Accuracy of three dry-chemistry methods for lipid profiling and risk factor classification

The purpose of this project was to determine the accuracy in lipids measurement and risk factor classification using Reflotron, Cholestech, and Ektachem DT-60 dry-chemistry analyzers. Plasma and capillary venous blood from fasting subjects (n = 47) were analyzed for total cholesterol (TC), high density lipoprotein (HDL-C), and triglycerides (TG) using these analyzers and a CDC certified laboratory. Accuracy was evaluated by comparing the results of each portable analyzer against the CDC reference method. One-way ANOVAs were performed for TC, HDL-C, and TG between all portable analyzers and the reference method. Chi-square was used for risk classification (2001 NIH Guidelines). Compared to the reference method, the Ektachem and Reflotron provided significantly lower values for TC (p < .05). In addition, the Cholestech and Ektachem values for HDL-C were higher than the CDC (p < .05). The Reflotron and Cholestech provided higher values of TG than the CDC (p < .05). Chi-squares analyses for risk classification were not significant (p > .45) between analyzers. According to these results, the Ektachem and Cholestech analyzers met the current NCEP III guidelines for accuracy in measurement of TC, while only Ektachem met guidelines for TG. All 3 analyzers provided a good overall risk classification; however, values of HDL-C should be only used for screening purposes.     

The validity of the Reflotron as a screening tool for blood cholesterol

Screening for blood cholesterol levels has become an essential need in many countries. The aim of this study was to evaluate the performance of Reflotron analyzer in screening for blood cholesterol in terms of its precision and accuracy. We have compared the results obtained by the Reflotron with those obtained by a standard hospital laboratory procedure for the same samples. An optimal precision that met the 1992 LSP standards for precision was observed (CV = 2.27%). On the other hand, a suboptimal accuracy of Reflotron was detected, where more than 80% of the Reflotron values differed from the reference laboratory values by more than 5%. As a consequence, 21% of individuals were misclassified as normal due to the very low sensitivity in spite of the optimum specificity observed for the Reflotron. Using the receiver operating characteristic curve analysis, the optimum cut-off points giving the best validity values for the test were 170 mg/dl and 190 mg/dl (4.4 mmol/L and 4.9 mmol/L) for the border-line and true hypercholesterolemia, respectively. At these levels, sensitivity was 0.89 and 0.86, specificity 0.93 and 0.93, and positive predictive value was 0.91 and 0.82, respectively. Considering some limitations of the study, it is concluded that the Reflotron could be of more potential validity for the use in cholesterol measurement surveys when the recommended cut-off points are used.     

In a quasi-simultaneous assessment, imprecise cholesterol monitoring and screening tests were improved

OBJECTIVE: To calibrate Reflotron-measured capillary total cholesterol (cTC) relative to a laboratory-measured venous total cholesterol (vTC) criterion standard for monitoring and screening hypercholesterolemia. STUDY DESIGN AND SETTING: Quasi-simultaneous assessment in 1999-2002 of Reflotron cTC and laboratory vTC in a random sample of 4,269 adult residents of Geneva, Switzerland (calibration development subsample n=3,067; validation subsample n=1,172), by means of bias, precision, correlation, sensitivity, and false positive percentage (calculated as 100-specificity) analyses of Reflotron cTC vs. laboratory vTC measures for predicting hypercholesterolemia. RESULTS: Total bias was small (-0.26 mmol/L), but there was substantial negative drift in Reflotron cTC (annual biases +0.08, -0.17, -0.27, and -0.60 mmol/L in 1999-2002). Overall, 57% of Reflotron cTC measurements for 894 hypercholesterolemic patients underestimated laboratory vTC (2%, 57%, 71%, and 98% in 1999-2002). Prior to calibration, sensitivity was 73% for the development and 35% for the validation subsample, with false positive at 4% (development) and 0.1% (validation). After calibration, sensitivity was 78% for the development and 37% for the validation subsample, with false positive at 5% (development) and 0.2% (validation). Using 95% upper prediction limits (UPL) for individual vTC values increased sensitivity to 99% and 83% and false positive percentage to 30% and 7% for the development and validation subsamples, respectively. CONCLUSION: Crude results of Reflotron-measured cTC have poor sensitivity. Instead, 95% UPL can be used for monitoring and screening. Simply adding 0.8 mmol/L to a patient's observed Reflotron cTC value provides a very good approximation to the 95% UPL.     

