Table 3.

Effect modification for the relationship between radon and UV-erythemal dose and mortality from malignant melanoma, age 60.

Subgroup	Radona	UV-erythemal dosea
	HR (per $100\mathrm{Bq}/{\mathrm{m}}^3$)	HR (per $1\mathrm{W}/{\mathrm{m}}^2$)
Sex
Males	1.14 (0.99, 1.31)	1.13 (1.00, 1.29)
Females	1.19 (1.01, 1.39)	1.09 (0.94, 1.26)
p-value for interactionb	0.72	0.71
Mother tongue
German	1.16 (1.01, 1.34)	1.06 (0.94, 1.20)
French	1.10 (0.90, 1.35)	1.04 (0.82, 1.32)
Italian	1.25 (0.88, 1.78)	1.85 (1.27, 2.67)
Other	1.07 (0.48, 2.38)	1.07 (0.60, 1.91)
p-value for interactionb	0.93	0.17
Outdoor occupation with UV exposure, at baselinec
No	1.17 (1.05, 1.31)	1.09 (0.99, 1.21)
Yes	0.95 (0.52, 1.74)	1.94 (1.17, 3.23)
p-value for interactionb	0.45	0.09

Note: HR, hazard ratio; UV, ultraviolet.

^aReported HRs and 95% confidence intervals are for the main model, that is, fully adjusted M2 models, for deaths from malignant melanoma.

^bp-value of the Chi-squared test used to assess between-strata heterogeneity.

^c“No” includes employed individuals working indoors, as well as those not employed or retired (i.e. unexposed to UV from outdoor occupation).