Measurement error in dietary data: implications for the epidemiologic study of the diet-disease relationship.

Abstract

To examine the effect of measurement error in dietary data on the relationship between diet and body mass index (BMI). To correct for the effect of measurement error on diet-BMI association by using replicate measurements of diet. The effect of measurement error on diet--BMI relationship was simulated, and its implications are discussed. Prospective study design. The first and second China Health and Nutrition Survey conducted in 1989 and 1991, respectively. Three thousand, four hundred and seventy-nine adults age 20-45 y at the 1989 survey. Statistical methods were used to demonstrate the effect of measurement error in dietary data on the diet-BMI association. By using the average of three replicate 24 h dietary recalls, the attenuation of diet-BMI association was reduced substantially. The regression coefficients of fat and energy intakes differed markedly from those computed by using only single measurement of diet. Measurement error in dietary data may significantly attenuate the diet-disease association. Where appropriate, specific emphasis may be needed to address the problem of measurement error in the study of diet-disease relationship.