Reflotron performance in a community screening program: results of the Massachusetts Model Systems for Blood Cholesterol Screening Project.

We evaluated the precision, accuracy, and durability of the Reflotron portable analyzer as part of the National Heart, Lung, and Blood Institute's Model Systems for Blood Cholesterol Screening Program. We conducted screenings in a wide variety of settings in four Massachusetts communities over a 16-month period. Fingerstick samples from 10,428 individuals were tested on the Reflotron at the screening sites. For comparison, we drew venous samples from 972 participants and analyzed them in a reference laboratory, which had met the requirements of the Centers for Disease Control's Lipid Standardization Program. All four Reflotrons tested met the 1988 guidelines for precision and accuracy established by the Laboratory Standardization Panel (LSP) of the National Cholesterol Education Program (NCEP). None of the analyzers consistently met the 1992 LSP standards for precision, although two met the 1992 standards for accuracy. More than 40% of Reflotron values differed from the reference laboratory values by more than 5%. As a consequence, more than 16% of individuals were misclassified in terms of the NCEP risk category into which their Reflotron readings fell. All four instruments malfunctioned at some point during the project, precluding their further usage. We recommend improvements in the precision, accuracy, and durability of this analyzer.     

Plasma lipids and their interrelationship in Turkish adults.

STUDY OBJECTIVE--The aim was to describe the plasma total cholesterol and triglyceride profiles in a random sample of Turkish adults and analyse the effects of certain coronary risk factors on these levels. DESIGN--This was a cross sectional population based survey. SETTING--59 communities scattered in all seven geographical regions of Turkey were surveyed in the summer of 1990. SUBJECTS--A random sample of 3689 men and women 20 years of age and over was studied. MEASUREMENTS AND MAIN RESULTS--Plasma total cholesterol, triglycerides, glucose (using Reflotron and with partial validation in reference laboratory), weight, height, and blood pressure were measured, and information on smoking, physical activity, and family income obtained. Hypercholesterolaemia (> or = 6.5 mmol/litre, 250 mg/dl) prevailed in 8.5%, and hypertriglyceridaemia (> 2.25 mmol/litre, 200 mg/dl) in 16.6% among men and women aged 40-59 years of age. Age adjusted total cholesterol values were 4.8 mmol/litre (185 mg/dl) in men and 5 mmol/litre (192 mg/dl) in women. A steep rise appeared in mean cholesterol levels between the ages of 20-29 and 40-49 years, in a ratio greater than the available data from some other populations indicated. Mean total cholesterol values increased substantially in both genders with diminishing grades of physical activity, rising serum triglyceride levels, in urban (opposed to rural) residents, in men with increasing income levels, and in the younger adults with rising body mass index. CONCLUSIONS--Turkish adults have comparatively low levels of total cholesterol and medium to moderately high levels of triglycerides. Lifestyle factors affect these levels in Turks as in other populations.     

Assessing risk using different cholesterol-screening methods

The purpose of this study was to compare total capillary, total venous, risk ratio, high-density lipoprotein and low-density lipoprotein measures of cholesterol to determine whether total capillary cholesterol is a valid measure to use in cholesterol screening. An announcement and a registration form were distributed with employee paychecks announcing a cholesterol-screening programme. Capillary and venous samples were collected from screening participants (n=285). Results indicated false negatives in total capillary cholesterol in 17.21-34.4% of cases compared with other methods of cholesterol measurement. Due to the high number of misclassifications, health educators should not use total capillary cholesterol as a predictor of risk for heart disease, nor as a measure for referral during cholesterol screenings.     

