Table 3.

Results of granger causality tests and regression analyses between legacy (vs. Social) media, risk perceptions, and protective behaviors in different populations – by pregnancy status, Zika infection risk, income, education level, age, and ethnicity.

Demographic variable	Legacy media						Social media
	Granger causality test F-value, p-value	Unstandardized coefficient	Standard error	95% CI	Adjusted R2	p-value	Granger causality test F-value, p-value	Unstandardized coefficient	Standard error	95% CI	Adjusted R2	p-value
Risk perceptions
Pregnancy statusa
Households with current/intended pregnancy	0.01, .909	−0.23	0.38	−1.06 to 0.59	.06	.284	9.02, .010	0.54	0.22	0.07 to 1.02	.38	.029
Households without current/intended pregnancy	5.14, .041	0.43	0.24	−0.10 to 0.97	.54	.006	32.99, < .001	0.59	0.11	0.34 to 0.84	.82	<.001
Geographic regionsb
High-risk	1.40, .258	0.23	0.23	−0.26 to 0.73	.54	.005	27.54, < .001	0.53	0.11	0.29 to 0.76	.84	<.001
Low-risk	7.03, .012*	0.69g −0.34h	0.23g 0.23h	0.16 to 1.23g −0.90 to 0.20h	.52	.052	3.18, .098	0.36	0.22	−0.13 to 0.85	.14	.179
Incomec
Low income	3.00, .107	0.30	0.26	−0.26 to 0.87	.49	.009	27.40, < .001	0.55	0.12	0.29 to 0.81	.81	<.001
High income	4.18, .062	0.50	0.27	−0.10 to 1.11	.48	.012	16.62, .001	0.57	0.15	0.23 to 0.90	.70	.001
Education leveld
Less educated	6.88, .021	0.62	0.24	0.09 to 1.16	.54	.006	11.73, .005	0.53	0.17	0.15 to 0.91	.60	.003
More educated	0.62, .447	0.11	0.27	−0.49 to 0.71	.38	.030	26.83, < .001	0.56	0.12	0.29 to 0.82	.79	<.001
Agee
Young adults	6.55, .024	0.59	0.24	0.05 to 1.12	.30	.056	6.16, .027	0.52	0.22	0.04 to 0.99	.30	.057
Adults	4.95, .045	0.46	0.25	−0.08 to 1.01	.57	.004	29.00, < .001	0.56	0.12	0.30 to 0.82	.82	<.001
Seniors	3.53, .083	0.48	0.32	−0.23 to 1.20	.18	.131	14.21, .002	0.63	0.19	0.21 to 1.04	.51	.008
Ethnicityf
Whites	3.99, .067	0.42	0.26	−0.16 to 1.00	.42	.019	38.75, < .001	0.63	0.11	0.38 to 0.88	.81	<.001
Blacks	4.00, .067	0.47	0.32	−0.23 to 1.18	.26	.078	1.95, .186	0.27	0.23	−0.23 to 0.77	.21	.111
Hispanics	7.33, .018	0.56	0.22	0.08 to 1.05	.49	.010	6.05, .029	0.47	0.21	0.01 to 0.94	.44	.016
‘Other’ ethnicities	0.35, .563	0.32	0.29	−0.32 to 0.95	.03	.330	3.93, .055*	0.69g 0.27h	0.23g 0.24h	0.15 to 1.23g −0.30–0.85h	.66	.018
Protective behaviors
Pregnancy statusa
Households with current/intended pregnancy	6.66, .017	0.30	0.12	0.06 to 0.54	.20	.039	8.84, .001ˆ	0.10g −0.04h 0.58i	0.12g 0.16h 0.14i	−0.16–0.36g −0.37 to 0.29h 0.27 to 0.88i	.62	.001
Households without current/intended pregnancy	2.51, .128	0.24	0.15	−0.07 to 0.55	.05	.215	2.39, .137	0.21	0.14	−0.07 to 0.50	.05	.228
Geographic regionsb
High-risk	10.13, .004	0.40	0.12	0.14 to 0.66	.42	.001	3.76, .066	0.26	0.14	−0.02 to 0.54	.27	.014
Low-risk	0.37, .548	0.08	0.13	−0.19 to 0.36	-.08	.831	3.08, .094	0.21	0.12	−0.04 to 0.46	.04	.238
Incomec
Low-income	4.66, .023*	0.24g 0.27h	0.13g 0.14h	−0.03–0.50g −0.02–0.57h	.31	.028	2.83, .107	0.21	0.12	−0.05 to 0.47	.11	.118
High-income	1.65, .213	0.19	0.15	−0.12 to 0.50	.03	.267	3.30, .083	0.25	0.14	−0.04 to 0.54	.10	.128
Education leveld
Less-educated	6.72, .017	0.32	0.12	0.06 to 0.57	.17	.054	1.00, .329	0.13	0.13	−0.14 to 0.41	-.05	.614
More-educated	1.90, .183	0.20	0.15	−0.10 to 0.51	.12	.096	3.47, .076	0.26	0.14	−0.03 to 0.54	.18	.048
Agee
Young adults	4.19, .053	0.26	0.13	−0.00 to 0.52	.13	.090	0.14, .716	0.05	0.14	−0.23 to 0.33	-.04	.571
Adults	2.94, .101	0.27	0.15	−0.06 to 0.59	.09	.149	3.19, .089	0.27	0.15	−0.04 to 0.58	.10	.134
Seniors	1.01, .326	0.12	0.12	−0.13 to 0.38	.03	.277	2.46, .132	0.19	0.12	−0.06 to 0.43	.09	.142
Ethnicityf
Whites	3.50, .052*	0.32g 0.09h	0.14g 0.15h	0.02 to 0.62g −0.23–0.40h	.23	.065	2.48, .130	0.21	0.13	−0.07 to 0.48	.03	.269
Blacks	2.56, .125	0.22	0.14	−0.07 to 0.51	.06	.200	2.32, .143	0.21	0.14	−0.08 to 0.50	.05	.223
Hispanics	5.14, .034	0.33	0.15	0.03 to 0.64	.22	.027	0.45, .510	0.11	0.16	−0.23 to 0.45	.05	.218
‘Other’ ethnicities	3.60, .039ˆ	0.29g −0.35h 0.43i	0.14g 0.15h 0.16i	0.00 to 0.58g −0.66 to -0.04h 0.08 to 0.77i	.39	.030	4.85, .039	0.31	0.14	0.02 to 0.60	.18	.048

