TABLE 5.

Adjusted ORs (95% CIs) for ferritin levels of less than 12 and less than 26 ng/mL in all subjects

Risk factor		Ferritin < 12 ng/mL		Ferritin < 26 ng/mL
Sex
	Female	3.46 (2.64, 4.54)		5.30 (4.23, 6.62)
	Male	Ref		Ref
Age group (years)		Female	Male	Female	Male
	18-19	2.77 (2.09-3.67)	1.60 (0.98-2.62)	2.50 (1.91-3.27)	1.56 (1.08-2.27)
	20-29	1.92 (1.55-2.38)	1.13 (0.82-1.55)	1.67 (1.37-2.03)	1.11 (0.87,1.41)
	30-39	1.24 (0.99-1.55)	1.31 (0.96-1.77)	1.07 0.88-1.31)	1.11 (0.88-1.41)
	40-49	Ref	Ref	Ref	Ref
	50-59	0.56 (0.46-0.69)	0.96 (0.74-1.25)	0.41 (0.34-0.50)	1.05 (0.86-1.28)
	60+	0.39 (0.32-0.49)	0.89 (0.69-1.15)	0.37 (0.30-0.44)	1.14 (0.94-1.39)
Race
	African American	0.81 (0.68-0.96)		0.86 (0.75-0.99)
	Asian	0.76 (0.62-0.91)		0.66 (0.57-0.77)
	Hispanic	1.25 (1.04-1.52)		1.19 (1.01-1.41)
	NHW	Ref		Ref
Donation frequency
	0	Ref		Ref
	1-2	1.86 (1.58-2.19)		2.22 (1.96-2.52)
	3-4	3.64 (3.03-4.38)		5.02 (4.33-5.83)
	5-6	6.68 (5.46-8.18)		9.66 (8.15-11.43)
	7+	10.21 (8.47-12.30)		17.04 (14.60-19.89)
Weight (per pound)		0.993 (0.992-0.995)		0.994 (0.993-0.995)
Iron supplement
	Daily	0.59 (0.52-0.66)		0.67 (0.61-0.75)
	Less than daily	0.81 (0.70-0.94)		0.95 (0.83-1.08)
	None	Ref		Ref
Smoking
	Yes	0.66 (0.54-0.81)		0.72 (0.61-0.84)
	Missing	1.10 (0.94-1.29)		1.16 (1.01-1.34)
	No	Ref		Ref
Antacids
	Yes	1.24 (1.08-1.42)		1.21 (1.08-1.37)
	No	Ref		Ref
Hormones
	Female	0.85 (0.72-1.0)		0.78 (0.67-0.90)
	Male	2.29 (1.35-3.89)		1.49 (0.92-2.41)
	None	Ref		Ref

^*Reference group is 40-year-old male with 0 donations in last 24 months, non-smoker, weight 180 pounds, not taking supplemental iron, hormones, or antacids.