Performance characteristics of a blood cholesterol measuring instrument used in screening programs

Four experiments were conducted to assess the precision and accuracy of the Boehringer Mannheim Diagnostics Reflotron, an instrument that is being adopted by many public health groups to conduct blood cholesterol screening programs. Our study is one of the first to evaluate and document the instrument's performance characteristics. Successive generations of reagent tabs supplied by the manufacturer were tested against a reference laboratory method standardized by the Centers for Disease Control. Three of the experiments also compared two or more Reflotrons to assess intermachine reliability. The Reflotron analyzer provided precise blood cholesterol measurements both in repeated tests and among instruments. The accuracy of the method varied across reagent lots, with an average negative bias of 21.05 milligrams per deciliter (mg per dl), decreasing steadily to a negative bias of 4.07 mg per dl. Reliability between and within analyzers was high. The data provide support for the use of the instrument in blood cholesterol screening efforts, yet signal the need for attention to quality control procedures, both by the manufacturer and operators, to ensure the validity and accuracy of the results.     

Serum cholesterol (total, low-density lipoprotein, and high-density lipoprotein cholesterol), triglyceride levels, and fat consumption among Jerusalem Arab and Jewish schoolchildren

As part of initial health screening for the "Know Your Body" Program-based comprehensive health education program, 841 Jerusalem first- and second-grade schoolchildren were tested for total serum cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides. The same population, which included 643 Jewish (76.5%) and 198 Arab children (23.5%), had their nutritional habits evaluated by means of a parent-completed food-frequency questionnaire. Arab schoolchildren had significantly lower total, high-density lipoprotein, and low-density lipoprotein cholesterol levels and higher triglyceride levels than the Jewish children studied (total cholesterol: Arab mean, 153.1 mg/dl, Jewish mean, 170.3 mg/dl; high-density lipoprotein cholesterol: Arab mean, 46.4 mg/dl, Jewish mean, 48.5 mg/dl; low-density lipoprotein cholesterol: Arab mean, 90.7 mg/dl, Jewish mean, 108.5 mg/dl; triglycerides: Arab mean, 77.9 mg/dl, Jewish mean, 66.3 mg/dl). No significant differences in consumption level of foods high in saturated fats and/or cholesterol were found between populations, although the Arab children showed a tendency to eat more of these foods. Significant differences in total cholesterol values were also found among Jewish children of different origins, but no significant differences were found in consumption levels of saturated fats and cholesterol. Further studies are needed to determine the reasons for the differences in total cholesterol and lipoprotein levels found between Jewish and Arab schoolchildren.     

Direct measurement of low-density-lipoprotein cholesterol is more effective than total cholesterol for the purpose of lipoprotein screening

BACKGROUND: We have developed a new method for chemically measuring blood low-density-lipoprotein (LDL) cholesterol. In the present study, we simulated guidelines of the National Cholesterol Education Program (NCEP) using our LDL cholesterol measurements. METHODS: Blood samples were collected from 1,069 individuals (519 males, 550 females) who were referred to our laboratory at Niigata University Hospital for lipoprotein analysis. LDL cholesterol levels were determined according to our assay protocol, which has been published previously. Subjects were categorized by NCEP guidelines and identified "false positives" and "false negatives" on the basis of LDL cholesterol levels measured by our method. RESULTS: The sensitivity of the NCEP guidelines is 87.5% and the specificity is 87.1%, provided we assume that every individual has fewer than two risk factors for coronary heart disease. If we assume that every individual has two or more risk factors, the sensitivity and specificity of the guidelines are 99 and 56.8%, respectively. CONCLUSION: This study presents an opportunity to reevaluate guidelines for routine lipoprotein screening. The chance that individuals with higher LDL cholesterol and lower high-density-lipoprotein cholesterol levels in serum would be missed at initial classification should be zero. The chance that individuals with desirable lipid levels would undergo further lipoprotein analysis should be decreased. Since the new method can be implemented cost-effectively in routine lipoprotein screening, direct measurement of LDL cholesterol could replace total cholesterol.     

