Changes In High-density Lipoprotein Cholesterol Levels Research Articles

Cross-sectional and Longitudinal Associations between High Density Lipoprotein Cholesterol and Women's Employment

This study examined the association between women's employment and high density lipoprotein (HDL) cholesterol. Subjects were 1.998 women aged 25-64 years who were sampled by the first MONICA Augsburg Survey (Monitoring of Trends and Determinants in Cardiovascular Disease). The women were sampled from the population of Augsburg, Federal Republic of Germany, in 1984-1985, were followed up for 3 years, and were reexamined in 1987-1988. In cross-sectional analysis (1984-1985), the mean HDL cholesterol level of employed women was 3.4 mg/dl higher than that of full-time homemakers (p less than 0.001). After adjustment for age, body mass, cigarette smoking, consumption of coffee and alcohol, use of sex hormones, leisure-time physical activity, and reproductive history, this difference decreased to 2.1 mg/dl and remained statistically significant (p less than 0.01). As was predicted from the cross-sectional findings, the mean HDL cholesterol levels of women who gave up employment and became full-time homemakers during the follow-up period decreased by 3.04 mg/dl (p less than 0.01), whereas homemakers who became employed showed no significant change in HDL cholesterol levels. The change in mean HDL cholesterol of employed women who had become homemakers could be explained in part by changes in alcohol consumption and in number of pregnancies. The authors conclude that giving up employment is related to life-style changes that are associated with a decrease in HDL cholesterol levels. Furthermore, the findings suggest that employment may exert a beneficial influence on coronary risk in women that is consistent with a positive association between employment and HDL cholesterol.

Effects of Chromium Supplementation on Serum High-Density Lipoprotein Cholesterol Levels in Men Taking Beta-Blockers

To determine the efficacy of glucose tolerance factor (GTF)-chromium for increasing serum levels of high-density lipoprotein (HDL) cholesterol in patients taking beta-blockers. Randomized, double-blind, placebo-controlled trial. Mixed primary and referral-based outpatient clinic at a university-affiliated VA Medical Center. Referred sample of 72 men receiving beta-blockers, mainly for hypertension. Sixty-three patients (88%) completed the study. Current medications, including beta-blockers, were continued. During the 8-week treatment phase, patients in the chromium group received a total daily dose of 600 micrograms of biologically active chromium divided into three equal doses; control patients received a placebo of identical appearance and taste. Serum levels of total cholesterol and HDL cholesterol were measured. Mean baseline levels of HDL and total cholesterol (+/- SD) were 0.93 +/- 0.28 mmol/L and 6.0 +/- 1.0 mmol/L (36 +/- 11.1 mg/dL and 232 +/- 38.5 mg/dL), respectively. The difference between groups in adjusted mean change in HDL cholesterol levels, accounting for baseline HDL cholesterol levels, age, weight change, and baseline total cholesterol levels, was 0.15 mmol/L (5.8 mg/dL) (P = 0.01) with a 95% Cl showing that the treatment effect was greater than +0.04 mmol/L (+1.4 mg/dL). Mean total cholesterol, triglycerides and body weight did not change significantly during treatment for either group. Compliance as measured by pill count was 85%, and few side effects were reported. Two months after the end of treatment, the between-group difference in adjusted mean change from baseline to end of post-treatment follow-up was -0.003 mmol/L (-0.1 mg/dL). Two months of chromium supplementation resulted in a clinically useful increase in HDL cholesterol levels in men taking beta-blockers.

A low-fat diet decreases high density lipoprotein (HDL) cholesterol levels by decreasing HDL apolipoprotein transport rates.

