Plasma insulin and serum lipids and lipoproteins in middle-aged non-insulin-dependent diabetic and non-diabetic subjects

The relationship between fasting plasma insulin and serum lipid and lipoprotein levels was studied in 1982-1983 in Kuopio, East Finland in 225 patients with non-insulin-dependent diabetes mellitus (119 men and 106 women) and 124 non-diabetic controls (65 men and 59 women). Compared to the non-diabetic controls, diabetic subjects showed significantly lower levels of high density lipoprotein (HDL) cholesterol and high density lipoprotein2 (HDL2) cholesterol and higher levels of total triglycerides and very low density lipoprotein (VLDL) triglycerides. Fasting plasma insulin correlated significantly with total triglycerides and VLDL triglycerides and negatively with HDL cholesterol and HDL2 cholesterol in both male and female diabetic subjects and non-diabetic control subjects. The correlation between fasting plasma insulin and HDL cholesterol remained statistically significant in non-insulin-dependent diabetic subjects and in female non-diabetic control subjects after adjustment for body mass index, alcohol intake, physical activity, smoking, and fasting plasma glucose. The correlation between fasting plasma insulin and total triglycerides remained significant after adjustment for these variables only in females. By multiple stepwise linear regression analysis, fasting plasma insulin had an independent association with HDL cholesterol in female non-diabetic control subjects and in male diabetic subjects and with triglycerides in female non-diabetic control subjects and in female diabetic subjects. The results show that hyperinsulinemia is related to low HDL cholesterol and HDL2 cholesterol and high total triglycerides and VLDL triglycerides in both non-insulin-dependent diabetic subjects and non-diabetic control subjects. This effect of hyperinsulinemia on lipid and lipoprotein patterns may be one explanation why high plasma insulin can promote accelerated atherosclerosis, particularly in patients with non-insulin-dependent diabetes mellitus.     

Exercise-induced changes in plasma lipids and lipoproteins

Men and women who participate in vigorous endurance-type exercise generally have plasma lipid and lipoprotein profiles consistent with lower risk for coronary heart disease. The major differences from matched physically inactive controls appear to be a lower plasma triglyceride concentration and greater high-density lipoprotein mass, due to increased levels of the subfraction HDL2 and apoprotein A-I. Plasma low-density lipoprotein cholesterol concentration is less likely to be lower than in the inactive controls. Exercise training studies suggest a lower threshold--of around 1,000 kcal per week of endurance-type exercise at moderate intensity--seems to be required to produce plasma lipid or lipoprotein changes. Above this level, dose-response relationship exists, with greater changes occurring up to an expenditure of 4,500 kcal per week. From the limited data available, it appears more difficult to change the plasma lipoprotein concentration in women by exercise training than in men. Modification of activity of enzymes involved in triglyceride and cholesterol synthesis, transport, and catabolism most likely mediates these exercise-induced changes.     

Determinants of total high density lipoprotein cholesterol and high density lipoprotein subfraction levels among Hispanic and non-Hispanic white persons with normal glucose tolerance: the San Luis Valley Diabetes Study.

Determinants of total high-density lipoprotein cholesterol (HDL-C) and HDL subfractions were assessed in Hispanic and non-Hispanic white persons (n = 932), aged 20-74 years, in the San Luis Valley, Colorado. Using multiple regression, BMI was negatively associated with HDL-C, HDL2-C, and HDL3-C in men and HDL-C and HDL3-C in women. Among females, current smokers had lower HDL-C and subfractions. Women on beta-blockers had lower HDL3-C levels. For both sexes, a positive association was observed between age and HDL-C and subfractions and physical activity with HDL-C and HDL3-C. Drinking alcohol (> or = 50 g/week) was associated with higher HDL-C and HDL3-C in both sexes and HDL2-C in women. The positive association of age and negative associations of the subscapular/triceps ratio and fasting insulin had consistent relationships with HDL-C, HDL2-C, and HDL3-C in men and women. Ethnicity was not significantly associated with HDL-C or subfractions after controlling for body fat distribution or fasting insulin.     

