Evaluation of risk due to chronic low dose ionizing radiation exposure on the birth prevalence of congenital heart diseases (CHD) among the newborns from high-level natural radiation areas of Kerala coast, India

Abstract

Background The human population residing in monazite bearing Kerala coast are exposed to chronic low dose and low dose rate external gamma radiation due to Th232 deposits in its beach sand. The radiation level in this area varies from < 1.0 to 45.0 mGy/year. This area serves as an ideal source for conducting large-scale epidemiological studies for assessing risk of low dose and low dose rate radiation exposure on human population. The areas with a dose level of ≤1.50 mGy/year are considered as normal level natural radiation areas (NLNRAs) and areas with > 1.50 mGy/year, as high level natural radiation areas (HLNRAs). HLNRAs were further stratified into three dose groups of 1.51-3.0 mGy/year, 3.01-6.00 mGy/year and > 6.0 mGy/year. The present study evaluates the effects of chronic low dose radiation (LDR) exposure on the birth prevalence of Congenital Heart Diseases (CHD) among the live newborns monitored in hospital based prospective study from NLNRAs and HLNRAs of Kerala coast, India. Methodology Consecutive newborns were monitored from two hospital units located in the study area for congenital malformations. Referred CHD cases among the newborns screened were confirmed by conducting investigations such as pulse oximetry, chest X-ray, electrocardiogram and echocardiogram etc. Results Among the newborns screened, 289 CHDs were identified with a frequency of 1.49‰ among 193,634 livebirths, which constituted 6.03% of overall malformations and 16.29% of major malformations. Multiple logistic regression analysis suggested that the risk of CHD among the newborns of mothers from HLNRAs with a dose group of 1.51-3.0 mGy/year was significantly lower as compared to NLNRA (OR = 0.72, 95% CI: 0.57-0.92), whereas it was similar in HLNRA dose groups of 3.01-6.00 mGy/year (OR = 0.55, 95% CI: 0.31-1.00) and ≥ 6.0 mGy/year (OR = 0.96, 95% CI: 0.50-1.85). The frequency of CHDs did not show any radiation dose related increasing trend. However, a significant (P = 0.005) reduction was observed in the birth prevalence of CHDs among the newborns from HLNRA (1.28‰) as compared to NLNRA (1.79‰). Conclusion Chronic LDR exposure did not show any increased risk on the birth prevalence of CHDs from high-level natural radiation areas of Kerala coast, India. No linear increasing trend was observed with respect to different background dose groups. The frequency of CHD was observed to be 1.49 per 1000 livebirths, which was similar to the frequency of severe CHD rate reported elsewhere in India and was much less than the reported frequency of 9 per thousand.

Non-linear dose response of DNA double strand breaks in response to chronic low dose radiation in individuals from high level natural radiation areas of Kerala coast

“…Interestingly, nonlinear trend of DSBs was observed in different background dose groups which is an important finding related to risk estimation of DSBs in response to chronic low dose IR. This data supports other epidemiological and biological studies conducted in this area in newborns and adults [ 13 –[ 14 , 29 ]– 30 , 49 – 59 , 60 ], where we have not observed any increased dose response at any of the end points studied.…”

“…Experimental data at low doses is insufficient as compared to high dose range, where plenty of data is available for epidemiology. Considerable progress has been made in assessing the dose response relationship of cancer and non-cancer diseases/disorders as well as biological response at low dose exposures by generating data on computed tomography (CT) scanning [ 6 – 8 ], natural background radiation [ 9 – 14 ] and other radiation exposed population based studies [ 15 , 16 ]. With the advent of newly discovered high throughput techniques, the underlying biological mechanisms are being explored by using sensitive assays and suitable bio-markers for assessment of cellular and molecular responses at low doses below 100 mGy.…”

A Novel Machine Learning-Based Prediction Method for Early Detection and Diagnosis of Congenital Heart Disease Using ECG Signal Processing

“…Congenital heart disease (CHD) refers to a group of structural abnormalities in the heart that occur during the prenatal stage of development [3]. These congenital abnormalities manifest during the prenatal period and affect the morphology and physiology of the heart, leading to various cardiovascular complications.…”