The spline function is adjusted for age, sex, consumption of fruit and vegetables, employment in the chemical industry for at least one year and traffic-related air pollution.

<p>The exposure distribution of average residential radon is marked on the x-axis. The spline function can be interpreted as the exposure-response association. The difference between two points on the y-axis on the curve is interpreted as the difference in loge(IRR) for the corresponding difference in exposure, which can be read on the x-axis between the same two points.</p

Adjusted^a incidence rate ratios for primary brain tumour in association with a 100 Bq/m³ increase in domestic radon^b within strata of NO_x at the residential address.

a<p>We adjusted the analyses for age (underlying time scale), sex, employment in the chemical industry for at least one year and consumption of fruit and vegetables.</p>b<p>Radon exposure was entered as a continuous variable in all models as the time-weighted average concentration at residences from 1. January 1971 until censoring.with inclusion of a 10 year latency period.</p>c<p>Test of the null hypothesis that the linear trends are identical, for Wald test for interaction.</p>d<p>Time-weighted average concentration for NO_x.</p

Crude and adjusted RRs for leukemia in association with distance to nearest power line.

a<p>The crude model.</p>b<p>Adjusted for socioeconomic status and urbanization.</p>c<p>Adjusted for the same as model 2 and for maternal age and birth order.</p>d<p>Adjusted for the same as model 3 and for domestic radon and air pollution.</p><p>Crude and adjusted RRs for leukemia in association with distance to nearest power line.</p

The joint effects of distance to nearest power line and domestic radon and air pollution, respectively, on leukemia.

1<p>Cut-point is the median.</p>2<p>The adjusted analysis includes following potential confounders: socioeconomic status, urbanization, maternal age, birth order and air pollution.</p>3<p>The adjusted analysis includes following potential confounders: socioeconomic status, urbanization, maternal age, birth order and domestic radon.</p><p>The joint effects of distance to nearest power line and domestic radon and air pollution, respectively, on leukemia.</p

Potential confounders by case-control status and distance to nearest power line.

1<p>Cut-point is the 50^th and 90^th percentile.</p><p>Potential confounders by case-control status and distance to nearest power line.</p

Characteristics of all study participants, basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and malignant melanoma (MM).

<p>^aRow percentages. All other percentages are column percentages.</p><p>^bTime-weighted average radon at the residencies for the period 1 January 1971, to censoring date.</p><p>Characteristics of all study participants, basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and malignant melanoma (MM).</p

Association between time-weighted average radon exposure^# and basal cell carcinoma, squamous cell carcinoma and malignant melanoma among 51,445 Diet Cancer Health cohort participants.

<p>^aAdjusted for age (underlying time scale) and sex.</p><p>^bAdjusted for skin reaction to sunlight, degree of freckles, degree of nevi, BMI, school attendance, area-level socio-economic status, leisure time physical activities including sports, cycling, walking and gardening as well as outdoor occupation (farming, mining, quarrying, roofing or asphalt road work) and mean daily hours of bright sunshine at the level of municipality of each residence.</p><p>Due to exclusion of cohort members with missing value in any covariate, the number of persons is identical in the crude and the adjusted analyses.</p><p>^#Radon exposure was entered as a continuous variable in all models as the time-weighted average at residences from 1 January 1971 until censoring.</p><p>Association between time-weighted average radon exposure<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135642#t002fn004" target="_blank">^#</a> and basal cell carcinoma, squamous cell carcinoma and malignant melanoma among 51,445 Diet Cancer Health cohort participants.</p