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Biomedical subjects

J D Boice

Publications and source records attributed to J D Boice.

At least 73 records · Page 4Linked to original sources
PubMed1997

The Estonian study of Chernobyl cleanup workers: II. Incidence of cancer and mortality.

A cohort of 4,742 men from Estonia who had participated in the cleanup activities in the Chernobyl area sometime between 1986 and 1991 and were followed through 1993 was analyzed with respect to the incidence of cancer and mortality. Incidence and mortality in the cleanup workers were assessed relative to national rates. No increases were found in all cancers (25 incident cases compared to 26.5 expected) or in leukemia (no cases observed, 1.0 expected). Incidence did not differ statistically significantly from expectation for any individual cancer site or type, though lung cancer and non-Hodgkin's lymphoma both occurred slightly more often than expected. A total of 144 deaths were observed [standardized mortality ratio (SMR) = 0.98; 95% confidence interval (CI) = 0.82-1.14] during an average of 6.5 years of follow-up. Twenty-eight deaths (19.4%) were suicides (SMR = 1.52; 95% CI = 1.01-2.19). Exposure to ionizing radiation while at Chernobyl has not caused a detectable increase in the incidence of cancer among cleanup workers from Estonia. At least for the short follow-up period, diseases directly attributable to radiation appear to be of relatively minor importance when compared with the substantial excess of deaths due to suicide.

Estonia↗
PubMed1997

Cumulative genetic damage in hematopoietic stem cells in a patient with a 40-year exposure to alpha particles emitted by thorium dioxide.

Thorotrast, a colloidal suspension of the long-lived radionuclide, thorium-232, was widely used as a radiographic contrast medium for several decades. Due to the poor excretion of the sol, however, Thorotrast would deposit in the liver, bone marrow and other tissue, and patients would receive alpha-particle irradiation for life. To gauge the cumulative genetic damage to hematopoietic stem cells due to chronic exposure to alpha particles, we conducted a multi-end-point evaluation in a 72-year-old man who had been administered a 32-ml bolus of Thorotrast during cerebral angiography performed over 40 years ago in 1950. Peripheral T lymphocytes were cultured to quantify the frequencies and cellular distributions of asymmetrical and symmetrical types of chromosome aberrations in first-division metaphases and micronuclei in cytokinesis-arrested interphase II cells. Aberrations were scored using classical chromosome group analysis methods and chromosome painting techniques. Assays of glycophorin-A (GPA) mutations in red blood cells were also performed to obtain a relative measurement of damage sustained by the erythroid stem cell population. Results revealed that approximately 30% of the lymphocytes in this patient contained one or more chromosome aberrations, the majority of which were of the "stable" type. About one-third of the lymphocytes with chromosome damage carried multiple aberrations, suggesting that significant numbers of stem cells survive exposures to alpha-particle radiation that induce complex genomic alterations. Increased frequencies of GPA mutations were observed, demonstrating that genomic damage is also induced in erythroid progenitors. The numbers of micronuclei in lymphocytes were only moderately increased compared to expected values for persons of comparable age, and thus this end point was not useful for quantifying exposure level. Despite the relatively severe burden of somatic cell damage induced by 40 years of internal alpha-particle irradiation, the patient remains surprisingly free of any serious illness.

Alpha Particles↗
PubMed1997

Biological dosimetry of radiation workers at the Sellafield nuclear facility.

