Table 4.

Evaluation of effect heterogeneity among selected atopic conditions and childhood rhabdomyosarcoma histologic subtypes

Exposure	Embryonal rhabdomyosarcoma n = 215		Alveolar rhabdomyosarcoma n = 66
	ORa	95% CI	ORa	95% CI	p for heterogeneity
Allergies
No	1.00	Ref.	1.00	Ref.
Yes	0.60	0.40–0.89	0.75	0.42–1.35	0.53
Hives
No	1.00	Ref.	1.00	Ref.
Yes	0.66	0.40–1.09	0.79	0.39–1.62	0.63
Day-care attendance
No	1.00	Ref.	1.00	Ref.
Yes	0.64	0.45–0.90	0.51	0.29–0.88	0.59
Breastfeeding duration, months
0	1.00	Ref.	1.00	Ref.
<6	0.90	0.58–1.40	0.88	0.45–1.71
6–12	0.88	0.53–1.47	0.63	0.26–1.54
≥12	0.38	0.19–0.74	0.43	0.14–1.31	0.65
Number of atopic conditions
0	1.00	Ref.	1.00	Ref.
1	1.02	0.54–1.90	0.92	0.39–2.20
2	0.70	0.36–1.35	0.80	0.32–1.98
≥3	0.32	0.17–0.60	0.37	0.15–0.95	0.90

^aAdjusted for age, race, and sex