No significant association between stable iodine intake and thyroid dysfunction in children after the Fukushima Nuclear Disaster: an observational study.

PURPOSE: Stable iodine prophylaxis helps prevent childhood thyroid cancer in nuclear emergencies; however, there is limited information on its effect on thyroid function. This study aimed to examine thyroid function and autoimmunity among children and adolescents that took stable iodine after the Fukushima Nuclear Disaster. METHODS: For this observational study, data were obtained from children and adolescents that underwent thyroid cancer screening at Hirata Central Hospital from April 2012 to March 2018. Participant characteristics, including possible hypothyroidism and hyperthyroidism, were compared between the prophylaxis and no-prophylaxis groups. Multivariable logistic regression models were used to assess for possible hypothyroidism, autoantibodies positive, and hyperthyroidism. RESULTS: A total of 1,225 participants with stable iodine prophylaxis and 3,946 without prophylaxis were enrolled. Of those participants, blood samples were available for 144 and 1,201 participants in the prophylaxis and no-prophylaxis groups, respectively. There were 17 (11.8%) and 146 cases (12.2%) of possible hypothyroidism or autoantibodies positive cases in the prophylaxis and no-prophylaxis groups, respectively, and there were no cases and 3 cases (0.2%) of possible hyperthyroidism in those two groups, respectively. Multivariable analysis for possible hypothyroidism revealed no association between stable iodine intake and possible hypothyroidism or autoantibodies positive [odds ratio 0.716 (95% confidence interval 0.399-1.284)] (p = 0.262). We did not perform multivariable analysis for hyperthyroidism due to the limited number of cases. CONCLUSION: Significant adverse effects of stable iodine intake on thyroid function were not observed among children and adolescents 7 years after the Fukushima Nuclear Disaster.

Quantitative Health Risk Assessment of Indoor Radon: A Systematic Review.

Exposure to radon is a well-established cause of lung cancer in the general population. The aim of the present work is to identify and summarize the results of studies that have assessed the risk of lung cancer due to indoor radon, based on a systematic review of relevant published studies. Sixteen studies from 12 different countries met eligibility criteria. Large differences in radon concentrations were noted between and within individual countries, and variety of risk models used to estimate the attributable fraction. Calculating again the attributable fraction in each of these studies using the same model (coefficient of 16% per 100 becquerels per cubic meter (Bq/m3) derived from the European residential radon study), the new attributable fraction of these selected studies ranged from 3% to 17%. Radon remains a public health concern. Information about radon health risks is important and efforts are needed to decrease the associated health problems.

Are dietary reports in a case-control study on thyroid cancer biased by risk perception of Chernobyl fallout?

BACKGROUND: In retrospective case-control studies performed following nuclear tests or nuclear accidents, individual thyroid radiation dose reconstructions are based on fallout and meteorological data from the residential area, demographic characteristics, and lifestyle as well as dietary information. Collecting the latter is a controversial step, as dietary declarations may be affected by the subjects' beliefs about their risk behavior. This report analyses the potential for such bias in a case-control study performed in eastern France. METHODS: The study included 765 cases of differentiated thyroid carcinoma matched with 831 controls. Risk perceptions and beliefs of cases and controls were compared using Chi2 tests and differences in dietary reports were analyzed using a two-way ANOVA. RESULTS: In general, atmospheric pollution and living near a nuclear power plant were the two major risks that may influence thyroid cancer occurrence cited by cases and controls. When focusing in particular on the consequences of the Chernobyl accident, cases were more likely to think that the consequences were responsible for thyroid cancer occurrence than controls. Vegetable consumption during the two months after the Chernobyl accident was correlated with the status of subjects, but not to their beliefs. Conversely, consumption of fresh dairy products was not correlated with the status or beliefs of subjects. CONCLUSION: We found no evidence of systematic bias in dietary reports according to the status or beliefs held by subjects about the link between thyroid cancer occurrence and Chernobyl fallout. As such, these dietary reports may be used in further studies involving individual dosimetric reconstructions.

[Assessment of radon-induced health risk for occupants of a house built on uranium ore residue]. / Évaluation des risques sanitaires induits par le radon pour les occupants d'une maison construite sur des résidus de minerais d'uranium.

BACKGROUND: At the request of French public authorities, the Institute of Radiological Protection and Nuclear Safety has assessed the radiological situation of a house built on uranium ore residues in Haute-Vienne and the health risks induced from exposure to radon for all occupants. Classified as a lung carcinogen by the World Health Organization, radon is a proven cause of lung cancer in case of regular inhalation over a long period, and the risk increases with cumulative exposure. METHODS: Radon exposure was reconstructed for various standard profiles of house occupancy. A risk model derived from a European epidemiological study was used to calculate the lifetime probability of death from lung cancer according to these standard profiles. RESULTS: Risk assessment of the occupants of the house highlighted the following main findings. For a resident school child having been exposed to radon from birth to the age of 7, the lifetime relative risk (LRR) was estimated at 5. For last adult and young adult residents having lived more than 10years in the house, the probability of death from lung cancer was in the same order of magnitude as that of a regular cigarette smoker, with a LRR from 10 to 13 and a lifetime probability of death from lung cancer between 3 and 4%. If these individuals smoked regularly, in addition to being exposed to radon, this probability would be between 6 and 32% (supposing an additive or multiplicative interaction). CONCLUSION: For former occupants (non-smokers) having been exposed 10years during childhood, the LRR was two-fold lower. For children having been in day care in the house, the increased probability of death from lung cancer was low, with a LRR lower than 2. Supposing, as in adults, that the risk decreases beyond 30years after the end of radon exposure, the increase was almost zero for former occupants exposed during childhood and during day care, with a LRR close to 1.

Involvement of cholinergic neurons in the release of dopamine elicited by stimulation of mu-opioid receptors in striatum.

The involvement of striatal cholinergic neurons in the release of dopamine (DA) elicited by the mu-opioid receptor agonist DAGO ([D-Ala2, NMePhe4-Gly5(ol)]enkephalin) was explored. The striatal release of DA was measured by microdialysis in rats anesthetized with chloral hydrate. When infused in the striatum, through the microdialysis probe, DAGO increased the extracellular levels of DA. The previous injection in striatum of AF 64-A, a toxin for cholinergic neurons, or the concomitant infusion of the M2-muscarinic antagonist methoctramine abolished the effect of DAGO on the DA release. It is concluded that stimulation of mu-opioid receptors, by inhibiting the acetylcholine release which stimulates tonically M2-muscarinic receptors likely associated with dopaminergic nerve endings, indirectly increases the striatal DA release.