The British Nuclear Fuels plc facility at Sellafield performs a range of nuclear-related activities. The site has been in operation since 1950 and has, in general, employed a stable work force, many of whom have accumulated relatively high occupational exposures to ionizing radiation. This paper compares the physical dosimetry with two biological end points for evaluating radiation exposure: fluorescence in situ hybridization with whole-chromosome painting probes to quantify stable chromosome aberrations (translocations and insertions), and glycophorin A (GPA) analysis of variant erythrocytes. For the cytogenetic analyses, 81 workers were evaluated in five dose categories, including 23 with minimal radiation exposure (< or = 50 mSv) and 58 with exposures ranging from 173 to 1108 mSv, all but 3 being > 500 mSv. In a univariate analysis, the mean stable chromosome aberration frequencies showed a significant increase with dose category (P = 0.032), and with cumulative dose when dose is treated as a continuous variable (P = 0.015). The slope of the dose response for stable aberrations is 0.79 +/- 0.22 aberrations per 100 cells per sievert (adjusted for smoking status), which is less than that observed among atomic bomb survivors, and suggests a dose and dose-rate effectiveness factor for chronic exposure of about 6. Analyses of the data for GPA N/O and N/N variants from 36 workers revealed no correlation with dose. Neither was there a correlation between the frequencies of N/O GPA variants and stable aberrations, although a weak negative association was observed between N/N variant frequency and stable aberrations (r = -0.38, P = 0.05). These results provide clear evidence for the accumulation of stable aberrations under conditions of chronic occupational exposure to ionizing radiation and show that stable chromosome aberrations are a more sensitive indicator for chronic radiation exposure than GPA variants. In comparison with human studies of brief exposure, chronic low-dose exposures appear substantially less effective for producing somatic effects as reflected by stable chromosome aberrations.

Cells, Cultured↗
PubMed1996

Second malignant neoplasms among long-term survivors of ovarian cancer.

Second malignant neoplasms were evaluated among 32,251 women with ovarian cancer, including 4,402 10-year survivors, within the nine population-based registries of the Surveillance, Epidemiology, and End Results Program of the National Cancer Institute (1973-1992) and the Connecticut Tumor Registry (1935-1972). Overall, 1,296 second cancers occurred against 1,014 expected [observed/expected (O/E), 1.28; 95% confidence interval (CI), 1.21-1.35]. Sites contributing 25 or more excess cancers included leukemia (O/E, 4.17; O, 111; 95% CI, 3.43-5.03) and malignancies of colon (O/E, 1.33; O, 188; 95% CI, 1.15-1.54), rectum (O/E, 1.43; O, 76; 95% CI, 1.13-1.79), breast (O/E, 1.18; O, 404; 95%, CI 1.07-1.30), and bladder (O/E, 2.07; O, 65; 95% CI, 1.59-2.63). Ocular melanoma (O/E, 4.45; O, 8; 95% CI, 1.92-8.77) was also significantly increased. Second cancer risk was high during all follow-up intervals, and cumulative risk at 20 years was 18.2%, compared with a population expected risk of 11.5%. Statistically significant relationships existed between serous adenocarcinoma of the ovary and breast cancer (O/E, 1.29; 95% CI, 1.06-1.56) and mucinous ovarian adenocarcinoma and rectal cancer (OE/E, 1.95; 95% CI, 1.09-3.22). Secondary leukemia appeared linked with antecedent chemotherapy, whereas radiotherapy was associated with cancers of connective tissue, bladder, and possibly pancreas. Genetic and reproductive factors predisposing to ovarian cancer may have contributed to the elevated risk of breast and colorectal neoplasms and possibly ocular melanoma. Thus, excess malignancies following ovarian cancer represent complications of curative therapies and/or underlying susceptibility states that have etiological and clinical ramifications.

Adult↗
PubMed1996

Childhood leukemia following phototherapy for neonatal hyperbilirubinemia (Denmark).

To test the hypothesis that exposure to high intensity lightning (around 400 nanometers) in neonatal nurseries increases the incidence of childhood leukemia, over 55,120 newborn children treated with phototherapy for hyperbilirubinemia were identified from the Danish Hospital Discharge Register for 1977-89. Linkage of the roster with the national cancer registry through 1991 revealed 87 childhood cancers, whereas 85 were expected from the rates for the general population. The incidence of leukemia in 34 children was not unusual (standardized incidence ratio [SIR] = 1.2, 95 percent confidence interval [CI] = 0.8-1.7). Subgroup analyses revealed no remarkable patterns for any category of leukemia subtype, gender, or age at diagnosis. We conclude that whole-body exposure to phototherapy (420-470 nm) shortly after birth is not a significant risk factor for childhood leukemia.

Adolescent↗
PubMed1996

Risks of non-Hodgkin's lymphoma, multiple myeloma, and leukemia associated with common medications.

