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. 2020 Jul 6;6(3):e17103. doi: 10.2196/17103

Table 5.

Stratified analyses of associations between state-level sentiment and birth outcomes among subgroups.

State level sentiment toward specific groups (tertiles for tweets that are negative) Low birth weighta,b,
incidence ratio (95% CI) or n
Preterm birtha,b,
incidence ratio (95% CI) or n
Middle Eastern people and Muslims (minorities)


Second tertile vs first tertile (lowest) 1.09 (1.04-1.14) 1.07 (1.03-1.12)

Third tertile 1.07 (1.02-1.12) 1.05 (1.02-1.09)

Number 4,920,300 4,921,577
Black people


Second tertile vs first tertile (lowest) 1.10 (1.04-1.17) 1.10 (1.06-1.16)

Third tertile 1.08 (1.03-1.14) 1.09 (1.04-1.15)

Number 1,413,336 1,413,938
Hispanic people


Second tertile vs first tertile (lowest) 0.96 (0.87-1.06) 0.96 (0.94-0.99)

Third tertile 0.96 (0.89-1.04) 0.90 (0.84-0.97)

Number 2,254,029 2,254,401
Asian people


Second tertile vs first tertile (lowest) 0.98 (0.91-1.04) 1.02 (0.97-1.07)

Third tertile 1.03 (0.93-1.13) 1.10 (1.00-1.21)

Number 599,580 599,769
White people


Second tertile vs first tertile (lowest) 1.01 (0.97-1.04) 1.00 (0.96-1.03)

Third tertile 1.02 (0.97-1.07) 0.98 (0.93-1.04)

Number 5,407,779 5,409,230

aData sources for health outcomes were 2015, 2016, and 2017 natality files. Tweets were collected from June 2015 to December 2017.

bAdjusted log binomial models were run for each outcome separately. Models were controlled for year and state-level factors including percent non-Hispanic black people, percent Hispanic people, southern state indicator, population density, and economic disadvantage (standardized factor score summarizing the following variables [%]: unemployed, some college education, high school diploma, children in poverty, single parent household, and median household income), as well as individual-level factors including maternal age, sex, race, ethnicity, foreign birth, education, marital status, smoking, body mass index, first birth status, and prenatal care. Twitter-derived characteristics were categorized into tertiles, with the lowest tertile serving as the reference group. Cluster-adjusted errors are reported.