Buccal mucosa micronuclei counts in relation to exposure to low dose-rate radiation from the Chornobyl nuclear accident and other medical and occupational radiation exposures

Table 4 Regression analysis of modifying effect of age at first exposure and time since last exposure on absolute and relative radiation-associated excess risk of micronucleus prevalence (after exclusion of 6 cancer cases)

	Age at first exposure (δ)(year⁻¹)	Time since last exposure (ϕ)(year⁻¹)
Absolute risk model (1)
Coefficient	−0.088 (−0.294^a, 0.079)	−0.464 (−1.249, 0.371)
p-value	0.3215	0.2733
Relative risk model (2)
Coefficient	−0.237 (−1.055^a, 0.069)	−0.753 (−23.843, 0.118)
p-value	0.1368	0.0949

All p-values relate improvement in fit of the model to a model without adjustment for the specific temporal effect (age at first exposure and time since last exposure), using models of the form considered in Tables 2 and 3, evaluated via an F-test. All models adjust for background variables that minimize Akaike Information Criterion (AIC), as in Appendix 1 Table 7. p-values and confidence intervals are adjusted for overdispersion
^aWald-based CI

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