Factors associated with disparities in out-of-pocket expenditure on dental care: results from two cross-sectional national surveys

Table 6 Interaction between education and ownership of supplemental health insurance, and their effect on the level of out-of-pocket expenditure for dental care (2018 survey)

	Ownership of a supplementary health insurance among those with an expense		Log coefficient (SE) for with supplementary insurance (vs *without)* stratified by education years
Years of education	No (N = 352)	Yes (N = 2349)
Years of education	Log coefficient (SE)	Log coefficient (SE)
0–8 (N = 96)	1.0 Reference category	1.11 (0.32)*
9–12 (N = 718)	0.61 (0.28)		0.24 (0.16)
13–15 (N = 539)	0.94 (0.32)*		−0.18 (0.23)
16+ (N = 1348)	0.58 (0.35)		0.06 (0.23)
Log coefficient (SE) for 9–12(vs0–8)stratified by ownership of supplementary insurance		−0.27 (0.24)
Log coefficient (SE) for 13–15(vs0–8)stratified by ownership of supplementary insurance		−0.36 (0.24)
Log coefficient (SE) for 16+(vs0–8)stratified by ownership of supplementary insurance		−0.48 (0.24)

SE standard error
*P < 0.05 after Bonferroni correction for multiple-comparisons
Notes: Weighted model, adjusted for sex, marital status, religiosity level, ethnicity, income deciles, peripherality index, ownership of an apartment, ownership of a car, and the age composition of the household; Supplementary insurance includes supplemental insurance of the health plans, private commercial health insurance, private dental insurance, long-term care insurance and other private health insurance