Table 2 Unadjusted and adjusted odds ratios for variables included in the conditional logistic regression model for the scoliosis

Age

1.28 (1.18–1.38)

1.17 (1.03–1.34)

Standing posture

Normal

ref

ref

Anterior pelvic tilt

2.36 (1.63–3.40)

2.73 (1.41–5.28)

Hunchback

1.88 (1.52–2.33)

1.27 (0.89–1.80)

Sitting posture

Straight

0.53 (0.44–0.64)

0.69 (0.50–0.96)

Leaning forward

1.25 (1.07–1.47)

1.10 (0.84–1.45)

Leaning left

1.52 (1.27–1.82)

1.33 (0.97–1.82)

Leaning right

1.26 (1.02–1.55)

0.89 (0.62–1.28)

Chest touching desk

0.97 (0.79–1.18)

Cross-legged

1.05 (0.88–1.25)

Others

0.96 (0.65–1.42)

Sleeping posture

Supine

ref

ref

Prone

0.73 (0.53–1.00)

0.76 (0.44–1.32)

Left lateral

1.41 (1.15–1.73)

1.12 (0.81–1.55)

Right lateral

1.51 (1.22–1.86)

1.38 (1.00–1.91)

Ever received posture improvement suggestions

Yes

ref

ref

No

0.85 (0.72–1.00)

1.00 (0.75–1.32)

Ever received postural education in school

Yes

ref

No

1.11 (0.93–1.32)

Napping on school desk

Yes

ref

No

1.18 (0.96–1.45)

School desk height

=

ref

ref

<

1.62 (1.34–1.95)

1.40 (1.04–1.90)

>

1.72 (1.32–2.25)

0.85 (0.54–1.32)

Home desk height

=

ref

ref

<

1.60 (1.31–1.95)

1.29 (0.93–1.78)

>

1.73 (1.36–2.21)

1.61 (1.09–2.38)

Eyesight*

Normal

0.89 (0.75–1.04)

Myopia

1.04 (0.89–1.23)

Regular change of sitting position in classroom

No

ref

ref

Yes

0.79

0.72 (0.53–0.98)

Classroom lighting

Appropriate

ref

Bright

0.84 (0.64–1.10)

Dark

1.17 (0.77–1.77)

Schoolbag use habits

Backpack on the back

ref

Backpack on the front

0.68 (0.43–1.10)

Shoulder bag

0.84 (0.50–1.41)

Cross shoulder bag

0.54 (0.27–1.09)

Shoe wear patterns

No difference

ref

Left shoe wears harder

1.11 (0.79–1.55)

Right shoe wears harder

1.13 (0.82–1.56)

Extracurricular classes

No

ref

Yes

0.91 (0.76–1.10)

PE class (per week)

None

ref

1

0.49 (0.12–2.03)

2

0.38 (0.10–1.50)

3

0.42 (0.11–1.65)

> 3

0.49 (0.12–1.96)

Average physical activity time (per week, min)

0.997 (0.995–0.999)

1.00 (0.99–1.00)

Annual height increment, mean (SD), mm

0.99 (0.98–1.00)

0.99 (0.99–1.00)

General health status

Fair

ref

Good

0.87 (0.48–1.58)

Poor

1.23 (0.70–2.17)

Low back pain

No

ref

Yes

0.91 (0.76–1.08)

Sports participation (after school)

Badminton

No

ref

ref

Yes

0.83 (0.70–0.98)

0.94 (0.71–1.24)

Basketball

No

ref

Yes

0.96 (0.78–1.17)

Running

No

ref

Yes

1.02 (0.87–1.18)

Swimming

No

ref

ref

Yes

0.69 (0.57–0.84)

0.83 (0.58–1.20)

Dancing

No

ref

Yes

1.09 (0.80–1.50)

Mountain climbing

No

ref

ref

Yes

0.68 (0.52–0.90)

0.83 (0.51–1.35)

Ping pong

No

ref

Yes

0.79 (0.59–1.05)

Morning exercises

No

ref

Yes

0.79 (0.63–1.01)

Football

No

ref

Yes

0.87 (0.64–1.19)

Stroll

No

ref

Yes

0.50 (0.20–1.24)