1985;217(5):481-9

Triglycerides--main lipid risk factor for cardiovascular disease in women?
Lapidus L, Bengtsson C, Lindquist O, Sigurdsson JA, Rybo E.

A 12-year longitudinal population study of 1462 women, aged 38-60, was carried out in Gothenburg, Sweden in 1968-69. Women with high initial serum triglyceride values had a higher 12-year incidence of myocardial infarction, stroke and total mortality than the others. The findings for serum triglycerides persisted for myocardial infarction, stroke and total mortality after adjustment for other possible risk factors for ischaemic heart disease such as age, systolic blood pressure, smoking, indices of obesity and serum cholesterol, while serum cholesterol did not predict any end-points studied when taking other risk factors including serum triglycerides into account.

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Ann Intern Med 1999 Sep 7;131(5):376-86

Potential new cardiovascular risk factors : left ventricular hypertrophy, homocysteine, lipoprotein(a), triglycerides , oxidative stress, and fibrinogen.

Harjai KJ.

Department of Cardiology, Ochsner Clinic, New Orleans, Louisiana 70121, USA. kharjai~ochsner.org

The 1996 Bethesda Conference acknowledged left ventricular hypertrophy, hyperhomocysteinemia, lipoprotein(a) excess, hypertriglyceridemia, oxidative stress, and hyperfibrinogenemia as possible new cardiac risk factors. This review summarizes the current literature that supports these conditions as cardiac risk factors. Left ventricular hypertrophy is an independent risk factor for vascular disease. Improvement or progression of left ventricular hypertrophy influences subsequent cardiovascular complications. Clinical trials are under way to assess the potential benefit of decreasing homocysteine levels. The role of lipoprotein(a) excess in vascular disease is controversial. The atherogenic potential of lipoprotein(a) seems to be neutralized by effective reduction of low-density lipoprotein cholesterol levels. Increasing evidence supports an independent role of hypertriglyceridemia in cardiovascular disease and a possible clinical benefit from decreasing triglyceride levels. Among antioxidant micronutrients, supplementation with vitamin E has been shown to be beneficial in primary and secondary prevention studies. Data supporting the use of other antioxidants are much weaker. Preliminary evidence suggests that reducing fibrinogen levels in patients with high baseline levels and coronary disease may be beneficial. Despite the potential relation between new risk factors and cardiovascular disease, routine clinical application of these conditions as cardiovascular risk factors would be premature. Evidence is needed that these conditions extend prognostic ability beyond conventional risk factors and that modification of these conditions can reduce the risk for cardiovascular events.