Relation between sex hormones and serum lipoprotein and lipoprotein(a) concentrations in premenopausal obese women

Body size in relation to urinary estrogens and estrogen metabolites (EM) among premenopausal women during the luteal phase

Estrogen metabolism profiles may play an important role in the relationship between body size and breast carcinogenesis. Previously, we observed inverse associations between current body mass index (BMI) and plasma levels of parent estrogens (estrone and estradiol) among premenopausal women during both follicular and luteal phases. Using data from the Nurses' Health Study II, we assessed whether height, current BMI, and BMI at age 18 were associated with the urinary concentrations of 15 estrogens and estrogen metabolites (jointly referred to as EM) measured during the luteal phase among 603 premenopausal women. We observed inverse associations with total EM for height (P (trend) = 0.01) and current BMI (P (trend) = 0.01), but not BMI at age 18 (P (trend) = 0.26). Six EMs were 18-27% lower in women with a height 68+ versus ≤62 in., primarily in the methylated catechol pathway (P (trend) = 0.04). Eight EMs were 18-50% lower in women with a BMI of 30+ versus <20, primarily in the 2-catechol and methylated catechol pathways (P (trend) < 0.001 for both). Our results suggest that height and current BMI are associated with estrogen metabolism profiles in premenopausal women. Further studies with timed urine and blood collections are required to confirm and extend our findings.

Association between Low-Molecular Weight Apolipoprotein(a) Isoforms and Obesity in Italian Women

OBJECTIVE

Low-molecular weight (MW) apolipoprotein(a) [apo(a)] isoforms are closely associated with an increased incidence of atherothrombotic disease, prevalence of which is higher in obese individuals, particularly in women. The hypothesis of this study was to assess whether there are differences in the distribution of apo(a) phenotypes between obese patients and healthy controls.

RESEARCH METHODS AND PROCEDURES

One hundred three obese Italian women (BMI > or = 30.0 kg/m2) were enrolled in the study, and apo(a) phenotyping was performed in all subjects. The prevalence of low-MW apo(a) isoforms, detected in plasma samples of our obese women, was compared with that found in a control group of 84 normal-weight, never-obese (BMI < 25.0 kg/m(2)), age-matched women.

RESULTS

The distribution of apo(a) isoforms in the population of obese women was significantly different from that found in normal-weight female subjects. In particular, the percentage of subjects in the obese group with at least one apo(a) isoform of low MW was significantly higher than that in the control group (51.4% vs. 32.1%, p = 0.0079).

DISCUSSION

Our results seem to suggest the possibility that small-sized apo(a) isoforms may be used together with other traditional risk factors to better assess the overall predisposition to atherothrombotic disease in obese women.

Estrogens in the breast tissue: a systematic review

The role of estrogens in breast carcinogenesis has been investigated at the level of whole body (plasma) and cell (molecular, receptors, etc.). Growing attention focused on the breast tissue being an intracrine organ, with potentially important local estrogen production in the breast. However, very little is known about the local breast tissue estrogen levels. Understanding the role of the tissue estrogens in breast carcinogenesis might open new avenues in breast cancer prevention. This systematic review summarizes published studies that measured local estrogen levels in the breast and offers suggestions for strategies to fill gaps in our existing scientific knowledge.

Correlation between lipoprotein(a) and other risk factors for cardiovascular disease and diabetes in Cherokee Indians: the Cherokee Diabetes Study

PURPOSE

To study the age and gender effects on the distribution of lipoprotein (a) [Lp(a)] and its relationship with other cardiovascular disease (CVD) and diabetes risk factors in the participants of the Cherokee Diabetes Study (CDS) (1995-2000).

METHODS

The CDS is a population based cross-sectional study of diabetes and its risk factors in Cherokee Indians aged 5 to 40 years of Oklahoma. Lp(a) levels were measured in 2205 participants.

