Case-control assessment of the association between non-Hodgkin's lymphoma and occupational radiation with doses assessed using a job exposure matrix.

BACKGROUND: Epidemiologic data for an association between radiation exposure and non-Hodgkin's lymphoma (NHL) have been inconclusive though the strongest evidence has been provided by studies of patients treated with radiotherapy. METHODS: We evaluated the association between occupational radiation exposure and non-Hodgkin's lymphoma in men using a population-based case-control study with 1,056 case and 1,860 control subjects sampled from eight geographic areas in the United States. Because dosimetry data were not available, doses were estimated for individuals who reported occupational radiation exposure using a radiation job exposure matrix developed for this purpose. Conditional logistic regression was used to model the association between reported occupational radiation exposure and NHL incidence. RESULTS: We found that most men (> 90%) did not report exposure to occupational sources of radiation. Among those who reported exposure, estimated cumulative doses were low, with an estimated mean of less than 0.02 Gray and a maximum of 0.12 Gray. The risk for NHL was not associated with ever having reported an occupational radiation exposure (OR = 0.90, 95% CI = 0.74-1.10) nor was there evidence of a dose-response relationship between risk and either the estimated cumulative doses or duration of exposure. CONCLUSIONS: The findings in this study are consistent with results from most current research on occupational radiation and NHL risk that have found no increased risk of NHL at low levels of occupational radiation exposure. While it should be noted that exposure misclassification likely biased our results toward the null, this large population-based case-control study adds to existing evidence which suggests that there is little to no increased risk for NHL associated with exposure to low levels of radiation such as that commonly found in many occupational settings.

Estimating occupational radiation doses when individual dosimetry information is not available: a job exposure matrix.

BACKGROUND: A job exposure matrix (JEM) was developed for a population based case control study to assess the possible association between occupational radiation and non-Hodgkin's lymphoma. METHODS: Using published radiation monitoring data, we developed a radiation JEM composed of estimated annual dose distributions, categorized by time period, for a broad range of occupational and industrial groups. RESULTS: When information is available to correctly assess an individual's exposure status, the annual dose distributions in the JEM can be used in conjunction with job histories to estimate the distribution of possible cumulative doses for individuals. The median of the cumulative dose distribution can then be used in standard epidemiologic analysis. In addition, methods can be applied that incorporate the uncertainty about each individual's true dose into risk estimates and associated confidence intervals. CONCLUSIONS: The JEM can be useful in estimating occupational radiation exposures in other studies, particularly population based case control studies which include detailed occupational histories.

Radon retesting and mitigation behavior among the U.S. population.

Relatively few data are available about how people comply with Environmental Protection Agency recommendations concerning retesting and mitigation after either an initial screening or long term test for radon gas. Using data from the 1990 and 1991 National Health Interview Surveys, we found that 40.7% (standard error 6.4%) of homes with radon levels above 148 Bq m(-3) in 1990 and 34.3% (standard error 4.9%) of homes with levels above 148 Bq m(-3) in 1991 were retested. Among homes that were retested and had either an initial screening or followup test above 148 Bq m(-3), 28.2% (standard error 6.4%) were mitigated in 1990 compared with 48.4% (standard error 14.4%) that did so in 1991. These results suggest that most people are not complying with current EPA recommendations for retesting and mitigation.

Knowledge about indoor radon in the United States: 1990 National Health Interview Survey.

The Year 2000 objectives for environmental health include radon testing in 40% of residences overall and in 50% of residences that house a smoker, former smoker, or a child. Baseline data about radon and radon testing were determined by questions included in the 1990 Health Promotion and Disease Prevention supplement for the National Health Interview Survey. Minorities and individuals with low income or minimal education were significantly less likely to have heard of indoor radon than were whites and those with more education or income. In this survey, only 3%-5% of residences had been tested for radon. A substantial increase above the rate of testing noted for 1990 will be needed to achieve the Year 2000 objectives for indoor radon.

Radon awareness and testing behavior: findings from the Behavioral Risk Factor Surveillance System, 1989-1992.

Radon is considered an important environmental risk factor for lung cancer. Previous studies have shown that relatively few homes have been tested for radon. Results from the Behavioral Risk Factor Surveillance System from 1989--1992 show significant interstate and demographic variation in levels of radon awareness and home testing. There was evidence that levels of radon awareness and testing homes for radon have increased from 1989 through 1992. Although these trends in the data are encouraging, the data also suggest that continued education and other interventions may be necessary to reach the Public Health Service's testing and mitigating objectives for residential radon.