Screening using National Cholesterol Education Program guidelines in a population of urban Hispanic mothers

We measured serum total cholesterol, high-density lipoprotein cholesterol, and triglycerides and calculated low-density lipoprotein cholesterol in 217 urban Hispanic mothers. On the basis of total cholesterol values, as recommended by the Expert Panel of the National Cholesterol Education Program, 6 subjects (2.8%) had high blood cholesterol (greater than or equal to 240 mg/dl), 27 (12.4%) had borderline-high blood cholesterol (200-239 mg/dl), and 184 (84.8%) had desirable blood cholesterol (less than 200 mg/dl). One of the 27 with borderline-high total cholesterol had two other coronary risk factors. Thus 7 of the 217 (3.2%, 95% confidence interval 1.4 to 6.8%) met Expert Panel criteria for lipoprotein measurement. Six of the seven had high-risk low-density lipoprotein cholesterol (greater than or equal to 160 mg/dl). Four additional subjects with borderline-high total cholesterol, not identified by this sequential screening strategy, also had high-risk low-density lipoprotein cholesterol. Thus a total of 10 of 217 (4.6%, 95% confidence interval 2.4 to 8.6%) met Expert Panel criteria for high-risk low-density lipoprotein cholesterol and initiation of cholesterol-lowering treatment. None of these 10 had been previously identified as having high-risk low-density lipoprotein cholesterol. Two years later subjects with high or borderline-high total cholesterol were rescreened. Seven of 22 subjects completing the second screening were classified differently with regard to having high-risk low-density lipoprotein cholesterol, illustrating the potential for misclassification of individuals on the basis of a single measurement. The prevalence of women with high-risk low-density lipoprotein cholesterol was not significantly different at the two screenings.(ABSTRACT TRUNCATED AT 250 WORDS)     

Implementation of a Pilot School-site Cholesterol Reduction Intervention

A school-based cholesterol reduction intervention was offered to primary grade students in two New York City public schools. Subjects were participating in the "Know Your Body" school health program which includes an annual cholesterol screening for all students. Students with total serum cholesterol values greater than 170 mg/dl were eligible for a workshop designed to teach students to identify the amount and type of fat and fiber in various foods and to recognize the negative health consequences of eating a diet high in cholesterol and saturated fat as well as the benefits of eating a diet high in complex carbohydrate and fiber. Thirty-four students completed the five-session behavioral group intervention. Following the workshop, mean total cholesterol for the 34 intervention participants fell 9.0% from baseline (196.9 mg/dl to 179.1 mg/dl). Cholesterol levels decreased 6.6% for a matched sample of comparison subjects (n = 118) participating only in the "Know Your Body" program. While several methodological limitations existed in this pilot study, the results suggest school-site cholesterol reduction interventions for high-risk individuals are feasible, cost-effective, and potentially efficacious.     

An evaluation of the Reflotron(R) for the determination of plasma cholesterol in capillary blood. Effect of operator variability

The availability of portable analysers potentially puts thedetection of individuals with high serum cholesterol levelson a similar footing to that of high blood pressure. The Reflotron^®,which can make cholesterol measurements on capillary blood sampleswithout the need for centrifugation, has been evaluated in clinicalpractice. In 94 consecutive patients capillary blood was usedfor the determination of serum cholesterol by the Reflotron,by a laboratory technician (n=37) and by a nursing sister (n=57).Venous blood was also taken from the same patients within afew minutes of the capillary sample for enzymic determinationof serum cholesterol at the hospital laboratory. Overall, theReflotron values were about 0.6 mmol/l lower than those obtainedat the hospital laboratory. The accuracy and precision of theresults obtained by the nurse were poorer than those obtainedby the technician, even though the nurse had attended a threeday training course. Our results indicate that the Reflotronis a suitable instrument for use in screening for serum cholesterol,provided personnel operating the machine have adequate trainingand experience, and provided it is borne in mind that the resultsobtained may be slightly lower than standard laboratory methods.     