RESULTS

The median Lp(a) (mg/dL) levels in the females were not significantly different among four age groups (5-9, 10-19, 20-29, and 30-40 years). However, the 20- to 29-year-old males had significantly lower Lp(a) levels than the males 10 to 19 and 30 to 40 years old. Females had significantly higher Lp(a) levels than males in the 20- to 29-year-old age group only. In the 5- to 19-year-old children/adolescents, Lp(a) levels were significantly negatively correlated with the degree of Indian heritage (DIH) and positively correlated with total cholesterol (TC), low-density lipoproteins (LDL), and apolipoprotein B (apoB) in girls, but not in boys. In the young adults aged 20 to 29 years, Lp(a) levels were significantly correlated with DIH, body mass index (BMI), waist-hip ratio (WHR), percentage of body fat (PBF), systolic blood pressure (SBP), triglycerides (TG), 2-hour plasma glucose (2hPG), and insulin in males, and DIH, PBF, TC, LDL, TG, and insulin in females. In adults aged 30 to 40 years, Lp(a) levels were significantly correlated with DIH, TG, and LDL in females, and DIH and insulin in males.

CONCLUSION

In the girls, Lp(a) levels appear to be associated with several CVD and diabetes risk factors at an early age (5-19 years), while in the boys, the association occurs at older ages (> 19 years). There are significant age and gender differences regarding the distribution of Lp(a) and its correlates in the 5 to 9, 10 to 19, and 20 to 29-year-old age groups, but the differences tend to be weaker in the 30- to 40-year-old age group. For the same age and gender groups, Lp(a) concentrations in Cherokee Indians were much lower than those reported in blacks and slightly lower than those in whites. In Cherokee Indians, the Lp(a) levels were consistently and positively correlated with LDL, and negatively correlated with DIH, TG, and insulin.

Free testosterone plasma levels are negatively associated with the intima-media thickness of the common carotid artery in overweight and obese glucose-tolerant young adult men

OBJECTIVE

To evaluate the relation between free testosterone (FT) levels and the intima-media thickness of the common carotid artery (IMT-CCA) in overweight and obese glucose-tolerant (NGT) young adult men.

DESIGN

Cross-sectional study of FT and IMT-CCA in obese men.

SUBJECTS

A total of 127 overweight and obese NGT male individuals, aged 18-45 y.

MEASUREMENTS

FT plasma levels; IMT-CCA, as measured by high-resolution B-mode ultrasound imaging; central fat accumulation, as evaluated by waist circumference; body composition, as measured by bioimpedance analysis; insulin resistance, as calculated by homeostatic model assessment (HOMA(IR)); systolic and diastolic blood pressure; and fasting concentrations of glucose, insulin, and lipids.

RESULTS

IMT-CCA was positively correlated with age, body mass index (BMI), fat mass (FM), waist circumference, and fasting glucose concentrations, and inversely associated with FT levels. After multivariate analysis, IMT-CCA maintained an independent association with BMI, FM, and FT levels. This study indicates that IMT-CCA is negatively associated with FT levels, independent of age, total body fat, central fat accumulation, and fasting glucose concentrations in overweight and obese NGT patients.

CONCLUSION

Hypotestosteronemia may accelerate the development of atherosclerosis and increase the risk for CHD in obese men.

Obesity and coronary heart disease

Obesity is commonly cited as a risk factor for the development of coronary heart disease (CHD). Epidemiologic studies tend to support this contention, particularly those focusing on patients with central obesity. Such studies however, are imprecise and prone to misclassification bias. Angiographic and post mortem studies have demonstrated little or no correlation of total fat mass and coronary atherosclerosis except in those with abdominal obesity. There is a strong association of obesity, particularly central obesity, and traditional risk factors for CHD such as hypertension, type II diabetes mellitus, and dyslipidemia. There may also be an association between obesity and several nontraditional risk factors such as hyperhomocystinemia, elevated Lp(a) levels and factors that increase thrombogenesis. Obesity may also alter endothelial function. Weight loss, although associated with favorable modification of multiple risk factors for CHD, has not been shown to independently and definitively reduce CHD risk.

