The effect of menopause on carotid artery remodeling, insulin sensitivity, and plasma adiponectin in healthy women

Changes in insulin resistance, glucose effectiveness, and first and second phases of insulin secretion in women aged 45-60 years old in Taiwan

BACKGROUND

In women after menopause, the incidence of diabetes mellitus increases. Increased insulin resistance (IR), decreased glucose effectiveness (GE), and the first and second phases of insulin secretion (FPIS and SPIS), are the four most important factors that trigger glucose intolerance and diabetes (diabetogenic factor [DF]). In the cross-sectional study, we enrolled nondiabetic women between the ages of 45 and 60 years to observe the changes in DFs during the perimenopausal period and to elucidate the underlying mechanisms of diabetes in menopausal women.

METHODS

We randomly enrolled 4194 women who underwent health checkups. Using demographic and biochemical data, IR, FPIS, SPIS, and GE were calculated using previously published equations. The relationship between the DFs and age was evaluated using a simple correlation.

RESULTS

Body mass index, blood pressure, fasting plasma glucose, low-density lipoprotein cholesterol, triglyceride, and SPIS were higher, and GE was lower in older women (≥52 years old). A significant decrease in GE and increased SPIS were observed with age. However, no changes were observed in IR or FPIS.

CONCLUSION

The IR and FPIS did not change during perimenopause. Increased SPIS may compensate for the decrease in GE, which is probably one of the reasons for the higher incidence of diabetes in menopausal women.

Important Hormones Regulating Lipid Metabolism

There is a wide variety of kinds of lipids, and complex structures which determine the diversity and complexity of their functions. With the basic characteristic of water insolubility, lipid molecules are independent of the genetic information composed by genes to proteins, which determine the particularity of lipids in the human body, with water as the basic environment and genes to proteins as the genetic system. In this review, we have summarized the current landscape on hormone regulation of lipid metabolism. After the well-studied PI3K-AKT pathway, insulin affects fat synthesis by controlling the activity and production of various transcription factors. New mechanisms of thyroid hormone regulation are discussed, receptor α and β may mediate different procedures, the effect of thyroid hormone on mitochondria provides a new insight for hormones regulating lipid metabolism. Physiological concentration of adrenaline induces the expression of extrapituitary prolactin in adipose tissue macrophages, which promotes fat weight loss. Manipulation of hormonal action has the potential to offer a new therapeutic horizon for the global burden of obesity and its associated complications such as morbidity and mortality.

Impact of moderate dietary protein restriction on glucose homeostasis in a model of oestrogen deficiency

The need to consume adequate dietary protein to preserve physical function during ageing is well recognized. However, the effect of protein intakes on glucose metabolism is still intensively debated. During age-related oestrogen withdrawal at the time of the menopause, it is known that glucose homeostasis may be impaired but the influence of dietary protein levels in this context is unknown. The aim of the present study is to elucidate the individual and interactive effects of oestrogen deficiency and suboptimal protein intake on glucose homeostasis in a preclinical model involving ovariectomy (OVX) and a 13-week period of a moderately reduced protein intake in 7-month-old ageing rats. To investigate mechanisms of action acting via the pancreas-liver-muscle axis, fasting circulating levels of insulin, glucagon, IGF-1, FGF21 and glycemia were measured. The hepatic lipid infiltration and the protein expression of GLUT4 in the gastrocnemius were analyzed. The gene expression of some hepatokines, myokines and lipid storage/oxidation related transcription factors were quantified in the liver and the gastrocnemius. We show that, regardless of the oestrogen status, moderate dietary protein restriction increases fasting glycaemia without modifying insulinemia, body weight gain and composition. This fasting hyperglycaemia is associated with oestrogen status-specific metabolic alterations in the muscle and liver. In oestrogen-replete (SHAM) rats, GLUT4 was down-regulated in skeletal muscle while in oestrogen-deficient (OVX) rats, hepatic stress-associated hyperglucagonaemia and high serum FGF21 were observed. These findings highlight the importance of meeting dietary protein needs to avoid disturbances in glucose homeostasis in ageing female rats with or without oestrogen withdrawal.

Body composition and cardiometabolic health across the menopause transition

Every year, 2 million women reach menopause in the United States, and they may spend 40% or more of their life in a postmenopausal state. In the years immediately preceding menopause-known as the menopause transition (or perimenopause)-changes in hormones and body composition increase a woman's overall cardiometabolic risk. In this narrative review, we summarize the changes in weight, body composition, and body fat distribution, as well as the changes in energy intake, energy expenditure, and other cardiometabolic risk factors (lipid profile, glucose metabolism, sleep health, and vascular function), that occur during the menopause transition. We also discuss the benefits of lifestyle interventions in women in the earlier stages of menopause before these detrimental changes occur. Finally, we discuss how to include perimenopausal women in research studies so that women across the life-span are adequately represented.

