A Cohort Study of Korean Radiation Workers: Baseline Characteristics of Participants
Abstract
:1. Introduction
2. Materials and Methods
2.1. Study Population and Cohort Enrollment
2.2. Dosimetry and Data for Cancer Incidence
2.3. Data Analysis
2.4. Ethics Approval
3. Results
3.1. Baseline Characteristics of the Cohort
3.2. Distribution of the Radiation Dose of the Cohort
3.3. Cancer Incidence of the Cohort
4. Discussion
5. Conclusions
Supplementary Materials
Author Contributions
Funding
Conflicts of Interest
References
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Characteristics | n | (%) |
---|---|---|
Sex | ||
Men | 17,831 | (86.5%) |
Women | 2777 | (13.5%) |
Birth year | ||
~1960 | 1391 | (6.7%) |
1961–1970 | 3449 | (16.7%) |
1971–1980 | 5891 | (28.6%) |
1981~ | 9877 | (47.9%) |
Education level | ||
Less than high school graduation | 159 | (0.8%) |
High school graduation | 4539 | (22.6%) |
College graduation and above | 15,402 | (76.6%) |
Marital status | ||
Unmarried | 7881 | (39.2%) |
Married/living together | 11,982 | (59.6%) |
Other (divorced, widow, separated) | 233 | (1.2%) |
BMI, kg/m2 | ||
Underweight (<18.5) | 490 | (2.6%) |
Normal weight (18.5–24.9) | 11,677 | (61.2%) |
Overweight (25.0–29.9) | 6012 | (31.5%) |
Obese (≥30.0) | 913 | (4.8%) |
Regular exercise | ||
No | 9061 | (44.3%) |
Yes | 11,385 | (55.7%) |
Smoking status | ||
Never (non-smoker) | 8442 | (41.3%) |
Ex-smoker | 3615 | (17.7%) |
Yes (smoker) | 8361 | (40.9%) |
Alcohol status | ||
No | 3276 | (16.0%) |
Yes | 17,239 | (84.0%) |
Characteristics | n | (%) |
---|---|---|
Occupation | ||
Public institute | 676 | (3.3%) |
Education institute | 2010 | (9.8%) |
Military | 165 | (0.8%) |
Industrial radiography | 3517 | (17.1%) |
Industry | 3886 | (18.9%) |
Research institute | 1139 | (5.5%) |
Nuclear power plant | 6328 | (30.7%) |
Medical institute | 2887 | (14.0%) |
Calendar year of hiring | ||
~1989 | 1272 | (6.2%) |
1990–1999 | 2694 | (13.1%) |
2000–2009 | 4569 | (22.2%) |
2010~ | 12,073 | (58.6%) |
Age at the start of radiation work, years | ||
<20 | 785 | (3.8%) |
20–29 | 12,168 | (59.0%) |
30–39 | 5449 | (26.4%) |
40–49 | 1565 | (7.6%) |
≥50 | 641 | (3.1%) |
Employment status | ||
Regular employment | 16,450 | (82.6%) |
Irregular employment (temporary contract) | 2885 | (14.5%) |
Irregular employment (daily contract) | 589 | (3.0%) |
Duration of employment, years | ||
≤4 | 9265 | (45.0%) |
5–9 | 4310 | (20.9%) |
10–14 | 2372 | (11.5%) |
≥15 years | 4661 | (22.6%) |
Experience of warning for exceeding 5 mSv per quarter | ||