We utilized data from two Kaiser Permanente medical care programs to evaluate risks of hematopoietic and lymphoproliferative (HLP) malignancies after use of 14 common medications. The subjects were adult cases of non-Hodgkin's lymphoma (NHL) (N = 94), multiple myeloma (N = 159), and leukemia (N = 257) and individually matched controls (N = 695). Abstractors reviewed medical records and recorded medication notations. Using a minimum 5-year exposure lag between first notation and malignancy diagnosis, the risk of NHL was greater among plan members who were prescribed amphetamines [odds ratio (OR) = 2.2; 95% confidence interval (CI) = 1.1-4.8], lidocaine (OR = 2.6; 95% CI = 1.2-5.5), and meprobamate (OR = 2.1; 95% CI = 1.03-4.3). The risk of NHL rose with increasing number of medical record notations for amphetamines; however, there was no association with number of notations for lidocaine or meprobamate. The odds ratio for total leukemia was decreased among patients who took chloramphenicol (OR = 0.4; 95% CI = 0.2-0.97).

Adult↗
PubMed1996

Childhood exposure to magnetic fields: residential area measurements compared to personal dosimetry.

We examined the relation between area measurements of residential magnetic fields and personal dosimetry measurements among 64 control children age 2-14 years from the National Cancer Institute-Children's Cancer Group's nine-state case-control study of childhood leukemia. During a typical weekday, an activity diary was completed, and a 24-hour measurement was obtained in each child's bedroom. According to the activity diaries, children spent more than 40% of the 24 hours in their bedrooms, and 68% of their time at home. We found that at-home personal dosimetry levels were highly correlated with total personal dosimetry levels in children under 9 years (Spearman correlation coefficient, R = 0.94), whereas the correlation was lower in older children (R = 0.59). For all children combined, bedroom 24-hour measurements correlated well with at-home personal dosimetry levels (R = 0.76). The 24-hour bedroom measurement was a useful predictor of both at-home and total personal dosimetry measurements. Particularly for younger children, our data suggest that in-home area measurements predict both current residential and current total magnetic field exposures. This information will be valuable for assessing the validity of exposure assessment in previous and ongoing studies and for developing measurement protocols for future studies.

Adolescent↗
PubMed1996

Radon measurements in underground dwellings from two prefectures in China.

Radon, an established lung carcinogen, remains the single most important environmental radiation exposure. Yet, an excess of lung cancer from breathing radon in homes has not been consistently demonstrated in studies conducted to date. To address several major problems that have hindered previous studies of lung cancer and radon in homes, we have embarked upon a lung cancer case-control study in Gansu Province, China, where a substantial proportion of the population live in underground dwellings. In this paper, we report on results of a pilot study in which radon measurements were made for 3 days in the summer in 40 homes under normal occupancy conditions using short-term E-PERM detectors and for 6 months from February through August in 49 homes using long-term alpha-track detectors. Useable E-PERM data were obtained from 38 homes and useable alpha-track data from 47 homes. For both types of detectors, measurements were approximately log-normally distributed. Arithmetic and geometric means were 233 and 185 Bq m-3 (range 74-1,590 Bq m-3) for E-PERM measurements and 165 and 158 Bq m-3 (range 74-592 Bq m-3) for alpha-track measurements, respectively; 68% of E-PERM measured homes and 55% of alpha-track measured homes exceeded 148 Bq m-3. Alpha-track measurements made at the entry, middle, and rear areas of the underground dwellings did not differ significantly (arithmetic means of 168, 162, and 165 Bq m-3 with standard deviations 63, 73, and 48, respectively), which suggests that air circulation may be minimal. The underground dwellings measured in the pilot study had high radon levels and the underground dwellers may provide an excellent population for studying indoor radon and risk of lung cancer.

Air Pollution, Indoor↗
PubMed1996

Comparison of dose histories for U.S. nuclear power plant workers, based on records held by a major dosimetry service company and on the NRC REIRS database.

