TABLE 3—

Results From Logistic Regression Analyses Showing the Association Between Public Bicycle Share Program Implementation and the Odds of a Bicycle-Related Injury Being a Head Injury: North America, 2007–2012

	PBSP Cities		Comparison Cities
Variable	OR (95% CI)	AOR (95% CI)	OR (95% CI)	AOR (95% CI)
Time
Preimplementation (Ref)	1.00	1.00	1.00	1.00
Postimplementation	1.37 (1.13, 1.67)	1.30 (1.05, 1.62)	0.91 (0.79, 1.06)	0.94 (0.79, 1.11)
Age, y
< 15	. . .	0.80 (0.62, 1.02)	. . .	1.19 (0.94, 1.50)
15–24	. . .	1.54 (1.16, 2.03)	. . .	0.87 (0.70, 1.08)
25–49 (Ref)	. . .	1.00	. . .	1.00
≥ 50	. . .	1.05 (0.82, 1.35)	. . .	0.94 (0.76, 1.17)
Unknown	. . .	1.57 (1.03, 2.39)	. . .	0.96 (0.64, 1.44)

Note. AOR = adjusted odds ratio; CI = confidence interval; OR = odds ratio (unadjusted); PBSP = public bicycle share program. We conducted separate models for PBSP and comparison cities because of the effect modification observed between city type and time. Unadjusted ORs show results from regression with only exposure variable. The AORs were adjusted for the following covariates in multivariable regression: exposure, age, and an indicator for each city. The PBSP cities were Montreal, QC; Washington, DC; Minneapolis, MN; Boston, MA; and Miami Beach, FL. The control cities were Vancouver, BC; New York, NY; Milwaukee, WI; Seattle, WA; and Los Angeles, CA.