No | 17,857 | (90.4%) |
Yes | 901 | (4.6%) |
I do not know | 987 | (5.0%) |
Night shifts | ||
None | 10,361 | (51.1%) |
<1 year | 2544 | (12.5%) |
1–5 years | 4215 | (20.8%) |
>5 years | 3152 | (15.5%) |
Radiation source | ||
None | 2873 | (14.6%) |
Sealed isotope | 5309 | (26.9%) |
Unsealed isotope | 2430 | (12.3%) |
Radiation-generating device | 5559 | (28.2%) |
Not sure | 3539 | (18.0%) |
Distance from radiation source | ||
<1 m | 3752 | (20.0%) |
1–3 m | 4866 | (25.9%) |
>3 m | 10,149 | (54.1%) |
While engaged in radiation work, white blood cell counts fell below the normal range | ||
No | 17,922 | (90.5%) |
Yes | 498 | (2.5%) |
Not sure (or had never had a health examination) | 1381 | (7.0%) |
Report Year | No. of Workers | Annual Collective Dose (man.mSv) | Annual Radiation Dose (mSv [mean ± SD]) | No. of Workers >20 mSv Per Year (%) | |
---|---|---|---|---|---|
1984 | 417 | 1876.55 | 4.5 ± 6.9 | 25 | (6.0) |
1985 | 563 | 1831.57 | 3.2 ± 5.5 | 14 | (2.5) |
1986 | 683 | 3150.87 | 4.6 ± 7.5 | 46 | (6.7) |
1987 | 870 | 2923.13 | 3.4 ± 5.8 | 25 | (2.9) |
1988 | 1085 | 4210.68 | 3.9 ± 7.2 | 64 | (5.9) |
1989 | 1213 | 3428.80 | 2.8 ± 4.9 | 20 | (1.6) |
1990 | 1348 | 4567.53 | 3.4 ± 6.0 | 42 | (3.1) |
1991 | 1491 | 3494.45 | 2.3 ± 4.4 | 21 | (1.4) |
1992 | 1690 | 4145.30 | 2.5 ± 4.4 | 19 | (1.1) |
1993 | 1763 | 4557.83 | 2.6 ± 4.7 | 24 | (1.4) |
1994 | 2041 | 4554.59 | 2.2 ± 4.2 | 18 | (0.9) |
1995 | 2457 | 6528.34 | 2.7 ± 5.1 | 47 | (1.9) |
1996 | 2725 | 6803.13 | 2.5 ± 4.5 | 32 | (1.2) |
1997 | 2890 | 5958.99 | 2.1 ± 3.8 | 14 | (0.5) |
1998 | 3140 | 6199.69 | 2.0 ± 3.6 | 7 | (0.2) |
1999 | 3502 | 6887.96 | 2.0 ± 3.3 | 6 | (0.2) |
2000 | 3696 | 7041.37 | 1.9 ± 3.4 | 14 | (0.4) |
2001 | 4008 | 7156.33 | 1.8 ± 3.4 | 9 | (0.2) |
2002 | 4212 | 6922.35 | 1.6 ± 2.9 | 10 | (0.2) |
2003 | 4463 | 6950.28 | 1.6 ± 2.8 | 8 | (0.2) |
2004 | 4925 | 8413.59 | 1.7 ± 3.3 | 15 | (0.3) |
2005 | 5302 | 8732.94 | 1.6 ± 3.1 | 17 | (0.3) |
2006 | 5812 | 9113.73 | 1.6 ± 2.9 | 14 | (0.2) |
2007 | 6447 | 10,275.9 | 1.6 ± 2.9 | 10 | (0.2) |
2008 | 6986 | 9385.69 | 1.3 ± 3.2 | 31 | (0.4) |
2009 | 7605 | 9844.92 | 1.3 ± 3.1 | 27 | (0.4) |
2010 | 8350 | 11,133.14 | 1.3 ± 3.3 | 46 | (0.6) |
2011 | 9440 | 10,743.07 | 1.1 ± 2.8 | 30 | (0.3) |
2012 | 10,803 | 13,282.39 | 1.2 ± 3.4 | 50 | (0.5) |
2013 | 11,965 | 15,290.65 | 1.3 ± 3.5 | 72 | (0.6) |
2014 | 13,419 | 11,881.34 | 0.9 ± 2.4 | 18 | (0.1) |
2015 | 15,568 | 10,974.39 | 0.7 ± 2.2 | 17 | (0.1) |
2016 | 18,861 | 11,352.00 | 0.6 ± 1.9 | 15 | (0.1) |
