. Author manuscript; available in PMC: 2013 Jun 5.

Published in final edited form as: Open Pediatr Med Journal. 2012 Dec 5;6(2012):46–52. doi: 10.2174/1874309901206010046

Table 3.

Odds Ratios for Migraines and Headache-Related Symptoms in Children According to Mother’s Report of Cell Phone Use Characteristics During Pregnancy

	n	%^a	Child gets Migraines (n=523)				Child has Headache-Related Symptoms (n=10,043)

			OR^b	95% CI	OR_adj^b,^c	95% CI	OR^b	95% CI	OR_adj^b,^c	95% CI

Use of hands-free device
No exposure (reference)	21,507		1.00		1.00		1.00		1.00
Never used hands-free device	16,205	79.1	1.32	1.07–1.63	1.11	0.85–1.44	1.35	1.28–1.42	1.15	1.08–1.23
Rarely used hands-free device	2,439	11.9	1.77	1.23–2.55	1.51	0.98–2.30	1.34	1.21–1.49	1.12	0.99–1.26
Often used hands-free device	1,745	8.5	1.83	1.21–2.77	1.82	1.15–2.90	1.26	1.11–1.42	1.12	0.97–1.29
Missing	93	0.5
P value for trend^d			0.69		0.69		<0.01		0.01

Frequency of cell phone use
No exposure (reference)	21,507		1.00		1.00		1.00		1.00
0–1 times per day	10,339	50.5	1.44	1.14–1.82	1.26	0.95–1.67	1.30	1.22–1.38	1.16	1.08–1.24
2–3 times per day	5,699	27.8	1.07	0.78–1.47	0.82	0.56–1.21	1.33	1.24–1.44	1.10	1.01–1.21
4–6 times per day	1,430	7.0	1.81	1.15–2.86	1.47	0.87–2.50	1.39	1.22–1.59	1.14	0.98–1.32
7 or more times per day	830	4.1	2.08	1.20–3.60	1.89	1.03–3.45	1.45	1.23–1.72	1.26	1.04–1.52
Missing	2,184	10.7
P value for trend^d			0.05		0.03		<0.01		0.03

Percent of time cell phone powered on
No exposure (reference)	21,507		1.00		1.00		1.00		1.00
Never or almost never	1,350	6.6	1.18	0.67–2.08	1.31	0.74–2.34	1.22	1.06–1.40	1.18	1.01–1.37
Less than 50% of the time	2,365	11.5	1.04	0.65–1.65	1.05	0.64–1.72	1.24	1.11–1.38	1.15	1.02–1.30
50–99% of the time	6,147	30.0	1.32	0.99–1.75	1.11	0.79–1.56	1.37	1.28–1.47	1.15	1.05–1.25
All the time	10,476	51.1	1.57	1.25–1.97	1.27	0.95–1.69	1.36	1.28–1.44	1.14	1.06–1.27
Missing	144	0.7
P value for trend^d			0.84		0.83		0.03		0.17

Percent among those with prenatal exposure.

Reference category is no cell phone exposure.

Estimates adjusted for mother’s age, socio-occupational status, mother’s history of migraine headaches, mother’s feelings of worry, burden, and stress during pregnancy, child’s exposure to environmental tobacco smoke, and postnatal exposure.

P value from Wald χ² test for linear trend. P value > 0.05 suggests a linear trend at 95% confidence.