Short term effects of a low-carbohydrate diet in overweight and obese subjects with low HDL-C levels.

BACKGROUND: The aim of this study was to evaluate short-term effects of a low-carbohydrate diet in overweight and obese subjects with low HDL-C levels. METHODS: Overweight (BMI between 25-30 kg/m2) or obese (BMI over 30 kg/m2) subjects with low HDL-C levels (men with HDL-C <1.03, women <1.29 mmol/l) were invited to the study. A 1400 kcal 75-gram carbohydrate (CHO) diet was given to women and an 1800 kcal 100-gram CHO diet was given to men for four weeks. The distribution of daily energy of the prescribed diet was 21-22% from CHO, 26-29% from protein and 49-53% from fat. Subjects completed a three-day dietary intake record before each visit. Anthropometric indices, body fat ratio, blood lipids, glucose and insulin were measured. Baseline and week-four results were compared with a Wilcoxon signed ranks test. RESULTS: Twenty-five women and 18 men participated. Basal median LDL-C level of men was 3.11 and basal median LDL-C level of women was 3.00 mmol/l. After four weeks of a low-carbohydrate diet, the median energy intake decreased from 1901 to 1307 kcal/day, daily energy from carbohydrate from 55% to 33%, body weight from 87.7 to 83.0 kg and HDL-C increased from 0.83 to 0.96 mmol/l in men (p < 0.002, for all). After four weeks of a low-carbohydrate diet, the median energy intake tended to decrease (from 1463 to 1243 kcal, p = 0.052), daily energy from carbohydrate decreased from 53% to 30% (p < 0.001) and body weight decreased from 73.2 to 70.8 kg (p < 0.001) in women, but HDL-C did not significantly change (from 1.03 to 1.01 mmol/l, p = 0.165). There were significant decreases in body mass index, waist circumference, body fat ratio, systolic blood pressure, total cholesterol, triglyceride and insulin levels in all subjects. CONCLUSIONS: HDL-C levels increased significantly with energy restriction, carbohydrate restriction and weight loss in men. HDL-C levels didn't change in women in whom there was no significant energy restriction but a significant carbohydrate restriction and a relatively small but significant weight loss. Our results suggest that both energy and carbohydrate restriction should be considered in overweight and obese subjects with low HDL-C levels, especially when LDL-C levels are not elevated.

Optimal waist:height ratio cut-off point for cardiometabolic risk factors in Turkish adults.

OBJECTIVE: To identify the optimal waist:height ratio (WHtR) cut-off point that discriminates cardiometabolic risk factors in Turkish adults. DESIGN: Cross-sectional study. Hypertension, dyslipidaemia, diabetes, metabolic syndrome score >or=2 (presence of two or more metabolic syndrome components except for waist circumference) and at least one risk factor (diabetes, hypertension or dyslipidaemia) were categorical outcome variables. Receiver-operating characteristic (ROC) curves were prepared by plotting 1 - specificity on the x-axis and sensitivity on the y-axis. The WHtR value that had the highest Youden index was selected as the optimal cut-off point for each cardiometabolic risk factor (Youden index = sensitivity + specificity - 1). SETTING: Turkey, 2003. SUBJECTS: Adults (1121 women and 571 men) aged 18 years and over were examined. RESULTS: Analysis of ROC coordinate tables showed that the optimal cut-off value ranged between 0.55 and 0.60 and was almost equal between men and women. The sensitivities of the identified cut-offs were between 0.63 and 0.81, the specificities were between 0.42 and 0.71 and the accuracies were between 0.65 and 0.73, for men and women. The cut-off point of 0.59 was the most frequently identified value for discrimination of the studied cardiometabolic risk factors. Subjects classified as having WHtR >or= 0.59 had significantly higher age and sociodemographic multivariable-adjusted odds ratios for cardiometabolic risk factors than subjects with WHtR < 0.59, except for diabetes in men. CONCLUSIONS: We show that the optimal WHtR cut-off point to discriminate cardiometabolic risk factors is 0.59 in Turkish adults.

Comparison between Turkish Cardiovascular Risk Platform and United States National Cholesterol Education Program Adult Treatment Panel III definitions of the metabolic syndrome in Turkish adults.