Lipid profile among school children in Campinas, Brazil

OBJECTIVE: To describe the lipid profile and the prevalence of hypercholesterolemia among schoolchildren aged 7 to 14 years in Campinas, S?o Paulo State, Brazil. METHODS: Plasma cholesterol levels, fractions, ratios and triglycerides were determined according to age and gender in a total of 1,600 schoolchildren. Hypercholesterolemia was considered borderline for 170 mg/dl/=200 mg/dl. RESULTS: Schoolchildren presented a cholesterol mean of 160 mg/dl, HDL-cholesterol mean of 49 mg/dl, LDL-cholesterol mean of 96 mg/dl, VLDL-cholesterol mean of 16 mg/dl, triglycerides mean of 79 mg/dl, cholesterol/HDL-cholesterol mean of 3.5 and LDL-cholesterol/HDL-cholesterol mean of 2.1. In general, females had higher cholesterol and triglycerides values than males. The prevalence of hypercholesterolemia was 35.0%: 15.6% was borderline high, 9.8% moderate and 9.5% severe. Females presented higher prevalence of hypercholesterolemia than males. CONCLUSIONS: The results pointed to the emergence of hypercholesterolemia as a public health problem in Brazil.     

Effects of saturated, monounsaturated, and omega-6 polyunsaturated fatty acids on plasma lipids, lipoproteins, and apoproteins in humans

The effects of dietary fats on plasma cholesterol, serum lipoproteins, and apoproteins (Apo), A-1, B, and CIII were studied. Twelve men consumed three different cholesterol-free formula diets in which polyunsaturated and saturated fats were partially substituted (20% of calories) for monoenoic fats with a constant of 40% of calories from fat. Total cholesterol and low-density lipoprotein cholesterol dropped from base-line values of 166 and 103 to 133 and 81 mg/dl (sat), 127 and 71 mg/dl (mono), and 123 and 65 mg/dl (poly), respectively. High-density lipoprotein cholesterol changed very little from base-line values of 46 to 40 mg/dl (sat), 45 mg/dl (poly), and 43 mg/dl (mono). The plasma concentrations of ApoB declined from base-line values of 80.3 mg/dl to 54.6 mg (mono), 51.8 mg (poly), and 59.6 mg (sat) while Apo CIII and Apo AI did not show any changes. This study demonstrates that: 1) changes in dietary fat affect serum lipids, lipoproteins, and apoproteins even when consumed on a cholesterol-free diet, and 2) omega-6 polyunsaturated fat lowers low-density lipoprotein cholesterol, total cholesterol, and ApoB to a greater extent than monounsaturated or saturated fat, 3) consumption of a cholesterol-free formula diet results in significant decreases in the concentrations of total and low-density lipoprotein cholesterol in plasma when compared to values obtained on a mixed food home diet containing approximately 300 mg cholesterol/day.     

A randomized controlled trial of dietary fiber intake on serum lipids

OBJECTIVE: Clinical trials have indicated that water-soluble fiber from oats reduces serum cholesterol among hypercholesterolemic patients on a low-fat diet. We examined the effect of dietary fiber intake on serum lipids among persons without hypercholesterolemia. DESIGN: Randomized controlled trial. SETTING AND SUBJECTS: We recruited 110 participants who were aged 30-65 years and had a serum cholesterol level < 240 mg/dl from community. INTERVENTION: Study participants were randomly assigned to receive 8 g per day of water-soluble fiber from oat bran or a control intervention. RESULTS: At baseline, the mean levels of serum cholesterol and other measured variables were comparable between the high-fiber and control groups. Over the 3-month intervention, mean changes (95% confidence interval (CI)) in total, HDL-, and LDL-cholesterol were -2.42 mg/dl (-8.90 to 4.05 mg/dl; P = 0.46), -0.24 mg/dl (-2.19 to 1.71 mg/dl; P = 0.81), and -1.96 mg/dl (-7.32 to 3.40 mg/dl; P = 0.47) in the fiber group and -0.02 mg/dl (-5.29 to 5.26 mg/dl; P = 0.99), 1.42 mg/dl (-0.74 to 3.59 mg/dl; P = 0.19), and -0.64 mg/dl (-5.30 to 4.03 mg/dl; P = 0.79) in the control group, respectively. The net changes (95% confidence interval) in total, HDL-, and LDL-cholesterol were -2.40 mg/dl (-10.6 to 5.81 mg/dl; P = 0.56), -1.66 mg/dl (-4.55 to 1.22 mg/dl; P = 0.26) and -1.33 mg/dl (-8.33 to 5.68 mg/dl; P = 0.71), respectively. CONCLUSIONS: Our study does not support the hypothesis that water-soluble fiber intake from oat bran reduces total and LDL-cholesterol in study participants with a normal serum cholesterol level.     

