Testosterone deficiency in men with Type 2 diabetes: pathophysiology and treatment

Abstract

Epidemiological studies consistently demonstrate that lowered serum testosterone is not only common in men with established Type 2 diabetes, but also predicts future diabetic risks and increased mortality. Preclinical studies report plausible mechanisms by which low testosterone could mediate dysglycaemia. Exogenous testosterone treatment consistently reduces fat mass, increases muscle mass and improves insulin resistance in some studies, but the majority of currently available randomized controlled trials (RCTs) do not report a consistent glycaemic benefit. In men with diabetes, testosterone treatment effects on androgen deficiency-like clinical features are inconsistent, and effects on sexual dysfunction may be attenuated compared with men without diabetes. The long-term risks of testosterone treatment in older men without medical disease of the hypothalamic-pituitary-testicular axis are not known. Current RCTs are not definitive, owing to their small size, short duration and enrolment of men with mostly relatively good baseline glycaemic control not specifically selected for the presence of androgen deficiency symptoms. Although large, well-designed clinical trials are needed, given the benefit-risk ratio of testosterone treatment is not well understood, routine serum testosterone testing or testosterone treatment of asymptomatic men with Type 2 diabetes is currently not recommended. Carefully selected, symptomatic men with low testosterone who are informed of the lack of high-level evidence regarding the long-term benefits and risks of this approach may be offered a trial of testosterone treatment in combination with lifestyle measures, weight loss and optimization of comorbidities.

Serum Vitamin D Affected Type 2 Diabetes though Altering Lipid Profile and Modified the Effects of Testosterone on Diabetes Status

“…Those indicated that the effect of vitamin D on the serum testosterone levels may be opposed between males and females. Moreover, several observational studies and randomized trials have proposed that low serum testosterone status were correlated with an increased risk of IFG and T2DM in males and the opposite in females [22,[53][54][55][56]. It seems plausible that males with higher vitamin D levels likely have higher testosterone levels, which decrease the risk of IFG and T2DM.…”

Late‐onset hypogonadism: metabolic impact

“…Previous observational studies, reviewed in detail recently (Grossmann, 2018;Gianatti & Grossmann, 2019), have reported that diabesity (including the metabolic syndrome) is associated with a more rapid decline in testosterone, suggesting a bidirectional association (see below). Consistent with earlier work, in a recent prospective study of 141 younger (mean age 43 years) mostly insulin resistant men, insulin resistance (measured using an octreotide-based pancreatic suppression test) predicted hypogonadism (defined as a total testosterone < 10.4 nmol/L) somewhat more strongly (risk ratio = 2.2) than hypogonadism predicted insulin resistance (risk ratio = 1.3) (p = 0.03) (Contreras et al, 2018).…”

“…RCTs in men with T2DM and/or the metabolic syndrome published before 2016 have been extensively reviewed elsewhere (Dhindsa et al ., 2018; Grossmann, 2018; Rastrelli et al ., 2018; Gianatti & Grossmann, 2019). Overall, findings suggested that testosterone treatment consistently and modestly increases lean mass (by about 2 kg), decreases fat mass (by about 2 kg), and modestly improves insulin resistance in most but not all studies.…”

Remission of type 2 diabetes in a young, hypogonadal man under long-term testosterone therapy: A case report

“…A 20-year-old man presented to a specialist for endocrinology and andrology with complaints of fatigue, dry mouth, and ED. The patient showed class III obesity with a body [18][19][20][21]. Recent study showed that long-term TTh may prevent prediabetes progression to T2D in men with hypogonadism, improve glycemic and lipid metabolism [22].…”