Can adverse effects of dietary fat intake be overestimated as a consequence of dietary fat underreporting?
OBJECTIVE
To describe the consequences of systematic reporting bias by the obese for diet-disease relationships.


METHODS
The present report used 24-hour urinary nitrogen and estimates of 24-hour energy expenditure to assess error in diet reporting, and examined the consequence of accounting for this error for associations between dietary fat intake and serum low-density lipoprotein (LDL)-cholesterol.


METHODS
Sub-study to the Danish MONICA (Monitoring Trends and Determinants in Cardiovascular Disease) project, carried out in 1987-1988.


METHODS
A random sub-sample of the adult Danish male population (n = 152).


RESULTS
Correcting dietary fat for underreporting error weakened, rather than strengthened, the association between dietary fat intake and LDL-cholesterol by reducing the slope of the regression from beta = 3.4, P = 0.02 to beta = 2.7, P = 0.04.


CONCLUSIONS
This example illustrates that systematic underreporting of dietary fat by high-risk groups such as the obese may produce an overestimated association. These results imply that previous epidemiological studies showing a positive association between percentage of energy from fat and other health outcomes, e.g. cancer and heart disease, may have overestimated the negative effects of a high-fat diet. If we were able to correctly assess dietary fat intake in general populations, recommendations for fat intake may be more liberal than the 30% suggested today. Improved assessment of fat intake in epidemiological studies is necessary for future development of evidence-based recommendations for diet and health .
Heitmann
Berit Lilienthal
BL
Research Unit for Dietary Studies and Danish Epidemiology Science Centre, Institute of Preventive Medicine, Copenhagen University Hospital, DK-1399 Copenhagen K, Denmark. blh@ipm.hosp.dk
Lissner
Lauren
L
D000328:Adult; D000368:Aged; D015982:Bias; D008078:Cholesterol, LDL / Q000097:blood*; D003718:Denmark; D004041:Dietary Fats / Q000008:administration & dosage* / Q000009:adverse effects; D004044:Dietary Proteins / Q000008:administration & dosage; D002149:Energy Intake; D004734:Energy Metabolism / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009584:Nitrogen / Q000652:urine; D018673:Nutrition Policy; D009765:Obesity / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D012044:Regression Analysis; D012650:Self Disclosure
D008078:Cholesterol, LDL; D004041:Dietary Fats; D004044:Dietary Proteins; D009584:Nitrogen