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 5 Regression analysis of modifying effect on radiation dose of days (active) work in the Chornobyl exclusion zone, liquidator type, cigarette smoking and alcohol consumption on absolute and relative excess risk of micronucleus prevalence data (after exclusion of 6 cancer cases)

Modifying effect	p-value
Modifying effect	Absolute risk model (1)	Relative risk model (2)
Days work in Chornobyl exclusion zone^a	0.2808	0.1671
Days active work in Chornobyl exclusion zone^b	0.2590	0.2156
Liquidator type^c	0.6681	0.7678
Cigarette smoking^d	0.8232	0.6922
Alcohol consumption^e	0.7291	0.7246

All p-values relate improvement in fit of a linear model in radiation dose without adjustment to the radiation term for the specific effect (days (active) work in Chornobyl exclusion zone, liquidator type, smoking consumption, alcohol consumption), using models of the form considered in Tables 2, 3 and 4, 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 are adjusted for overdispersion
^abased on days work in Chornobyl exclusion zone treated as a categorical variable (unknown number of days or number < 30, days work ≥30 and <90, days work ≥90)
^bbased on days active work in Chornobyl exclusion zone treated as a categorical variable (number of active days <30, active days work ≥30 and <90, active days work ≥90)
^cbased on liquidator work treated as a categorical variable (unknown + early responders + firefighters + nuclear power workers, military personnel, drivers + construction workers)
^dbased on cigarette smoking treated as a categorical variable (unknown smoking status or never smoker, 1–9 cigarettes per day, ≥10 cigarettes per day)
^e based on alcohol consumption treated as a categorical variable (never + drinks once per month or less, drinks 2–3 times per month + once per week, drinks more than once per week + every day)

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