Sex-specific differences in left ventricular mass and myocardial energetic efficiency in non-diabetic, pre-diabetic and newly diagnosed type 2 diabetic subjects

Abstract

Background: Women with type 2 diabetes (T2DM) have a higher excess risk for cardiovascular disease (CVD) than their male counterparts. However, whether the risk for CVD is higher in prediabetic women than men is still debated. We aimed to determine whether sex-related differences exist in left ventricular mass index (LVMI), and myocardial mechano-energetic efficiency (MEEi) in with normal glucose tolerant (NGT), pre-diabetic and newly diagnosed type 2 diabetic subjects.

Methods: Sex-related differences in LVMI and myocardial MEEi, assessed by validated echocardiography-derived measures, were examined among 1562 adults with NGT, prediabetes, and newly diagnosed T2DM, defined according to fasting glucose, 2-h post-load glucose, or HbA1c.

Results: Worsening of glucose tolerance in both men and women was associated with an increase in age-adjusted LVMI and myocardial MEEi. Women with newly diagnosed T2DM exhibited greater relative differences in LVMI and myocardial MEEi than diabetic men when compared with their NGT counterparts. Prediabetic women exhibited greater relative differences in myocardial MEEi, but not in LVMI, than prediabetic men when compared with their NGT counterparts. The statistical test for interaction between sex and glucose tolerance on both LVMI (P < 0.0001), and myocardial MEEi (P < 0.0001) was significant suggesting a sex-specific association.

Conclusions: Left ventricle is subject to maladaptive changes with worsening of glucose tolerance, especially in women with newly diagnosed T2DM. The sex-specific increase in LVM and decrease in MEEi, both being predictors of CVD, may have a role in explaining the stronger impact of T2DM on the excess risk of CVD in women than in men.

Keywords: Cardiovascular disease; Left ventricular mass; Myocardial mechano-energetic efficiency; Prediabetes; Sex-differences; Type 2 diabetes.

Fig. 1

The estimated marginal means of cardiovascular variables adjusted for age according to sex and glucose tolerance status. a BMI; b waist circumference; c HOMA-IR index; d systolic blood pressure; and e diastolic blood pressure

Fig. 2

a Mean differences in LVMI (g/m²) between prediabetic and newly diagnosed diabetic men and women as compared with their NGT counterparts; b Mean differences in myocardial MEEi (ml/s g⁻¹) between prediabetic and newly diagnosed diabetic men and women as compared with their NGT counterparts. *P values refer to results after analyses with adjustment for age. ** P values refer to results after analyses with adjustment for age, smoking status, and antihypertensive therapy

Fig. 3

The estimated marginal means of cardiovascular variables adjusted for age according to sex and glucose tolerance status. a LVMI (g/m²); b myocardial MEEi (ml/s g⁻¹)