Table 1.

Baseline Characteristics of Fracture Cases and Controls in a Study of Vitamin D Intake and Serum Levels and Early-Childhood Fracture Risk, Toronto, Ontario, Canada, 2009–2013

	Cases (n = 206)			Controls (n = 343)			P Valuea
	Mean (SD)	No. of Childrenb	%	Mean (SD)	No. of Children	%
Age, months	43.03 (18.79)			42.84 (18.86)			0.91c
Neighborhood median after-tax household income, Can$/year	63,133 (29,890)			57,013 (20,693)			0.01
Height, cm	99.90 (13.60)			99.35 (13.19)			0.64c
Outdoor free play, minutes/day	69.93 (57.83)			60.73 (61.59)			0.09
Waist circumference z scored	0.01 (1.47)			0.06 (0.95)			0.64
Child's birth weight, kg	3.39 (0.57)			3.27 (0.67)			0.04
Sex
Male		116	56		191	56	0.89c
Female		90	44		152	44
Age, months
<18		20	10		30	9	0.75c
18–35		63	31		93	27
36–60		69	33		128	37
>60		54	26		92	27
Seasone
Winter		112	54		193	56	0.66c
Summer		94	46		150	44
History of fracture
No		186	92		321	97	0.01
Yes		17	8		11	3
Fitzpatrick skin typef
I or II (lightest)		81	39		185	54	0.01
III		56	27		84	24
IV		35	17		38	11
V or VI (darkest)		30	15		32	9
Typical soda intake, cups/day
0		181	88		292	85	0.04
≥1		19	9		14	4
Location of fractureg
Lower extremity		77	37		NA
Upper extremity		129	63		NA

Abbreviations: NA, not applicable; SD, standard deviation.

^a The t test was used for continuous variables, and the χ² test was used for categorical variables.

^b Values may not sum to totals because of missing data.

^c Matched variable; no significant difference expected.

^d Age- and sex-standardized.

^e Winter was defined as October–April and summer as May–September.

^f Skin type was determined by trained research assistants on the basis of the Fitzpatrick scale (21).

^g Lower-extremity fractures included fractures of the femur, tibia, fibula, talus, and metatarsal; upper-extremity fractures included fractures of the humerus, olecranon, condyle, radius, ulna, clavicle, elbow, forearm, and radius.