Metabolic correlates of menopause: an update

Effects of menopause and high-intensity training on insulin sensitivity and muscle metabolism

OBJECTIVE

To investigate peripheral insulin sensitivity and skeletal muscle glucose metabolism in premenopausal and postmenopausal women, and evaluate whether exercise training benefits are maintained after menopause.

METHODS

Sedentary, healthy, normal-weight, late premenopausal (n = 21), and early postmenopausal (n = 20) women were included in a 3-month high-intensity exercise training intervention. Body composition was assessed by magnetic resonance imaging and dual-energy x-ray absorptiometry, whole body glucose disposal rate (GDR) by hyperinsulinemic euglycemic clamp (40 mU/m/min), and femoral muscle glucose uptake by positron emission tomography/computed tomography, using the glucose analog fluorodeoxyglucose, expressed as estimated metabolic rate (eMR). Insulin signaling was investigated in muscle biopsies.

RESULTS

Age difference between groups was 4.5 years, and no difference was observed in body composition. Training increased lean body mass (estimate [95% confidence interval] 0.5 [0.2-0.9] kg, P < 0.01) and thigh muscle mass (0.2 [-0.1 to 0.6] kg, P < 0.01), and decreased fat percentage (1.0 [0.5-1.5]%, P < 0.01) similarly in the two groups. The postmenopausal women had lower eMR in vastus lateralis muscle than the premenopausal women (-14.0 [-26.0 to -2.0] μmol/min/kg, P = 0.02), and tended to have lower eMR in femoral muscles (-11.2 [-22.7 to 0.4] μmol/min/kg, P = 0.06), and also GDR (-59.3 [-124.8 to 6.3] mg/min, P = 0.08), but increased similarly in both groups with training (eMR vastus lateralis muscle: 27.8 [19.6-36.0] μmol/min/kg, P < 0.01; eMR femoral muscle: 20.0 [13.1-26.7] μmol/min/kg, P < 0.01, respectively; GDR: 43.6 [10.4-76.9] mg/min, P = 0.01). Potential mechanisms underlying the training-induced increases in insulin sensitivity included increased expression of hexokinase (19.2 [5.0-24.7] AU, P = 0.02) and glycogen synthase (32.4 [15.0-49.8] AU, P < 0.01), and also increased insulin activation of Akt2 (20.6 [3.4-29.0], P = 0.03) and dephosphorylation of glycogen synthase (-41.8 [-82.9 to -0.7], P = 0.05).

CONCLUSIONS

Insulin sensitivity was reduced in early postmenopausal women. However, postmenopausal women increased peripheral insulin sensitivity, skeletal muscle insulin-stimulated glucose uptake, and skeletal muscle mass to the same extent as premenopausal women after 3 months of high-intensity exercise training.

High-Fat Feeding Improves Anxiety-Type Behavior Induced by Ovariectomy in Rats

Menopause-induced changes may include increased incidence of both depression/anxiety and obesity. We hypothesized that behavioral changes that may develop after ovarian failure could be related to neurochemical and metabolic aspects affected by this condition and that high-fat intake may influence these associations. The present study investigated in rats the effects of ovariectomy, either alone or combined with high-fat diets enriched with either lard or fish-oil, on metabolic, behavioral and monoaminergic statuses, and on gene expression of neuropeptides and receptors involved in energy balance and mood regulation. Female rats had their ovaries removed and received either standard chow (OvxC) or high-fat diets enriched with either lard (OvxL) or fish-oil (OvxF) for 8 weeks. The Sham group received only chow diet. Ovariectomy increased feed efficiency and body weight gain and impaired glucose homeostasis and serotonin-induced hypophagia, effects either maintained or even accentuated by the lard diet but counteracted by the fish diet. The OvxL group developed obesity and hyperleptinemia. Regarding components of hypothalamic serotonergic system, both ovariectomy alone or combined with the fish diet increased 5-HT2C expression while the lard diet reduced 5-HT1B mRNA. Ovariectomy increased the anxiety index, as derived from the elevated plus maze test, while both high-fat groups showed normalization of this index. In the forced swimming test, ovariectomy allied to high-lard diet, but not to fish-oil diet, reduced the latency to immobility, indicating vulnerability to a depressive-like state. Linear regression analysis showed hippocampal AgRP to be negatively associated with the anxiety index and hypothalamic AgRP to be positively associated with the latency to immobility. These AgRp gene expression associations are indicative of a beneficial involvement of this neuropeptide on both depression and anxiety measures. The present findings demonstrate metabolic, neurochemical and behavioral alterations after ovaries removal and highlight a positive effect of high-fat feeding on the anxiety-like behavior shown by ovariectomized animals. Since the polyunsaturated ômega-3 intake (fish diet), unlike the saturated fat intake (lard diet), failed to induce deleterious metabolic or neurochemical consequences, further studies are needed focusing on the potential of this dietary component as an adjuvant anxiolytic agent after menopause.

Effects of high-intensity training on cardiovascular risk factors in premenopausal and postmenopausal women

BACKGROUND

Menopause is associated with increased risk of cardiovascular disease and the causal factors have been proposed to be the loss of estrogen and the subsequent alterations of the hormonal milieu. However, which factors contribute to the deterioration of cardiometabolic health in postmenopausal women is debated as the menopausal transition is also associated with increased age and fat mass. Furthermore, indications of reduced cardiometabolic adaptations to exercise in postmenopausal women add to the adverse health profile.

