. 2015 Nov 4;10:30. doi: 10.1186/s13013-015-0056-5

Table 2.

Association of rod fracture risk with demographic characteristics

Confounders	Subgroups	Rod(s) fracture		Odds ratio (95 % Cl: min; max)	P(χ ²)
Confounders	Subgroups	Yes	No	Odds ratio (95 % Cl: min; max)	P(χ ²)
Gender	Female	3	47	0.3 (0.07; 1.6)	0.2
Gender	Male	4	21	0.3 (0.07; 1.6)	0.2
Age	24–59 years	2	33
	60–82 years	5	35	0.4 (0.08; 2.3)	0.3
Ethnicity	Caucasian	6	60	N/A	>0.5
	Hispanic	0	4
	Refused	1	4
Body mass index (BMI)	>30	2	14	1.2 (0.2; 6.7)	>0.5
Body mass index (BMI)	≤30	5	41	1.2 (0.2; 6.7)	>0.5
Previous thoracolumbar surgery	Primary	0	16	N/A	0.3
Previous thoracolumbar surgery	Reoperation	7	52	N/A	0.3
Smoking status	Never smoker	3	30	0.9 (0.2; 4.2)	>0.5
Smoking status	Ever smoker	4	35	0.9 (0.2; 4.2)	>0.5
Pseudarthrosis present at operation	Yes	2	13	1.7 (0.3; 9.7)	>0.5
Pseudarthrosis present at operation	No	5	55	1.7 (0.3; 9.7)	>0.5