Serum Testosterone Level, QT Internal and Systemic Arterial Blood Pressure in Non-obese, Generally Obese and Centrally Obese Adult Male Subjects

ABSTRACT

Introduction: Cardiovascular complications in obesity are associated with various electrocardiographic (ECG) abnormalities. Testosterone is a regulator of the action potential duration, ventricular repolarization and tendency to ventricular arrhythmias. Low testosterone levels are frequently encountered in obese men.

Objective: The present study aimed to study serum testosterone level, QT interval and systemic arterial blood pressure in non-obese, generally obese and centrally obese adult male subjects.

Methods: A community-based cross-sectional comparative study was done. Ninety male adult subjects of age 18-35 years residing in Magway Township were recruited by using multistage sampling method according to inclusion and exclusion criteria. The subjects were divided into three groups: non-obese (n=30), generally obese (n=30) and centrally obese group (n=30). Serum testosterone level was determined by enzyme-linked immunosorbent assay (ELISA). Systemic brachial arterial blood pressure was measured in lying position by indirect method, using mercury sphygmomanometer. The QT interval was measured by routine 12-lead ECG with Lead II rhythm strip for 10 seconds and corrected QT interval (QTc) was calculated.

Results: Mean serum testosterone level of centrally obese subjects (3.41±1.31 ng/mL) was significantly lower than that of generally obese subjects (4.55±1.24 ng/mL) (p< 0.05) as well as non-obese subjects (5.81±2.35 ng/mL) (p< 0.001). Mean QTc were 395.87±25.43 ms, 437.22±53.38 ms and 488.28±63.18 ms for non-obese, generally obese and centrally obese subjects, respectively. There was significant difference of QTc between the study groups (p< 0.001). Systolic blood pressure values of centrally obese, generally obese and non-obese subjects were 137.00±3.47, 130.20±4.99 and 114.33±9.98 mmHg, respectively. There was significant difference in SBP between all three groups (p< 0.001). Diastolic blood pressure of non-obese subjects (76.53±7.57 mmHg) was significantly lower than that of generally obese subjects (83.47±5.82 mmHg) (p< 0.001) as well as centrally obese subjects.

(86.80±5.55 mmHg) (p< 0.001) whereas there was no significant difference in DBP between generally obese and centrally obese groups (p=0.138). Mean arterial blood pressure of centrally obese (103.53±4.11 mmHg) was significantly higher than that of non-obese (89.13±7.62 mmHg) (p< 0.001) as well as generally obese subjects (99.05±4.79 mmHg) (p< 0.01). Similarly, mean arterial blood pressure of generally obese subjects was significantly higher than that of non-obese subjects (p< 0.001). There was significant negative correlation between serum testosterone level and QTc (r = – 0.246; p< 0.05, n = 90). Likewise, there was significant negative correlation between serum testosterone level and systolic blood pressure (r = – 0.328, p< 0.01, n = 90) and mean arterial blood pressure (r = – 0.259, p< 0.05, n = 90). Nevertheless, there was no significant correlation between serum testosterone level and diastolic blood pressure (r = – 0.172, p = 0.106, n = 90). Serum testosterone level was significantly and negatively correlated with body mass index (BMI)

(r = – 0.473, p< 0.001, n=90) as well as waist circumference (WC) (r = – 0.567, p< 0.001, n=90).

Conclusion: Serum testosterone level was significantly lower in centrally obese subjects than that of generally obese subjects. QTc and systemic arterial blood pressure were significantly higher in centrally obese subjects than that of generally obese subjects. Moreover, there was significant negative weak correlation between serum testosterone level and QTc as well as systemic arterial blood pressure. These findings suggested that low testosterone level might partly attribute to prolonged QTc and hypertension in obese male subjects.

Dr. Maung Maung Htay
MBBS, MMedSc (Int Med), MMed(NUS, Singapore), MRCP(UK), MAcadMED
Parami General Hospital

This is an interesting study, describing the various stages of obesity correlated with cardiovascular complications, corrected QT interval QTc and hypertension due to low testosterone level in young adult age 18 to 35 years.

BMI, QTc and Testerone level are well chosen for this study. Testosterone level does not decline with age in normal urologic and sexual function healthy men [1]. The central obesity is closely related with Metabolic Syndrome (MetS) and need to be done subgroup analysis in this group [2-4].