OBJECTIVE

We sought to evaluate risk factors for type 2 diabetes and cardiovascular disease in late premenopausal and early postmenopausal women, matched by age and body composition, and investigate the effect of high-intensity training.

STUDY DESIGN

A 3-month high-intensity aerobic training intervention, involving healthy, nonobese, late premenopausal (n = 40) and early postmenopausal (n = 39) women was conducted and anthropometrics, body composition, blood pressure, lipid profile, glucose tolerance, and maximal oxygen consumption were determined at baseline and after the intervention.

RESULTS

At baseline, the groups matched in anthropometrics and body composition, and only differed by 4.2 years in age (mean [95% confidence limits] 49.2 [48.5-49.9] vs 53.4 [52.4-54.4] years). Time since last menstrual period for the postmenopausal women was (mean [95% confidence limits] 3.1 [2.6-3.7] years). Hormonal levels (estrogen, follicle stimulation hormone, luteinizing hormone) confirmed menopausal status. At baseline the postmenopausal women had higher total cholesterol (P < .001), low-density lipoprotein-cholesterol (P < .05), and high-density lipoprotein-cholesterol (P < .001) than the premenopausal women. The training intervention reduced body weight (P < .01), waist circumference (P < .01), and improved body composition by increasing lean body mass (P < .001) and decreasing fat mass (P < .001) similarly in both groups. Moreover, training resulted in lower diastolic blood pressure (P < .05), resting heart rate (P < .001), total cholesterol (P < .01), low-density lipoprotein-cholesterol (P < .01), total cholesterol/high-density lipoprotein-cholesterol index (P < .01), and improved plasma insulin concentration during the oral glucose tolerance test (P < .05) in both groups.

CONCLUSION

Cardiovascular risk factors are similar in late premenopausal and early postmenopausal women, matched by age and body composition, with the exception that postmenopausal women have higher high- and low-density lipoprotein-cholesterol levels. A 3-month intervention of high-intensity aerobic training reduces risk factors for type 2 diabetes and cardiovascular disease to a similar extent in late premenopausal and early postmenopausal women.

Metabolic syndrome in hypertensive adults from rural Northeast China: an update

BACKGROUND

The last study reported the prevalence of Metabolic Syndrome (MetS) in hypertensive residents from rural Northeast China was conducted approximately ten years ago. The purpose of this study was to update the prevalence and epidemiological features of Metabolic syndrome (MetS).

METHODS

This survey was conducted from July 2012 to August 2013. In this study, a total of 5866 hypertensive residents from the rural Northeast China were randomly selected and examined. MetS was defined according to the to the International Diabetes Federation (IDF) criteria. Data regarding the demographic and lifestyle characteristics and the blood biochemical indexes of these participants were collected by well-trained personnel.

RESULTS

The overall prevalence of MetS among hypertensive residents was 43.1%. Women had significantly higher incidence of MetS than men (56.4%vs. 29.2%, P < 0.001). Overall, 51.7%, 39.6%, 29.3% and 55.9% of the hypertensive adults had abdominal obesity, hypertriglyceridemia, low HDL-C, and increased fasting glucose. Multivariate logistic regression, after adjusting for possible confounders, revealed the following factors that increased the risk of MetS: being female, older age, completion of education through high school, obesity, current smoking. Moderate physical activity, a family income between 5000-20000 CNY per year and higher diet score were correlated with lower rates of MetS.

CONCLUSIONS

The prevalence of MetS was dramatically high and exhibited a remarkably increasing trend in hypertensive rural Northeast Chinese. Female had higher incidence of MetS while male had more drastically increasing trend.

Metabolic syndrome in premenopausal and postmenopausal women with type 2 diabetes: loss of protective effects of premenopausal status

Background

Diabetes is probably responsible for worsening of metabolic syndrome (MetS)components. The aim of the present study was to compare the components of MetS between premenopausal and postmenopausal women with type 2 diabetes (T2DM).

Method

In this cross sectional study, we studied 639 women with T2DM that were divided in pre-menopausal (n = 221) and post-menopausal (n = 418) group. They were selected from participants of a diabetes clinic and assessed for MetS and its components. All MetS components were evaluated to follow age and duration of diabetes adjusted according to the ATP III criteria.

Results

The mean ages of pre-menopausal and post-menopausal were 43.33 ± 0.47 and 60.35 ± 0.38 years, respectively. MetS was defined for 88.3% of total subjects (87.5% and 87.7% in pre-menopausal and post-menopausal women with T2DM respectively). Systolic blood pressure (SBP) and waist circumference (WC) were significantly higher in post-menopausal women with T2DM in comparison with pre-menopausal ones. There were no significant differences in triglyceride (T.G) level, diastolic blood pressure (DBP) and high density lipoprotein cholesterol (HDL-C) between the two groups. Myocardial infarction (MI) occurred in 1% total subjects (1.3% and 1.8%) in pre-menopausal and post-menopausal women with T2DM, respectively (p = 0.21).

Conclusion

Worsening of MetS and its components except for SBP and waist circumference has been shown in pre-menopausal women with T2DM similar to post-menopausal ones. The observed differences may be explained by increasing age. With respect to increasing of myocardial infarction in premenopausal subjects, we suggest that diabetes can abolish the protective effects of premenopausal status for MetS and MI.