Table 2.

Associations between RF-EMF exposures and ‘Headache’ (symptom)

Symptom	Symptom categories (N for unadjusted model/N for adjusted model)	Exposure	Exposure categories (N for unadjusted model/N for adjusted model)	Unadjusted OR (95% CI) for each exposure category	Adjusted OR (95% CI) for each exposure category	Confounders in model
Headache	No, hardly ever (204/194)	Cordless calls > 10 mins. made and rec’d weekly	0 (64/59)	1	1	Cold/flu*+
	1 or 2 weekly (87/84)		1-2 (104/103)	1.27 (0.90-1.77)	1.28 (0.90-1.83)	Woken by phone+
	3 or 4 weekly (25/24)		3-9 (84/78)	1.40 (0.98-1.98)	1.35 (0.92-1.96)	Light out time
	Most days (16/15)		10-120 (80/77)	1.76 (1.23-2.51)*	1.41 (0.95-2.09)
Headache	No, hardly ever (216/216)	Minutes on cordless phone daily	0-4 (148/148)	1	1	Cold/flu**+
	1 or 2 weekly (89/89)		5-15 (104/104)	0.83 (0.49-1.41)	0.78 (0.45-1.32)
	3 or more times weekly (43/43)		16-240 (96/96)	1.88 (1.14-3.12)	1.74 (1.05-2.90)
Headache	No, hardly ever (218/213)	Cellphone calls >10 minutes weekly	0 (277/271)	1	1	Cold/flu**+
	1 or 2 times weekly (91/91)		1-6 (66/66)	1.27 (0.95-1.69)	1.14 (0.84-1.53)	Woken by phone*+
	3 or 4 times weekly (29/29)		7-35 (12/12)	2.37 (1.21-4.62)	2.40 (1.19-4.83)
	Most days (17/16)
Headache	No, hardly ever (-/215)	Cellphone headset	No (320)	Model invalid	1	Cold/flu**+
	1 or 2 weekly (-/91)		Wired (16)		1.29 (0.71-2.36)	Woken by phone
	3 or more weekly (-/43)		Wireless (13)		2.23 (1.10-4.53)	Light out time
Headache	No, hardly ever (-/93)	Cordless phone frequency	Not exposed (-/28)	Model invalid	1	Cold/flu**+
	1 or 2 weekly (-/38)		≤ 900 MHz (-/19)		1.04 (0.38-2.90)	Woken by phone
	3 or more weekly (-/14)		1.8-1.9 GHz (-/27)		1.42 (0.61-3.34)
			2.4 GHz (-/53)		0.74 (0.34-1.63)
			5.8 GHz (-/18)		1.55 (0.61-3.96)

Bold font Sig. p < 0.05; *Sig. p ≤ 0.01; **Sig. p ≤ 0.001; + positive association; ‘Model invalid’ means it did not meet the criteria outlined in the methods.