Diets that reduce atherosclerosis risk lower levels of HDL cholesterol (HDL-C), but the significance of this is unclear. To better understand the mechanism of this phenomenon we studied the turnover of HDL apolipoproteins A-I and A-II in 13 subjects on two contrasting metabolic diets. Upon changing from high to low intake of saturated fat and cholesterol the mean HDL-C decreased 29% from 56 +/- 13 (SD) to 40 +/- 10 mg/dl, while apo A-I levels fell 23% from 139 +/- 22 to 107 +/- 22 mg/dl (both P less than 0.001). Mean apo A-II levels did not change. The fractional catabolic rate (FCR) of apo A-I increased 11% from 0.228 +/- 0.048 to 0.254 +/- 0.063 pools/d, while its absolute transport rate (TR) decreased 14% from 12.0 +/- 2.7 to 10.3 +/- 3.4 mg/kg per d (both P = 0.005). The decrease in HDL-C and apo A-I levels correlated with the decrease in apo A-I TR (r = 0.79 and 0.83, respectively; P less than 0.001), but not with the increase in apo A-I FCR (r = -0.04 and -0.02, respectively). In contrast, within each diet the HDL-C and apo A-I levels were inversely correlated with apo A-I FCR both on the high-fat (r = -0.85 and -0.77, P less than 0.001 and = 0.002, respectively) and low-fat diets (r = -0.67 and -0.48, P = 0.012 and 0.098, respectively) but not with apo A-I TR. In summary, diet-induced changes in HDL-C levels correlate with and may result from changes in apo A-I TR. In contrast, differences in HDL-C levels between people on a given diet correlate with and may result from differences in apo A-I FCR. Therefore, the mechanism of dietary effects on HDL levels differs substantially from the mechanism explaining the differences in levels between individuals on a fixed diet. In assessing coronary heart disease risk, it may be inappropriate to conclude that diet-induced decreases in HDL are equivalent to low HDL within a given diet.

Effects of a Iow-dose estrogen-antiandrogen combination (Diane-35) on lipid and carbohydrate metabolism in patients with polycystic ovary syndrome

This study was undertaken in order to evaluate the effect of an oral contraceptive containing 35 micrograms of ethinyl estradiol and 2 mg of cyproterone acetate (Diane-35) on carbohydrate and lipid metabolism in patients with polycystic ovary syndrome (PCOS). Twenty three patients with PCOS were treated with Diane-35 for between 9 and 18 cycles without interruption (a total of 318 treated cycles). Metabolic evaluations, which included measurements of fasting blood glucose, insulin, C-peptide, total cholesterol, triglyceride, total lipids, HDL-cholesterol, LDL-cholesterol and apolipoproteins (Apo A1, Apo A2 and Apo B), were performed before treatment and every 3rd cycle during the treatment period. In the case of 5 women an oral glucose tolerance test (oGTT) was performed before and after the 12th cycle of Diane-35 treatment, with blood samples taken for glucose, insulin and C-peptide measurements. Total cholesterol showed a significant increase after the 6th cycle (p less than 0.001) and reached the mean maximal value after the 9th cycle. A similar increasing trend was observed with LDL-cholesterol, which also reached the maximal mean level after the 9th cycle of treatment (p less than 0.05). There were no significant changes in HDL-cholesterol levels. Significant increases in serum triglyceride (p less than 0.01) and total lipids (p less than 0.001) were observed after the 3rd cycle. Apo A2 concentrations increased significantly after the 6th cycle (p less than 0.001) and showed an increasing trend thereafter. A significant increase was also observed in Apo B concentrations after the 6th cycle but these decreased after the 12th cycle. In spite of these observed increases in serum lipids and lipoproteins, the mean levels remained within the normal range throughout the treatment period. Fasting serum glucose, insulin and C-peptide concentrations did not show any significant changes during the study. Higher insulin and C-peptide responses during the oGTT were observed after the 12th cycle but the differences in the areas under the curve before and after treatment were not significant. A deterioration of blood glucose was observed after treatment with Diane-35, a significant difference in mean values being noted 150 minutes after the glucose overload (p less than 0.005). However, the areas under the curve in blood glucose response before (34.92 +/- 4.12) and after (43.45 +/- 3.61) treatment were not significantly different.(ABSTRACT TRUNCATED AT 400 WORDS)

Hypertension, changes in high-density lipoproteins and antihypertensive therapy

The risk for development of coronary heart disease (CHD) is related to a number of factors. Among these, both hypertension and various lipid abnormalities have been shown to play an important role. A clear inverse relation between high-density lipoprotein (HDL) cholesterol and CHD has been observed in numerous observational and short studies. Pharmacologic treatment of hypertension has been shown to reduce dramatically some of the sequelae of high blood pressure—renal failure, cerebrovascular accidents and congestive heart failure. However, a consistent reduction in associated CHD has not been demonstrated, and the dissociation between reducing blood pressure and reduction in CHD has not been definitively explained. One of the suggested explanations relates to alterations in blood lipid levels that may be induced by certain antihypertensive agents. Changes in HDL cholesterol levels or other lipid alterations due to antihypertensive therapy could modify the beneficial effects achieved by the direct reduction of blood pressure. If so, antihypertensive agents could be subclassified as atherogenic or antiatherogenic depending on the associated changes in lipid levels. Therefore, the antihypertensive agents of choice for patients whose cholesterol levels are a concern would be those that reduce the CHD risk factor of hypertension without compromising the risk factor associated with a patient's lipid profile.