A comparison of the effect of diets containing beef protein and plant proteins on blood lipids of healthy young men

The effect of plant and animal protein on blood lipid levels was investigated in eight healthy normolipidemic men aged 18 to 27 yr. All subjects were fed both plant and animal protein diets in a cross-over design. Each diet was consumed for a 21-day period. Proteins from commonly used plant sources made up the plant protein diet. Beef protein was substituted for 55% of the plant proteins in the animal protein diet. Fasting venous blood samples were collected at the beginning of the study and at 7-day intervals throughout the 42-day study. Serum was analyzed for total cholesterol and triglycerides. Plasma low-density and high-density lipoprotein cholesterol were determined. There were not any statistically significant differences in mean serum total cholesterol or mean plasma low-density lipoprotein cholesterol when subjects consumed the diets. Mean plasma high-density lipoprotein cholesterol levels were significantly (p less than 0.05) elevated at the end of the 21-day period when the animal protein diet was consumed (48 +/- 3 mg/dl) compared to the period when the plant protein diet was fed (42 +/- 2 mg/dl). Mean serum triglyceride values were significantly (p less than 0.05) increased at day 7 of the plant protein diet period (136 +/- 19 mg/dl) compared to the same time period when the animal protein diet was consumed (84 +/- 12 mg/dl). The results of the study indicated that the ingestion of a diet in which 55% of the protein was supplied by beef protein was not associated with a hypercholesterolemic effect in healthy normolipidemic young men.     

Ten-year changes in the obesity, abdominal adiposity, and serum lipoprotein cholesterol measures of Western Samoan men

Previously reported associations between abdominal adiposity and coronary heart disease (CHD) may be mediated through serum lipids. In the present longitudinal study, 43 Western Samoan men who participated in a 1982 study were recontacted for a second determination of anthropometric and serum lipoprotein cholesterol levels. The men showed dramatic increases in weight (mean change ± SD: 10.5 ± 8.8 kg), abdominal circumference (10.0 ± 7.6 cm), total cholesterol (49.5 ± 26.4 mg/dl), and non-HDL cholesterol (53.1 ± 26.6 mg/dl). A new indicator was used to estimate changes in abdominal adiposity: the residual from the regression of change in the abdominal circumference on change in body weight (the AR). The AR was significantly correlated with changes in total (r = 0.38) and non-HDL cholesterol (r = 0.39). Changes in HDL cholesterol were correlated with changes in weight only (r = −0.37). These bivariate relations remained significant in multiple linear regression analyses. These longitudinal results are the first to suggest changes in abdominal adiposity are related to changes in total and non-HDL cholesterol levels.     

