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Kopecky
Thyroid neoplasia, autoimmune thyroiditis, and hypothyroidism in persons exposed to iodine 131 from the Hanford nuclear site.Davis S, Kopecky KJ, Hamilton TE, Onstad L; Hanford Thyroid Disease Study Team. JAMA. 2004 Dec 1;292(21):2600-13.
"CONTEXT: Approximately 740,000 Ci (2.73 x 10(16) Bq) of iodine 131 (131I) were released to the atmosphere from the Hanford Nuclear Site in Washington State from 1944 through 1957. The risk of thyroid disease resulting from prolonged environmental 131I exposure is poorly understood. OBJECTIVE: The Hanford Thyroid Disease Study (HTDS) was conducted to determine if thyroid disease is increased among persons exposed as children to atmospheric releases of 131I from Hanford. DESIGN: Retrospective cohort study. Exposure could have occurred from December 1944 through 1957. Follow-up occurred until the time of the HTDS examination (December 1992-September 1997). Participants' thyroid radiation doses from Hanford's 131I releases were estimated from interview data regarding residence and dietary histories. SETTING: The cohort included a sample of all births from 1940 through 1946 to mothers with usual residence in 1 of 7 counties in eastern Washington State. PARTICIPANTS: Of 5199 individuals identified, 4350 were located alive and 3440 were evaluable; ie, had sufficient data for dose estimation and received an HTDS evaluation for thyroid disease, including a thyroid ultrasound, physical examination, and fine needle biopsy if required to evaluate thyroid nodularity. MAIN OUTCOME MEASURES: Thyroid cancer, benign thyroid nodules, total neoplasia, any thyroid nodules, autoimmune thyroiditis, and hypothyroidism. RESULTS: There was no evidence of a relationship between Hanford radiation dose and the cumulative incidence of any of the outcomes. These results remained unchanged after taking into account several factors that might confound the relationship between radiation dose and the outcomes of interest. CONCLUSION: These results do not support the hypothesis that exposure during infancy and childhood to 131I at the dose levels (median, 97 mGy; mean, 174 mGy) and exposure circumstances experienced by our study participants increases the risk of the forms of thyroid disease evaluated in this study."
Thyroid ultrasound abnormalities in persons exposed during childhood to 131I from the Hanford nuclear site.Kopecky KJ, Onstad L, Hamilton TE, Davis S. Thyroid. 2005 Jun;15(6):604-13. [abstract only]
"Approximately 740,000 Ci of 131I were released into the atmosphere from the Hanford Nuclear Site in Washington State during 1944-1957. The Hanford Thyroid Disease Study (HTDS), conducted to determine if thyroid disease is increased among persons exposed as children to that 131I, also investigated whether thyroid ultrasound (US) abnormalities might be increased. The HTDS cohort (n = 5199) was selected from 1940-1946 births to mothers with usual residence in seven Washington counties. Of these, 4350 were located alive, 3447 attended HTDS clinics (1992-1997), and 3440 (1747 females) had evaluable clinical results and sufficient data to characterize their Hanford 131I exposures. US abnormalities were observed in 55.5% of women and 37.4% of men. Thyroid radiation doses from Hanford 131I, which could be estimated for 3191 evaluable participants, ranged from 0.0029 to 2823 mGy (mean, 174 mGy). Estimated dose was not significantly associated with the prevalence of any US abnormality (p = 0.21), US nodules with maximum dimension 5 mm or more (p = 0.64), or average number of US nodules per person (p = 0.80 for nodules with maximum dimension 5 mm or more). These results remained unchanged after accounting for factors that might confound or modify dose-response relationships and for uncertainty of the dose estimates. This study does not support the hypothesis that 131I exposure at Hanford's dose levels and dose rates during infancy and childhood increases the prevalence of adult thyroid US abnormalities."
Hyperparathyroidism in persons exposed to iodine-131 from the Hanford Nuclear Site.Hamilton TE, Davis S, Onstad L, Kopecky KJ. J Clin Endocrinol Metab. 2005 Dec;90(12):6545-8. Epub 2005 Oct 4. [abstract only]
"CONTEXT: The risk of primary hyperparathyroidism from exposure to external radiation has been well documented in the last 20 yr. However, it remains unclear whether hyperparathyroidism might also be caused by internal exposure to radioactive iodine. OBJECTIVE: The objective of this study was to determine whether exposure to 131I from the Hanford Nuclear Site during 1944-1957 increased the risk of hyperparathyroidism among people living in the area. DESIGN: The Hanford Thyroid Disease Study was conducted as a retrospective cohort study. SETTING: The study setting was the general community in Washington State. PARTICIPANTS: The participants were 5199 persons born to mothers with usual residence in one of seven counties in eastern Washington State, randomly selected from birth records for the years 1940-1946. INTERVENTION: Of the 5199 selected, 3440 underwent a Hanford Thyroid Disease Study clinical evaluation, including an evaluation for hyperparathyroidism. Individual thyroid radiation dose, which could be estimated for 3191 study participants, ranged from 0.0029-2823 mGy (mean, 174 mGy). MAIN OUTCOME MEASURE: Hyperparathyroidism was the main outcome measure. RESULTS: Of 3440 evaluable participants, we confirmed 12 cases of primary hyperparathyroidism (0.35%). We found no evidence that the cumulative incidence of hyperparathyroidism increased with increasing radiation dose. CONCLUSION: In summary, this study shows no evidence that 131I, received at young ages and at the doses and exposure conditions experienced by this cohort, increased the risk of primary hyperparathyroidism. However, the effects of different doses and conditions of exposure to 131I on the risk of hyperparathyroidism remain to be defined."
Estimation of thyroid radiation doses for the hanford thyroid disease study: results and implications for statistical power of the epidemiological analyses.Kopecky KJ, Davis S, Hamilton TE, Saporito MS, Onstad LE. Health Phys. 2004 Jul;87(1):15-32. [abstract only]
"to I released into
the atmosphere from operations at the Hanford Nuclear Site from
1944 through 1972, especially in the late 1940's and early
1950's. This paper describes the estimated doses to the thyroid
glands of the 3,440 evaluable participants in the Hanford Thyroid
Disease Study, which investigated whether thyroid morbidity was
increased in people exposed to radioactive iodine from Hanford
during 1944-1957. The participants were born during 1940-1946 to
mothers living in Benton, Franklin, Walla Walla, Adams, Okanogan,
Ferry, or Stevens Counties in Washington State. Whenever possible
someone with direct knowledge of the participant's early life
(preferably the participant's mother) was interviewed about the
participant's individual dose-determining characteristics
(residence history, sources and quantities of food, milk, and
milk products consumed, production and processing techniques for
home-grown food and milk products). Default information was used
if no interview respondent was available. Thyroid doses were
estimated using the computer program Calculation of Individual
Doses from Environmental Radionuclides (CIDER) developed by the
Hanford Environmental Dose Reconstruction Project. CIDER provided
100 sets of doses to represent uncertainty of the estimates.
These sets were not generated independently for each participant,
but reflected the effects of uncertainties in characteristics
shared by participants. Estimated doses (medians of each
participant's 100 realizations) ranged from 0.0029 mGy to 2823
mGy, with mean and median of 174 and 97 mGy, respectively. The
distribution of estimated doses provided the Hanford Thyroid
Disease Study with sufficient statistical power to test for
dose-response relationships between thyroid outcomes and exposure
to Hanford's I."
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