Nested case-control study of external ionizing radiation dose and mortality from dementia within a pooled cohort of female nuclear weapons workers

Background A prior investigation of this cohort of female nuclear workers found increased deaths from mental disorders, including dementia. The present study estimates the effect of workplace exposures to ionizing radiations and other hazards on mortality from dementia. Methods A nested case-control study within a pooled cohort of 67,976 female nuclear workers compared 91 cases of death from dementia with 910 controls. Adjusted odds ratios (ORs) were employed to estimate the effects of maximum annual and total lifetime radiation doses on the occurrence of dementia in 168 monitored workers. Results Both maximum annual (OR = 2.11, 95% confidence interval (CI) = 0.98, 4.40) and total lifetime radiation doses (OR = 2.09, 95% CI = 1.02, 4.29) were associated with death from dementia. Significant dose-response trends were present for both exposures. Conclusions Occupational exposure to ionizing radiation (IR) may be associated with increased risk of death from dementia in female workers. Since these findings are based on a small number of cases, replication with a larger case sample should be pursued. (C) 2003 Wiley-Liss, Inc.