Diabetes in Menopause: Risks and Management

The aim of this review is to present, critically appraise and qualitatively synthesize current evidence on the risk of type 2 diabetes mellitus (T2DM) development during menopause, the management of climacteric symptoms in women with T2DM and the management of T2DM in postmenopausal women. Menopause represents the end of reproductive life in women, as a result of ovarian aging. It is characterized by substantial decrease in the endogenous oestrogen concentrations and it is accompanied by alterations in body weight, adipose tissue distribution and energy expenditure, as well as insulin secretion, insulin sensitivity and activity that can predispose to the development of T2DM, independently of, and additively to, aging. Many women in midlife experience climacteric symptoms, including hot flushes and night sweats, resulting in an indication to receive Hormone Replacement Treatment (HRT). HRT has a favourable effect on glucose homeostasis both in women without and with T2DM. The latter was considered in the past as a cardiovascular disease (CVD) equivalent, which would suggest that women with the disease should not receive HRT. However, nowadays evidence exists to support an individualized approach of women based on their CVD risk, as some women with T2DM may be excellent candidates for HRT. Regarding T2DM management for women in menopause, lifestyle intervention, including diet and exercise, constitutes its cornerstone. However, most of these women will eventually require pharmacologic therapy. The most suitable agents should be selected according to their metabolic, cardiovascular and bone effects, taking into consideration the specific characteristics and comorbidities of each postmenopausal woman.

Metabolic Syndrome During Menopause

The metabolic syndrome (MetS) comprises individual components including central obesity, insulin resistance, dyslipidaemia and hypertension and it is associated with an increased risk of cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM). The menopause per se increases the incidence of MetS in aging women. The effect(s) of menopause on individual components of MetS include: i) increasing central obesity with changes in the fat tissue distribution, ii) potential increase in insulin resistance, iii) changes in serum lipid concentrations, which seem to be associated with increasing weight rather than menopause itself, and, iv) an association between menopause and hypertension, although available data are inconclusive. With regard to the consequences of MetS during menopause, there is no consistent data supporting a causal relationship between menopause and CVD. However, concomitant MetS during menopause appears to increase the risk of CVD. Furthermore, despite the data supporting the association between early menopause and increased risk of T2DM, the association between natural menopause itself and risk of T2DM is not evident. However, the presence and the severity of MetS appears to be associated with an increased risk of T2DM. Although the mechanism is not clear, surgical menopause is strongly linked with a higher incidence of MetS. Interestingly, women with polycystic ovary syndrome (PCOS) have an increased risk of MetS during their reproductive years; however, with menopausal transition, the risk of MetS becomes similar to that of non-PCOS women.

Circulating triacylglycerols but not pancreatic fat associate with insulin secretion in healthy humans

BACKGROUND

Loss of adequate insulin secretion for the prevailing insulin resistance is critical for the development of type 2 diabetes and has been suggested to result from circulating lipids (triacylglycerols [TG] or free fatty acids) and/or adipocytokines or from ectopic lipid storage in the pancreas. This study aimed to address whether circulating lipids, adipocytokines or pancreatic fat primarily associates with lower insulin secretion.

SUBJECTS/METHODS

Nondiabetic persons (n=73), recruited from the general population, underwent clinical examinations, fasting blood drawing to measure TG and adipocytokines and oral glucose tolerance testing (OGTT) to assess basal and dynamic insulin secretion and sensitivity indices. Magnetic resonance imaging and ¹H-magnetic resonance spectroscopy were used to measure body fat distribution and ectopic fat content in liver and pancreas.

RESULTS

In age-, sex- and BMI-adjusted analyses, total and high-molecular-weight adiponectin were the strongest negative predictors of fasting beta-cell function (BCF; β=-0.403, p=0.0003 and β=-0.237, p=0.01, respectively) and adaptation index (AI; β=-0.210, p=0.006 and β=-0.133, p=0.02, respectively). Circulating TG, but not pancreatic fat content, related positively to BCF (β=0.375, p<0.0001) and AI (β=0.192, p=0.003). Similar results were obtained for the disposition index (DI).

CONCLUSIONS

The association of serum lipids and adiponectin with beta-cell function may represent a compensatory response to adapt for lower insulin sensitivity in nondiabetic humans.