The relation of physical activity to cardiovascular disease risk factors in Mauritians. Mauritius Noncommunicable Disease Study Group

The authors investigated the relation between physical activity and cardiovascular disease risk factors in a random sample of 4,658 Asian Indian, Creole, and Chinese adults aged 25-74 years from the island nation of Mauritius. Subjects known to have diabetes were excluded from analyses. Subjects were divided into "active" and "inactive" groups on the basis of a combined leisure and occupational physical activity score determined at interview (April 1987). Two-hour plasma glucose concentration and fasting and 2-hour serum insulin concentrations were significantly lower and high density lipoprotein (HDL) cholesterol was significantly higher in active subjects of both sexes. Plasma uric acid and fasting triglyceride levels were also lower among active subjects, but significantly so only in females. Systolic and diastolic blood pressure levels, body mass index (weight (kg)/height (m)2), and waist:hip ratio varied little between the two activity groups. In multiple linear regression analyses, physical activity made an independent negative contribution to the models for 2-hour glucose and insulin in both males and females, as well as for fasting insulin in males. When glucose and insulin were not included, physical activity also made an independent contribution to the models for plasma triglycerides (inversely) in females and HDL cholesterol and HDL cholesterol as a proportion of total cholesterol (positively) in males. The authors have demonstrated improved cardiovascular disease profiles associated with physical activity in Mauritians. The data suggest that much of the effect is modulated via an effect on insulin-glucose metabolism. Promotion of exercise should become an important strategy in the prevention of cardiovascular disease and glucose intolerance in this population.     

Parental history of coronary heart disease, hypertension, diabetes, and stroke: Relationship to coronary heart disease risk factor variables in their adult children

Relationships of parental (familial) history of coronary heart disease, stroke, hypertension, and diabetes to major coronary heart disease (CHD) risk factors were examined in 738 adults (average age, 40 years) in the Cincinnati Lipid Research Clinics Princeton School study. Men reporting parental CHD had higher plasma triglyceride and higher systolic and diastolic blood pressure than comparison group men reporting no parental CHD, stroke, hypertension, or diabetes. Women reporting parental CHD had higher plasma triglycerides than comparison group women reporting no parental CHD, stroke, hypertension, or diabetes. Men reporting stroke in one parent had higher total plasma cholesterol and triglyceride levels than comparison men. Women reporting stroke in one parent had higher triglyceride levels than comparison group women. Women reporting hypertension in one parent had higher mean triglyceride and systolic blood pressure than comparison women. Men and women reporting diabetes in one parent had higher triglyceride than comparison adults. Matching men whose fathers had died of CHD with those whose fathers were free of CHD revealed significant increments in triglyceride levels, systolic, and diastolic blood pressure in the men with positive family history of CHD. Matching women whose fathers had died of CHD with those whose fathers were free of CHD revealed higher total plasma cholesterol, low-density lipoprotein cholesterol, and Quetelet index. In men, categorical assessment by CHD risk factor levels (low, intermediate, high), revealed that plasma triglycerides and systolic blood pressure were positively associated with a parental history of CHD, while high-density lipoprotein cholesterol was inversely related. In women, similar observations were made for triglycerides. Family history is a practical tool for identification of risk to CHD, hypertension, stroke, and diabetes. Serial risk factor measurements in offspring from CHD-, hypertension-, stroke-, and diabetes-positive families should have considerable utility in early recognition and documentation of CHD risk factor levels which, in turn, should facilitate primary intervention designed to ameliorate or prevent the development of CHD.     

Interdependence of associations of physical activity, smoking, and alcohol and coffee consumption with serum high-density lipoprotein and non-high-density lipoprotein cholesterol--a population study in eastern Finland

The interdependence of the associations of physical activity, smoking, and consumption of alcohol and coffee with serum high-density lipoprotein and non-high-density lipoprotein cholesterol concentrations was studied in 9,347 persons ages 25-64 years from east and southwest Finland. In covariance analyses with corrections for age, body mass index, saturated fat index, and fasting time, the mean adjusted serum high-density lipoprotein to non-high-density lipoprotein cholesterol ratio was high among physically active male non-smokers but not among smokers (P = 0.024 for two-way interaction). The cholesterol ratio was lower among both men (P = 0.010 for two-way interaction) and women (P = 0.030 for two-way interaction) reporting no or very little use of alcohol, and this association was stronger among smokers and women with high coffee consumption (P less than 0.001 for two-way interaction). Our data suggest that the elevating effect of regular physical exercise on serum high-density lipoprotein cholesterol may be absent in smokers, whereas that of alcohol is greater in smokers than nonsmokers. High coffee consumption associates with decreased serum high-density lipoprotein cholesterol levels in smokers but increased levels in non-smokers.     