The Turkish Cardiovascular Risk Platform (TCRP) calls for the diagnosis of the metabolic syndrome (MS) if insulin resistance, impaired fasting glucose, impaired glucose tolerance, or diabetes mellitus and >or=2 other established criteria are present. TCRP defines insulin resistance as a homeostasis model assessment >2.7. The aim of this cross-sectional study was to compare TCRP guidelines with the United States National Cholesterol Education Program Adult Treatment Panel III (NCEP) definition of MS in Turkish adults (N=1690). The age- and sex-adjusted prevalence of MS was 25% with the TCRP and 40% for the NCEP definition. Patients with MS identified by the NCEP definition but not by the TCRP definition had lower body mass index and less insulin resistance, but had a similarly adverse cardiovascular risk factor profile to those with TCRP-identified MS, with high blood pressure, waist circumference, triglycerides, and total cholesterol/high-density lipoprotein cholesterol ratio. Other national health organizations should avoid using homeostasis model assessment as a prerequisite for diagnosing MS. Modification of the NCEP definition would be more appropriate for ethnic groups with different body sizes.

Modulation of high-density lipoproteins in a population in istanbul, Turkey, with low levels of high-density lipoproteins.

The extent to which high-density lipoprotein (HDL) cholesterol levels can be increased in patients with low HDL cholesterol is important because low HDL cholesterol levels increase the risk of coronary heart disease (CHD). During the past 14 years, we have assessed risk factors in Turks, a population in which extremely low HDL cholesterol levels (mean 36 mg/dl in men, 42 mg/dl in women) are a prime CHD risk factor. Although genetically determined to a significant extent, these low HDL cholesterol levels can be modulated by lifestyle factors, as in other populations. We measured the HDL cholesterol levels in men and women residing in Istanbul at 3 time points: 1990 to 1993, 1996 to 2000, and 2003. The mean HDL cholesterol levels increased from 45.3 +/- 9.5 mg/dl in 1990 to 1993 to 49.7 +/- 12 mg/dl in 2003 (p <0.0001) in women, but were virtually unchanged in men (38 +/- 8 vs 39 +/- 10 mg/dl). In contrast to previous years, the HDL cholesterol levels in women in 2003 were markedly affected by education level and socioeconomic status, averaging 56 +/- 9 mg/dl in those with a university education and 48 +/- 12 mg/dl in those with a primary school education. Part of this difference could be explained by less smoking and more exercise and lower body mass index (average 25.6 +/- 4.9 vs 29.7 +/- 5.1 kg/m(2)) of the highly educated women. It is important to note the increase in the prevalence of obesity between the 1990 to 1993 interval and 2003 in men and women, including a remarkable change from 9.4% to 45.2% among women with a primary school education. None of these factors affected the HDL cholesterol levels of men by >2 mg/dl at any of the 3 points. In conclusion, because CHD risk changes by as much as 2% to 4% per 1 mg/dl difference in HDL cholesterol level, the 8 mg/dl difference may reflect as much as a 20% to 30% reduction in CHD risk associated with the benefit of higher education in women. Why education failed to affect the HDL cholesterol levels in Turkish men remains unclear.

Managing dyslipidemia in Turkey: suggested guidelines for a population characterized by low levels of high density lipoprotein cholesterol.

Based on data from the Turkish Society of Cardiology and others, it is established that Turks have a high prevalence of coronary heart disease (CHD). Several risk factors are prominent in Turks: dyslipidemia, cigarette smoking, and hypertension. The dyslipidemia is unique in that very low levels of HDL-C and typically "normal" LDL-C levels characterize the Turkish population. The low HDL-C levels appear to be genetic in origin and are largely independent of high triglyceride levels (73% of Turkish men and 94% of women with HDL-C <40 mg/dl have triglyceride levels <150 mg/dl; only 15% of men and 3% of women with HDL-C <40 mg/dl have triglyceride levels >200 mg/dl). HDL-C levels are 10-15% mg/dl lower in Turks than seen in the United States or western Europe. Low HDL-C is a major risk factor; CHD risk increases 2-4% for every 1 mg/dl decrease in HDL-C levels. Existing treatment guidelines focus on plasma LDL-C levels and fail to take into account the continuous increase in CHD risk that occurs as HDL-C levels decrease. However, several studies show that patients with CHD or free of CHD but with multiple risk factors, who have low HDL-C and near optimal LDL-C, benefit very significantly from lipid-lowering therapy. Many of these patients with low HDL-C levels do not qualify for drug therapy based on existing guidelines. Therefore, we believe that unique guidelines must be developed to guide the treatment of low HDL-C Turkish patients. We suggest that treatment based on both the LDL-C level and the total cholesterol/HDL-C (TC/HDL-C) ratio is the best way to address treatment of patients with low HDL-C levels. The most effective drug treatment available presently in Turkey relies on lowering LDL-C levels to optimize the TC/HDL-C ratio.