Table 2.

Association of income, education, and demographic factors with snacking(yes-no), CHNS 1991–2009^†

Factor	Model 1‡		Model 2§
	β	p-value	β	p-value
Intercept	−2.90	<.0001	−2.67	<.0001
Year 2004	0.19	<.0001	−0.04	0.64
Year 2006	0.88	<.0001	0.56	<.0001
Year 2009	1.36	<.0001	1.12	<.0001
Middle income	0.27	<.0001	0.14	0.06
High income	0.65	<.0001	0.22	0.002
High education	0.25	<.0001	0.25	<.0001
Age 7–12y	−0.48	<.0001	−0.47	<.0001
Age 13–18y	−0.90	<.0001	−0.91	<.0001
Age 19–44y	−1.18	<.0001	−1.19	<.0001
Age ≥45y	−1.23	<.0001	−1.24	<.0001
Female	0.22	<.0001	0.22	<.0001
Urbanicity	0.02	<.0001	0.02	<.0001
Medium income*year 2004			0.04	0.74
High income*year 2004			0.49	<.0001
Medium income*year 2006			0.20	0.04
High income*year 2006			0.61	<.0001
Medium income*year 2009			0.18	0.05
High income*year 2009			0.42	<.0001
Likelihood ratio test		p<0.001

^†A person is defined as a snacker if he or she consumes any snack during the three days investigated in this study.

^‡Model1 adjusts for only potential confounders with no interaction terms.

^§Model2 includes both confounders and significant time-income interaction items (time-education and income-education interactions are not significant; p<0.05); the referent in the model 1 and model 2 was year 1991, low income, low education, male, age 2–6 years.