Research Findings

Mortality Studies - All Causes

Hyperthyroidism, Hypothyroidism, and Cause-Specific Mortality in a Large Cohort of Women (2017)
 Among 75,076 female radiologic technologists, women with a history of hyperthyroidism had an increased risk of dying from breast cancer after age 60 compared to those with no thyroid disease. Women with hypothyroidism had increased risks for mortality from diabetes, cardiovascular disease, and cerebrovascular disease.
Cancer risks in U.S. radiologic technologists working with fluoroscopically guided interventional procedures, 1994-2008 (2016)
 In a study of 90,957 U.S. radiologic technologists, elevated risks were observed for brain cancer, breast cancer, and melanoma among technologists who performed fluoroscopically-guided interventional procedures compared to technologists who did not perform such procedures.
Body-mass index and all-cause mortality: individual participant-data meta-analysis of 239 prospective studies in four continents (2016)
 In a pooled analysis of 10.6 million people from 239 prospective studies in Asia, Australia/New Zealand, Europe, and North America, all-cause mortality increased with increasing BMI, and risks were consistent across all four continents.
Leisure time physical activity and mortality: a detailed pooled analysis of the dose-response relationship (2015)
 In a pooled analysis of 6 prospective cohorts, individuals who reported 1-5 times the recommended minimum leisure time physical activity of 7.5 metabolic-equivalent hours per week experienced 31-39% lower mortality from all causes, and similar reductions in mortality from cardiovascular disease and cancer, compared to those with no leisure time physical activity.
Cancer and circulatory disease risks in US radiologic technologists associated with performing procedures involving radionuclides (2015)
 Among U.S. radiologic technologists who completed the second and third study surveys, squamous cell carcinoma of the skin was increased with ever performing diagnostic radionuclide procedures, myocardial infarction and all-cause mortality were elevated with ever performing brachytherapy, and all-cause mortality, breast cancer, and myocardial infarction were increased with ever performing other radionuclide procedures (excluding brachytherapy and radioactive iodine); risks increased with increasing frequency performed, especially before 1980.
Association between class III obesity (BMI of 40-59 kg/m2) and mortality: A pooled analysis of 20 prospective studies (2014)
 In a pooled analysis of 313,575 participants from 20 prospective cohort studies, including 22,872 radiologic technologists, individuals with Class III obesity (BMI=40.0-59.9) had substantially higher risks for mortality from all causes, heart, cancer, cerebrovascular, diabetes and other diseases than their normal weight (BMI=18.5-24.9) counterparts.
Work history and mortality risks in 90,268 U.S. radiologic technologists (2014)
 Mortality risks were evaluated in 90,268 U.S. radiologic technologists according to work history factors, including year first worked, total number of years worked, number of years worked in different time periods, and number of times held patients for exams. Technologists who began working in the early time periods and for more years before 1950, when occupational radiation doses were higher, were at increased risks for mortality from some cancers (breast, stomach, leukemia) and circulatory system diseases (ischemic heart, cerebrovascular).
Body mass index and risk of death in Asian Americans (2014)
 Similar to the patterns observed for Whites and Blacks in the United States, Asian Americans with high body mass index had increased risks for mortality from all causes, cancer, and cardiovascular disease in a pooled study of nearly 27,000 individuals.
Body-mass index and mortality in 1.46 million white adults. Authors' response (2011)
 RESPONSE
Body mass index and mortality among 1.46 million white adults (2010)
 Using pooled data from 21 cohort studies in the National Cancer Institute Cohort Consortium, including the U. S. Radiologic Technologist Study, researchers found that overweight, obesity, and possibly underweight were associated with elevated mortality from all causes in white adults. All-cause mortality was lowest in individuals with BMI in the range of 20.0-24.9.
Body mass index and all-cause mortality in a nationwide US cohort (2006)
 The USRT study has been particularly useful in examining issues relating to the growing prevalence of obesity, including the nature of the relationship between body mass index (BMI) and all-cause mortality. In this study, investigators found that over a 15-year follow-up period, mortality in younger and middle-aged, but not older participants increased with increasing BMI. These findings suggest the importance of assessing whether other markers of body composition, such as waist-hip ratio, better explain mortality risks in older adults.
