Relatively high coronary death and event rates in Turkish women. Relation to three major risk factors in five-year follow-up of cohort

Prognostic Modelling Studies of Coronary Heart Disease—A Systematic Review of Conventional and Genetic Risk Factor Studies

This study aims to provide an overview of multivariable prognostic modelling studies developed for coronary heart disease (CHD) in the general population and to explore the optimal prognostic model by comparing the models’ performance. A systematic review was performed using Embase, PubMed, Cochrane, Web of Science, and Scopus databases until 30 November 2019. In this work, only prognostic studies describing conventional risk factors alone or a combination of conventional and genomic risk factors, being developmental and/or validation prognostic studies of a multivariable model, were included. A total of 4021 records were screened by titles and abstracts, and 72 articles were eligible. All the relevant studies were checked by comparing the discrimination, reclassification, and calibration measures. Most of the models were developed in the United States and Canada and targeted the general population. The models included a set of similar predictors, such as age, sex, smoking, cholesterol level, blood pressure, BMI, and diabetes mellitus. In this study, many articles were identified and screened for consistency and reliability using CHARM and GRIPS statements. However, the usefulness of most prognostic models was not demonstrated; only a limited number of these models supported clinical evidence. Unfortunately, substantial heterogeneity was recognized in the definition and outcome of CHD events. The inclusion of genetic risk scores in addition to conventional risk factors might help in predicting the incidence of CHDs; however, the generalizability of the existing prognostic models remains open. Validation studies for the existing developmental models are needed to ensure generalizability, improve the research quality, and increase the transparency of the study.

Predicting the health impact of lowering salt consumption in Turkey using the DYNAMO health impact assessment tool

OBJECTIVE

To estimate the impact of three daily salt consumption scenarios on the prevalence and incidence of ischaemic heart disease (IHD) and cerebrovascular disease in 2025 in the Turkish population aged ≥30 years using the DYNAMO Health Impact Assessment tool.

STUDY DESIGN

Statistical disease modelling study.

METHODS

DYNAMO health impact assessment was populated using data from Turkey to estimate the prevalence and incidence of IHD and cerebrovascular disease in 2025. TurkSTAT data were used for demographic data, and national surveys were used for salt consumption and disease-specific burden. Three salt consumption scenarios were modelled: (1) reference scenario: mean salt consumption stays the same from 2012-2013 until 2025; (2) gradual decline: daily salt intake reduces steadily by 0.47 g per year by lowering salt intake from bread by 50% and from table salt by 40% by 2025; and (3) World Health Organization (WHO) advice: daily salt intake of 5 g per day from 2013 until 2025.

RESULTS

The gradual decline scenario would lead to a decrease in the prevalence of IHD and cerebrovascular disease by 0.3% and 0.2%, respectively, and a decrease in the incidence by 0.6 and 0.4 per 1000, respectively. Following WHO's advice would lead to a decrease in the prevalence of IHD and cerebrovascular disease by 0.8% and 0.5%, respectively, and a decrease in the incidence by 1.0 and 0.7 per 1000, respectively.

CONCLUSION

This model indicates that Turkey can lower its future cardiovascular disease burden by following the gradual decline scenario. Following WHO's advice would achieve an even greater benefit.

Low-grade inflammation, and dysfunction of high-density lipoprotein and its apolipoproteins as a major driver of cardiometabolic risk

Dysfunction of high-density lipoprotein (HDL) particles that even become proinflammatory or lose atheroprotective properties is known through analyses of HDL isolated from diabetic subjects. Recently, high concentrations of HDL or apolipoprotein (apo) A-I in individuals with diabetes or coronary heart disease were found to reveal dysfunction in some population-based studies. Such dysfunction of HDL and its apos A-I, A-II, and C-III has been observed in a general population for the first time among Turkish adults. Functional defectiveness manifested itself by unexpected correlations with inflammatory biomarkers and, in long-term follow-up, by lack of protection against diabetes and coronary heart disease, accounting for the excess incidences in Turks. Female sex was more pronouncedly affected by this process that presumably exists in other ethnicities in South Asia, East Europe, and the Middle East. In contradistinction, in Western and East Asian population, only individuals with glucose intolerance or those at risk for cardiometabolic disease are considered to be or were documented in a review of clinical trials to have been affected by impaired function of HDL. High-density lipoprotein dysfunctionality is closely linked to obesity and low-grade inflammation yet seems to act partly independently of them. Cigarette smoking in overweight women with low-grade inflammation appears to offer limited protection against cardiometabolic risk. The great impact in public health of the dysfunction of protective serum proteins requires individual clinical recognition, appropriate preventive measures, and delineation of management, including with anti-inflammatory drugs.