The effect of obesity and low-dose oral contraceptives on carbohydrate and lipid metabolism

BackgroundCombination oral contraceptives (OCs) have little effect on carbohydrate and lipid metabolism in normal-weight women. Based on lack of change in intermediate markers, as well as results of epidemiologic studies, low-dose OCs do not increase the risk of diabetes or cardiovascular disease. Obesity is a risk factor for impaired glucose tolerance, diabetes and coronary artery disease, and most previous OC studies excluded these women; thus, we have limited information about carbohydrate and lipid metabolism in obese OC users.Study DesignThis study compared changes in carbohydrate and lipid parameters in 71 normal-weight and 38 obese women initiating the OC. Women were randomized to two pills: 30 mcg ethinyl estradiol (EE)/150 mcg levonorgestrel (LNG) or 20 mcg EE/100 mcg LNG. Participants underwent baseline and cycle-3 measurements of fasting serum glucose; insulin; triglycerides and total, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol.ResultsNormal-weight and obese participants experienced similar changes in mean glucose, insulin and log homeostatic model assessment, as well as similar changes in total cholesterol, HDL and triglycerides; however, change in mean LDL (?4.9±20.6 mg/dL vs. +3.8±17.3 mg/dL) was different between the obese and normal-weight groups, respectively. Among the obese participants, change in glucose was marginally greater with the higher dose pill (p=.06); otherwise, changes between the body mass index groups were not modified by pill dose.ConclusionsObesity had little effect on any OC-induced changes in carbohydrate or lipid metabolism except for a borderline adverse interaction between obesity and OC dose with respect to fasting glucose and a positive interaction between obesity and OC use with respect to LDL cholesterol.     

Low-density lipoprotein subclass distribution pattern and adiposity-associated dyslipidemia in postmenopausal women

OBJECTIVE: A predominance of small, dense low-density lipoprotein (LDL) particles (subclass pattern B) is associated with increased risk for coronary heart disease and is characterized by elevated triglycerides and depressed high-density lipoprotein (HDL) cholesterol concentrations. The present analysis was undertaken to assess the impact of LDL subclass distribution pattern and adiposity on serum lipids in postmenopausal women. METHODS: Anthropometric measurements and fasting lipid data were obtained from 254 postmenopausal women 70 years of age or younger, not receiving sex hormone replacement, who were participating in a clinical trial designed to assess the influence of hormone replacement regimens on coronary heart disease risk markers. RESULTS: The prevalence of LDL subclass pattern B was 32%. Triglyceride levels were higher and HDL cholesterol lower (both p<0.001) in women with pattern B vs. pattern A, but total and LDL cholesterol levels did not differ. LDL subclass pattern contributed independently to the variance in HDL cholesterol (p<0.001) and log(e) triglyceride (p<0.001) concentrations explained by anthropometric variables (waist circumference or body mass index). Compared to women with LDL subclass pattern A and waist circumference below the median value of 83.0 centimeters, those with pattern B and waist > or =83.0 centimeters had markedly lower HDL cholesterol levels [44.0 (41.6-47.4) vs. 57.2 (54.1-60.3) mg/dL, mean (95% CI)] and increased triglyceride concentrations [geometric mean 147.8 (131.6-165.7) vs. 95.4 (88.2-102.5) mg/dL]. CONCLUSIONS: These data suggest that adiposity and LDL subclass distribution pattern are independent determinants of plasma triglyceride and HDL cholesterol concentrations in postmenopausal women.     

The relation between serum insulin levels and 8-year changes in lipid, lipoprotein, and blood pressure levels.

