Depression and polymorphism G-174C (rs1800795) of the <I>IL-6</I> gene in an open population of 25–44 year old in Russia/Siberia (WHO international program MONICA-psychosocial)

Abstract

Objective: to study the association of the G-174C (rs1800795) polymorphism of the IL-6 gene with depression in an open population of 25–44 year old in Novosibirsk.Patients and methods. In 2013–2016 years we examined 403 men (mean age – 34±0.4 years, response – 71%) and 531 women (mean age – 35±0.4 years, response – 72%) from an open population of 25–44 year old residents of the Oktyabrsky district, Novosibirsk, the sample was representative. Depression was assessed using the MONICA-MOPSY psychosocial questionnaire. Genotyping of the studied gene polymorphisms was carried out in the Laboratory of Molecular Genetic Research of Scientific Research Institute for Therapy and Preventive Medicine, Federal Research Center Institute of Cytology and Genetics, Russian Academy of Sciences, Novosibirsk.Results and discussion. A severe level of depression occurred in 12.8% of the population, among men – in 8.9%, among women – in 15.8%; and moderate level – in 24.5% of the population (among men – 21.3%, among women – 26.9%). The most common in the population was the heterozygous C/G genotype (45.1%), the G/G genotype was observed in 34.6% of the population and, finally, C/C in 20.3% of participants. The most common allele of the IL-6 gene of the G-174C polymorphism (rs1800795) was the G allele in 57.5% of the population, and the C allele in only 42.5%. Among carriers of the G/G genotype of the IL-6 gene, a moderate (39.7%) or severe level of depression (37.3%) prevailed, while there was no depression in the carriers of the C/C genotype of the IL-6 gene (24.2%; χ2 = 10.962; df=4; p=0.027). Carrying the C/G genotype of the IL-6 gene increased the chance of developing a severe level of depression by almost 2.9–3.3 times in comparison with the carriage of the C/C genotype. Among carriers of the G/G genotype of the IL-6 gene, a severe level of depression was 3.3 times more common than in carriers of the C/C genotype. Individuals carrying the G allele of the IL-6 gene were 1.6 times more likely to experience a severe level of depression than those carrying the C allele.Conclusion. The data obtained suggest that the carriage of the G allele of the G-174C polymorphism (rs1800795) of the IL-6 gene may be associated with a severe level of depression.