Table 3 Effect measure modification of income on the effect between CALD and mean number of missing teeth among Australian adults between 2004-06 and 2017-18

NSAOH 2004-06

No CALD

CALD

Household income

Mean MT (95% CI)

Mean Ratio (95% CI)

Mean MT (95% CI)

Mean Ratio (95% CI)

Low (<$60,000)

9.8 (9.5–10.1)

1.66 (1.57–1.74)

7.4 (6.6–8.1)

1.43 (1.33–1.54)

High (< 60,000+)

3.9 (3.7-4.0)

1 (ref)

3.5 (2.9–4.1)

0.98 (0.84–1.16)

Relative Excess Risk due to Interaction: -0.23 (95% CI: -0.36, -0.08)

Mean ratios adjusted for: age, sex, residential location and last dental visit

NSAOH 2017-18

No CALD

CALD

Household income

Mean MT (95% CI)

Mean Ratio (95% CI)

Mean MT (95% CI)

Mean Ratio (95% CI)

Low (<$60,000)

9.7 (9.4–10.0)

1.57 (1.50–1.64)

8.8 (7.9–9.8)

1.43 (1.34–1.52)

High (< 60,000+)

4.3 (4.2–4.5)

1 (ref)

3.6 (3.3-4.0)

0.97 (0.88–1.07)

Relative Excess Risk due to Interaction: -0.11 (95% CI: -0.19, -0.04).

Mean ratios adjusted for: age, sex, residential location and last dental visit.