Hyperinsulinemia is associated with an adverse pattern of cardiovascular risk factors, including obesity, elevated triglyceride levels, low levels of high-density lipoprotein (HDL) cholesterol, and elevated blood pressure. Whether hyperinsulinemia precedes (and perhaps causes) this deterioration in the risk factors or merely accompanies the deterioration is controversial. We therefore examined the 8-year changes in lipids, lipoproteins, and blood pressure as a function of baseline levels of fasting insulin in 1,383 nondiabetic Mexican-American and non-Hispanic white subjects enrolled between October 1979 and November 1982 in the San Antonio Heart Study, a population-based longitudinal study of cardiovascular risk factors and diabetes in San Antonio, Texas. After age and concomitant changes in body mass index were adjusted for, fasting insulin at baseline was found to be correlated positively with 8-year changes in triglyceride levels and negatively with 8-year changes in HDL cholesterol levels (p less than 0.05). Among the non-Hispanic whites, insulin was more strongly correlated with a decline in HDL cholesterol levels in women than in men (p less than 0.001). Fasting insulin was also positively correlated with changes in both systolic and diastolic blood pressure in non-Hispanic whites, but not in Mexican Americans, although these correlations were slightly diminished and no longer achieved statistical significance after subjects receiving antihypertensive medications were excluded. These results support the hypothesis that in nondiabetic subjects, insulin has a direct regulatory effect on triglyceride and HDL cholesterol levels. These data provide evidence for a possible role for insulin in blood pressure regulation, at least in non-Hispanic whites, although further analysis of this issue is warranted.     

Lower extremity arterial disease in older women: the Rancho Bernardo Study

Most studies of lower extremity arterial disease (LEAD) have not included women. To study the frequency of LEAD and its association with cardiovascular disease risk factors and estrogen use in community-dwelling postmenopausal women, we conducted a cross-sectional study of LEAD in 826 women whose average age was 74 years. Cardiovascular disease risk factors and medical history, body mass index (BMI), blood pressure, glucose tolerance, lipids and lipoproteins, and current and past medication use were determined using a standard protocol. Ankle-brachial artery index (ABI) of systolic blood pressure was measured by a trained technician using Doppler ultrasound. LEAD was defined as ABI <0.8. LEAD prevalence increased with age from nearly 5% in the 60-69-year-old group to >25% in women aged 90 and older. In age-adjusted analyses, women with LEAD had significantly lower levels of high-density lipoprotein (HDL) cholesterol, were less likely to exercise regularly, and were less likely to have ever used estrogen replacement therapy. They also had significantly higher levels of blood pressure, low-density lipoprotein (LDL) cholesterol, triglycerides, glucose, and insulin. In multivariate analyses, high HDL cholesterol, regular exercise, and estrogen use were each associated with a reduced risk of LEAD, whereas age, high blood pressure, and abnormal glucose tolerance were each associated with increased risk. Few women (6%) were smokers, but they had twice the risk of LEAD compared with nonsmokers. Estrogen was independently associated with LEAD in a model containing all covariates except LDL and HDL, and this association was no longer significant in a second model adjusting for these lipoproteins. LEAD is common in older women and associated with modifiable risk factors. The apparent protection associated with estrogen should be studied in clinical trials.     

Cancer mortality and lipid and lipoprotein levels. Lipid Research Clinics Program Mortality Follow-up Study

The associations of serum lipid and lipoprotein levels with the risk of cancer mortality were assessed in 2,753 men and 2,476 women aged 40-79 years at baseline (1972-1976) who participated in the Lipid Research Clinics Program Mortality Follow-up Study through 1984. Seventy-nine cancer deaths occurred in men and 65 occurred in women during an average follow-up time of 8.4 years. Total cholesterol and low-density lipoprotein (LDL) cholesterol were significantly inversely associated with overall cancer mortality in men, but no relation was observed in women. Neither high-density lipoprotein (HDL) cholesterol nor triglycerides were significantly related to total cancer mortality in either sex, although in women. HDL cholesterol was positively associated with risk of death from gynecologic cancers. Compared with men with higher cholesterol levels, the relative risk of death from colon cancer, adjusted for age, body mass, cigarette smoking, and alcohol consumption, was 5.20 (95 percent confidence interval (Cl) 1.61-16.8) in men with total cholesterol levels less than or equal to 187 mg/dl and 4.79 (95 percent CI 1.37-16.8) in those with LDL cholesterol levels less than or equal to 119 mg/dl. Death from smoking-related cancers was inversely related to baseline total cholesterol but not to LDL cholesterol. The absence of an association with HDL cholesterol, which has been shown to be lower in persons with clinically manifest malignancy, and evidence from survival curves suggest that the inverse relation in men is not due to preexisting disease.     