Gender differences in LDL- and HDL-cholesterol subfractions in patients after the acute ischemic stroke and their association with oxidative stress markers

The aim of our study was to examine gender differences of LDL- and HDL-cholesterol subfractions in patients after the acute ischemic stroke with focus on small LDL and HDL subfractions, and their association with oxidative stress markers. In addition, we have monitored the 7-day effect of cholesterol-lowering drugs administered to patients after the acute ischemic stroke, on these subfractions. Eighty two stroke patients and 81 age matched controls were included in this study. Blood was collected from patients within 24 h after the stroke (group A) and re-examined at the 7-day follow-up (group B). We have found gender differences in LDL- and HDL-subfractions in stroke patients, lipid-lowering drugs administered to acute ischemic stroke patients significantly reduced all measured parameters of lipoprotein profile. In the group A LDL1 subfraction positively correlated with activity of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase) indicating a protective role of this subfraction. On the contrary, small HDL subfractions positively correlated with lipoperoxide levels and negatively with trolox equivalent antioxidant capacity in plasma suggesting a negative role of these subfractions. In this work we have confirmed the hypothesis of atherogenic properties of small HDL subfractions and anti-atherogenic properties of large LDL1-subfractions.

Menopausal Hormone Therapy and Type 2 Diabetes Prevention: Evidence, Mechanisms, and Clinical Implications

Type 2 diabetes has reached epidemic proportions in the United States. Large, randomized controlled trials suggest that menopausal hormone therapy (MHT) delays the onset of type 2 diabetes in women. However, the mechanisms and clinical implications of this association are still a matter of controversy. This review provides an up-to-date analysis and integration of epidemiological, clinical, and basic studies, and proposes a mechanistic explanation for the effect of menopause and MHT on type 2 diabetes development and prevention. We discuss the beneficial effects of endogenous estradiol with respect to insulin secretion, insulin sensitivity, and glucose effectiveness; we also discuss energy expenditure and adipose distribution, both of which are affected by menopause and improved by MHT, which thereby decreases the incidence of type 2 diabetes. We reconcile differences among studies that investigated the effect of menopause and MHT formulations on type 2 diabetes. We argue that discrepancies arise from physiological differences in methods used to assess glucose homeostasis, ranging from clinical indices of insulin sensitivity to steady-state methods to assess insulin action. We also discuss the influence of the route of estrogen administration and the addition of progestogens. We conclude that, although MHT is neither approved nor appropriate for the prevention of type 2 diabetes due to its complex balance of risks and benefits, it should not be withheld from women with increased risk of type 2 diabetes who seek treatment for menopausal symptoms.

Lipid Changes Around the Final Menstrual Period Predict Carotid Subclinical Disease in Postmenopausal Women

BACKGROUND AND PURPOSE

Atherogenic changes in lipids occur among women around the time of the natural menopause, that is, within 1 year of the final menstrual period (FMP). We investigated whether lipid changes around the FMP are related to carotid intima-media thickness, interadventitial diameter, and plaque in postmenopausal women.

METHODS

A total of 863 natural postmenopausal women with no history of heart attack or stroke underwent carotid ultrasound scans at follow-up year 12 or 13 of the Study of Women's Health Across the Nation. Estimates of their annual change in lipids were segmented into the year before and after the FMP, before the year before FMP, and 1 year after FMP. Multivariate analyses were adjusted for sociodemographic characteristics, time from FMP to scan, baseline body mass index and systolic blood pressure, and use of medications for hypertension and diabetes mellitus at the scan.

RESULTS

Smaller increases in high-density lipoprotein cholesterol and apolipoprotein A1 within 1 year of the FMP were related to greater interadventitial diameter, β (SE)=-0.036 (0.015), P=0.02, and β (SE)=-0.035 (0.013), P=0.006, respectively. Greater increases in low-density lipoprotein cholesterol within 1 year of FMP were related to greater likelihood of plaque scores ≥2, odds ratio, 1.071; 95% confidence interval, 1.018-1.127; P=0.009. Magnitude of associations was reduced but remained significant with further adjustment for premenopausal lipid levels. The difference in probability of elevated plaque scores was 50% between those in the highest and lowest low-density lipoprotein cholesterol change tertiles.

CONCLUSIONS

Changes in lipids as women approach the FMP provide useful clinical information for understanding postmenopausal carotid indices.

Cardiovascular Risk in Women With Premature Ovarian Insufficiency Compared to Premenopausal Women at Middle Age

CONTEXT

A young age at menopause has been associated with increased cardiovascular disease (CVD) risk.

OBJECTIVE

To compare the cardiovascular risk profile between women with premature ovarian insufficiency (POI) and premenopausal controls of comparable age.

DESIGN

Cross-sectional case control study.

SETTING

Two university medical centers.

PARTICIPANTS

Women above 45 years of age who were previously diagnosed with POI (n = 83) and premenopausal population controls of comparable age (n = 266).

MAIN OUTCOME MEASURES

Blood pressure, body mass index, waist circumference, electrocardiogram, bilateral carotid intima media thickness, estradiol, T, androstenedione, dehydroepiandrosterone sulfate, SHBG, insulin, glucose, lipids, TSH, free T4, N-terminal pro-B-type natriuretic peptide, C-reactive protein, uric acid, creatinine, and homocysteine were measured. Potential associations between POI status and subclinical atherosclerosis were assessed.