2017 a | 18,411 | 2844.70 | 0.2 ± 0.7 | 3 | (0.0) |
Total | 20,608 | 242,198.04 | 1.3 ± 3.2 | 602 | (2.9) |
Cancer/Site | Men (n = 16,943) | Women (n = 2584) | ||||
---|---|---|---|---|---|---|
Obs | SIR (95% CI) | Obs | SIR (95% CI) | |||
All cancers combined (C00–C96) | 189 | 0.76 | (0.66–0.88) | 23 | 0.84 | (0.56–1.26) |
Oral cavity (C03–C06) | 1 | 1.15 | (0.16–8.13) | 0 | 0 | (0–99.86) |
Salivary gland (C07–C08) | 3 | 2.98 | (0.96–9.25) | 0 | 0 | (0–42.80) |
Stomach (C16) | 44 | 0.95 | (0.70–1.27) | 1 | 0.63 | (0.09–4.45) |
Small intestine (C17) | 1 | 0.84 | (0.12–5.94) | 0 | 0 | (0–74.90) |
Colon (C18) | 15 | 0.93 | (0.56–1.54) | 0 | 0 | (0–4.68) |
Rectum (C19) | 10 | 0.56 | (0.30–1.04) | 0 | 0 | (0–5.08) |
Liver (C22) | 7 | 0.20 | (0.10–0.43) | 0 | 0 | (0–8.81) |
Nose, sinuses, etc. (C30–C31) | 2 | 2.98 | (0.74–11.91) | 0 | 0 | (0–99.86) |
Lung (C33–C34) | 4 | 0.23 | (0.09–0.61) | 0 | 0 | (0–5.76) |
Bone (C40–C41) | 1 | 0.89 | (0.13–6.31) | 0 | 0 | (0–33.29) |
Melanoma of skin (C43) | 1 | 1.41 | (0.20–9.98) | 0 | 0 | (0–74.90) |
Other skin (C44) | 1 | 0.30 | (0.04–2.11) | 0 | 0 | (0–18.72) |
Breast (C50) | 0 | 0 | (0–14.97) | 9 | 1.51 | (0.79–2.90) |
Cervix uteri (C53) | - | - | - | 1 | 0.65 | (0.09–4.60) |
Uterus, part unspecified (C55) | - | - | - | 1 | 25.86 | (3.64–183.60) |
Prostate (C61) | 5 | 0.88 | (0.37–2.12) | - | - | - |
Testis (C62) | 2 | 0.98 | (0.24–3.91) | - | - | - |
Kidney (C64) | 10 | 1.07 | (0.57–1.98) | 0 | 0 | (0–13.02) |
Bladder (C67) | 2 | 0.46 | (0.11–1.82) | 0 | 0 | (0–59.91) |
Brain, nervous system (C70–C72) | 1 | 0.25 | (0.04–1.79) | 0 | 0 | (0–11.98) |
Thyroid (C73) | 72 | 1.94 | (1.54–2.44) | 11 | 0.92 | (0.51–1.66) |
Adrenal grand (C74) | 1 | 4.29 | (0.60–30.43) | 0 | 0 | (0–149.79) |
Hodgkin lymphoma (C81) | 1 | 1.36 | (0.19–9.66) | 0 | 0 | (0–42.80) |
Non-Hodgkin lymphoma (C82–C86) | 2 | 0.28 | (0.07–1.13) | 0 | 0 | (0–8.32) |
Multiple myeloma (C90) | 1 | 0.86 | (0.12–6.10) | 0 | 0 | (0–74.90) |
Leukemia (C91–C95) | 2 | 0.33 | (0.08–1.32) | 0 | 0 | (0–7.88) |
Characteristics | n | All Cancers Combined | All Cancers Combined Excluding Thyroid Cancer | Thyroid Cancer | ||||||
---|---|---|---|---|---|---|---|---|---|---|
Obs | SIR (95% CI) | Obs | SIR (95% CI) | Obs | SIR (95% CI) | |||||
Occupation | ||||||||||
Public institute | 644 | 10 | 1.03 | (0.55–1.91) | 8 | 0.98 | (0.49–1.96) | 2 | 1.29 | (0.32–5.14) |
Education institute | 1805 | 10 | 0.70 | (0.38–1.30) | 8 | 0.77 | (0.38–1.53) | 2 | 0.51 | (0.13–2.05) |
Military | 164 | 2 | 2.25 | (0.56–8.99) | 0 | 0 | (0–4.68) | 2 | 8.26 | (2.07–33.04) |