Low testosterone level associated with cardiovascular health, including incidence of coronary artery disease (CAD), congestive heart failure (CHF) and prolonged corrected QT interval (QTc). The roles of testosterone on risk factors for atherosclerosis are Type 2 Diabetes Mellitus (T2DM), Obesity and Inflammation [5].

This study was well done in Obesity association with low testosterone and QTc especially in centrally obese patients. Hypertension is multifactorial in obese patients and low testosterone is one of the contribution factors and weak association. In centrally obese patients, high blood pressure is one of the criteria for diagnosis of metabolic syndrome (MetS).

In this study, testosterone level is significantly negatively associated with QTc length, regulating ventricular polarization, a risk factor for CAD and torsades de pointes [6-7]. In 26 hypogonadal men, testosterone replacement normalizes in all subjects with prolonged QTc length [7].

Total testosterone levels are inversely related to BMI in this study is supported by Swedish MrOS study [8]. Testosterone therapy has been shown to improve obesity, with significant reduction in BMI (-1.3 kg/m2 at 30 weeks) [9] and fat mass (2.19%) [10]. Testosterone increases lipolysis and reduces fat deposition in central adipose tissue [5].

Despite evidence of importance role of testosterone on the cardiovascular system, Endocrine Society guidelines do not recommend for testosterone screening in heart disease patients. Furthermore, testosterone therapy in heart disease was not recommended [11].

Testosterone therapy should be reserved for well-documented cases of hypogonadism, according to updated clinical practice guidelines [12-13]. Testosterone therapy is not routinely recommended for male obesity with low testosterone.

References:

1. Mehta A., et al. “Testosterone levels do not decline with age in healthy men”, Open Journal of Urology 3 (2013): 172-178.
2. MuraleedharanV., et al. “Testosterone and the metabolic syndrome”, Therapeutic Advamced in Endocrinology Metabolism. 1.5 (2010): 207-223.
3. Cunningham GR., et al. “Testosterone and metabolic syndrome”, Asian Journal ofAndrology. 17.2 (2015):192-6.
4. Salam R., et al. “Testosterone and metabolic syndrome: The link”, Indian Journal of EndocrinologyMetabolism. 16.Suppl1(2012): S12–S19.
5. MesbahOskui P., et al. “Testosterone and the Cardiovascular System: A Comprehensive Review of the Clinical Literature”, Journal of the American Heart Association. 2 (2013): 1-22.
6. NoordcV., et al. “The association of serum testosterone levels and ventricularrepolarization”, European Journal of Epidemiology. 25(2010):21–28.
7. PecoriGiraldi F., et al. “Increased prevalence of prolonged QT interval in maleswith primary or secondary hypogonadism: A pilot study”, International Journal of Andrology. 33 (2010), e132–e138.
8. Ohlsson C. et al. “High serum testosterone is associated with reduced risk of cardiovascular events in elderly men. The MrOS (Osteoporotic Fractures in Men) study in Sweden”. Journal of American College of Cardiology. 58.16 (2011):1674-1681.
9. Kalinchenko SY., et al. “Effects of testosterone supplementation on markers of the metabolic syndrome and inflammation in hypogonadal men with the metabolic syndrome: the double-blinded placebo-controlled Moscow study”. Clinical Endocrinology (Oxf) 73.5(2010):602-612.
10. Corona G., et al. “Type 2 diabetes mellitus and testosterone: a meta-analysis study”. International Journal of Andrology 34.6 Pt 1(2011):528-540.
11. Bhasin S., et al. “Testosterone therapy in adult men with androgen deficiency syndromes: an endocrine society clinical practice guideline”. Journal of Clinical Endocrinology Metabolism. 91.6(2006):1995-2010.
12. Bhasin S., et al. “Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline”. Journal of Clinical Endocrinology Metabolism. 103.5(2018):1-30.
13. Bhasin S., et al. “Testosterone therapy in men with androgen deficiency syndromes: an Endocrine Society clinical practice guideline”. Journal of Clinical Endocrinology Metabolism. 95.6(2010):2536-2559.

Zarchi Theint Theint Hlaing
M.B.,B.S, M.Med.Sc (Physiology)
Department of Physiology, UMMG