Twinning in the offspring of parents with chronic radiation exposure from nuclear testing in Kazakhstan.

The population of the Semipalatinsk region of Kazakhstan was chronically exposed to radioactive fallout from above-ground nuclear tests conducted during 1949-1956 by the Soviet Union. We investigated the effect of radiation exposure and other factors on risks of twinning overall and of same- and different-sex twinning and hence estimated dizygotic and monozygotic twinning rates in 11,605 deliveries around Semipalatinsk, 141 of which were twin, to 3992 mothers exposed to fallout during 1949-1956. Overall, the same-sex twinning rate was 7.85 [95% confidence interval (CI): 6.24, 9.47] per 1000 and the opposite-sex twinning rate was 4.45 (95% CI: 3.23, 5.67). Twinning rates did not differ significantly between radiation exposure categories, parental age at main radiation exposure, or year of birth. Different-sex, but not same-sex, twinning increased with maternal age (P(trend) = 0.04) but not with other demographic factors and was increased soon after radiation exposure [OR = 4.08 (95% CI: 1.11, 15.07)] for births occurring within 5 years compared with more than 20 years after exposure; this effect was similar in villages with low and high radiation exposure, however, so interpretation is uncertain.

Sex ratio in the offspring of parents with chronic radiation exposure from nuclear testing in Kazakhstan.

The former Soviet Union conducted a nuclear test program in the Semipalatinsk region of northeastern Kazakhstan in 1949-1989. The population in the vicinity of the test site was chronically exposed to radiation fallout, especially from above-ground tests during 1949-1956. Male:female sex ratio has been proposed as a measure of reproductive health, with some reports suggesting an alteration in the sex ratio of offspring of parents exposed to radiation. We investigated the impact of radiation exposure and other factors on the sex ratio in the population inhabiting the exposed region. A total of 11,464 singleton births of 3,992 mothers exposed to radiation during 1949-1956 were analyzed. The overall sex ratio was 1.07, similar to the current sex ratio in Kazakhstan (1.06). The sex ratio increased from 1.04 where mothers received <20.0 cSv to 1.12 where mothers received > or =60.0 cSv. However, the linear trend across exposures was not significant (P = 0.42). No consistent association was found between the sex ratio and the time since parental radiation exposure, parental age at exposure, or year of birth. Sex ratio was significantly associated with maternal age, birth order and possibly ethnicity but not with paternal age, parental educational level or season. In conclusion, no significant association was found between radiation exposure level and sex ratio, but some previously suggested demographic factors were positively associated with sex ratio.

Risk of second malignancy after non-Hodgkin's lymphoma: a British Cohort Study.

PURPOSE: To assess long-term site-specific risks of second malignancy following non-Hodgkin's lymphoma (NHL) in relation to treatment and demographic factors. PATIENTS AND METHODS: A cohort of 2,456 patients with NHL who were first treated from 1973 to 2000 and were younger than 60 years from centers in the British National Lymphoma Investigation were observed, and occurrences of second malignancy was compared with expectations based on general population cancer rates in England and Wales. RESULTS: In total, 123 second malignancies occurred. Relative risks (RRs) were significantly elevated for all malignancies combined (RR = 1.3; 95% CI, 1.1 to 1.6) and for leukemia (RR = 8.8; 95% CI, 5.1 to 14.1) and lung cancer (RR = 1.6; 95% CI, 1.1 to 2.3). RRs of malignancy overall diminished significantly with increasing age at first treatment. Leukemia risk was significantly increased after chemotherapy (RR = 10.5; 95% CI, 5.0 to 19.3) and mixed-modality treatment (RR = 13.0; 95% CI, 5.2 to 26.7). Relative risks of lung (RR = 1.9; 95% CI, 1.1 to 3.1) and colorectal (RR = 2.1; 95% CI, 1.1 to 3.6) cancers were significantly raised following chemotherapy. CONCLUSION: NHL patients are at elevated risk of developing second malignancy, particularly leukemia and lung cancer. The relative risk is greater with patients who are younger at first treatment. Chemotherapy predisposes patients toan increased risk of leukemia, and possibly lung and colorectal cancers. The role of specific drug treatments in the etiology of solid cancers after NHL deserves further investigation.