American Journal of Clinical Nutrition, Vol 48, 1161-1165, Copyright © 1988 by The American Society for Clinical Nutrition, Inc

ORIGINAL RESEARCH COMMUNICATIONS

Diet and blood cholesterol in population surveys--lessons from analysis of the data from a major survey in Israel

A Keys
Division of Epidemiology, School of Public Health, University of Minnesota, Minneapolis 55455.

A careful survey of the diet and serum cholesterol of civil servants in Israel covered 8829 men, aged 40-60 y born in six different areas. The authors were disappointed in their failure to find relationships between the diets and serum cholesterol of the individual men. Their report gives mean values for calories, diet fatty acids, and serum cholesterol for the men grouped by areas of birth. Regression analysis shows highly significant relations of serum cholesterol means to means of diet fatty acids for areas of birth. The relations found conform closely to expectations from dietary experiments in metabolic wards. Failure to consider intraindividual relations in the variables explains the disappointment of the authors of the report on the Israelis. Similar lack of attention to intraindividual variability is frequent in surveys and epidemiological studies and leads to error, controversy, and waste of time and money.