Lipid responses to a dietary docosahexaenoic acid supplement in men and women with below average levels of high density lipoprotein cholesterol

OBJECTIVE: To assess fasting lipid responses to a docosahexaenoic acid (DHA) supplement in men and women with below-average levels of high-density lipoprotein (HDL) cholesterol. METHODS: This randomized, double-blind, controlled clinical trial included 57 subjects, 21-80 years of age, with fasting HDL cholesterol concentrations < or =44 mg/dL (men) and < or =54 mg/dL (women), but > or =35 mg/dL. Subjects were randomly assigned to receive either 1.52 g/day DHA from capsules containing DHA-rich algal triglycerides or olive oil (control) for six weeks. RESULTS: There were no significant differences between groups in baseline lipid values. The DHA supplemented group showed significant changes [-43 (DHA) vs. -14 (controls) mg/dL, p = 0.015] and percent changes [-21% (DHA) vs. -7% (controls), p = 0.009] in triglycerides, total (12 vs. 3 mg/dL; p = 0.021 and 6% vs. 2%; p = 0.018) and low-density lipoprotein (17 vs. 3 mg/dL; p = 0.001 and 12% vs. 3%; p = 0.001) cholesterol concentrations, and in the triglyceride to HDL cholesterol ratio (-1.33 vs. -0.50, p = 0.010), compared with controls. In addition, there was a significant reduction in the percentage of LDL cholesterol carried by small, dense particles in the DHA supplemented group (changes = -10% vs. -3%, p = 0.025). CONCLUSIONS: Supplementation with 1.52 g/d of DHA in men and women with below-average HDL cholesterol concentrations raised the LDL cholesterol level, but had favorable effects on triglycerides, the triglyceride/HDL cholesterol ratio and the fraction of LDL cholesterol carried by small, dense particles. Further research is warranted to evaluate the net impact of these alterations on cardiovascular risk.     

Sex differences in high-density lipoprotein cholesterol and subfractions among young black adults

The high-density lipoprotein cholesterol and high-density lipoprotein subfraction (HDL2 and HDL3) concentrations were examined in 170 young black adults. The women examined had significantly higher total high-density lipoprotein cholesterol concentrations than the men, i.e., 57.0 mg/dl vs 51.2 mg/dl, P less than 0.002. The increased high-density lipoprotein cholesterol among women represented a significant increase in both HDL2 and HDL3 cholesterol concentrations. The sex differential could not be explained by body mass index, alcohol consumption, or physical activity. The determinants of high-density lipoprotein cholesterol for men appeared to be different than those for women.     

Lipoproteins as predictors of ischemic heart disease in non-insulin-dependent diabetic men

In order to determine whether low levels of high-density lipoprotein cholesterol (HDL-C), which are predictive of ischemic heart disease in the general population, can also predict death from ischemic heart disease among diabetic men, we contrasted lipoprotein and other heart disease risk factors in 62 men with non-insulin-dependent diabetes mellitus, 14 of whom died of ischemic heart disease during a 12-year follow-up period. Compared to all other diabetic men, those who died of ischemic heart disease were older, had higher levels of fasting plasma glucose (FPG) total plasma cholesterol, and triglycerides, lower HDL-C levels, and higher low-density lipoprotein cholesterol (LDL-C) levels and were more likely to have been cigarette smokers; only total cholesterol, LDL-C, and the LDL/HDL ratio were statistically significant. Age, FPG, total plasma cholesterol, and LDL-C were all independently predictive of fatal heart disease by multivariate analysis. Neither HDL-C nor the LDL/HDL ratio predicted ischemic heart disease death better than the total plasma cholesterol or LDL-C. The use of HDL-C, LDL-C, or total plasma cholesterol level in the model did not eliminate the significant association with FPG, which suggests that the noxious effect of hyperglycemia is independent of the changes in blood lipids.     

