Table 1.

Age-adjusted and fully adjusted hazard ratios (HRs) for childhood cancer and residential radon exposure.

Cancer type	Radon exposure	No. of cancer cases	Person-years	Age-adjusted HR (95% CI)	Fully adjusted HR (95% CI)a
For the categorical analysis, radon exposure levels were categorized at 50th and 90th percentile of the exposure ­distribution. aIn addition to using age as the underlying time scale, adjusted for child sex, birth order, socioeconomic status of the parents, environmental gamma radiation, and period effects.
All cancers	EGPhE	525	3,838,101	Reference	Reference
	77.7–139.9 Bq/m3	373	3,034,923	0.90 (0.79, 1.03)	0.89 (0.78, 1.02)
	≥ 139.9 Bq/m3	99	754,623	0.96 (0.78, 1.19)	0.93 (0.74, 1.16)
	per 100 Bq/m3	997		1.01 (0.87, 1.16)	0.99 (0.85, 1.14)
All leukemias	EGPhE	149	3,838,101	Reference	Reference
	77.7–139.9 Bq/m3	104	3,034,923	0.90 (0.70, 1.15)	0.86 (0.67, 1.11)
	≥ 139.9 Bq/m3	30	754,623	1.04 (0.70, 1.54)	0.95 (0.63, 1.43)
	per 100 Bq/m3	283		0.97 (0.74, 1.27)	0.90 (0.68, 1.19)
ALL	EGPhE	121	3,838,101	Reference	Reference
	77.7–139.9 Bq/m3	81	3,034,923	0.86 (0.65, 1.15)	0.83 (0.63, 1.11)
	≥ 139.9 Bq/m3	23	754,623	0.99 (0.63, 1.55)	0.90 (0.56, 1.43)
	per 100 Bq/m3	225		0.94 (0.69, 1.28)	0.86 (0.63, 1.19)
CNS tumors	EGPhE	132	3,838,101	Reference	Reference
	77.7–139.9 Bq/m3	99	3,034,923	0.95 (0.73, 1.23)	0.95 (0.73, 1.23)
	≥ 139.9 Bq/m3	27	754,623	1.05 (0.69, 1.59)	1.05 (0.68, 1.61)
	per 100 Bq/m3	258		1.18 (0.91, 1.54)	1.19 (0.91, 1.57)