Genetic regulation of testosterone level in overweight males from the Kazakh population and its association with hypogonadism

Male hypogonadism and erectile dysfunction in different populations are associated with excess body weight. A key aspect in most studies is the metabolism of sexual hormones, primarily testosterone. At the same time, the binding protein sex hormone binding globulin (SHBG) can play a large role, as it determines the ratio of total and bioavailable testosterone in blood, i.e. both the hormone content and level of its production. Recent research has identified common mutations that affect SHBG levels, such as the rs727428 polymorphic locus, which is associated with alterations in histone protein function, affecting the regulation of ribonucleic acid (RNA) protein SHBG synthesis. Similar relationships have been observed for prevalent mutations, including rs5934505 and rs10822184, in diverse populations. This study involved 300 individuals of Kazakh nationality from the Eastern Kazakhstan region, examining three polymorphic variants of the SHBG gene (rs727428, rs5934505, and rs10822184). The participants were categorized into three groups: individuals with hypogonadism and obesity (group 1, n=85), those with excess body weight but no hypogonadism (group 2, n=70), and individuals with neither excess body weight nor hypogonadism (group 3, n=145). The frequency of mutant gene alleles impacting GPS (SHBG) synthesis in the Kazakh population was notably high, comparable to European and South-East Asian populations. However, the association between excess body weight and these mutations exhibited varying patterns. Hypogonadism was linked to decreased GPS levels, strongly correlating with total testosterone but not bioavailable testosterone. The retention of sexual functions in overweight men was not always directly related to BMI levels and GPS concentrations.

Evaluation of the sexual function of men in Kazakhstan during 2021-2022: A cross-sectional study

Background and Aims

Assessing male sexual function is an important public health issue in every country. In Kazakhstan, there are currently no reliable statistics on male sexual function. The study aimed at the assessment of sexual function in men in Kazakhstan.

Methods

Men between the ages of 18 and 69 from Astana, Almaty, and Shymkent, three of Kazakhstan's biggest cities, were included in the cross-sectional study in 2021-2022. A standardized and modified Brief Sexual Function Inventory (BSFI) tool was used for participants' interviews. The World Health Organization STEPS questionnaire was employed to gather sociodemographic information, including smoking and alcohol use.

Results

Respondents from three cities: n = 283 from Almaty, n = 254 from Astana, and n = 232 from Shymkent were interviewed. All participants' average age was 39.2 ± 13.4. Kazakhs made up 79.5% of the respondents by nationality; 19.1% who answered questions on physical activity verified that they were involved in high-intensity labor. According to the BSFI questionnaire, the respondents from Shymkent had an average total score of 2.82 ± 0.92, (p ≤ 0.05), which was higher than the total scores of respondents from Almaty (2.69 ± 0.87) and Astana (2.69 ± 0.95). A relationship was found between sexual dysfunction and age indicators over 55 years. Participants with overweight had a relationship with sexual dysfunction with an odds ratio (OR): 1.84 (p = 0.01). According to the smoking factor, in study participants with sexual dysfunction, a relationship was also determined, OR: 1.42; 95% confidence interval (CI): 0.79-1.97 (p = 0.001). The presence of high-intensity activity (OR: 1.58; 95% CI: 0.04-1.91), and physical inactivity (OR: 1.49; 95% CI: 0.89-1.97) were associated with the presence of sexual dysfunction, p ≤ 0.05.

Conclusions

Our research indicates that men over 50 who smoke, are overweight, and are physically inactive are at risk for sexual dysfunction. Early health promotion may be the most effective method to reduce the negative effects of sexual dysfunction on the health and wellbeing of men over 50.

Effect of SHBG Polymorphism on the Levels of Bioavailable Testosterone and Lipid Metabolism in Older Men of the Kazakh Population

This study is aimed at investigating the effect of SHBG (rs727428; rs10822184) and LPL (rs754493647) single nucleotide polymorphisms on the concentration of the bioavailable fraction of testosterone in older men. Materials and methods To study gene mutations, 417 residents of the East Kazakhstan region of Kazakh nationality were examined. The main group included 135 men with signs of hypogonadism (AMS 37-49), and the control group consisted of 282 healthy men (AMS 17-26) of the corresponding age (p = 0.5). Single nucleotide polymorphisms rs 727428 [C / T]; rs10822184 [T / C]; rs754493647 [T / C], was determined by the TaqMan method. Results Analysis of the rs727428 polymorphism has revealed that the TT allele (rs727428) has a lower level of albumin (p = 0.03), bioavailable testosterone (p = 0.04), and free testosterone (p = 0.6) than in carriers of the CC and CT genotypes. Also, it has shown a decrease in total testosterone (p = 0.001) and an increase in SHBG levels (p = 0.07) in men with the TT genotype of the rs727428 gene polymorphism. The rs10822184 polymorphism demonstrated an increase in triglyceride and LDL levels in TT genotype (p ≤ 0.04), in comparison with CC and CT genotypes. Conclusion It has been proven that rs727428 (p = 0.001) is associated with testosterone levels and therefore can determine the concentration of bioavailable testosterone. Decreased levels of bioavailable testosterone are a sign of male hypogonadism. This study confirms the effect of rs10822184 on LDL (p = 0.01) and triglyceride (p = 0.04) levels, but its association with androgen levels has not been proven. Our results may be of interest for understanding the etiology of early development of hypogonadism and lipid metabolism disorders in men. To confirm the conclusions, a more detailed study with a large sample of men from the Kazakh population may be required.