The association of low levels of HDL cholesterol and arteriographically defined coronary artery disease.

Epidemiologic studies have found associations between low levels of high density lipoprotein (HDL) cholesterol and increased risk of coronary artery disease, using myocardial infarction or angina pectoris as endpoints. However, since most studies have not correlated HDL cholesterol with the presence, severity, or location of anatomically proven coronary disease, the present study measured HDL cholesterol levels in 483 men and women undergoing coronary arteriography. Consistent and statistically significant trends of decreasing mean HDL cholesterol levels with increasing numbers of diseased coronary arteries were observed in both men and women and in younger and older age groups. Although women without coronary disease had much higher levels of HDL cholesterol than men without coronary disease, the differences between men and women with similar degrees of coronary disease were small. Low levels of HDL cholesterol were associated with left main coronary disease; patients with both triple vessel disease and left main disease had lower levels of HDL cholesterol than did patients with triple vessel disease without left main disease. These results were not explained by the possible associations of low density lipoprotein cholesterol or triglycerides with HDL cholesterol. These findings suggest that low levels of HDL cholesterol are important risk factors for the development of atherosclerosis and that they may be useful for identifying patients at high risk of certain anatomic patterns of coronary artery disease.     

Leisure time physical activity and its relationship to coronary risk factors in a population-based sample. The Minnesota Heart Survey

Energy expenditure in leisure time physical activity was measured using the Minnesota Leisure Time Physical Activity Questionnaire in a probability sample of 25- to 74-year-old residents of the seven-county metropolitan area of Minneapolis-St. Paul, Minnesota. Geometric mean estimates of leisure time physical energy expenditure were 193 kcal per day for men and 111 kcal per day for women. Only 34% of men and 17% of women expended 2,000 kcal or more per week in leisure time physical activity. Energy expenditure, especially in heavy intensity activities, declined with age, more so for women than men. Significant associations were observed between leisure time physical activity, particularly heavy intensity activity, and other coronary heart disease risk factors. Greater heavy intensity activity was associated with higher education (r = 0.14 to 0.26), greater Type A behavior (r = 0.14 to 0.15), higher serum high density lipoprotein (HDL) cholesterol levels (r = 0.09 to 0.10), lower serum thiocyanate (r = 0.10 to -0.14), lower body mass index (r = -0.10 to -0.11), lower heart rate (r = -0.07 to -0.10), and lower systolic blood pressure (r = -0.06 to -0.09). Thus, although energy expenditure was generally low in this population, greater leisure time physical activity for the most part was associated with lower coronary risk factors.     

Physical activity and plasma total- and HDL-cholesterol levels in Western Samoan men

This study examines effects of physical activity on plasma total- and high-density lipoprotein (HDL) cholesterol and derived variables in Western Samoan men who differ in rural/urban residence and occupation. Rural agriculturalists have significantly higher HDL cholesterol and HDL:total ratio than men employed in either physically active or physically sedentary occupations in an urban setting. Total cholesterol levels do not vary significantly, but when the differences in HDL cholesterol are accounted for, the means for agriculturalists and active workers are significantly lower than those for sedentary workers who do not play sports. These differences in HDL- and non-HDL-cholesterol levels are consistent with measures of physical activity among the groups. Variation in physical activity due to residence and occupation in Western Samoan men is related to lipoprotein cholesterol levels, but not to total cholesterol levels, and some effects may be secondary to differences in body composition.     