Industrial radiography | 3415 | 12 | 0.36 | (0.20–0.63) | 10 | 0.38 | (0.20–0.70) | 2 | 0.28 | (0.07–1.13) |
Industry | 3645 | 42 | 0.96 | (0.71–1.30) | 26 | 0.75 | (0.49–1.05) | 16 | 2.15 | (1.32–3.50) |
Research institute | 1071 | 17 | 0.63 | (0.39–1.02) | 11 | 0.47 | (0.26–0.85) | 6 | 1.75 | (0.78–3.89) |
Nuclear power plant | 6037 | 93 | 0.88 | (0.72–1.08) | 53 | 0.59 | (0.45–0.77) | 40 | 2.68 | (1.97–3.65) |
Medical institute | 2746 | 26 | 0.63 | (0.43–0.93) | 13 | 0.43 | (0.25–0.73) | 13 | 1.23 | (0.72–2.12) |
Birth year | ||||||||||
~1950 | 103 | 8 | 0.45 | (0.23–0.91) | 8 | 0.46 | (0.23–0.93) | 0 | 0 | (0–8.32) |
1951–1960 | 1241 | 52 | 0.62 | (0.47–0.81) | 41 | 0.52 | (0.39–0.71) | 11 | 2.01 | (1.11–3.63) |
1961–1970 | 3350 | 71 | 0.76 | (0.60–0.96) | 49 | 0.62 | (0.47–0.83) | 22 | 1.46 | (0.96–2.22) |
1971–1980 | 5719 | 61 | 1.04 | (0.81–1.34) | 23 | 0.58 | (0.39–0.88) | 38 | 1.97 | (1.44–2.71) |
1981–1990 | 7314 | 18 | 0.88 | (0.55–1.40) | 7 | 0.59 | (0.28–1.24) | 11 | 1.27 | (0.71–2.30) |
1991~ | 1800 | 2 | 1.85 | (0.46–7.40) | 1 | 1.43 | (0.20–10.17) | 1 | 2.61 | (0.37–18.56) |
Cancer | Exposed Workers (n = 12,065) | Non-Exposed Workers (n = 7462) | Crude RR (95% CI) | Adj† RR (95% CI) | ||||
---|---|---|---|---|---|---|---|---|
Obs | SIR (95% CI) | Obs | SIR (95% CI) | |||||
All cancers combined | 151 | 0.69 | (0.59–0.81) | 61 | 1.05 | (0.82–1.36) | 0.64 (0.47–0.86) | 0.82 (0.60–1.12) |
All cancers combined excluding thyroid cancer | 92 | 0.51 | (0.42–0.63) | 37 | 0.79 | (0.58–1.10) | 0.64 (0.44–0.94) | 0.83 (0.56–1.24) |
Thyroid cancer | 59 | 1.55 | (1.20–2.00) | 24 | 2.17 | (1.46–3.24) | 0.63 (0.39–1.01) | 0.83 (0.49–1.38) |
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Park, S.; Seo, S.; Lee, D.; Park, S.; Jin, Y.W. A Cohort Study of Korean Radiation Workers: Baseline Characteristics of Participants. Int. J. Environ. Res. Public Health 2020, 17, 2328. https://doi.org/10.3390/ijerph17072328
Park S, Seo S, Lee D, Park S, Jin YW. A Cohort Study of Korean Radiation Workers: Baseline Characteristics of Participants. International Journal of Environmental Research and Public Health. 2020; 17(7):2328. https://doi.org/10.3390/ijerph17072328
Chicago/Turabian StylePark, Soojin, Songwon Seo, Dalnim Lee, Sunhoo Park, and Young Woo Jin. 2020. "A Cohort Study of Korean Radiation Workers: Baseline Characteristics of Participants" International Journal of Environmental Research and Public Health 17, no. 7: 2328. https://doi.org/10.3390/ijerph17072328