Table 1.

Usual Daily Intakes of Caffeine and Caffeine-Related Beverages Calculated From the FFQ and the 24HDR (n = 249) in the BioCycle Study, 2005–2007

	FFQa		24HDRb		P Valuec	Correlation
	Mean (SD)	Median (IQR)	Mean (SD)	Median (IQR)		Rd	Re
Caffeine, mg/day	114.1 (146.1)	68.1 (19.5–147.5)	92.6 (95.1)	59.8 (19.4–140.8)	0.006	0.68	0.73
Coffee, cups/dayf,g	0.76 (1.34)	0.09 (0.00–1.00)	0.51 (0.75)	0.00 (0.00–0.94)	<0.001	0.91	0.99
Coffee drinks/cocoa, cups/dayh	0.18 (0.50)	0.05 (0.00–0.15)	0.09 (0.33)	0.00 (0.00–0.00)	<0.001	0.39	0.40
Tea, cups/day	0.38 (0.75)	0.09 (0.00–0.39)	0.36 (0.49)	0.17 (0.00–0.50)	0.38	0.57	0.59
Soda, cups/day	0.41 (0.68)	0.12 (0.03–0.42)	0.57 (0.71)	0.31 (0.00–0.80)	<0.001	0.68	0.71

Abbreviations: FFQ, food frequency questionnaire; 24HDR, 24-hour dietary recall; IQR, interquartile range; SD, standard deviation.

^a Average of FFQ1 and FFQ2 over 2 cycles.

^b Average of eight 24HDRs over 2 cycles.

^c Wilcoxon's matched-pairs signed-ranks test.

^d Pearson's product-moment correlation coefficient on log-transformed data. All correlations were considered significant at P < 0.001.

^e Pearson's deattenuated product-moment correlation coefficient on log-transformed data.

^f Coffee is all types but “not lattes or mochas.”

^g 1 cup = 237 mL.

^h Coffee drinks/cocoa includes “latte, cappuccino, mocha, or hot chocolate.”