Mary Bishop Stone

Thyroid disease associated with exposure to the Nevada nuclear weapons test site radiation: A reevaluation based on corrected dosimetry and examination data

Background: A study was begun in 1965 to 1966 to determine whether children exposed to radioactive iodine from nuclear weapons testing at the Nevada Test Site from 1951 through 1962 were at higher risk of thyroid disease. In 1993, we reported that among those examined in 1985 to 1986 (Phase II) there was an association between radiation from the Nevada Test Site and thyroid neoplasms. Methods: We reevaluated the relationship between exposure to Nevada Test Site fallout and thyroid disease using newly corrected dose estimates and disease outcomes from the Phase II study. A prospective cohort of school children 12 to 18 years old living in Utah, Nevada, and Arizona was first examined for thyroid disease in 1965 to 1966 and reexamined in 1985 to 1986. In the Phase II report, 2497 subjects formed the basis for this analysis. Thyroid disease, including thyroid neoplasms and thyroiditis, was expressed as cumulative incidence and risk ratios (RRs) with a dose–response expressed as excess risk ratio (ERR/Gy). Results: The RR between thyroid radiation dose in the highest dose group and thyroid neoplasms increased from 3.4 (in the earlier analysis) to 7.5. The RR for thyroiditis increased from 1.1 to 2.7 with an ERR/Gy of 4.9 (95% confidence interval = 2.0 to 10.0). There were too few malignant thyroid neoplasms to estimate risk. Conclusions: Persons exposed to radioactive iodine as children have an increased risk of thyroid neoplasms and autoimmune thyroiditis up to 30 years after exposure.

Indoor Radon and Lung Cancer Risk in Connecticut and Utah

Radon is a well-established cause of lung cancer in miners. Residents of homes with high levels of radon are potentially also at risk. Although most individual studies of indoor radon have failed to demonstrate significant risks, results have generally been consistent with estimates from studies of miners. We studied 1474 incident lung cancer cases aged 40–79 yr in Connecticut, Utah, and southern Idaho. Population controls (n = 1811) were identified by random telephone screening and from lists of Medicare recipients, and were selected to be similar to cases on age, gender, and smoking 10 yr before diagnosis/interview using randomized recruitment. Complete residential histories and information on known lung cancer risk factors were obtained by in-person and telephone interviews. Radon was measured on multiple levels of past and current homes using 12-mo alpha-track etch detectors. Missing data were imputed using mean radon concentrations for informative subgroups of controls. Average radon exposures were lower than anticipated, with median values of 23 Bq/m3 in Connecticut and 45 Bq/m3 in Utah/southern Idaho. Overall, there was little association between time-weighted average radon exposures 5 to 25 yr prior to diagnosis/interview and lung cancer risk. The excess relative risk (ERR) associated with a 100-Bq/m3 increase in radon level was 0.002 (95% CI −0.21, 0.21) in the overall population, 0.134 (95% CI −0.23, 0.50) in Connecticut, and −0.112 (95% CI −0.34, 0.11) in Utah/Idaho. ERRs were higher for some subgroups less prone to misclassification, but there was no group with a statistically significant linear increase in risk. While results were consistent with the estimates from studies of miners, this study provides no evidence of an increased risk for lung cancer at the exposure levels observed. We are grateful to Drs. Stuart Shalat and Keith Schiager, who made early contributions to the design and implementation of this study, and to Patty Blanton for expert data management. Lynne Rothney-Kozlak and Jan A. J. Stolwijk were formerly affiliated with Yale University School of Public Health, New Haven, Connecticut, USA.

Improving Quality of Life of Children With Oral Clefts: Perspectives of Parents

Quality of life is increasingly recognized as an important health outcome in people with surgically treatable conditions. However, few data are available on children with oral clefts. Focus groups provide a rich exploratory approach to understanding health-related quality of life issues. We report findings from 2 focus groups of parents of children with oral clefts (cleft lip, cleft palate, and cleft lip and palate) in Utah and Idaho. Participants were guided into a discussion of issues and drivers of quality of life, from diagnosis through treatment to school entry. Parents identified crucial factors including the early need for support (including parent support groups), for credible information, and for advice for daily life. Surgery was a major factor affecting satisfaction and quality of life, and satisfaction depended not only on surgical results but importantly on communication, empathy, expectations, postsurgical care, and discharge management. Many parents underscored as critically important the preparation and the postsurgery experience, rather than the surgery itself. Parents also identified crucial milestones, including birth, diagnosis, the first surgery, and school entry. Combining these crucial issues with a life-stage approach provides a framework for intervention that focuses on drivers of quality of life at selected milestones in the life of children with oral clefts.

