A frequently used method for quantifying dietary intake is in the form of quintiles. Compute quintiles for each nutrient and each method of recording, and relate the nutrient composition for DR and FFQ using the quintile scale. (That is, how does the quintile category based on DR relate to the quintile category based on FFQ for the same individual?) Do you get the same impression about the concordance between DR and FFQ using quintiles as in Problem 2.27, in which raw (ungrouped) nutrient intake is considered?

In nutritional epidemiology, it is customary to assess nutrient intake in relation to total caloric intake. One measure used to accomplish this is nutrient density, which is defined as 100% × (caloric intake of a nutrient/total caloric intake). For fat consumption, 1 g of fat is equivalent to 9 calories?

Refer to Problem 2.27,

Use descriptive statistics to relate nutrient intake for the DR and FFQ. Do you think the FFQ is a reasonably accurate approximation to the DR? Why or why not?

Table: 2.18 Format for VALID.DAT

Variable ________________________ Format or code
ID number............................................XXXXX.XX
Saturated fat—DR (g) .........................XXXXX.XX
Saturated fat—FFQ (g)........................XXXXX.XX
Total fat—DR (g)..................................XXXXX.XX
Total fat—FFQ (g)................................XXXXX.XX
Alcohol consumption—DR (oz)..........XXXXX.XX
Alcohol consumption—FFQ (oz) .......XXXXX.XX
Total calories—DR (K-cal).................XXXXXX.XX
Total calories—FFQ (K-cal) ..............XXXXXX.XX