RESULTS

Women with POI exhibited an increased waist circumference (β = 5.7; 95% confidence interval [CI], 1.6, 9.9), C-reactive protein (β = 0.75; 95% CI, 0.43, 1.08), free T4 levels (β = 1.5; 95% CI, 0.6, 2.4), and lower N-terminal pro-B-type natriuretic peptide (β = -0.35; 95% CI, -0.62, -0.08), estradiol (β = -1.98; 95% CI, -2.48, -1.48), T (β = -0.21; 95% CI, -0.37, -0.06), and androstenedione (β = -0.54; 95% CI, -0.71, -0.38) concentrations compared to controls, after adjusting for confounders. After adjustment, a trend toward increased hypertension (odds ratio = 2.1; 95% CI, 0.99; 4.56) and decreased kidney function was observed in women with POI (creatinine β = 3.5; 95% CI, -0.05, 7.1; glomerular filtration rate β = -3.5; 95% CI, -7.5, 0.46). Women with POI exhibited a lower mean carotid intima media thickness (β = -0.17; 95% CI, -0.21, -0.13) and decreased odds of plaque presence compared to controls (odds ratio = 0.08; 95% CI, 0.03; 0.26).

CONCLUSIONS

Women with POI exhibited an unfavorable cardiovascular risk profile, including higher abdominal fat, elevated chronic inflammatory factors, and a trend toward increased hypertension and impaired kidney function compared to controls. However, we observed no signs of increased subclinical atherosclerosis in women with POI. Additional studies are required to identify specific determinants of long-term CVD risk in women with POI.

Circulating adiponectin and carotid intima-media thickness: A systematic review and meta-analysis

BACKGROUND

Adiponectin (APN) is an adipokine with insulin-sensitizing, anti-inflammatory, and vasculoprotective properties. Hypoadiponectinemia has been linked with disease states, such as obesity, type 2 diabetes, and cardiovascular disease. Carotid intima-media thickness (cIMT) is a strong and independent predictor of both coronary and cerebrovascular events, and has been used as a surrogate marker of subclinical atherosclerosis. The aim of this report is to systematically review the evidence on the relationship between APN and cIMT in a wide range of individuals.

MATERIALS AND METHODS

Medline, Embase, Biosis, Scopus, Web of Science, and Pubmed were searched for published studies and conference abstracts. The "sign test" and "vote count" methods were used to estimate the direction and significance of the relationship between APN and cIMT. The quality of the eligible studies was evaluated using an adapted version of the New Castle Ottawa quality assessment scale.

RESULTS

Fifty-five articles fulfilled the inclusion criteria, comprised of only cross-sectional studies, including healthy subjects, general population, and individuals with metabolic, inflammatory, or other chronic diseases. Most associations between APN and cIMT followed a negative direction in the healthier and general populations, and also in cohorts with metabolic disorders and other chronic diseases, but not in those with inflammatory diseases (sign test). These associations were generally found to be weak or non-significant among all cohort groups studied (vote count).

CONCLUSION

Our results are suggestive but not conclusive for an inverse association between APN levels and cIMT in diseased and non-diseased populations.

Diabetes and Menopause

During menopause, women's body composition, sex hormone profile, and metabolic profile may change dramatically. In this review, we summarize studies examining whether the menopausal transition and physiologic factors characterizing the transition are associated with increased risk of diabetes. We review the evidence for estrogen therapy and diabetes risk and studies examining the relationship between diabetes and menarche, which represents an extension of the reproductive life span at the opposite end of the age spectrum. Although studied less extensively, the presence of type 1 or type 2 diabetes may increase the risk of ovarian failure, and we review this literature. In conclusion, we note that the evidence linking menopausal sex hormone changes with increased diabetes risk is weak, although rapid changes as observed with oophorectomy may increase risk. Further studies should investigate the contradictory effects of estrogen therapy upon hepatic and glucose metabolism in mid-life women.

Metabolic Syndrome and Menopause: Pathophysiology, Clinical and Diagnostic Significance

Menopause is a risk factor for cardiometabolic diseases, including metabolic syndrome (MetS), type 2 diabetes, and cardiovascular diseases. MetS is a constellation of interdependent factors such as insulin resistance, abdominal obesity, dyslipidemia, and hypertension. The prevalence of MetS in postmenopause is due to loss of the protective role of estrogens and increased circulating androgens resulting in changes to body fat distribution and development of abdominal obesity. Excessive visceral adipose tissue plays an important role due to synthesis and secretion of bioactive substances such as adipocytokines, proinflammatory cytokines, reactive oxygen species, prothrombotic, and vasoconstrictor factors. MetS may also impact risk assessment of breast cancer, osteoporosis and chronic kidney disease, and quality of life during the menopausal transition. Increased MetS has stimulated the exploration of new laboratory tests for early detection and therapies.