Lowering Cholesterol With Granulocyte-Macrophage Colony-Stimulating Factor-Reply

In Reply.— We appreciate the comments of Dr Goldstein and Drs Mazur and Herbert regarding our recent report in JAMA . We have data available on changes in low-density lipoprotein and high-density lipoprotein (HDL) cholesterol concentrations in five of the eight patients reported (Table). In three of these patients HDL-cholesterol decreased slightly, but in all instances the decrease in HDL-cholesterol was proportionally less than the decrease in low-density lipoprotein cholesterol, resulting in a lower low-density lipoprotein/HDL cholesterol ratio. In one of the patients HDL-cholesterol levels increased during GM-CSF therapy and in the other patient there was no real change in HDL-cholesterol levels. The low-density lipoprotein/HDL cholesterol ratios decreased in all patients, a favorable direction in considering the possible treatment or prevention of atherosclerosis with GM-CSF or other factors that use similar mechanisms. Our findings are indeed preliminary, but we are actively exploring the mechanism of action of GM-CSF's cholesterollowering activity. As

The association between physical fitness and cardiovascular disease risk factors in children in a five-year follow-up study.

The relation between physical fitness and cardiovascular disease (CVD) risk factors was studied in 633 children selected from all fourth grades in 37 elementary schools in New York. They were participating in the control group of an intervention study to reduce CVD risk factors in children. Blood pressure, total and high-density lipoprotein (HDL) cholesterol and physical fitness were measured at baseline and at four subsequent examinations during five years of follow-up. Systolic blood pressure (SBP) at baseline was highest in children with poor physical fitness. The five-year change in physical fitness was inversely associated with the change in SBP, ie, children with the strongest decline in physical fitness showed the largest rise in SBP. HDL cholesterol at baseline was lowest in boys with poor physical fitness. The five-year change in physical fitness was positively related to the change in HDL cholesterol levels in boys; ie, boys with the largest decline in physical fitness had the largest decrease in HDL cholesterol level. These observations indicate that unfavourable long-term changes in physical condition in childhood may be related to unfavourable changes in blood pressure and serum lipids.

Lipid Alterations and Decline in the Incidence of Coronary Heart Disease in the Helsinki Heart Study

In the Helsinki Heart Study, a randomized five-year, double-blind trial, a 34% reduction in the incidence of coronary heart disease (CHD) was observed in dyslipidemic men treated with gemfibrozil. Averaged over the five years of the trial, gemfibrozil therapy produced, compared with placebo, mean decreases of 10% in serum total cholesterol level, 14% in non-high-density lipoprotein (HDL) cholesterol level, 11% in low-density lipoprotein (LDL) cholesterol level, 35% in triglyceride level, and a mean increase of 11% in HDL cholesterol level from baseline levels measured prior to treatment. While changes in HDL cholesterol level were similar in all Fredrickson types, the effect on concentrations of total cholesterol and LDL cholesterol was largest in type IIA and on LDL minimal in type IV. The reduction of CHD incidence over placebo was largest in type IIB and smallest in type IIA. The lipid changes were dependent on lipid levels prior to treatment and on compliance with the medication regimen. When risk factors for CHD, including age, blood pressure, smoking and drinking habits, baseline lipid levels, and exercise and relative weight, were controlled by applying the Cox proportional hazards model, the changes in serum HDL and LDL cholesterol levels were both statistically significantly associated with the decline in CHD incidence within the gemfibrozil-treated group. The large decrease in serum triglyceride levels had relatively small effect on CHD incidence. Thus, the results of this study, together with earlier observations, suggest that both elevating HDL and lowering LDL cholesterol levels are effective in the primary prevention of CHD.