Complement C3 and cleavage products in cardiometabolic risk

This review summarizes available evidence on the role of serum complement component 3 (C3), produced by liver, adipocytes and activated macrophages at inflammation sites, and C3 cleavage products linking lipoproteins and metabolism to immunity. C3 and cleavage products are modified in several associated metabolic disorders including obesity, insulin resistance, type-2 diabetes, dyslipidemia, and cardiovascular diseases. Circulating C3 is independently and linearly associated with serum triglycerides, C-reactive protein (CRP), waist circumference and in some populations inversely with current smoking. The complement cascade is activated during myocardial ischemia and likely mediates immune and inflammatory responses in ischemic myocardium. Serum complement activation is elevated in unstable rather than stable angina pectoris suggesting added contribution to damage extension in acute coronary syndromes. In logistic regression models for incident metabolic syndrome (MetS), increasing C3 concentrations predicted MetS in women, after adjusting for continuous values of 3 major MetS components and other confounders, with a relative risk similar in magnitude to an established component suggesting elevated C3 likely constitutes part of the cluster of MetS in women. C3 interacts with MetS in men for independently conferring risk of incident type-2 diabetes and coronary heart disease (CHD). In women, though C3 is equally predictive of cardiometabolic risk, it is less so additively to MetS components or to CRP. Evidence suggests that circulating C3 might serve as a signal for an immune process that enhances - via mediation of increased apolipoprotein (apo) E levels - the development of dysfunctional apoA-I particles rendering them diabetogenic and atherogenic in populations prone to MetS or subsets of populations harboring impaired glucose tolerance. C3 activation also leads to production of chemoattractants C3a and C5a, and acylation stimulating protein (ASP, C3adesArg), a lipogenic hormone, which contribute additionally to the metabolic phenotypes generated. These observations have clinical and public health implications.

Evaluation of coronary artery disease by computed tomography angiography in patients treated for childhood Hodgkin's lymphoma

PURPOSE To detect pathologies in coronary arteries by computed tomography angiography (CTA) in survivors of childhood Hodgkin's lymphoma who have been treated with radiotherapy and/or cardiotoxic agents. PATIENTS AND METHODS Patients with HL who have been in remission for at least 2 years after completion of therapy were included. CBC, lipid profile, urine analysis, brain natriuretic peptide, troponin-T, creatinine kinase-myocardial band, ECG, telecardiography, echocardiography, and CTA of the patients were performed. Cardiac vascular abnormalities were noted. Results A total of 119 patients were included in the study. In 19 patients (16%), we found coronary artery abnormalities. There was a significant difference between the patients who received mediastinal radiotherapy and those who did not (P = .02). By multivariate analysis, in patients receiving mediastinal radiotherapy the risk of developing a coronary artery abnormality was found to increase 6.8 times compared with patients who did not receive mediastinal radiotherapy (P = .009). Stent implantation was performed in a 28-year-old patient because of critical stenosis in right coronary. In two patients some irregularities were detected both in CTA and conventional angiography, and they remained in close follow-up. A 22-year-old patient whose CTA showed critical stenosis in his left anterior descending artery refused the conventional angiography. CONCLUSION To our knowledge, this is the first large study using CTA for detection of coronary abnormalities in patients treated for HL in pediatric age group. Coronary CTA is a minimally invasive tool for early diagnosis of coronary artery disease in patients who were treated with mediastinal radiotherapy and/or cardiotoxic chemotherapy.

Which fasting triglyceride levels best reflect coronary risk? Evidence from the Turkish Adult Risk Factor Study

BACKGROUND

Association between raised low-density lipoprotein cholesterol (LDL-C) levels and high risk for coronary heart disease (CHD) is well established and taken into account in guidelines on coronary prevention.

HYPOTHESIS

The relationship between risk for coronary heart disease (CHD) and the levels of fasting plasma triglycerides was studied in the cohort of the Turkish Adult Risk Factor Study, a representative random sample of an adult population.