Nulliparity is associated with less healthy markers of subclinical cardiovascular disease in young women with overweight and obesity

OBJECTIVE

Higher parity is associated with increased subclinical cardiovascular disease (CVD) in mid-life and older women and with increased CVD risk overall. The relationship between parity, subclinical CVD, and infertility in young women with overweight and obesity has been infrequently evaluated.

METHODS

Reproductive histories were obtained in 191 (66%) young women with overweight and obesity (BMI 25-39.9 kg/m(2) ) participating in a weight loss trial. Baseline carotid intima-media thickness (IMT) and inter-adventitial diameter (IAD) were assessed via B-mode ultrasound. Linear regression was used to estimate the relationship between parity and carotid measures, adjusted for demographic, cardiovascular, and reproductive risk factors.

RESULTS

Nulliparous women (n = 70, age 34.9 ± 7.1) had increased common carotid IAD (0.230 mm, SE 0.08, P = 0.003) and mean common carotid artery (CCA) IMT (0.031 mm, SE 0.01, P = 0.007) compared with parous women (n = 102, age 39.5 ± 4.9), persisting after adjustment for age, race, and CVD risk factors. No other reproductive factors were statistically significantly associated.

CONCLUSIONS

Nulliparity is associated with markers of less healthy carotid arteries in a sample of disease-free 25- to 45-year-old women with overweight or obesity. This may represent a beneficial effect of pregnancy or indicate overall better health in women with overweight/obesity who are capable of childbearing.

Task force on: 'Early markers of atherosclerosis: influence of age and sex'

Atherosclerosis and its complications are the most important causes of death all over the world, especially in Western countries. Diet habits, modern stress life, smoking, sedentary way of life and an involvement of genetic pattern of individuals lead to a sure degeneration of quality of life increasing the risk of atherosclerosis development. For this reason, the main purpose of actual medicine is to identify all the markers that could allow the physicians to evaluate the first moments of the development of this dangerous pathological process. The aim is to reduce the speed of its evolution, trying to delay indefinitely the risk coming from the morphological alterations of the vessels. 'Endothelium function' could allow physicians to detect the first moment of the natural history of atherosclerosis process. Its impairment is the first step in the degeneration of vascular structures. Many methods [flow-mediated vasodilatation (FMD); antero-posterior abdominal aorta diameter (APAO); intima-media thickness of the common carotid artery (CCA-IMT); arterial stiffness; and so on] try to evaluate its function, but many limitations come from general population characteristics. A standardization of the methods should take into account individuals' peculiarities. Two elements, not modifiable, should be taken into account for vascular evaluation: age and sex. The aim of this review is to outline the linkage among age, sex and instrumental evaluation of patients considered for a noninvasive assessment of their cardiovascular risk profile.

Cardiometabolic risk profiles in pre- versus postmenopausal women with spinal cord injury:: preliminary findings

OBJECTIVE

To compare the cardiometabolic risk (CMR) profile of premenopausal and postmenopausal women with spinal cord injury (SCI).

METHOD

Post hoc analysis of a multicenter cross-sectional study assessing CMR. Seventeen women with ASIA Impairment Scale (AIS) A or B SCI between C5 and T12 were stratified into 2 groups according to menopausal status (11 premenopausal vs 6 postmenopausal women). Data collected included demographic, social, medical, menopausal, hormone use, and menstrual histories. Assessments included physical, anthropometric, and blood pressure measures; fasting serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), and hemoglobin A1C (Hb1Ac); calculated low-density lipoprotein (LDL-C); and an oral glucose tolerance test.

RESULTS

The premenopausal group had a mean age of 32.4 years compared with 56.0 years in the postmenopausal group. Similar group findings included body mass index (BMI) (22.4 vs 22.2), HDL-C (52.5 vs 53 mg/dL), HbA1c (4.9 vs 5.1%), fasting blood glucose (FBG) (79.3 vs 84.8 mg/dL), and systolic blood pressure (SBP) (104.6 vs 111.8 mm Hg). TG, TC and LDL-C were significantly higher in postmenopausal group (55.7 vs 101.8 mg/dL, P = .01; 158.3 vs 191.6 mg/dL, P = .04; 94.7 vs 118.2 mg/dL, P = .04).

CONCLUSIONS

The findings from this study suggest that postmenopausal women with SCI have CMR trends similar to those observed in nondisabled women, characterized by increases in TG, TC, and LDL-C despite favorable BMIs and glycemic indices. Even though the present study includes significant limitations, future evidence may also suggest that heightened surveillance and guideline-driven interventions are indicated for perimenopausal and postmenopausal women with SCI.

Progression rates of carotid intima-media thickness and adventitial diameter during the menopausal transition

OBJECTIVE

The aim of this study is to assess whether the levels and progression rates of carotid intima-media thickness (IMT) and adventitial diameter (AD) vary by menopausal stage.