Failure of family history to predict high blood cholesterol among hispanic preschool children

Recommendations for screening children for high blood cholesterol remain controversial. The American Academy of Pediatrics, the American Heart Association, and the National Institutes of Health (NIH) Consensus Conference have recommended targeted screening of children with positive family history. We examined data from a sample of 108 Hispanic preschool children and their families to test targeted screening strategies. Thirty-seven children (34.3%) had total cholesterol levels of greater than or equal to 4.40 mmole/liter (170 mg/dl). Using the American Academy of Pediatrics definition of family history, sensitivity (proportion of those with high blood cholesterol with positive family history) was 0.57 (95% confidence interval, 0.40 to 0.73) and accuracy (overall proportion correctly classified) was 0.58 (0.48 to 0.68). Using the American Heart Association and NIH Consensus Conference definition of family history, sensitivity was 0.46 (0.30 to 0.63) and accuracy was 0.62 (0.52 to 0.71). Classification of children based on the mother's total cholesterol level of greater than or equal to 5.17 mmole/liter (200 mg/dl), the mother's low-density lipoprotein cholesterol level of greater than or equal to 4.14 mmole/liter (160 mg/dl), the mother's low-density lipoprotein cholesterol level of greater than or equal to 3.36 mmole/liter (130 mg/dl), or the child's own body mass index greater than or equal to 75th percentile was less sensitive and no more accurate. These findings indicate that current recommendations as well as other potential strategies for targeted cholesterol screening in young children have serious shortcomings and lend support to universal cholesterol screening in childhood.     

Comparisons of referral criteria for public screening of blood cholesterol levels

Total and high-density lipoprotein (HDL) cholesterol levels of 2,387 adults were screened at a worksite and a bloodbank. Hypothetical referral decisions were made according to three sets of guidelines: the 1984 National Institutes of Health Consensus Conference guidelines (NIHCC), a single referral cutpoint of 5.2 millimoles per liter (mmol per L), and the current National Cholesterol Education Program (NCEP) guidelines for screening in physicians' office. Under the NIHCC guidelines, 31 percent of the participants would have been referred to their physicians, 32 percent under the NCEP guidelines, and 56 percent would have been referred had the 5.2 mmol per L cutpoint been used. Twenty-four percent of the participants would have been referred under both the NIHCC and NCEP guidelines; 7 percent would have been referred under the NIHCC guidelines, but not the NCEP's. Eight percent would have been referred under the NCEP guidelines, but not the NIHCC's. Those who would have been referred were older, and more likely to be male and to have low levels of HDL cholesterol than the 7 percent who would have been referred under NIHCC guidelines only. All of the 8 percent had coronary heart disease, or two or more other coronary risk factors, whereas none of the 7 percent did. If low HDL had been used as a risk factor under NCEP guidelines, the number of persons referred would have increased slightly (to 34 percent) and low HDL levels would have become one of the most prevalent risk factors. The researchers concluded that public cholesterol screening programs should use the NCEP guidelines (with or without HDL), rather than the NIHCC guidelines, or a single 5.2 mmol per L cutpoint.     

Particle size of LDL is affected by the National Cholesterol Education Program (NCEP) step II diet in dyslipidaemic adolescents

The objective was to determine the effects of the National Cholesterol Education Program (NCEP) step II diet on LDL and HDL particle size in dyslipidaemic adolescents. Forty-four dyslipidaemic adolescents, aged 10-18 years, participated in this case-control study. The control diet was a diet similar to what most Tehranian adolescents eat. NCEP step II diet was a diet with 30 % of energy as total fat, less than 7 % saturated fat, less than 200 mg cholesterol/d, less than 15 % of energy as MUFA and less than 10 % as PUFA. Lipoprotein particle size was the major outcome variable, which was measured after 3 months of intervention. Comparison was made by the repeated measurement ANOVA. The mean BMI was 26.3 (sd 4.2) kg/m2. There were no significant changes in weight or physical activity in the two groups during the study. The NCEP diet resulted in higher reduction in total cholesterol ( - 13 (sd 4) v. - 2 (sd 0.3) mg/dl, P < 0.001) and LDL ( - 9 (sd 2) v. 3 (sd 0.6) mg/dl, P < 0.01), and higher increase in size of the LDL (1.7 (sd 0.4) v. 0.1 (sd 0.4) nanometer, P < 0.001). HDL particle size did not change significantly. NCEP step II diet had a favourable effect on the LDL particle size. The related mechanism needs to be studied in future experimental designs.