Table 3 Combined effect between Ca intake and physical activity on dental caries

Ca intake

 Reach recommendation level

Ref

Ref

Ref

 Not reach recommendation level

1.44 (1.20–1.72)

< 0.001

1.28 (1.10–1.49)

0.002

1.43 (1.22–1.67)

< 0.001

Physical activity

 = 7

Ref

Ref

Ref

 < 7

1.58 (1.30–1.92)

< 0.001

1.26 (1.07–1.48)

0.007

1.27 (1.07–1.50)

0.007

Combined effect

 Ca reach recommendation level & physical activity = 7

Ref

Ref

Ref

 Ca reach recommendation level & physical activity < 7

1.46 (1.07–1.99)

0.018

1.26 (0.94–1.68)

0.123

1.22 (0.91–1.62)

0.173

 Ca not reach recommendation level & physical activity = 7

1.32 (1.01–1.72)

0.046

1.28 (0.99–1.66)

0.062

1.38 (1.08–1.76)

0.012

 Ca not reach recommendation level & physical activity < 7

2.07 (1.54–2.80)

< 0.001

1.59 (1.23–2.06)

< 0.001

1.77 (1.38–2.27)

< 0.001

 P for trend

< 0.001

< 0.001

< 0.001