Effects of menopause and obesity on lipid profiles in middle-aged Taiwanese women: the Chin-Shan Community Cardiovascular Cohort Study

In this cross-sectional study, we examined the associations between lipid profiles and menopausal status, age, and obesity in Taiwanese women. The study population, established in 1990-91, consisted of 671 premenopausal and 872 postmenopausal women from the Chin-Shan Community Cardiovascular Cohort (CCCC). The associations of age, body mass index (BMI), and menopausal status with serum levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), apoproteins (Apo) A-1 and B, and lipoprotein (a) [Lp (a)] were evaluated. The results showed that menopause was associated with significant increases in TC, LDL-C, TG, and Apo B levels (all P < 0.001). Total cholesterol, LDL-C, TG, and Apo B levels increased consistently with BMI in middle-aged women, regardless of menopausal status. Among women aged 45-49, menopausal women had significantly higher levels of TC and LDL-C than premenopausal women (P < 0.01). However, TG and Apo B levels were higher in postmenopausal than in premenopausal women aged 50-54 years (P < 0.05). Standardized regression analyses showed all lipid variables, except those of Apo A1 and Lp (a) before menopause and TC, LDL-C, and Lp (a) after menopause, were significantly associated with BMI (all P < 0.01). We conclude serum lipid levels in Taiwanese women are no more strongly associated with menopause and BMI than with age.

Correlates of lipoprotein(a) levels in a biracial cohort of young girls: the NHLBI Growth and Health Study

Elevated levels of lipoprotein(a) [Lp(a)] are associated with increased risk for coronary heart disease (CHD). However, racial differences in both Lp(a) levels and their associated CHD risk are observed, with African Americans having, on average, higher Lp(a) levels than US whites but not the expected increase in CHD risk. We determined Lp(a) levels and their correlates in a large cohort (n = 2379) of black and white girls, ages 9 to 10 years, at the baseline visit of a longitudinal study of obesity development, the National Heart, Lung, and Blood Institute Growth and Health Study. Lp(a) levels were available for 1269 girls. The median Lp(a) level in black girls was over 3-fold higher than that in white girls. Associations were examined between Lp(a) levels and low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol, apolipoprotein B, triglycerides, adiposity, pubertal maturation stage, body fat patterning (triceps/truncal skinfold ratio), and dietary fat (Keys' score). In black girls multiple regression analysis identified LDL-C (P <.001) and adiposity (P =. 08) as predictors of Lp(a) levels. In white girls only LDL-C (P =. 02) was associated with Lp(a). In conclusion, the level of Lp(a) was significantly higher in black girls. Our study also revealed a racial difference in correlates of Lp(a), such as LDL-C and adiposity. Whether this racial difference is due to an underlying biologic difference or is merely a reflection of a greater statistical power to detect a relationship with the level, which was 2.5-fold higher in black girls than in white girls, needs further investigation.

Lipoprotein (a) level in the population in Taiwan: relationship to sociodemographic and atherosclerotic risk factors

To examine the lipoprotein(a) (Lp(a)) level in the Taiwanese population and its association with cardiovascular risk factors, 1703 men and 1899 women aged 35 years and above were enrolled in a community-based study cohort established between 1990 and 1991. The distributions of Lp(a) levels were skewed to the right, and females were more likely than males to have Lp(a) levels greater than 30 mg/dl (14.3% versus 11.6%, P < 0.05). The Lp(a) level increased with age. Socioeconomic status did not seem to have consistent influence on the level of Lp(a). Smoking and alcohol use also had no effect on Lp(a) levels. Multivariate analysis indicated that older age and high level of low-density-lipoprotein cholesterol corresponded to an elevated Lp(a) level, while hypertriglyceridemia, low high-density-lipoprotein cholesterol level, obesity and high insulin resistance corresponded to a lower Lp(a) level. In univariate analysis, hyperinsulinemia was negatively associated with Lp(a) level (-0.107, P < 0.01) only in males. In females, use of oral contraceptive lowered Lp(a) levels, but menopause did not change Lp(a) levels. We also found that different correlation patterns existed for selected coagulation profiles between sexes. There was a significant correlation between Lp(a) and fibrinogen levels in males (0.154, P < 0.001) but not in females (0.007, P > 0.05). These data provided clues for investigating atherosclerotic risk factors and coagulation parameters for the Taiwanese population.

Acute effects of a surgical menopause on serum concentrations of lipoprotein(a)

OBJECTIVE

The aim of this study was to investigate acute changes in serum concentrations of lipoprotein(a) and other atherogenic lipids and lipoproteins after a surgical menopause.

