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Background: Although high-dose ionising radiation is associated with increased breast cancer risks, the association with protracted low-dose-rate exposures remains unclear. The US Radiologic Technologist study provides an opportunity to examine the association between low-to-moderate dose radiation and breast cancer incidence and mortality.Methods: One thousand nine hundred and twenty-two self-reported first primary cancers were diagnosed during 1983-2005 among 66 915 female technologists, and 586 breast cancer deaths occurred during 1983-2008 among 83 538 female cohort members. Occupational breast dose estimates were based on work histories, historical data, and, after the mid-1970s, individual film badge measurements. Excess relative risks were estimated using Poisson regression with birth cohort stratification and adjustment for menopause, reproductive history, and other risk factors.Results: Higher doses were associated with increased breast cancer incidence, with an excess relative risk at 100 mGy of 0.07 (95% confidence interval (CI): -0.005 to 0.19). Associations were strongest for technologists born before 1930 (excess relative risk at 100 mGy=0.16; 95% CI: 0.03-0.39) with similar patterns for mortality among technologists born before 1930.Conclusions: Occupational radiation to the breast was positively associated with breast cancer risk. The risk was more pronounced for women born before 1930 who began working before 1950 when mean annual doses (37 mGy) were considerably higher than in later years (1.3 mGy). However, because of the uncertainties and possible systematic errors in the occupational dose estimates before 1960, these findings should be treated with caution. [ABSTRACT FROM AUTHOR]

Objective:To investigate whether the nature of the relationship between body mass index (BMI (kg/m2)) and all-cause mortality is direct, J- or U-shaped, and whether this relationship changes as people age.Design:Prospective nationwide cohort study of US radiologic technologists (USRT).Subjects:Sixty-four thousand seven hundred and thirty-three female and 19 011 male certified radiation technologists.Methods:We prospectively followed participants from the USRT study who completed a mail survey in 1983–1989 through 2000. During an average of 14.7 years of follow-up or 1.23 million person-years, 2278 women and 1495 men died. Using Cox's proportional-hazards regression analyses, we analyzed the relationship between BMI and all-cause mortality by gender and by age group (<55 years; 55 years). We also examined risk in never-smokers after the first 5 years of follow-up to limit bias owing to the confounding effects of smoking and illness-related weight loss on BMI and mortality.Results:Risks were generally J-shaped for both genders and age groups. When we excluded smokers and the first 5 year of follow-up, risks were substantially reduced in those with low BMIs. In never-smoking women under the age of 55 years (excluding the initial 5-year follow-up period), risk rose as BMI increased above 21.0 kg/m2, whereas in older women, risk increased beginning at a higher BMI (25.0 kg/m2). Among younger men who never smoked (excluding the initial 5-year follow-up period), risk began to rise above a BMI of 23.0 kg/m2, whereas in older men, risk did not begin to increase until exceeding a BMI of 30.0 kg/m2.Conclusions:In younger/middle-aged, but not older, women and men, mortality risks appear directly related to BMI. The more complicated relationship between BMI and mortality in older subjects suggests the importance of assessing whether other markers of body composition better explain mortality risk in older adults.International Journal of Obesity (2006) 30, 822–829. doi:10.1038/sj.ijo.0803193; published online 10 January 2006 [ABSTRACT FROM AUTHOR]

We evaluated the usefulness of a recent measure of drinking water nitrate as a predictor of long-term average nitrate exposure calculated from historic data. Exposure estimates were calculated for 214 study participants who used public water supplies between 1947 and 1980 in Minnesota. Long-term average nitrate was calculated by linking residential histories to historical nitrate data. For recent exposures, we averaged nitrate measurements in 1980, or the next closest year with measurements. The Spearman correlation coefficient for the relationship between the two measures was 0.54 (95% confidence interval [CI] = 0.44-0.63). Agreement was highest among those residing 34 or more years in their town as of 1980 (r[SUBs] = 0.70; 95% CI = 0.55-0.80). These findings suggest that taking into account the study participants' duration of residence may enhance the validity of using a recent measure as an indicator of past exposures. [ABSTRACT FROM AUTHOR]

A population-based case-control study was conducted in Washington County, Maryland (United States) to explore the association between incident bladder cancer and exposure to drinking water from chlorinated surface sources. Cancer cases were White residents, enumerated in a 1975 county census and reported to the Washington County Cancer Registry (n = 294) between 1975 and 1992. White controls, frequency matched by age (+/- 5 years) and gender, were selected randomly from the census (n = 2,326). Households receiving municipal water, which generally derived from chlorinated surface waters, were treated as having 'high exposure' and all others, as 'low exposure.' Duration of exposure to type of drinking water was based on length of residence in the census household prior to 1975. Odds ratios (OR) were calculated using logistic regression methods, adjusting for age, gender, tobacco use, and urbanicity. Bladder cancer risk was associated weakly in the general population with duration of exposure to municipal water. The association was limited to those who had smoked cigarettes. In ever-smokers compared with never-smokers with low exposure, the adjusted ORs for bladder cancer risk with increasing exposure were 1.3, 1.4, 1.4, 1.7, 2.2, 2.8, respectively, for 0, 1-10, 11-20, 21-30, 31-40, > 40 years' exposure duration. The ORs in smokers were not diminished after adjusting for smoking history and intensity. [ABSTRACT FROM AUTHOR]