Genetic Monitoring of the Human Population from High-Level Natural Radiation Areas of Kerala on the Southwest Coast of India. II. Incidence of Numerical and Structural Chromosomal Aberrations in the Lymphocytes of Newborns

Cheriyan, V. D.; Kurien, C.J.; Das, Birajalaxmi; Ramachandran, E.N.; Karuppasamy, C.V.; Thampi, Madhavi; George, K.; Kesavan, P. C.; Koya, P. K. M.; Chauhan, Prashant

doi:10.2307/3580136

Cited by 57 publications

(28 citation statements)

References 11 publications

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“…This is reflected in the dicentric frequency which is significantly raised in comparison with the partner group of comparable age and the offspring group. Studies involving a wide age range have generally shown that frequencies of dicentrics increase with age [34][35][36][37] and, although the difference between the partner group and the offspring group did not reach statistical significance, there is a suggestion of a similar effect in the present study. Studies that have examined acentric frequencies in relation to age have reported both increases [36,37] and no effect [34], with the present study revealing a significant increase in acentrics in the partner group compared with the offspring group.…”

Section: Discussionsupporting

confidence: 40%

Chromosome analysis in childhood cancer survivors and their offspring—No evidence for radiotherapy-induced persistent genomic instability

Tawn¹,

Whitehouse²,

Winther

et al. 2005

Mutation Research/Genetic Toxicology and Environmental Mutagene

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Suggestions that the induction of genomic instability could play a role in radiation-induced carcinogenesis and heritable disease prompted the investigation of chromosome instability in relation to radiotherapy for childhood cancer. Chromosome analysis of peripheral blood lymphocytes at their first in vitro division was undertaken on 25 adult survivors of childhood cancer treated with radiation, 26 partners who acted as the non-irradiated control group and 43 offspring. A statistically significant increase in the frequency of dicentrics in the cancer survivor group compared with the partner control group was attributed to the residual effect of past radiation therapy. However, chromatid aberrations plus chromosome gaps, the aberrations most associated with persistent instability, were not increased. Therefore, there was no evidence that irradiation of the bone marrow had resulted in instability being transmitted to descendant cells. Frequencies of all aberration categories were significantly lower in the offspring group, compared to the partner group, apart from dicentrics for which the decrease did not reach statistical significance. The lower frequencies in the offspring provide no indication of transmissible instability being passed through the germline to the somatic cells of the offspring. Thus, in this study, genomic instability was not associated with radiotherapy in those who had received such treatment, nor was it found to be a transgenerational radiation effect.

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Section: Discussionsupporting

confidence: 40%

Chromosome analysis in childhood cancer survivors and their offspring—No evidence for radiotherapy-induced persistent genomic instability

Tawn¹,

Whitehouse²,

Winther

et al. 2005

Mutation Research/Genetic Toxicology and Environmental Mutagene

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“…Extensive epidemiological surveys on populations living in Kerala, India [79,80,81], Iran [82], China [83] and the USA [84,85] have been presented in the literature. In one of the most studied areas, Kerala, no detectable increases have been identified in total death rates or the frequency of chromosomal aberrations or congenital malformations.…”

Section: Indications For Beneficial Effects Of Higher Natural Backgromentioning

confidence: 99%

Hormesis, an update of the present position

Johansson

2003

Eur J Nucl Med Mol Imaging

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The ongoing debate over the possible beneficial effects of ionising radiation on health, hormesis, is reviewed from different perspectives. Radiation hormesis has not been strictly defined in the scientific literature. It can be understood as a decrease in the risk of cancer due to low-dose irradiation, but other positive health effects may also be encompassed by the concept. The overwhelming majority of the currently available epidemiological data on populations exposed to ionising radiation support the assumption that there is a linear non-threshold dose-response relationship. However, epidemiological data fail to demonstrate detrimental effects of ionising radiation at absorbed doses smaller than 100-200 mSv. Risk estimates for these levels are therefore based on extrapolations from higher doses. Arguments for hormesis are derived only from a number of epidemiological studies, but also from studies in radiation biology. Radiobiological evidence for hormesis is based on radio-adaptive response; this has been convincingly demonstrated in vitro, but some questions remain as to how it affects humans. Furthermore, there is an ecologically based argument for hormesis in that, given the evolutionary prerequisite of best fitness, it follows that humans are best adapted to background levels of ionising radiation and other carcinogenic agents in our environment. A few animal studies have also addressed the hormesis theory, some of which have supported it while others have not. To complete the picture, the results of new radiobiological research indicate the need for a paradigm shift concerning the mechanisms of cancer induction. Such research is a step towards a better understanding of how ionising radiation affects the living cell and the organism, and thus towards a more reliable judgement on how to interpret the present radiobiological evidence for hormesis.