2004 Update of Dosimetry for the Utah Thyroid Cohort Study

Abstract Simon, S. L., Anspaugh, L. R., Hoffman, F. O., Scholl, A. E., Stone, M. B., Thomas, B. A. and Lyon, J. L. 2004 Update of Dosimetry for the Utah Thyroid Cohort Study. Radiat. Res. 165, 208–222 (2006). In the 1980s, individual thyroid doses and uncertainties were estimated for members of a cohort of children identified in 1965 in Utah and Nevada who had potentially been exposed to fallout from the Nevada Test Site. That reconstruction represented the first comprehensive assessment of doses received by the cohort and was the first large effort to assess the uncertainty of dose on an individual person basis. The data on dose and thyroid disease prevalence during different periods were subsequently used in an analysis to determine risks of radiogenic thyroid disease. This cohort has received periodic medical follow-up to observe changes in disease frequency and to reassess the previously reported radiation-related risks, most recently after a Congressional mandate in 1998. In a recent effort to restore the databases and computer codes used to estimate doses in the 1980s, various deficiencies were found in the estimated doses due to improperly operating computer codes, corruption of secondary data files, and lack of quality control procedures. From 2001 through 2004, the dosimetry system was restored and corrected and all doses were recalculated. In addition, two parameter values were updated. While the mean of all doses has not changed significantly, many individual doses have changed by more than an order of magnitude.

The UTAH VBAC Study.

Background: In July 1999, The American College of Obstetricians and Gynecologists (ACOG) issued Practice Guideline number 5 on vaginal birth after cesarean section (VBAC) and trial of labor (TOL). This updated guideline recommends that a physician be immediately available during a TOL in the rare case of complications. We examined the effect this new guideline would have on physician’s VBAC/TOL practices in Utah. Objective: 1) Explore physician knowledge of ACOG Practice Guideline number 5; 2) Evaluate change in physician’s VBAC practices in the previous 12 months; 3) Evaluate physician’s ability to comply with ACOG Practice Guideline number 5 recommendations by rural, suburban, and urban location. Methods: In spring 2001, we surveyed by mail all physicians practicing obstetrics in Utah. Questions included demographics, hospital data, VBAC/TOL practice patterns and awareness of ACOG Practice Guideline number 5. Physicians were classified as urban, suburban, or rural by their primary delivery hospital. Results: We found 97% of obstetricians and 79% of family physicians were aware of ACOG Practice Guideline number 5. Forty-five percent of all physicians reported a decline in VBAC practices in the preceding 12 months. Urban physicians’ use of VBAC/TOL decreased the least, followed by rural and suburban. Eighty-seven percent of physicians had C/S “immediately” available during TOL: urban physicians 100%, suburban 88%, and rural physicians 76%. Emergency C/S delivery was performed fastest at urban hospitals, slower at suburban, and slowest at rural hospitals. Conclusion: Physicians use of VBAC/TOL has changed. TOL is offered less by obstetrical providers in Utah and more repeat C/S are performed since 1999 when ACOG updated this policy guideline. This decline has been more noticeable in suburban and rural hospitals and is consistent with recent national trends. Many rural physicians are unable to comply with ACOG Practice Guideline number 5 recommendations.

Childhood Thyroid Radioiodine Exposure and Subsequent Infertility in the Intermountain Fallout Cohort

Background: Above-ground and underground nuclear weapon detonation at the Nevada Test Site (1951–1992) has resulted in radioiodine exposure for nearby populations. Although the long-term effect of environmental radioiodine exposure on thyroid disease has been well studied, little is known regarding the effect of childhood radioiodine exposure on subsequent fertility. Objectives: We investigated early childhood thyroid radiation exposure from nuclear testing fallout (supplied predominantly by radioactive isotopes of iodine) and self-reported lifetime incidence of male or female infertility or sterility. Methods: Participants were members of the 1965 Intermountain Fallout Cohort, schoolchildren at the time of exposure who were reexamined during two subsequent study phases to collect dietary and reproductive histories. Thyroid radiation exposure was calculated via an updated dosimetry model. We used multivariable logistic regression with robust sandwich estimators to estimate odds ratios for infertility, adjusted for potential confounders and (in separate models) for a medically confirmed history of thyroid disease. Results: Of 1,389 participants with dosimetry and known fertility history, 274 were classified as infertile, including 30 classified as sterile. Childhood thyroid radiation dose was possibly associated with infertility [adjusted odds ratio (AOR) = 1.17; 95% CI: 0.82, 1.67 and AOR = 1.35; 95% CI: 0.96, 1.90 for the middle and upper tertiles vs. the first tertile of exposure, respectively]. The odds ratios were attenuated (AOR = 1.08; 95% CI: 0.75, 1.55 and AOR = 1.29; 95% CI: 0.91, 1.83 for the middle and upper tertiles, respectively) after adjusting for thyroid disease. There was no association of childhood radiation dose and sterility. Conclusion: Our findings suggest that childhood radioiodine exposure from nuclear testing may be related to subsequent adult infertility. Further research is required to confirm this.