METHODS

A total of 100 premenopausal Chinese women who were booked for hysterectomy for benign gynecological disorders were recruited. They study group comprised 40 subjects undergoing hysterectomy as well as bilateral oophorectomy. The control group consisted of 60 subjects undergoing hysterectomy with conservation of the ovaries. Complete data were available from 30 of the 40 subjects in the study group and from 44 of the 60 controls. Serum concentrations of lipoprotein(a) and other atherogenic lipids and lipoproteins were measured before surgery and these measurements were repeated 3 days, 8 weeks and 6 months postoperatively. Those study patients who received hormone replacement therapy and control patients who became menopausal, according to biochemical criteria, during the study period were excluded from analysis.

RESULTS

Three days after surgery, there was a significant increase in the mean lipoprotein(a) concentration in the control group from 19.1 to 23.0 mg/dl (p < 0.01), but there was no significant change in the study group. There were no significant changes from baseline in the mean lipoprotein(a) concentration in either group 8 weeks or 6 months after surgery. There was a significant increase in the mean concentration of total cholesterol in the study group 8 weeks after surgery from 5.08 to 5.45 mmol/l (p < 0.01), in low density lipoprotein cholesterol from 3.22 to 3.49 mmol/l (p < 0.01), and in apolipoprotein B from 95.6 to 103.0 mg/dl (p < 0.05). However, the mean concentrations 6 months after surgery were not significantly different from baseline levels. The mean concentrations of high density lipoprotein cholesterol, apolipoprotein A-1 and triglycerides also did not differ significantly from baseline in the study group, either 8 weeks or 6 months after surgery.

CONCLUSIONS

These results suggest that any increase in concentrations of lipoprotein(a), and other atherogenic lipids and lipoproteins which occur after the menopause, develops relatively slowly. The changes in concentrations which occurred within 8 weeks of surgery were probably an acute-phase reaction after surgery rather than a response to a decreasing estradiol concentration.

Standardization and clinical management of lipoprotein(a) measurements

The present article proposes personal suggestions to improve determinations and clinical interpretation of results of lipoprotein(a) assays. Methods and procedures for sampling and quantification of the various isoforms of lipoprotein(a) in serum, plasma and urine are reviewed with the aim of improving the reliability and reproducibility of results and reinforcing the clinical utility of lipoprotein(a) measurements.

Sex hormone-binding globulin and insulin resistance in African-American women

Sex hormone-binding globulin (SHBG) binds testosterone, determining the level of free, biologically active hormone, and is a sensitive indicator of androgen status in women. SHBG is strongly correlated with high-density lipoprotein (HDL), central obesity, and insulin sensitivity in Caucasian and Mexican-American women, thereby acting as a biologic marker for cardiovascular disease risk. The purpose of this study was to determine if SHBG was a significant correlate of metabolic cardiovascular risk factors in African-American women. Eighty-one nondiabetic, normotensive African-American women were enrolled (mean age, 30 years). After excluding women on oral contraceptives (n = 19), 62 women were examined during the follicular phase of the menstrual cycle. All subjects underwent an oral glucose tolerance test (OGTT) and a euglycemic-hyperinsulinemic insulin clamp, and the lipid and sex hormone levels were measured. Correlation analyses showed a significant correlation between SHBG and the following variables in women: central obesity, body mass index (BMI), HDL cholesterol, apolipoprotein B (apoB), insulin sensitivity adjusted for lean mass (M'), and the sum of insulin during the OGTT. The strongest correlates of SHBG in women were measures of insulin resistance (r = .421, P < .001). SHBG appears to be a biologic marker for insulin resistance, which is linked to cardiovascular risk, in African-American women.

Lower androgenicity is associated with higher plasma levels of prothrombotic factors irrespective of age, obesity, body fat distribution, and related metabolic parameters in men

