Features of coronary heart disease development in emergency workers of the Chornobyl accident depending on the action of radiation and non-radiation risk factors and genotypes of single nucleotide polymorphism rs966221 of phosphodiesterase 4D gene

Abstract

This study devoted to specific features of coronary heart disease (CHD) development in emergency work ers (EW) of the accident at the Chernobyl nuclear power plant (ChNPP) based on analysis the interaction between radiation and non radiation risk factors and single nucleotide polymorphism (SNP) rs966221 of phosphodiesterase (PDE) 4D gene. It was examined 397 men with CHD, including 274 EW of 1986-1987 and 123 non irradiated persons (con trol group) who were 66±10 and 69±11 years old relatively. The program studies included clinical examination, elec trocardiography (ECG), ECG daily monitoring, ECG stress testing, echo doppler cardiography, analysis of serum lipid spectrum, polymerase chain reaction with restriction of reaction products, retrospective analysis of case histories. Diagnosis of CHD or its approval was carried out in accordance with the standards of diagnosis, accepted in Ukraine. All EW before their taking part in cleaning ChNPP territory did not suffered from CHD. According to the analysis of contingency tables, carriers of the TT genotype of rs966221 increased the risk of myocardial infarction (MI) in 2.538 times compared with carriers of genotypes CC and CT. The use of Kaplan Meier method showed that a half of EW with the TT genotype developed MI before 64 years old, while with the other geno types up to 78.7 years old. In the control group statistically significant increase of cumulative proportion of patients with MI, carriers of the TT genotype, began from 60 years old. Compared to the non irradiated patients EW fell ill with CHD on 9.4 years earlier. Using proportional hazards analysis (Cox regression), it was found that EW had 3.9 times higher risk of CHD than in non irradiated individuals. Smoking and overweight brought three times less but significant risk - 1.37 and 1.33 respectively. The TT genotype unlike genotypes CC and CT gene PDE4D increased risk of MI in 1.757 times more both in EW and control group. The risk of CHD development was determined by radiation factor, such as the involvement in the emer gency works of the accident consequences, as well as non radiation factors, namely smoking and overweight. Only one factor, the TT genotype of rs966221 PDE4D gene, determined the risk of MI occurrence in EW and non irradiated controls. In the post emergency period, CHD developed 6 years earlier in EW with the TT genotype than in patients with genotypes CC and CT.