METHODS

Two hundred forty-nine women (aged 42-57 y; 49% premenopausal and 46% early perimenopausal) from the Study of Women's Health Across the Nation were included in the current analysis. Participants were followed up for up to 9 years (median, 3.7 y) and underwent up to five carotid scans. Linear mixed-effect models were used for the analysis.

RESULTS

The overall rate of change in IMT was 0.007 mm/year. Independent of age and race, the progression rate of IMT increased substantially in the late perimenopausal stage (0.017 mm/y) compared with both the premenopausal stage (0.007 mm/y) and the early perimenopausal stage (0.005 mm/y; P ≤ 0.05). For AD, although the overall rate of change was negative (-0.009 mm/y), significant positive increases in the rate of change were observed in the late perimenopausal stage (0.024 mm/y) and the postmenopausal stage (0.018 mm/y) compared with the premenopausal stage (-0.032 mm/y; P < 0.05). In the final models, the postmenopausal stage was independently associated with higher levels of IMT and AD (P < 0.05) compared with the premenopausal stage.

CONCLUSIONS

During the menopausal transition, the carotid artery undergoes adaptation that is reflected in adverse changes in IMT and AD. These changes may have an impact on the vulnerability of the vessel to disease in older women.

Gender-specific differences in carotid intima-media thickness and its progression over three years: a multicenter European study

BACKGROUND AND AIMS

This multicentre European study evaluated, in a young-to-middle-aged healthy population without carotid atherosclerosis, the gender-related differences in carotid intima-media thickness (IMT) and its short-term (3-year) progression, and whether these differences are related to different vascular ageing rate, cardiovascular risk profile or different susceptibility to family predisposition to cardiovascular diseases (CVD).

METHODS AND RESULTS

366 men and 422 women (age between 30 and 60 years) underwent B-mode carotid ultrasound at baseline and after 3-year follow-up period. IMT in 3 carotid segments was higher in men than in women (p < 0.0001 for all segments). When evaluated according to age decade, differences between men and women disappeared in the 6th decade, as in this decade a 3-year IMT progression rate accelerated in women (p < 0.05 as compared to the 4th and 5th age decade). Age was a major determinant of baseline all-segment IMT in women; in men all-segment IMT was influenced by age and LDL-cholesterol. IMT progression did not correlate with established cardiovascular risk factors, their short-term changes or family predisposition to CVD. Yet, a 3-year IMT progression in common carotid artery (CCA) was higher in men (p = 0.01) and women (p < 0.01) in whom relative Framingham risk increased during the corresponding period.

CONCLUSION

This study provides reference values on IMT and its short-term progression in healthy young-to-middle-aged population, and demonstrates gender-related differences in the susceptibility of carotid wall to ageing and LDL-cholesterol. Increase in Framingham risk accelerated a short-term CCA IMT progression rate in both genders, whereas family predisposition to CVD did not influence carotid IMT.

Endogenous sex hormones impact the progression of subclinical atherosclerosis in women during the menopausal transition

OBJECTIVE

To determine whether endogenous sex hormones (estradiol (E2), testosterone (T), sex hormone binding globulin (SHBG), and follicle stimulating hormone (FSH)) are longitudinally associated with progression of atherosclerosis among women at midlife.

METHODS

249 Pre- or early peri-menopausal women (42-57 years) from the Study of Women's Health Across the Nation (SWAN) were followed for up to 9 years (median = 3.7 years) and had up to 5 repeated measures of common carotid intima-media thickness (IMT) and adventitial diameter (AD). Linear mixed models were used for statistical analysis. Final models included age at baseline, time since baseline, cycle day of blood draw, race, income, SBP, BMI, insulin resistance index, lipids, C-reactive protein and co-morbidity.

RESULTS

In final models for IMT, each one log unit decrease in SHBG was associated with a 0.005 mm/year increase in IMT progression (P = 0.003). E2, T, and FSH were not associated with level or progression of IMT. For AD, each one log unit decrease in E2 was associated with a 0.012 mm/year increase in AD progression (P = 0.04) and each one log unit increase in FSH was associated with a 0.016 mm/year increase in AD progression (P = 0.003). T and SHBG were not associated with progression or level of AD.

CONCLUSIONS

Independent of SBP, BMI, lipids and other covariates, lower E2 and SHBG, and higher FSH were associated with increased subclinical atherosclerosis progression in women at midlife.

Iliac vessel wall thickness in menstrual and hormone treated and untreated postmenopausal women

OBJECTIVE

To assess iliac vessel wall thickness in different groups of women.