The purpose of this study was to examine the relationships between androgenic status and plasma levels of both prothrombotic and antithrombotic factors in men, irrespective of obesity, body fat distribution, and metabolic parameters. Sixty-four apparently healthy men, 40 with a body mass index (BMI) greater than 25 kg/m2 (overweight and obese [OO]) and 24 non-obese controls with a BMI less than 25, were selected and evaluated for (1) plasma concentrations of plasminogen activator inhibitor-1 (PAI-1) antigen, PAI-1 activity, fibrinogen, von Willebrand factor (vWF) antigen, vWF activity, and factor VII (FVII) as the prothrombotic factors; (2) plasma levels of tissue plasminogen activator (TPA) antigen, protein C, and antithrombin III as the antithrombotic factors; (3) fasting plasma concentrations of insulin and glucose and the lipid pattern (triglycerides [TG] and total and high-density lipoprotein [HDL] cholesterol) as the metabolic parameters; and (4) free testosterone (FT), dehydroepiandrosterone sulfate (DHEAS), and sex hormone-binding globulin (SHBG) serum levels as the parameters of androgenicity. Body fat distribution was evaluated by the waist to hip ratio (WHR). In OO and non-obese subjects taken together, plasma levels of PAI-1 antigen, fibrinogen, and FVII were inversely associated with FT (r = .255, P < .05, r = -3.14, P < .05, and r = -.278, P < .05, respectively), and the negative relationships of both fibrinogen and FVII with FT were maintained after stepwise multiple regression analysis. Plasma concentrations of PAI-1 antigen and PAI-1 activity were also negatively correlated with SHBG (r = -.315, P < .05 and r = -.362, P < .01, respectively), and these associations held irrespective of the other parameters investigated. None of the antithrombotic and fibrinolytic factors were independently related to serum androgen levels. Subjects with a BMI higher than 25 kg/m2 had higher plasma concentrations of PAI-1 antigen, PAI-1 activity, and fibrinogen as compared with non-obese controls (P < .001, P < .001, and P < .01, respectively). In addition, in OO and control subjects as a whole, multiple stepwise regression analysis showed that the associations of BMI with PAI-1 activity, fibrinogen, vWF antigen, and vWF activity were independent of any other metabolic and hormonal parameters. Plasma concentrations of PAI-1 antigen, PAI-1 activity, and fibrinogen were also directly correlated with WHR in all subjects taken together, irrespective of the other parameters investigated. Evaluation of antithrombotic factors showed that OO subjects had higher TPA plasma concentrations than non-obese controls (P < .001), whereas protein C and antithrombin III did not differ in the two groups. TPA was also directly correlated with BMI (r = .415, P < .001) and WHR (r = .393, P < .001) in all subjects. The results of this study indicate that (1) men with lower FT serum levels have higher fibrinogen and FVII plasma concentrations, and those with lower SHBG serum levels also have higher levels of PAI-1 antigen and activity; (2) irrespective of other factors, obesity per se may account for higher concentrations of PAI-1, fibrinogen, and vWF; (3) plasma levels of PAI-1 (antigen and activity) and fibrinogen correlate independently with WHR; and (4) among the investigated antithrombotic factors (TPA antigen, protein C, antithrombin III), only TPA antigen plasma concentrations are higher in men with abdominal obesity. Thus, because of the increase in several prothrombotic factors, men with central obesity, particularly those with lower androgenicity, seem to be at greater risk for coronary heart disease (CHD). Apparently, this risk is not counteracted by a parallel increase in plasma concentrations of antithrombotic factors.

Effects of nandrolone decanoate (Decadurabolin) on serum Lp(a), lipids and lipoproteins in women with postmenopausal osteoporosis

Although lipoprotein(a) (Lp(a)) concentrations are mainly regulated genetically, it has been reported that variations in sex hormone concentrations may have effects on serum Lp(a). We evaluated the effect of nandrolone decanoate, a testosterone-derived synthetic anabolic steroid, on serum Lp(a), lipids and lipoproteins in 19 postmenopausal women who were given parenteral nandrolone decanoate (Decadurabolin) once a week for 3 weeks. At the 4th week, a significant decrease was observed for total cholesterol (p = 0.003), Lp(a) (p = 0.0003), apolipoprotein A-I (apo A-I) (p < 0.0001), and high density lipoprotein-cholesterol (HDL-C) (p < 0.0001). Moreover, a significant decrease in serum albumin concentration (p = 0.002) was concomitantly observed. We conclude that the administration of nandrolone decanoate significantly affects the lipid profile of postmenopausal women, showing controversial effects in terms of cardiovascular risk.

