Table 5. Construction of the final model of association between scoliosis and lifestyle and ergonomics in school children in Santa Cruz, 2011.

Variables	Model 1	Model 2	Model 3	Model 4	Final Model
	PR (95% CI)	PR (95% CI)	PR (95% CI)	PR (95% CI)	PR (95% CI)
	Gender
Male	1	1	1	1	1
Female	2.52 (1.27–4.98)*	2.48 (1.26–4.88)**	2.49 (1.28–4.85)**	2.44 (1.26–4.74)**	2.54 (1.33–4.86)**
Age
7 to 9 years old	1	1		1	1
10 to 12 years old	1.02 (0.4–2.57)	1 (0.41–2.42)	1.03 (0.43–2.47)	1.12 (0.47–2.65)	1.6 (0.75–3.42)
13 to 15 years old	2.67 (0.86–8.24)	2.86 (0.99–8.25)	3.12 (1.11–8.79)*	3.43 (1.23–9.5)*	5.35 (2.17–13.21)**
16 to 17 years old	0.87 (0.18–4.1)	1.09 (0.25–4.72)	1.39 (0.34–5.67)	1.45 (0.36–5.9)	2.32 (0.65–8.26)
Hand to ground distance
Fingers touching the ground	1	1	1	1	1
Fingers not touching the ground	1.58 (0.78–3.19)	1.64 (0.82–3.28)	1.8 (0.91–3.56)	1.81 (0.92–3.58)	1.78 (0.91–3.49)
Habit of sleeping in a hammock
No	1	1	1	1	1
Yes	0.46 (0.22–0.94)*	0.41 (0.21–0.79)**	0.44 (0.23–0.84)*	0.45 (0.24–0.85)*	0.44 (0.23–0.81)**
Sexual maturation level
Prepubertal	1	1	1	1
Pubertal	2.38 (0.99–5.69)	2.24 (0.94–5.3)	2.21 (0.95–5.15)	2.15 (0.92–4.99)
Post-pubertal	2.82 (0.73–10.81)	2.88 (0.76–10.83)	2.64 (0.72–9.67)	2.54 (0.69–9.24)
Seat height to provide free movement of the thighs
Appropriate	1	1	1
Inappropriate	1.94 (0.72–5.19)	1.81 (0.68–4.81)	1.62 (0.62–4.18)
Hours of sleep every night
<8 hours	1	1
8 to 10 hours	0.16 (0.01–1.58)	0.16 (0.01–1.51)
>10 hours	0.15 (0.01–1.39)	0.15 (0.01–1.36)
Nutritional status
Eutrophic	1
Malnourished	1.18 (0.41–3.37)
Overweight/obese	1.87 (0.79–4.45)

*P < 0.05, **P < 0.01.

CI, confidence interval; PR, prevalence rate.