METHODS

In 829 men and 907 women aged > or =27 years (mean 48.5+/-11), plasma lipids and lipoproteins were measured by the enzymatic dry method in the postabsorptive state. A sample of values was validated in a reference laboratory. Apoliprotein (apo) A-I and B were measured by the turbidimetric immunoassay using commercial kits in part of the cohort. Blood pressure and anthropometric measurements were made. Criteria for the diagnosis of CHD were based on history, cardiovascular examination, and Minnesota coding of resting electrocardiograms. Coronary heart disease was diagnosed in about 7% of the subjects. Participants were divided into four categories depending on their triglyceride levels: I = < 100 mg/dl (282 men, 400 women), II = 100-139 mg/dl (204 men, 228 women), III = 140-212 mg/dl (188 men, 180 women), and IV = > or = 212 mg/dl (155 men, 99 women).

RESULTS

After adjustment for age, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol, smoking, and body mass index by logistic regression analysis, and after assigning the CHD risk of 1 to Category I, the relative risk for men and women combined rose to 1.42 in Category III (p<0.045) while it diminished to 0.94 in Category IV (p = 0.79). In women, the odds ratio (OR) rose gradually up to 1.78 (p< 0.025) in Category III, only to decline in Category IV. The OR in men was slightly, insignificantly, and equally elevated in Categories III and IV. Patients with CHD in Category III were not distinguished from those in Category IV by the studied risk parameters. It was suggested that high risk for CHD--particularly in subjects with slightly elevated or normal cholesterol levels-is often not reflected by extreme increases of fasting triglycerides but best by modest elevations (140-212 mg/dl), which serve better as a marker of triglyceride-rich lipoprotein particles. This knowledge may prove to be of value in population screening and individual risk assessment.

The paradox of high apolipoprotein A-I levels independently predicting incident type-2 diabetes among Turks

BACKGROUND

Predictive value of apolipoprotein (apo) A-I for incident hypertension, metabolic syndrome (MetS), type 2 diabetes (DM) and coronary heart disease (CHD) needs further exploration.

METHODS

A representative sample of Turkish adults was studied with this purpose prospectively. Sex-specific apoA-I tertiles were examined regarding cardiometabolic risk.

RESULTS AND CONCLUSIONS

A total of 1044 men and 1067 women (aged 49+/-12 years at baseline) were followed up over 7.4 years. High serum apoA-I levels were significantly associated in multivariable analysis with female sex, aging, alcohol intake, (inversely) cigarette smoking and, in women, with systolic blood pressure. Risk of diabetes was predicted in logistic regression in both genders by top versus bottom apoA-I tertile (RR 1.98; [95%CI 1.31; 3.0]), additive to age, body mass index (BMI), C-reactive protein (CRP), HDL-cholesterol and lipid lowering drugs. By adding sex hormone-binding globulin to the model in a subset of the sample, the association between high apoA-I and incident diabetes was attenuated only in women. ApoA-I tertiles tended to be positively associated also with hypertension and CHD only in women but this did not reach significance. High compared with low serum apoA-I levels nearly double the risk for incident diabetes, additively to age, BMI, CRP, HDL-cholesterol among Turks. Systemic inflammation concomitant with prevailing MetS might turn apoA-I into proinflammatory particles.

Atherosclerotic vascular disease and risk factors in Turkey: from past to present

The prevalence of atherosclerotic vascular disease is unexpectedly high in Turkey despite its young population, with a median age of 29. The mean total cholesterol is lower than in Western European countries; however, smoking is very prevalent, the incidence of metabolic syndrome high and obesity, diabetes and hypertension are becoming a major problem, especially in women. Having these risk factors as well as lower HDL levels leads to high cardiovascular morbidity and mortality at younger ages. This problem is expected to become worse with increasing industrialisation, adaptation to Western diets, a sedentary lifestyle and increasing obesity. A National Heart Health Policy has been developed to overcome this epidemic and combat the risk factors and reduce the burden of atherosclerotic vascular disease.

Guideline implementation in a multicenter study with an estimated 44% relative cardiovascular event risk reduction

BACKGROUND

The extent of cardiovascular risk reduction by implementing coronary prevention guidelines needs to be documented in various population samples.

HYPOTHESIS

This is a multicenter study to assess the impact of risk reduction in cardiovascular events upon implementation of coronary prevention guidelines in patients with or at high risk for coronary heart disease (CHD) in the setting of clinical practice.