In order to conduct valid epidemiological studies of nuclear power plant workers, good information on the workers' radiation dose histories is essential. Dose records held by a major dosimetry service company and on the Nuclear Regulatory Commission's Radiation Exposure Information and Recording System have been compared for a sample of 99 workers. About half of the workers in the sample had no records on the Radiation Exposure Information and Recording System, since they had not terminated employment at a Nuclear Regulatory Commission-licensed facility; accordingly, their career doses (as recorded by the service company) were generally higher than those for workers on the Radiation Exposure Information and Recording System. For nearly half of the workers with records on both databases, the total dose recorded for terminated employments at nuclear power plants differed by at least a factor of 5 between the databases. In absolute terms, these differences were of the order of 100 mSv or more. An approach that utilized both the Radiation Exposure Information and Recording System and the dosimetry service company's records might be of value in constructing dose histories for a large epidemiological study. However, the comparisons presented here support the initiatives of the Nuclear Regulatory Commission to request licensees to report voluntarily career doses for current employees. These data are essential if a large and valid epidemiological study of nuclear plant workers is to be conducted in the foreseeable future.

Humans↗
PubMed1996

Leukemia following low-dose total body irradiation and chemotherapy for non-Hodgkin's lymphoma.

PURPOSE: Low-dose total body irradiation (TBI) is used to treat non-Hodgkin's lymphoma (NHL) and several other malignancies. Large volumes of bone marrow and other tissue receive considerable exposure, but few studies have quantified late carcinogenic sequelae. PATIENTS AND METHODS: A cohort of 61 2-year survivors of NHL treated initially with low-dose TBI was monitored for second cancer occurrence. Data on primary and subsequent therapy were collected, and cumulative dose of radiation to active bone marrow (ABM) (median, 5.2 Gy) was reconstructed. RESULTS: Thirteen second primary cancers occurred. Four patients developed acute nonlymphocytic leukemia (ANLL), which represents a relative risk (RR) of 117 (95% confidence interval [CI], 31.5 to 300) compared with population rates. A fifth patient was diagnosed with myelodysplastic syndrome (MDS). All five patients with secondary hematologic malignancies subsequently received salvage treatment, with either alkylating agents alone (n = 1) or combined modality therapy (CMT) (n = 4). Overall, eight solid tumors were observed (RR = 2.0; 95% CI, 0.9 to 4.0). The 15-year cumulative risks of all second cancers and secondary ANLL were 37% and 17%, respectively. CONCLUSIONS: Despite the small number of subjects, a considerable risk of leukemia was observed among patients treated with low-dose TBI in combination with CMT including alkylating agents. Based on these results, approximately eight to nine excess ANLLs might be expected to occur among 100 NHL patients treated with low-dose TBI and salvage treatment and followed-up for 15 years.

Adolescent↗
PubMed1996

Thyroid cancer after diagnostic administration of iodine-131.

To provide quantitative data on the risk of thyroid cancer after exposure to 131I, 34,104 patients administered 131I for diagnostic purposes were followed for up to 40 years. The mean thyroid dose was estimated as 1.1 Gy, and 67 thyroid cancers occurred in contrast to 49.7 expected (standardized incidence ratio = 1.35; 95% confidence interval 1.05-1.71). Excess cancers were apparent only among patients referred because of a suspected thyroid tumor, and no increased risk was seen among those referred for other reasons. Further, risk was not related to radiation dose to the thyroid gland, time since exposure or age at exposure. The slight excess of thyroid cancer thus appeared to be due to the underlying thyroid condition and not radiation exposure. Among those under age 20 years when 131I was administered, a small excess risk (3 cancers compared to 1.8 expected) was about 2-10 times lower than that predicted from data for the A-bomb survivors. These data suggest that protraction of dose may result in a lower risk than an acute X-ray exposure of the same total dose.

Adolescent↗
PubMed1996

Cancer following irradiation in childhood and adolescence.

The child appears more sensitive than the adult to the carcinogenic effects of radiation for certain sites such as the breast and thyroid. However, there are few studies of persons who were exposed as children and adolescents who have been followed for 40 or 50 years into the adult ages. Thus, it is extremely important that follow-up studies of children continue to evaluate the lifetime cancer risk that might be related to radiation exposures in childhood.

Adolescent↗