Low-Level Cigarette Smoking and Longitudinal Change in Serum Cholesterol Among Adolescents

The current study was conducted to determine if smokers and nonsmokers differ in serum concentrations of high-density lipoprotein cholesterol (HDL-C) before smoking initiation and if a decline in HDL-C levels could be detected among adolescents during the first two years of smoking. Changes in HDL-C levels and smoking were observed longitudinally in 1983, 1984, and 1985 among 691 seventh and eighth graders (age range, 12 to 14 years) from two German cities; 82% were nonsmokers at baseline. For these baseline nonsmokers, no differences in baseline HDL-C concentrations were found between those who became smokers and those who remained nonsmokers. In contrast, those who became light (one to 39 cigarettes per week) or moderate (greater than or equal to 40 cigarettes per week) smokers by one or two years after the initial examination evidenced lower mean HDL-C concentrations relative to persistent nonsmokers at follow-up, constituting a decrement of -0.016 mmol/L [SE = .035] (-0.6 mg/dL) [SE = 1.4] for light smokers and -0.114 mmol/L [SE = .064] (-4.4 mg/dL) [SE = 2.5] for moderate smokers. These findings suggest that short-term exposure to cigarette smoke at low levels may have atherogenic consequences.

L-Carnitine treatment in the hyperlipidemic rabbit

A study was designed to examine the hypolipidemic effect of l-carnitine treatment (4 weeks, 170 mg/kg/d) in rabbits fed a high fat diet ( 5% corn oil 0.5% cholesterol , w w ). Eight weeks of exposure to the high fat diet significantly increased plasma total cholesterol and triglycerides. VLDL associated triglycerides, cholesterol, apo-B, and total protein were also significantly increased with the diet. There was no change in HDL-cholesterol levels. Plasma concentration of carnitine (free, acyl, and total) all increased significantly with the high fat diet. The content of free, short-chain, and total carnitine were decreased in the liver whereas the content of long-chain acylcarnitines was increased. The diet generated a significant steatosis within the livers of these animals. Four weeks of treatment of l-carnitine reduced the extent of the liver steatosis and significantly decreased plasma total cholesterol, triglycerides, VLDL associated triglycerides, cholesterol, and total protein. HDL-cholesterol levels were unaffected by the treatment. All plasma fractions of carnitine (free, acetyl, acyl, and total) were significantly increased above those levels seen after 8 weeks of the high fat diet alone. The content of liver carnitine and its esters was normalized following treatment. The high fat diet decreased liver HMG-CoA reductase activity and increased the activities of 7-α-hydroxylase and acylcholesterol acyltransferase (ACAT). l-Carnitine treatment blunted the magnitude of the diet induced increase in 7α-hydroxylase activity, yet overall the activity still remained elevated relative to controls. ACAT activity increased (1.5 times) with the high fat diet and increased further (4.5 times) following carnitine treatment. The mechanism(s) underlying the hypolipidemic effect of l-carnitine treatment in this animal model remain to be elucidated.

Prolonged Exercise Augments Plasma Triglyceride Clearance

We studied ten male distance runners before and after a marathon to determine the effects of prolonged exercise on serum lipoprotein values and the capacity to clear plasma triglycerides. Serum lipid and lipoprotein concentrations, intravenous fat clearance, and postheparin plasma lipolytic activities were measured 24 hours before and 18 hours after the race. The clearance rate of exogenous fat increased 76% +/- 64%, postheparin lipoprotein lipase activity increased 46% +/- 35%, and fasting triglyceride levels decreased 26% +/- 13% after the race. High-density lipoprotein (HDL) cholesterol level increased 10% +/- 8%, primarily due to a 19% +/- 17% increase in the HDL2 subfraction. Changes in the clearance rate of exogenous fat were directly related to changes in HDL cholesterol level and the HDL2 subfraction. Thus, the rise in HDL cholesterol concentrations after prolonged exercise may be a consequence of enhanced fat clearance.

