Table 4 Odds ratio (OR) and confidence interval (CI) of recurrent low back pain at follow up by flexibility, endurance strength, and physical activity at baseline, and age, body mass index (BMI), and physical activity at follow up.

Variable	Men				Women
	Univariate		Multivariate		Univariate		Multivariate
	OR (95% CI)	p Value	OR (95% CI)	p Value	OR (95% CI)	p Value	OR (95% CI)	p Value
Age at follow up	1.01 (0.90 to 1.13)	0.87	0.95 (0.82 to 1.09)	0.45	1.01 (0.89 to 1.16)	0.85	1.05 (0.90 to 1.23)	0.52
BMI at follow up	1.03 (0.99 to 1.10)	0.15	1.08 (1.02 to 1.15)	0.021	1.05 (1.01 to 1.10)	0.031	1.04 (0.98 to 1.10)	0.17
Flexibility tertiles
Low	1 (Reference)*		1 (Reference)		1 (Reference)		1 (Reference)
Intermediate	0.98 (0.60 to 1.61)	0.94	1.08 (0.63 to 1.82)	0.73	1.14 (0.66 to 1.97)	0.65	1.19 (0.67 to 2.11)	0.56
High	0.91 (0.55 to 1.49)	0.70	0.94 (0.55 to 1.59)	0.80	1.16 (0.68 to 1.98)	0.59	1.17 (0.67 to 2.11)	0.56
Endurance strength tertiles
Low	1 (Reference)		1 (Reference)		1 (Reference)		1 (Reference)
Intermediate	1.02 (0.62 to 1.68)	0.95	1.08 (0.63 to 1.82)	0.79	0.99 (0.58 to 1.71)	0.98	1.11 (0.62 to 1.97)	0.72
High	1.14 (0.68 to 1.90)	0.62	1.37 (0.78 to 2.35)	0.28	1.03 (0.59 to 1.81)	0.91	1.24 (0.68 to 2.28)	0.47
School age physical activity
Inactive	1 (Reference)		1 (Reference)		1 (Reference)		1 (Reference)
Active	0.61 (0.42 to 0.88)	0.009	0.62 (0.39 to 0.98)	0.039	0.69 (0.45 to 1.05)	0.084	0.80 (0.48 to 1.32)	0.39
Physical activity at follow up
Less than once a week	1 (Reference)		1 (Reference)		1 (Reference)		1 (Reference)
1–4 times a week	1.08 (0.72 to 1.62)	0.71	1.31 (0.80 to 2.14)	0.29	0.60 (0.37 to 0.97)	0.038	0.65 (0.37 to 1.15)	0.14
5–7 times a week	0.84 (0.45 to 1.56)	0.58	0.88 (0.41 to 1.87)	0.74	0.58 (0.29 to 1.14)	0.11	0.54 (0.25 to 1.18)	0.12

*Denominator of odds ratios.