*Biological Determinants of Sleep Disorders DOI: http://dx.doi.org/10.5772/intechopen.101765*


**Table 6.**

*Frequencies of genotypes and alleles of VNTR polymorphism of the* DRD4 *gene in the population and their association with sleep disorders (screening III).*

### **3.6 Carriers of allele 6 of the** *DRD4* **gene more often rated their sleep as "poor" (19%)**

a. rather than "satisfactory" (6.1%) in carriers of all other alleles OR = 3.6 (95% CI 1.7–7.4); (χ<sup>2</sup> = 14.224 υ =1p < 0.0001) and in comparison with carriers of allele 2 (χ<sup>2</sup> = 8.097 υ =1p < 0.004), allele 3 (χ<sup>2</sup> = 3.905 υ =1p < 0.05), allele 4 (χ<sup>2</sup> = 12.665 υ =1p < 0, 00001);

b. rather than "good" (3.5%) compared to carriers of all other alleles OR = 6.4 (95% CI 2.9–14); (χ<sup>2</sup> = 27.626 υ =1p < 0.0001); carriers of allele 2 (χ<sup>2</sup> = 19.379 υ =1p < 0.0001), allele 3 (χ<sup>2</sup> = 5.437 υ =1p < 0.05), allele 4 (χ<sup>2</sup> = 5.048 υ =1p < 0.05), and allele 5 (χ<sup>2</sup> = 5.147 υ = 1 p = 0.05);

c. and also rather "very good" (3.8%) in comparison with carriers of all other alleles OR = 5.8 (95% CI 1.2–26.7); (χ<sup>2</sup> = 6.463 υ =1p < 0.01) (**Table 6**).

In the frequency distribution of VNTR genotypes of the *DAT* gene polymorphism in a population of men aged 25–64 years with different self-assessed sleep, no significant differences were found. Positive sleep assessments were more common—41.9% of carriers of genotype 9/10 had "good" sleep, among carriers of genotype 10/10, "very good" sleep was observed in 61.5%. Among the carriers of the 9/9 genotype, 8.3% considered their sleep to be "poor" (χ<sup>2</sup> = 25.486 υ = 32 p > 0.05). The distribution of the remaining carriers of various *DAT* genotypes and self-assessment of sleep did not exceed 3.8% (**Table 7**).

There were no significant differences in the frequency distribution of the *DAT* gene alleles in a population of men aged 25–64 years, with different self-assessment of sleep. There was a tendency for an increase in positive responses 78.8% of carriers of allele 10 reported having "very good" sleep, while 26.4% carriers of allele 9 assessed their sleep as "poor." The distribution of the other alleles of the *DAT* gene did not exceed 3.8% (χ<sup>2</sup> = 16.777 υ = 20 p > 0.05) (**Table 7**).

### **3.7 Association of G308A polymorphism of TNF- α gene with sleep disorders**

The frequency of genotypes G308A polymorphism of the tumor necrosis factor *TNF-α* gene in the male population of Novosibirsk city is presented in **Table 8**. The G/G genotype of the *TNF-α* gene was found in 79.1% of individuals, the A/G genotype was found in 19% of cases, and finally, the A/A genotype was only found in 1.9% of men. In the population, 88.6% of men had allele G and only 11.4% had allele A (**Table 8**).

There was a tendency that the G/G genotype of the *TNF-α* gene was more common not only in individuals with very good (88.2%) and good (83.3%) sleep but also in the group with sleep disorders: poor (84.2%) and very poor (100%) sleep. The genotype A/G of the *TNF-α* gene was most often found among men who consider their sleep "satisfactory" (30%). The A/A genotype of the *TNF-α* gene did not exceed 5.3% among all categories of sleep disorders (χ<sup>2</sup> = 12,012 df = 8 p = 0,151).

There was also a tendency toward a more frequent occurrence of the G allele of the *TNF-α* gene among all categories of men with different assessments of their sleep, and the A allele of the *TNF-α* gene in the group of men who rate their sleep as satisfactory (17.5%) (χ<sup>2</sup> = 9.451 df = 4 p = 0.051).

Comparative analysis in groups with various self-assessment of sleep showed that among carriers of genotype G/G gene *TNF-α*, in comparison with carriers of all other genotypes, assessment of sleep as "good" (98.3%) rather than satisfactory (67.5%) χ<sup>2</sup> = 36,943 df = 1 p = 0.0001; OR = 27,685 (95% CI 6339–120,906), and "good" (98.3%), followed by "poor" (84.2%) χ<sup>2</sup> = 9151 df = 1 p = 0.02; OR = 10,781
