Assessment of energy intake in women with chronic obstructive pulmonary disease: a doubly labeled water method study

To maintain energy balance, reliable methods for assessing energy intake and expenditure should be used in patients with chronic obstructive pulmonary disease (COPD). The purpose of this study was to validate the diet history and 7-day food diary methods of assessing energy intake (EI) using total energy expenditure (TEE) with the doubly labeled water (DLW) method (TEEDLW) as the criterion method in outpatient women with COPD.

EI was assessed by diet history (EIDH) and a 7-day food diary (EIFD) in 19 women with COPD, using TEEDLW as the criterion method. The three methods were compared using intra-class correlation coefficients (ICC) and Bland-Altman analyses. The participants were classified according to their reporting status (EI/TEE) as valid-reporters 0.79-1.21, under-reporters < 0.79 or over-reporters > 1.21.

Diet history underestimated reported EI by 28%, and 7-day food diary underestimated EI by approximately 20% compared with TEEDLW. The ICC analysis showed weak agreement between TEEDLW and EIDH (ICC=-0.01; 95%CI-0.10 to 0.17) and between TEEDLW and EIFD (ICC=0.11; 95%CI -0.16 to 0.44). The Bland-Altman plots revealed a slight systematic bias for both methods. For diet history, six women (32%) were identified as valid-reporters, and for the 7-day food diary, twelve women (63%) were identified as valid-reporters. The accuracy of reported EI was only related to BMI.

The diet history and 7-day food diary methods underestimated energy intake in women with COPD compared with the DLW method. Individuals with higher BMIs are prone to underreporting. Seven-day food diaries should be used with caution in assessing EI in women with COPD.