. 2021 Sep 2;25(7):1893–1903. doi: 10.1017/S1368980021003785

Table 2.

Validation of uncalibrated and calibrated energy intake against TEE measured using the DLW method

	TEE (kJ/d)^†		Energy intake (kJ/d)^†				Difference against DLW (kJ/d)^‡				CC by DLW^§				P-value^íí
	TEE (kJ/d)^†		Energy intake (kJ/d)^†				Difference against DLW (kJ/d)^‡				Uncalibrated		Calibrated
	DLW		Uncalibrated		Calibrated		Uncalibrated		Calibrated		Crude	Deattenuated	Crude	Deattenuated
	Median	IQR	Median	IQR	Median	IQR	Median	IQR	Median	IQR	r	r	r	r
Total (n 72)	8559	7466–10 118	7088	6308–8003	9269	8249–10 060	−1847	−2785–-1096^*	463	−330–1541	0.275^*	0.306^*	0.517^*	0.576^*	0.016
Sex
Women (n 31)	7742	6389–8859	6541	5977–7053	8173	7563–8504	−1569	−2168–-1064^*	722	−695–1390	0.115	0.130^*	0.340^*	0.383^*	0.217
Men (n 41)	9489	8401–10 433	7837	6996–8420	9900	9469–10 267	−2197	−2954–-1453^*	285	−218–1691	0.246	0.277^*	0.469^*	0.528^*	0.049
Age (years)
<75 (n 47)	8815	7046–10 185	6928	6015–7642	9132	8301–10 099	−2168	−2954–-1489^*	609	−227–1384	0.284	0.310^*	0.598^*	0.652^*	0.014
≥75 (n 25)	8401	7732–9619	7837	6726–8895	9360	7921–9797	−1193	−2140–-516	310	−392–1723	0.168	0.191^*	0.333^*	0.377^*	0.290
BMI (kg/m²)
<18.5 (n 7)	6728	6370–8438	7533	6128–8913	9203	7521–9673	−1353	−1707–-289	1295	764–2929	0.464	0.526^*	0.821^*	0.931^*	0.076
18.5–24.9 (n 45)	9288	7439–10 306	6996	6496–7897	8987	8189–10 099	−1846	−2863–-1097^*	77	−1030–1067	0.213	0.237^*	0.475^*	0.529^*	0.016
≥25 (n 20)	8093	7795–9109	7147	6077–7983	9462	8650–9978	−2154	−2770–-1528^*	942	108–1716	0.291	0.326^*	0.541^*	0.605^*	0.049

CC, correlation coefficient; DLW, doubly labelled water; IQR, interquartile range; TEE, total energy expenditure.

Indicates statistical significance (P < 0 05).

^†

The variables are shown as median (IQR).

^‡

The values are shown as median difference (IQR). Statistical analysis was conducted by using a Wilcoxon signed-rank test.

^§

The values are shown as Spearman’s rank correlation coefficient. Deattenuated correlation coefficients were calculated using Willett’s equation⁽³⁾ to correct within-person variation in the twice-performed DLW method in May–June and August 2012. The deattenuated correlation was calculated according to the following: r _c = r _o (1 + (S² _w/S² _b)n)^0.5; r _c, corrected correlation coefficient; r _o, observed correlation coefficient; S² _w, within-person variance; S² _b, between-person variance; n, number of replicates per person. Details of the within- and between-person variations used in this calculation are provided in Supplemental Table 1.

^||

To compare the ranking of an individual’s energy intake between uncalibrated and calibrated estimates determined from FFQ data, we used the Meng et al. equation⁽²⁷⁾. If the results presented significant differences, these relationships were interpreted as not being equivalent.

Energy intake conversion factor: 1 kJ = 0.239 kcal.