METHOD

Three groups of women were menopausal and were classified by hormone replacement therapy (HRT) (n = 32), atherosclerotic risk factors (n = 14) and an untreated group of postmenopausal women (n = 29), two groups of menstrual women, above 35 years (N = 35) and below 35 years (n = 16). In these groups of women, a 3.5 MHz ultrasound was used to assess the combined vessel wall thickness of the right iliac artery inner wall and vein outer wall.

RESULTS

The iliac vessel wall thickness was found significantly high in the menopausal group of women possessing high risk factors for atherosclerosis (4.3 ± 0.08 mm) and the untreated menopausal group of women (3.9 ± 0.08 mm) compared to the other three groups (p < 0.0001) (Mann-Whitney U test). The vessel wall thickness of the HRT group was 2.96 ± 0.09 mm, the older menstrual group 2.61 ± 0.07 mm, and 2.0 ± 0.06 mm in the young menstrual group. The HRT group had a significantly thicker iliac vessel wall compared to the young menstrual group (p < 0.001).

CONCLUSION

These results confirm the significant impact of high risk factors, such as smoking, hyperlipidaemia and diabetes, on the vessel wall thickness due to accelerated atherosclerosis. This study also suggests that the oestrogenaemic state of a woman may affect the health of the vessel wall.

Factors influencing endothelial function in healthy pre- and post-menopausal women of the EU-RISC study

BACKGROUND

We studied the impact of lifestyle, body composition, different insulin sensitivity indices and the first insulin response in healthy pre- and post-menopausal women with a low cardiovascular risk profile (the EU-RISC study, 'Relationship between Insulin Sensitivity and Cardiovascular Disease' (n = 51, 47 ± 4 years, body mass index 23.6 ± 3.7 kg/m(2), waist girth 79.2 ± 10.3 cm) on endothelial function (flow mediated arterial dilatation (FMD)), an early marker for atherosclerosis.

RESULTS

Waist circumference (p = 0.06), tobacco consumption (p = 0.02) and leucocyte count (p = 0.09) were inversely related with FMD in both pre- and post-menopausal women. Neither insulin sensitivity nor first insulin response indices were correlated with FMD. In pre-menopausal women (n = 24), waist (p < 0.02), waist-to-hip ratio (p < 0.02), HDL cholesterol (p < 0.01) and smoking habits (p < 0.03) were significantly correlated with endothelial function. In postmenopausal women (n = 27) age (r = -0.17, p = 0.04) was related with FMD.

CONCLUSION

Smoking and waist circumference, a simple marker of visceral adiposity, were related with endothelial function in healthy pre- and post-menopausal women.

Sex differences in lipid and lipoprotein metabolism: it's not just about sex hormones

It is commonly thought that sex hormones are important regulators of plasma lipid kinetics and are responsible for sexual dimorphism in the plasma lipid profile. Here we discuss the findings from studies evaluating lipid and lipoprotein kinetics in men and women in the context of what we know about the effects of exogenous sex hormone administration, and we conclude that it is more complicated than that. It has become clear that normal physiological alterations in the hormonal milieu (i.e. due to menopause or throughout the menstrual cycle) do not significantly affect plasma lipid homeostasis. Furthermore, parenterally administered estrogens have either no effect or only very small beneficial effects, whereas orally administered estrogens raise plasma triglyceride concentrations--a phenomenon that is not consistent with the observed sex differences and likely results from the hepatic "first-pass effect." The effects of progestogens and androgens mimic only in part the differences in plasma lipids between men and women. Thus, the underlying physiological modulators of plasma lipid metabolism responsible for the differences between men and women remain to be elucidated.

Normative values and correlates of mean common carotid intima-media thickness in the Korean rural middle-aged population: the Atherosclerosis RIsk of Rural Areas iN Korea General Population (ARIRANG) study

Carotid intima-media thickness (CIMT) is considered as a surrogate marker for cardiovascular disease (CVD). We determined the normative value of CIMT and correlates of CVD risk factors and Framingham risk score (FRS) in Korean rural middle-aged population. We measured CIMT with a B-mode ultrasonography in 1,759 subjects, aged 40 to 70 yr, in a population-based cohort in Korea. A healthy reference sample (n = 433) without CVD, normal weight and normal metabolic parameters was selected to establish normative CIMT values. Correlates between CIMT and conventional CVD risk factors were assessed in the entire population. Mean values of CIMT (in mm) for healthy reference sample aged 40-49, 50-59, and 60-70 yr were 0.55, 0.59, and 0.66 for men and 0.48, 0.55, and 0.63 for women, respectively. In multivariate regression analysis, CIMT was correlated with older age, higher BMI, male gender, higher LDL-cholesterol level and history of diabetes mellitus. The mean CIMT was also correlated with FRS in both gender (r(2) = 0.043, P < 0.01 for men; r(2) = 0.142, P < 0.01 for women). We identified normative value of CIMT for the healthy Korean rural middle-aged population. The CIMT is associated with age, obesity, gender, LDL-cholesterol, diabetes mellitus and FRS.