Effects of visceral fat and weight loss on lipoprotein(a) concentration in subjects with obesity

We studied the relationships between regional body fat distribution and metabolic variables with lipoprotein(a) [Lp(a)] as well as the effects of weight loss on Lp(a) in 25 women and 9 men with obesity. Regional body fat distribution, as evaluated by the use of computed tomography; Lp(a); and fasting glucose, insulin, cholesterol, and triglycerides were analyzed before and after a very low-energy diet. No significant correlations were found between visceral, subcutaneous, and total fat and Lp(a) or between metabolic variables and Lp(a). All anthropometric variables significantly decreased after a very low-energy diet. Fasting glucose, insulin, triglycerides, and cholesterol significantly decreased after a very low-energy diet. No significant changes in Lp(a) concentration after a very low-energy diet were found. The correlation between the initial values of Lp(a) and changes of Lp(a) after a very low-energy diet was slightly significant (rho = 0.33, p < 0.06). In conclusion, our study shows that Lp(a) is not influenced by obesity, visceral fat, metabolic variables, or weight loss induced by a very low-energy diet.

Lipoprotein (a) distribution in a Nigerian population

OBJECTIVES

To determine the distribution and determinants of lipoprotein (a) (Lp(a)) concentration among Nigerians.

METHODS

Subjects were recruited from civil servants living in Benin City, Nigeria. The height and weight of the individuals were measured and their use of alcohol and tobacco estimated by questionnaire. Laboratory analyses of blood samples involved Lp(a), total cholesterol (TC), high-density lipoprotein (HDLc), HDL2c, HDL3c, triglyceride (TG) and insulin.

RESULTS

The analyses indicate that the Lp(a) concentrations are elevated among Nigerian populations and more skewed towards high levels than is observed for caucasian and oriental groups. The median levels for Lp(a) were 24.0 mg dl-1 and 19.0 mg dl-1 for women and men, respectively. This difference was significant (P < 0.05) but after stratifying by age, only the 45-54 year-old group of women (30.1 mg dl-1) had significantly higher (p < 0.001) median concentrations of Lp(a) than men (18.4 mg dl-1). Age, 20-64, had no influence on Lp(a) levels in men but in women Lp(a) concentrations increased significantly with age (p < 0.05). Among males alcohol consumption, smoking and body mass index (BMI) were not related to Lp(a) concentrations but a significant effect (p < 0.05) was noted for waist-hip ratio (WHR). Among females no relationship was observed between Lp(a) levels and alcohol consumption, BMI and WHR. All serum lipids measured (TC, HDLc, HDL2c, HDL3c, low-density lipoprotein (LDLc), and TG) were correlated with Lp(a) concentrations among men. A significant association with TC and LDLc remained after correcting for Lp(a) cholesterol. Among women, the Lp(a) levels were associated with TC, HDLc, HDL3c, and LDLc but not with HDL2c, and TG. The correlations with TC and LDLc were not significant after correcting for Lp(a) cholesterol. Insulin did not correlate with Lp(a) levels in either men or women.

CONCLUSIONS

Lp(a) concentrations are high in Nigerians, particularly among women, and the association between the Lp(a) concentrations and other lipoproteins is stronger than in white populations.

Lipoprotein(a) concentrations and non-insulin-dependent diabetes mellitus: relationship to glycaemic control and diabetic complications

The aim of our study was to determine the lipoprotein(a) (Lp(a)) levels in patients with non-insulin-dependent diabetes mellitus (NIDDM) and to evaluate Lp(a) concentrations in relation to glycaemic control and diabetic complications. We evaluate in a cross-sectional study a total of 103 NIDDM patients (52 males and 51 females; mean age of 62.5 years; mean of diabetes duration: 12 years) referred to our hospital because of poor glycaemic control, and a group of 108 non-diabetic subjects (57 males and 51 females).

RESULTS

mean Lp(a) concentration did not significantly differ between NIDDM patients and non-diabetic subjects (11.1 +/- 14 vs. 16.2 +/- 14 mg/dl). The distribution of Lp(a) levels was highly skewed towards the lower levels in both groups, being over 30 mg/dl in only 6% of NIDDM patients and 12% of controls. Patients with Lp(a) levels over 10 mg/dl had lower haemoglobin Alc (HbA1c) than patients with Lp(a) levels over 10 mg/dl (8.5% vs. 10.4%; P < 0.01). Lp(a) concentration was positively correlated with body mass index (BMI) (P < 0.05) and HbA1c (P < 0.05). No association was found between Lp(a) and sex, age, other lipidic parameters, microalbuminuria, type of treatment and presence of cardiovascular disease. These findings may suggest that glycaemic control could have a modulatory role on Lp(a) concentration in NIDDM patients. In this study, diabetic complications did not seem to be associated with higher Lp(a) concentrations.

