Table 2.

Association between childhood cancer and dose rate of external background radiation in the Swiss National Cohort.

Outcome	Dose rate (nSv/hr)	Cases (n)	IRa	HR (95% CI)b
All cancers	< 100	659	10.56	1.00 (reference)
	100 to < 150	982	11.16	1.06 (0.96, 1.17)
	150 to < 200	112	12.32	1.17 (0.96, 1.43)
	≥ 200	29	17.22	1.64 (1.13, 2.37)
Leukemia	< 100	201	3.22	1.00 (reference)
	100 to < 150	288	3.27	1.02 (0.85, 1.22)
	150 to < 200	30	3.30	1.03 (0.70, 1.51)
	≥ 200	11	6.53	2.04 (1.11, 3.74)
ALL	< 100	158	2.53	1.00 (reference)
	100 to < 150	225	2.56	1.01 (0.82, 1.24)
	150 to < 200	24	2.64	1.05 (0.68, 1.61)
	≥ 200	9	5.34	2.12 (1.09, 4.16)
Lymphoma	< 100	122	1.96	1.00 (reference)
	100 to < 150	186	2.11	1.08 (0.86, 1.36)
	150 to < 200	17	1.87	0.96 (0.58, 1.59)
	≥ 200	3	1.78	0.91 (0.29, 2.86)
CNS tumors	< 100	150	2.40	1.00 (reference)
	100 to < 150	239	2.72	1.13 (0.92, 1.39)
	150 to < 200	26	2.86	1.19 (0.79, 1.81)
	≥ 200	8	4.75	1.99 (0.98, 4.05)
Other malignant tumors	< 100	186	2.98	1.00 (reference)
	100 to < 150	269	3.06	1.03 (0.85, 1.24)
	150 to < 200	39	4.29	1.44 (1.02, 2.04)
	≥ 200	7	4.16	1.39 (0.66, 2.97)
Abbreviations: ALL, acute lymphoblastic leukemia; CNS, central nervous system; HR, hazard ratio; IR, incidence rate.aPer 100,000 person-years at risk. bFrom Cox proportional hazards models adjusting for sex and birth year.