Differences in left and right carotid intima-media thickness and the associated risk factors

AIM

To investigate the difference between the left and right carotid artery intima-media thickness (CIMT) with increasing age and to analyse the importance of the various risk factors associated with left and right CIMT, respectively.

MATERIALS AND METHODS

Four hundred and forty-seven people were assigned into six groups based on age. CIMT and haemodynamic parameters of both carotid arteries were measured using the Quality Intima-Media Thickness (QIMT) technique. In addition, biochemical and anthropometric indices were also measured. Their associations were evaluated using simple and partial correlation analysis, adjusted for age.

RESULTS

Bilateral CIMTs became thicker with age (p<0.001) and the left CIMT was significantly thicker compared with the right between the ages of 35 and 65 years (p=0.01-0.05). In addition, the right CIMT thickened 10 years later compared with the left. Partial correlation analysis showed that the right CIMT correlated better with haemodynamic parameters compared with the left CIMT, but the left CIMT showed better correlation with biochemical indices.

CONCLUSION

Haemodynamic and biochemical changes had different effects on the CIMT depending on the side affected. In addition, the left CIMT was thicker than the right between the ages of 35 and 65 years old.

Estrogen deficiency after menopause does not result in male very-low-density lipoprotein metabolism phenotype

CONTEXT

Sex differences in lipid metabolism result in a less proatherogenic plasma lipid profile in premenopausal women than men. The mechanisms responsible for this are unclear but are thought to be related to differences in the sex hormone milieu in men and women.

OBJECTIVE

Our objective was to evaluate the effect of endogenous sex hormones on very-low-density lipoprotein (VLDL) triglyceride (TG) and apolipoprotein B-100 (apoB-100) metabolism. EXPERIMENTAL DESIGN AND MAIN OUTCOME MEASURES: We measured basal VLDL-TG and VLDL-apoB-100 concentrations and kinetics by using stable isotope-labeled tracers.

SETTING AND PARTICIPANTS

Eight premenopausal women [age, 43 + or - 8 yr; body mass index (BMI), 35 + or - 4 kg/m(2); mean + or - sd], eight postmenopausal women (age, 55 + or - 4 yr; BMI, 34 + or - 4 kg/m(2)), and eight men (age, 41 + or - 13 yr; BMI, 34 + or - 4 kg/m(2)) were studied at Washington University School of Medicine, St. Louis, MO.

RESULTS

VLDL-TG secretion rate was approximately double (P < 0.05) in postmenopausal women and men compared with premenopausal women but not different in postmenopausal women and men. The secretion rate of VLDL-apoB-100 was not different in pre- and postmenopausal women but was greater (P < 0.05) in men than in women.

CONCLUSIONS

Endogenous ovarian sex steroids are responsible for sexual dimorphism in VLDL-TG secretion, whereas VLDL-apoB-100 secretion is not regulated by female reproductive hormones.

Metabolic actions of insulin in men and women

Insulin is an important regulator of glucose, lipid, and protein metabolism. It suppresses hepatic glucose and triglyceride production, inhibits adipose tissue lipolysis and whole-body and muscle proteolysis, and stimulates glucose uptake in muscle. In this review we discuss what is currently known about the control of substrate metabolism by insulin in men and women. The data available so far indicate that women are more sensitive to insulin with regards to glucose metabolism (both in the liver and in muscle), whereas there are no differences between men and women in insulin action on lipolysis. Potential differences exist in the regulation of plasma triglyceride concentration and protein metabolism by insulin and in changes in insulin action in response to stimuli (e.g., weight loss and exercise) that are known to alter insulin sensitivity. However, these areas have not been studied comprehensively enough to draw firm conclusions.

Influence of menopause on diabetes and diabetes risk

Many postmenopausal women live with diabetes mellitus; however, little information is available about how the changes that occur around the time of menopause might uniquely affect management of diabetes mellitus in this population. Although the weight gain that commonly occurs during the menopausal transition is largely attributable to aging rather than the transition itself, changes in body composition have been independently associated with menopausal status. These changes in body composition have, in turn, been associated with alterations in insulin sensitivity and glucose metabolism in postmenopausal women. Hormone therapy seems to have neutral or beneficial effects on the adverse changes in body composition associated with menopause. Whether menopausal status independently influences diabetes risk remains controversial. Nevertheless, consistent findings from large clinical trials suggest that postmenopausal hormone therapy decreases the risk of developing diabetes mellitus. Similarly, many studies suggest that postmenopausal hormone therapy has neutral or beneficial effects on glycemic control among women already diagnosed as having diabetes mellitus. Future studies are needed to elucidate the mechanisms that underlie these relationships and to determine how these observations should influence recommendations for the care of postmenopausal women with diabetes mellitus.