Table 1.

Reviewed articles on physical hazards and leukemia

Researcher	Year	Type of study	Exposure	Main findings
A. Ionizing radiation and leukemia
1) Update of LSS study findings
Little et al. [6]	2009	Review	Ionizing radiation	Leukemia RR follows the pattern of LSS study for low dose (occupational) exposure - Lower RR per dose unit for higher doses of radiation
Richardson et al. [9]	2009	Cohort study	Ionizing radiation	Exposure to >5 mGy of radiation is responsible for 1/3 of leukemia cases after 5 decades – ERR/Gy follows a quadratic dose-response model for AML. ALL and CML mortality follow a linear dose-response model.
2) Cleanup workers employed in Chernobyl nuclear incident
Rahu et al. [27]	2006	Cohort study	Ionizing radiation	No significant increase in leukemia incidence among workers (SIR 1.53, 95% CI 0.62 - 3.17). A marginally significant increase has been observed among Latvian workers but it was based on a small number of cases.
Abramenko et al. [28]	2008	Cohort study	Ionizing radiation	Among a cohort of CLL patients, specific genetic polymorphisms where observed more frequently among cleanup workers exposed to radiation following the nuclear accident in Chernobyl than in non-exposed CLL patients
Romanenko et al. [29,30]	2008	Nested case-control study	Ionizing radiation	Positive linear trend (p = 0.03) between increasing exposure to radiation and leukemia risk. The ERR/Gy for leukemia was 3.44 (95% CI 0.47 – 9.78). A linear dose - response relationship has been shown for ALL and (surprisingly) for CLL.
Kesminiene et al. [31]	2008	Case-control study	Ionizing radiation	A statistically significant association was shown (at 90% but not at 95% level) between AL and employment as a cleanup worker in the surrounding area (<30 km) of Chernobyl accident site (OR 8.31, 90% CI 1.17 - 122).
3) Workers in nuclear industry
Boice et al. [32]	2006	Cohort study	Ionizing radiation	No significant increase in leukemia mortality (SMR 1.21, 95% CI 0.69- 1.97) or increased leukemia risk for the highly-exposed group (RR 1.34, 95% CI 0.73–2.45) was shown among workers.
Richardson et al. [33]	2007	Cohort study	Ionizing radiation (& exposure to chemicals)	A borderline significant increase of leukemia mortality was shown (at 90% but not at 95% level) only for operators and manual workers (SMR 1.36, 90% CI 1.02 - 1.78) and for workers employed >30 years (SMR 1.63, 90% CI 1.07 - 2.52).
Richardson et al. [34]	2007	Nested case-control study	Ionizing radiation	Assuming a 3-year time lag, no significantly increased ERR/10 mSv was shown for all leukemias (0.041, 90% CI -0.001 – 0.116), for leukemias excluding CLL (0.077, 90% CI 0.014 – 0.198) or for myeloid leukemia (0.123, 90% CI 0.021 - 0.354).
Schubauer-Berigan et al. [35]	2007	Nested case-control study	Ionizing radiation	A non-significant positive association between radiation dose and leukemia risk was shown for doses 10 - 100 mSv, with an estimated ERR/10 mSv of 0.068 (95% CI -0.029 - 0.24).
Schubauer-Berigan et al. [36]	2007	Nested case-control study	Ionizing radiation	A non-significant positive association between radiation dose and CLL risk was shown for doses 10 - 100 mSv, with an estimated ERR/10 mSv of 0.20 (95% CI -0.035 – 0.96).
Matanoski et al. [37]	2008	Cohort study	Ionizing radiation	No statistically significant increase of leukemia mortality (SMR 0.91, 95% CI 0.56 – 1.39 and 0.42, 95% 0.11 – 1.07 for exposure to > 5.0 mSv and <5.0 mSv of radiation respectively) was shown among workers
Ashmore et al. [38]	2010	Review	Ionizing radiation	Previous study of IARC (2005) who found no statistically significant association between leukemia and radiation exposure among workers in nuclear industry could be biased due to inaccurate estimation of exposure.
4) Medical applications of radiation
Lie et al. [39]	2008	Cohort study	Ionizing radiation	No significant increase in leukemia risk was found for the group nurses with the longest (> 30 years) employment in posts exposed to radiation compared to the group of non-exposed nurses (RR 0.77, 95% CI 0.35 – 1.69).
Samerdokiene et al. [40]	2009	Cohort study	Ionizing radiation	No significant increase in leukemia incidence (SIR 3.3, 95% CI 0.68- 9.63 for men and 2.67, 95% CI 0.92-4.2 for women) was shown among personnel employed in medical applications of ionizing radiation.
Ramos et al. [41]	2008	Case-control study (exposure assessment)	Ionizing radiation	The projected risk of leukemia cases/1000 person-years based on cumulative radiation exposure among a group of interventional radiologists differed between 2 methods of exposure assessment (1.07-3.98 according to the physical method compared to 1.07-11.21 for the biological method) suggesting a potential improper use of personal dosimeters.
Ramos et al. [42]	2009	Molecular epidemiological study	Ionizing radiation	The projected LAR of leukemia (cases/1000 person-years) among interventional radiologists due to radiation exposure, was much higher according to biological methods of exposure assessment (9.2) compared to physical methods (2.18).
5) Industrial applications of ionizing radiation
Ahn et al. [43]	2008	Cohort study	Ionizing radiation (industrial applications)	No statistically significant increase of leukemia SMR or SRR was shown among personnel exposed to radiation (workers in medical applications, research laboratories, nuclear facilities, non-destructive testing, military facilities etc.).
6) Extraction and use of uranium compounds
Storm [44]	2006	Cohort study	Depleted uranium	No statistically significant increase of leukemia incidence was found among military personnel exposed to depleted uranium used during military operations (SIR 1.4, 95% CI 0.4 - 3.5).
Mohner [45]	2006	Case-control study	Uranium mining (radionuclides)	No significant increase of leukemia risk was found in the group with the highest cumulative exposure to radon (> 400 mSv) compared to the low exposure group (OR 2.21, 90% CI 1.25–3.91).
Mohner [46]	2010	Case-control study	Uranium mining (radionuclides)	No significant increase of leukemia risk was found among the group of workers with the highest (> 200 mSv) cumulative exposure (OR 1.33, 90% CI 0.82-2.14).
B. Non-ionizing radiation (EMF) and leukemia
Roosli [47]	2007	Cohort-study	ELF EMF	A significantly increased Hazard Ratio was shown for myeloid leukemia among the workers with the highest exposure to ELF EMF (HR 4.74, 95% CI 1.04-21.6, p=0.035).
Kheifets [48]	2008	Meta-analysis	EMF	A small but statistically significant increase in leukemia risk was found among the exposed group (RR 1.16, 95% CI 1.11-1.22 for all leukemias).