Table 5

Risk factors for injury in 197 football players using a Cox proportional hazard regression model

Univariate analysis	n	Hazard ratio	95% CI	p Value
Categorical variables*
Previous injury	151	2.7	1.7 to 4.3	<0.0001
1–2 previous injuries	80	2.2	1.4 to 3.6	0.0013
3–4 previous injuries	38	3.0	1.7 to 5.3	<0.0001
⩾5 previous injuries	33	5.1	2.9 to 9.0	<0.0001
Categorical variables†
Age >1SD below mean (⩽21 years)	43	1.2	0.8 to 1.8	0.38
Age >1SD above mean (⩾31 years)	29	1.2	0.8 to 1.9	0.36
Height >1SD below mean (⩽176 cm)	27	0.8	0.5 to 1.2	0.27
Height >1SD above mean (⩾188 cm)	29	0.7	0.5 to 1.2	0.21
Weight >1SD below mean (⩽72 kg)	26	0.8	0.5 to 1.2	0.27
Weight >1SD above mean (⩾86 kg)	32	0.9	0.6 to 1.4	0.74
BMI>1SD below mean (⩽22 kg/m²)	47	1.0	0.7 to 1.5	0.96
BMI >1SD above mean (⩾26 kg/m²)	30	1.3	0.8 to 1.9	0.29
Continuous variables†
Previous injury	151	1.2	1.1 to 1.3	<0.0001
Age (years)	197	1.0	1.0 to 1.0	0.80
Height (cm)	197	1.0	1.0 to 1.0	0.98
Weight (kg)	197	1.0	1.0 to 1.0	0.52
BMI (kg/m²)	197	1.1	0.9 to 1.2	0.29

Multivariate analysis	n	Age adjusted hazard ratio	95% CI	p Value
*Reference group uninjured players.
†Reference group intermediate group (mean (1SD)).
‡Relative risk for 1 measured unit increase.
BMI, Body mass index.
Previous injury (categorical)*	151	2.7	1.7 to 4.3	<0.0001
1–2 previous injuries	80	2.2	1.4 to 3.6	0.0014
3–4 previous injuries	38	3.0	1.8 to 5.3	<0.0001
⩾5 previous injuries	33	5.2	2.9 to 9.0	<0.0001
Previous injuries (continuous)‡	151	1.2	1.1 to 1.3	<0.0001