The mortality risk of smoking and obesity combined (2006)
 We evaluated mortality risks from the first survey through 2002 according to body mass index and smoking history. For all age-gender groups, both obesity and smoking, especially current smoking, contributed substantially to all-cause mortality, with 3.5- to 5-fold risks for very obese current smokers compared to normal weight never smokers. Current smoking was the predominant risk factor for cancer mortality. Obese current smokers under age 65 had 6- to 11-fold higher mortality from cardiovascular disease than normal weight never smokers.
Interventional radiography and mortality risks in U.S. radiologic technologists (2006)
 We assessed overall and cause-specific mortality from the first survey through 2003 according to whether and how frequently radiologic technologists performed or assisted with interventional radiography procedures during three time periods. Risks of dying from all causes combined, all circulatory system diseases combined, all cancers combined and female breast cancer were not associated with use of interventional radiography procedures. Based on small numbers of deaths (151 total), we found non-statistically significant excesses (40-70%) in cerebrovascular disease mortality among technologists who ever worked with these procedures.
Cancer and other causes of mortality among radiologic technologists in the United States (2003)
 We examined the mortality patterns of radiation technologists in the USRT cohort from 1926 through 1997. Just as we had found in an earlier study of the USRT cohort, through 1990, radiologic technologists had a lower risk of dying from all causes compared to similar people in the general U.S. population. Compared to the U.S. population, mortality rates for both cardiovascular disease and cancer were lower in both male and female technologists. We also analyzed risks within the cohort of technologists to examine the effects of working during early periods (as an indicator of exposure to higher doses of radiation) compared to first working in later periods when exposures were lower. We found those working before 1940 had a slightly higher risk of death due to cancer than those first working after 1960, even after we adjusted for age. In particular, radiologic technologists who began working before 1950 had a somewhat higher risk of dying from leukemia than those who started working in 1950 or later. We also saw an elevated risk of breast cancer death among those first working before 1950. The elevated risks that we observed for leukemia and breast cancer are consistent with greater occupational exposures to radiation before 1950.
Mortality among Catholic nuns certified as radiologic technologists. (2000)
 We also studied mortality risks in a subgroup of the radiologic technologists who were Catholic nuns. Compared to other female radiologic technologists, the nuns had higher risks of dying from all causes, especially heart disease, digestive diseases, ulcers, diabetes, and stomach cancer, but their mortality risks for lung, breast, and cervical cancers were lower. Compared to women in the general population of similar age, the mortality experience of nuns was favorable and reflected the "healthy worker effect" commonly seen in occupational studies. The nuns had lower mortality risks for all causes combined and for all major disease categories (cancer, circulatory, respiratory, others), although their risks for tuberculosis and breast cancer were elevated. The tuberculosis excess may be a result of their work with patients in tuberculosis sanitaria, while the breast cancer excess may be at least partially explained by their different lifestyle and reproductive patterns. The breast cancer excess was concentrated among nuns first certified before 1940, when radiation doses were likely highest, but the risk did not increase with increasing number of years certified suggesting that exposure to radiation did not completely explain the difference.
Mortality among United States radiologic technologists, 1926-90 (1998)
 We compared the number of deaths among US radiologic technologists that occurred between 1926 and 1990 to the number of deaths that we expected based on the general US population. Nearly all of the causes of death examined showed risks lower than expected in the general population. This difference is due, in part, to the fact that radiologic technologists are employed in or retired from an occupation that is physically demanding. Similar to other occupational cohorts, workers tend to be healthier than the general population, which includes chronically ill people. When comparing subgroups of radiologic technologists, we found that risk of dying from breast cancer was higher in women who were certified before 1940 compared to those certified in 1970 or later, and in women certified for 30 or more years compared to those certified for less than 10 years. Among women first certified before 1940, risk increased significantly with increasing number of years certified. This trend was not seen in women who were certified in 1940 or later