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“…Historic dosimetry and small sample size especially from the control area were some of the weaknesses of the mitochondrial DNA study-the risk of mutation in HLNR area relative to control area, as estimated from the data was 7.39 with a very wide 95 % CI of 1.003 to 54.5, reflecting lack of precision in the estimate. Our studies on biological and health effects of high-level natural radiation on the inhabitants, conducted at the field laboratory established by Department of Atomic Energy, Government of India, did not find any evidence to implicate high-level natural radiation in any of the outcomes like chromosomal aberrations, karyotype anomalies, micronuclei, overall congenital anomalies, stillbirths, late onset diseases, or telomere length in human adults (Jaikrishan et al 1999;Cheriyan et al 1999;Thampi et al 2002Thampi et al , 2005Das and Karuppasamy 2009;Das et al 2009). Studies on cancer incidence among population of the HLNR area also failed to show any relationship with the high-level natural radiation (Nair et al 1999;Nair et al 2009).…”

Section: Discussionmentioning

confidence: 68%

“…Radiation may induce germline mutations that may cause or abet congenital anomalies. Therefore, newborns from high and normal-level radiation areas are being monitored for the past three decades to study the association of elevated levels of natural radiation with congenital anomalies detectable at birth (Jaikrishan et al 1999;Cheriyan et al 1999;Thampi et al 2002Thampi et al , 2005. Further analysis is attempted to assess adverse pregnancy outcomes of stillbirth and overall as well as specific major congenital anomalies (MCA) like clubfoot, heart disease, Down syndrome, cleft lip/ palate, neural tube defects, and hypospadias after controlling for the effects of confounding/competing factors like maternal age at birth, gravida status, ethnicity, consanguinity, and gender of the newborn.…”

Section: Introductionmentioning

confidence: 99%

Study of stillbirth and major congenital anomaly among newborns in the high-level natural radiation areas of Kerala, India

et al. 2012

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Monitoring newborns for adverse outcomes like stillbirth and major congenital anomalies (MCA) is being carried out in government hospitals since 1995 in and around high-level natural radiation areas, a narrow strip of land on the southwest coast of Kerala, India. Natural deposits of monazite sand containing thorium and its daughter products account for elevated levels of natural radiation. Among 141,540 newborns [140,558 deliveries: 139,589 singleton, 957 twins (6.81 ‰), 11 triplets (0.078 ‰), and one quadruplet] screened, 615 (4.35 ‰) were stillbirth and MCA were seen in 1,370 (9.68 ‰) newborns. Clubfoot (404, 2.85 ‰) was the most frequent MCA followed by hypospadias (152, 2.10 ‰ among male newborns), congenital heart disease (168, 1.19 ‰), cleft lip/palate (149, 1.05 ‰), Down syndrome (104, 0.73 ‰), and neural tube defects (72, 0.51 ‰). Newborns with MCA among stillbirths were about 20-fold higher at 190.24 ‰ (117/615) compared to 8.89 ‰ (1,253/140,925) among live births (P<.001). Logistic regression was carried out to compare stillbirth, overall, and specific MCA among newborns from areas with dose levels of ≤1.5, 1.51-3.0, 3.01-6.0 and >6 mGy/year after controlling for maternal age at birth, gravida, consanguinity, ethnicity, and gender of the baby. Clubfoot showed higher prevalence of 3.26 ‰ at dose level of 1.51-3.0 mGy/year compared to 2.33 ‰ at ≤1.5 mGy/ year (OR01.39; 95 % CI, 1.12-1.72), without indication of any clear dose-response. Prevalences of stillbirth, overall MCA, and other specific MCA were similar across different dose levels and were relatively lower than that reported elsewhere in India, probably due to better literacy, health awareness, and practices in the study population.

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Genetic Monitoring of the Human Population from High-Level Natural Radiation Areas of Kerala on the Southwest Coast of India. II. Incidence of Numerical and Structural Chromosomal Aberrations in the Lymphocytes of Newborns

Cited by 57 publications

References 11 publications

Chromosome analysis in childhood cancer survivors and their offspring—No evidence for radiotherapy-induced persistent genomic instability

Chromosome analysis in childhood cancer survivors and their offspring—No evidence for radiotherapy-induced persistent genomic instability

Hormesis, an update of the present position

Study of stillbirth and major congenital anomaly among newborns in the high-level natural radiation areas of Kerala, India

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