The relation of body size to plasma levels of estrogens and androgens in premenopausal women (Maryland, United States)

We analyzed data from a cross-sectional study of 107 premenopausal women to evaluate the relations of height, weight, and body mass index (BMI) with plasma hormone levels. Participants were 20- to 40-year old women residing in Maryland (United States), whose reported menstrual cycle lengths were not more than 35 days and whose measured weights for height were 85 to 130 percent of 'desirable' based on 1983 Metropolitan Life Insurance tables. Fasting blood specimens were collected on each of days 5-7, 12-15, and 21-23 of every participant's menstrual cycle and pooled to create follicular, midcycle, and luteal phase samples, respectively, for analysis. Adjusted for age, taller women had significantly higher follicular-phase plasma-estradiol levels (percent difference/cm = 1.5, 95 percent confidence interval [CI] = 0.3-2.7, and heavier women had significantly lower plasma sex-hormone binding globulin (SHBG) levels averaged across the menstrual cycle phases (percent difference/kg = -1.2; CI = -1.9-(-0.6). Body weight within the range studied, however, was not related significantly to the concentration of SHBG-bound estradiol during any phase of the menstrual cycle. The results of this cross-sectional study suggest a possible mechanism by which height may influence breast cancer risk.

Lp(a) lipoprotein in cardiovascular disease

The article summarizes the increased knowledge about the enigmatic Lp(a) lipoprotein and its clinical importance over the past 20 years. The mode of inheritance, the unique features of Lp(a) composition and structure and the unusual distribution of the mainly genetically determined plasma Lp(a) levels are discussed. The main factors that can significantly change the inherited plasma Lp(a) levels are endocrine disorders and hormone treatment. It seems possible that sex hormones protect females to a large extent from the potentially deleterious effects of inherited high Lp(a) levels until menopause. The exceptionally strong independent association found in most studies between Lp(a) lipoprotein levels and atherosclerotic disorders indicates that Lp(a) is a factor of outstanding importance in the pathogenesis of atherosclerosis. Probable pathogenetic mechanisms are reviewed. The associations found between LP(a) and insulin release, rheumatoid arthritis and renal diseases suggest that Lp(a) may be involved in immunological mechanisms. In a new hypothesis it is suggested that an autoimmune process might especially occur in individuals with inherited high Lp(a) levels and certain HLA class II genotypes, triggered by a concurrent infection.

Close relation between lipoprotein (a) levels and atherothrombotic disease in Japanese subjects > 75 years of age

Levels of lipoprotein (a) (Lp[a]) and various hemostatic factors were studied in 132 Japanese aged > 75 years (mean 83). The group consisted of 50 healthy persons, 36 hypertensive subjects, 31 patients with chronic cerebral infarction, and 15 with coronary artery disease. Lp(a) levels were slightly lower in the healthy "old old" subjects than in the 184 healthy younger adults (mean +/- SD: 10.7 +/- 7.9 vs 12.1 +/- 10.1 mg/dl). There were no gender-related differences in the Lp(a) levels of healthy adults and healthy old old subjects. Lp(a) levels were higher in the hypertensive old old subjects (14.6 +/- 15.4 mg/dl) and the old old patients with cerebral infarction (21.3 +/- 16.2 mg/dl) and coronary artery disease (26.5 +/- 20.4 mg/dl). The prevalence of subjects with high Lp(a) levels (> 30 mg/dl) was the greatest among old old patients with coronary artery disease (27%). Lp(a) levels in the 132 old old subjects showed positive correlations with sialic acid, fibrinogen, factor VII activity, and D-dimer levels. These results indicate a close association between Lp(a) levels and atherothrombotic disease as well as the characteristics of Lp(a) as an acute phase reactant in old old Japanese. Subjects with higher Lp(a) levels may develop cardiovascular disease later in life, whereas the remaining healthy old old subjects have lower Lp(a) levels.