Pharmacodynamic assessment of dihydroxyprogesterone acetophenide plus estradiol enanthate as a monthly injectable contraceptive

The pharmacodynamics of the combination of dihydroxyprogesterone acetophenide (DHPA) and estradiol enanthate (E2-EN) following its intramuscular administration at two doses were studied in 16 healthy women of reproductive age. Subjects were randomly allocated in two groups: group I (n = 9) received the combination DHPA 150 mg + E2- EN 10 mg on three consecutive monthly injections, while group II (n = 7) received half-dose of the same formulation. Ovarian function and endometrial bleeding patterns were investigated in all participants for one pre-treatment cycle, three treatment intervals and two post-treatment cycles. The results disclosed that ovulation was inhibited for at least 30 days following DHPA/E2-EN administration in all participants from both groups. The circulating estradiol levels 30 days after last injection were sligthly elevated as compared with those observed in normal early follicular phase. Return to ovulatory cycles was documented within 90 days after treatment. The length of the bleeding-free intervals during treatment was shortened in both groups, particularly in group II. No significant changes in HDL-cholesterol levels were observed throughout the study. It is envisaged however, that large modification of the formulation and additional long-term safety studies will be required prior to its recommendation.

A Comparison of Plasma Cholesterol, Triglycerides and High Density Lipoprotein Cholesterol Levels in Women Using Contraceptive Pills and a Control Group

Plasma cholesterol, triglycerides and HDL cholesterol levels were compared in a group of 45 young, normotensive, nonobese and nondiabetic women who used modern combined minidose contraceptive pills, to a matched group of 39 women who did not use any hormonal preparations. Our results show an increase in triglyceride levels as well as significant increase in cholesterol level in the ‘pill’ users group. We failed to show a significant change in HDL cholesterol levels and HDL cholesterol to total cholesterol ratio between the two groups. Our results concerning triglyceride levels are in consent to previous studies in the medical literature, while the elevation in cholesterol levels has rarely been reported in contemporary papers about minidose pill users. It seems that the contradicting effect of estrogen and progesterone on plasma HDL levels neutralizes each other’s effect on this lipoprotein fraction. The elevation in plasma triglycerides and cholesterol may have importance in the vascular abnormalities seen in such pill users.

Effect of Alcohol Intake on High-Density Lipoprotein Cholesterol Levels in Runners and Inactive Men

Plasma high-density lipoprotein cholesterol (HDLC) level was measured before and after alcohol abstinence and after resumption of a controlled alcohol dose in 16 marathon runners, 15 joggers, and 13 inactive men. A three-week period of abstinence resulted in a significant decrease in HDLC concentration in the inactive men (49.8 to 41.8 mg/dL). Three weeks of alcohol consumption (1,065 mL of beer per day) produced a significant increase in HDLC level to 50.9 mg/dL. No change in HDLC level was found for the marathon group or the joggers during abstinence or three weeks of alcohol intake. The consumption of alcohol in moderation seems to be associated with increased HDLC levels in inactive men but not in men who engage in regular running or jogging.

The effect of rapid weight loss due to jejunoileal bypass on total cholesterol and high-density lipoprotein

Twelve patients undergoing a 10 to 4 inch end-to-side jejunoileal bypass for morbid obesity were measured pre- and postsurgically for total cholesterol and high-density lipoprotein (HDL) cholesterol levels. After a mean weight loss period of 7 months, results showed a significant decrease in total cholesterol (p less than 0.001) and in the total cholesterol: HDL cholesterol level (p less than 0.01). The change in HDL cholesterol levels was not significant (p less than 0.05). The decrease in total cholesterol accompanied by no change in HDL cholesterol indicates an increased transport of cholesterol as HDL in these patients. This results suggests that these subjects are placed at a decreased risk of coronary heart disease postsurgically.

Effect of colestipol and clofibrate on plasma lipid and lipoproteins in Type IIa hyperlipoproteinemia

The effects of 2.0 g of clofibrate and 15, 20 and 30 g of colestipol on plasma lipid and lipoprotein levels were evaluated in adult patients with Type IIa hyperlipoproteinemia. Clofibrate treatment was associated with decreases of 11.0% in plasma cholesterol, 15.2% in LDL cholesterol, 26.1% in triglycerides, and an 11.3% increase in HDL cholesterol. The reductions in total cholesterol with the various doses of colestipol ranged from 11.9 to 17.8% and reductions in LDL cholesterol ranged from 16.1 to 27.3%. Colestipol treatment was not associated with any significant change in HDL cholesterol levels and minor increases in triglycerides. The addition of clofibrate to patients receiving colestipol resulted in a significant increase in HDL cholesterol and a decrease in triglycerides, but no additional reduction in total or LDL cholesterol.