Note.

Absence of a symbol specification refers to a lag length 1, an asterisk refers to a lag length 2, and a caret refers to a lag length 3, the bold font style indicates the results were of a significance level of p-values ≤ .05.

^aPregnancy status: Respondents who answered “yes” to questions either about current or intended pregnancy in the next twelve months were grouped to the households with current/intended pregnancy whereas those who answered “no” to these questions were coded as households without current/intended pregnancy.

^bGeographic regions: The state-level laboratory-confirmed symptomatic Zika virus disease cases and presumptive viremic blood donors reported to ArboNET were collected from the CDC, https://www.cdc.gov/Zika/geo/united-states.html. We identified Florida, New York, California, and Texas as geographic regions with high-risk because they contained over 50% of the reported cases in the United States. Respondents from these states were coded as from high-risk region, and the rest as from a low-risk region.

^cIncome: The median household income (i.e., US$55,775), reported in the 2015 American Community Survey was used as a threshold to identify high- and low-income populations. Using the answers of a question about household income (1 = Less than $15,000 to 15 = $250,000 or more), we divided respondents into the high-income group if an option 7 (i.e., $75,000 but less than $100,000) or higher was chosen, and those who selected an option 6 or lower were in the low-income group.

^dEducation level: More- (vs. less-) educated populations were defined as those with (vs. without) a college or university degree. Answers to the question about the level of education that the respondent completed were used for grouping. Respondents with a two-year associate degree from a college or university or a higher level were in the more-educated group whereas those without any college degree were in the less-educated group.

^eAge: According to the age groups of the U.S. Census Bureau, respondents who reported between 18 and 24 years were classed as in the young adult populations, those who reported 25–64 years were classed as being in the adult populations, and those who reported being 65 years or older were categorized as being in the senior populations.

^fEthnicity: The responses to the question about individuals' identification of their own ethnicity, including “White non-Hispanic”, “Black non-Hispanic”, “White Hispanic” “Black Hispanic,” and “Unspecified Hispanic” were used to form four ethnic categories, i.e., White, Black, Hispanic, and ‘other’ ethnicities.

^gLagged media with one week.

^hLagged media with two weeks.

ⁱLagged media with three weeks.