Food Questionnaire or Food Record for Teens with AN?

Anorexia nervosa (AN) is now the third most common chronic illness among teenage girls. Because low bone mineral density is such a common component of the disease, and because it can cause deficient peak bone accrual, it is essential to track calcium and vitamin D intake among these patients. Researchers at Massachusetts General Hospital and Harvard Medical School recently found a food frequency questionnaire (FFQ) helpful for following teens with AN (JADA 2009; 109:479).

Catherine Taylor and a group working with Dr. Madhusmita Misra, recently used both a 4-day food record and an FFQ to assess calcium and vitamin D intake among 107 girls aged 12 to 18 years. Some girls completed one but not the other, but 36 girls with AN and 39 controls completed both questionnaire and food record.  The food record  included 3 weekdays and 1 weekend day, and was validated for use in young women. The subjects were asked to describe portion sizes and preparation methods for all foods listed in the record. Only calcium and vitamin D intake from food, but not supplements, was included. The researchers then calculated the nutrient intake using special software (Minnesota Nutrition Data system, software version 4.03).

Compliance was better with the FFQ

As expected, girls with AN had lower body mass index (BMI, kg/m2) scores and BMI z-scores than did controls (17.4 vs. 21.4, and -1.1 vs. 0.04, respectively). There was no significant difference between energy intake in patients and controls.  Based on the FFQ, 31% of controls and 61% of girls with AN met the Dietary Reference Intake (DRI) for calcium intake, and 5% of controls and 17% of girls with AN met the DRI for vitamin D intake.

Just as Dr. Misra and the team had anticipated, compliance was better with the FFQ than with the 4-day food record, and FFQ results were completed by all but one girl with AN. Completing the food record is more time-consuming and requires girls to remember to fill in the information over several days. Of 107 subjects, 31 did not complete their food records, and two-thirds of non-completers were girls with AN. The authors note that the poor compliance may be due to the reality that filling out a food record over 4 days is a burden for patients who are participating in active treatment programs and already seeing multiple care providers. It also is possible that the girls with AN might have faked their reports, making their intake seen better than it really was.

The higher calcium intake among younger girls with AN and overall in girls with lower BMIs might be an indication of greater self- or parental awareness and attention to diet in younger and lower-weight girls. The age pattern was reversed among the control group, where older girls had a higher intake of calcium than did younger girls.

The authors note that the use of the FFQ led to better compliance than did use of the food record, and that the questionnaire is helpful for assessing calcium and vitamin D intake in teenaged girls with AN.