Table 2.

Risk ratios for smallness for gestational age among 76 pregnant women based on self-reported ENDS/smoking status and hair nicotine, Little Rock, Arkansas, USA, 2015–2016

ENDS/smoking status	n	SGA† n	Risk %	Risk ratio	95% CI	p
By self-report
Non-users/non-smokers	38	3	7.9	1 (referent)
Current ENDS dual users	11	3	27.3
Crude				3.5	0.8–14.8	0.11
Adjusted*				3.9	0.9–16.2	0.06
Current smokers	27	7	25.9
Crude				3.3	0.9–11.6	0.08
Adjusted*				3.9	1.1–13.6	0.03
By hair nicotine level
<2.77 ng/mg	30	1	3.3	1 (referent)
≥2.77 ng/mg	46	12	26.1
Crude				7.8	1.1–57.1	0.01
Adjusted				7.7	1.1–56.0	0.01
By self-reports confirmed by hair nicotine levels
Non-users/non-smokers	25	1	4.0	1 (referent)
Current ENDS dual users	9	3	33.3
Crude				8.3	1.0–70.2	0.05
Adjusted				8.3	1.0–69.1	0.05
Current smokers	24	7	29.2
Crude				7.3	1.0–54.9	0.05
Adjusted				7.8	1.0–59.0	0.05

^†Adjusted for gestational age and fetal sex.

^*Adjusted for maternal age.