Relation of body fatness and its distribution to cardiovascular risk factors in young blacks and whites. The role of insulin

Persons whose body fat is distributed predominantly in the abdomen compared with the hips are at increased risk of several chronic diseases. This study examined the cross-sectional relation of percent body fat, computed from skinfold thickness, and fat distribution, measured by the waist-to-hip girth ratio, to physiologic cardiovascular risk factors in a biracial sample (blacks and whites) of young adults aged 18-30 years. The subjects were persons who were examined at baseline (1984-1986) in the Coronary Artery Risk Development in Young Adults Study in four US metropolitan areas. The two hypotheses tested were that 1) after adjusting for percent body fat, waist-to-hip girth ratio is associated with several physiologic risk factors, and 2) fasting concentrations of serum insulin partly explain such association. Percent body fat was significantly associated with all measured blood lipids, lipoproteins, apolipoproteins, uric acid, and blood pressure. Waist-to-hip girth ratio was significantly, although more weakly, associated in multivariate models with blood concentrations of triglycerides, high density lipoprotein (HDL) cholesterol, HDL2 cholesterol, apolipoproteins A-I and B, low density lipoprotein cholesterol (in women only), uric acid, and systolic blood pressure, but was not associated in either sex with total cholesterol, HDL3 cholesterol, or diastolic blood pressure. Fasting serum insulin concentrations were significantly associated with percent body fat (Pearson r = 0.45-0.53), waist-to-hip girth ratio (Pearson r = 0.18-0.27), and most of the physiologic risk factors. Inclusion of fasting insulin in multivariate models reduced, but rarely eliminated, associations between waist-to-hip girth ratio and the physiologic risk factors. These findings suggest that obese young adults, especially those with abdominal fat preponderance, carry a physiologic profile that places them at higher risk of cardiovascular disease, and that fasting insulin concentrations are only partly explanatory.     

Improved iron status parameters may be a benefit of hormone replacement therapy

One of the benefits of hormone replacement therapy (HRT) is to decrease cardiovascular disease. A mechanism whereby HRT may play a role in reducing cardiovascular risk is through improved iron status parameters. High serum ferritin has been related to increased risk of coronary heart disease, whereas low iron-binding capacity has been identified as an important risk factor for myocardial infarction. This study examined iron status parameters in a group of postmenopausal women taking oral HRT (n = 27) and those not taking oral HRT (n = 27) at two times 1 year apart. Women were compared on the following serum measures: estradiol, lipids, iron, total iron-binding capacity, and ferritin. Women taking HRT had higher levels of estradiol (p < 0.001) and improved lipid profiles (p < 0.001) (lower total and low-density lipoprotein [LDL] cholesterol and higher levels of high-density lipoprotein [HDL] cholesterol). In addition, women on HRT had better iron status parameters than those not on HRT (p = 0.002). Total iron-binding capacity was greater for women on HRT compared with women not on HRT, and serum ferritin levels were lower in women on HRT than those not on HRT. The groups were comparable in age, body mass index, and physical activity. Our results confirm previous findings and indicate that women taking HRT have higher serum levels of estradiol and improved lipid profiles compared with those not taking HRT. In addition, we have found that iron status parameters are better in women taking HRT, suggesting the need to further examine this effect as it relates to decreased cardiovascular risk in postmenopausal women.     

Stability of indicators of the metabolic syndrome from childhood and adolescence to young adulthood: the Québec Family Study

The stability of indicators of the metabolic syndrome from childhood and adolescence to young adulthood was examined. The sample included 76 males and 71 females measured between the ages of 8 and 18 years and again as young adults (12 year follow-up). Indicators included the sum of three trunk skinfolds (SF3), mean blood pressure (MBP), and fasting blood glucose (GLY), high-density lipoprotein cholesterol (HDL-C), ratio of total cholesterol to HDL-C (CHOL/HDL), and triglycerides (TG). The indicators were subjected to principal components analysis to obtain a composite risk factor index (RFI). Partial interage correlations, controlling for initial age and length of follow-up, were 0.70 and 0.50 for SF3, 0.40 and 0.54 for MBP, 0.58 and 0.56 for HDL-C, 0.51 and 0.57 for CHOL/HDL, 0.37 and 0.20 (NS) for TG, 0.30 and 0.14 (NS) for GLY, and 0.51 and 0.46 for the RFI, in males and females, respectively. The results indicate that indicators of the metabolic syndrome are moderately stable from childhood and adolescence into young adulthood.