METHODS

Enrolled volunteers numbered 2,021. Inclusion criteria postulated a minimum of 20-40% cardiovascular event risk in the subsequent 10 years as estimated from the risk table of the European Society of Cardiology (ESC) Guidelines. The estimated CHD risk reduction was assessed in terms of the Framingham risk scores at baseline and at 12 months, computed from the data of each individual. Data of the compliant group (making up half of the initial participants) at the end of the study, along with absolute and relative risk reductions in the compliant group, were analyzed.

RESULTS

Mean global risk burden was 25.9% at baseline, reduced through multilateral preventive measures in absolute terms by 9.4% at 6 months and by 11.7% at 12 months; the latter represents a relative risk reduction of 44%. Independent variables determining the (enhanced) reduction in risk level at the end of 12 months included (high) level of baseline risk, (high) degree of compliance with treatment, younger age, female gender, smoking, and (high) baseline triglyceride/high-density lipoprotein cholesterol (TC/HDL-C) ratio. While the relative reduction in patients with CHD amounted to 43%, a reduction of 46% (p<0.001) was obtained in the setting of primary prevention. Diabetes emerged as a factor modestly limiting the extent of risk reduction. While subjects without hypertension revealed a decline of coronary risk by merely 8.7%, those with hypertension showed a decline by 12.7% (p<0.001). Risk reductions were accompanied by a decrease of mean low-density lipoprotein cholesterol (LDL-C) level of 25.4%, a rise in mean HDL-C level of 5 mg/dl, a decrease in mean systolic blood pressure of 26 mmHg. Forty-five percent of smokers succeeded in discontinuing the habit.

CONCLUSION

By implementing standard prevention guidelines in the Turkish population among 1,000 compliant high-risk men and women and among 1,000 patients with CHD, prevention of cardiovascular events could be expected in 117 persons in the subsequent 10 years.

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.

Which patients have the highest cardiovascular risk? A follow-up study from Turkey

BACKGROUND

Recent guidelines target individuals at highest risk as a priority. However, implementation of guidelines even in this group is sub-optimal.

DESIGN

A multicenter, observational follow-up study.

METHODS

A total of 5600 consecutive patients > or =55 year with high risk of vascular events were evaluated for risk factors and medication usage and followed for 1 year for primary end-points (death, myocardial infarction, stroke), and secondary end-points (revascularization, hospitalization).

RESULTS

The patients were divided into two groups: those without and with vascular disease. In the first group, mortality at 1 year was significantly higher in those with end organ damage (5.8 versus 2.7%, P=0.005). Similarly, the mortality in patients with known vascular disease (CAD, peripheral vascular disease, ischaemic stroke) was higher in the presence of a previous vascular event (7.8 versus 5.3%, P=0.055, vascular event: non-fatal MI/stroke). The use of antiplatelets, statins, beta-blockers and angiotensin-converting enzyme inhibitors was low and did not improve in the follow-up period. The most important predictors of cardiovascular mortality were the presence of end organ damage [odds ratio (OR) 1.65, P=0.001], pre-existing vascular disease (OR 1.49, P=0.023) and protectively, the consistent use of angiotensin-converting enzyme inhibitors (OR 0.49, P=0.001).

CONCLUSION

In a high-risk Turkish population, the early mortality and morbidity due to cardiovascular events was unacceptably high and medical treatment inadequate. The presence of end organ damage and a previous vascular event increased the risk even further and should be vigorously questioned. Aggressive lifestyle modification and medical therapy should be instituted in these patients.

Cardiovascular risk factors in Turkish immigrants with type 2 diabetes mellitus: Comparison with Dutch patients

BACKGROUND

Based on recent epidemiological studies the need for a similar approach towards management of cardiovascular risk factors in type 2 diabetics with different ethnic background can be questioned. We compared the prevalence of cardiovascular risk factors and 10-year absolute risk for a coronary heart disease between Turkish and Dutch type 2 diabetes patients.

METHODS

A cross-sectional study was performed using databases from three Dutch studies on type 2 diabetes, comparing 147 Turkish to 294 Dutch diabetes patients, matched for age and gender. Main outcome measures were: total (t-) cholesterol, high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), triglyceride, blood pressure, and smoking. The 10-year absolute risk for a coronary event was calculated by means of the Framingham risk equation.

RESULTS

In Turkish diabetics t-cholesterol was lower than in Dutch (5.4 vs. 5.9 mmol/l; p < 0.001), in Turkish males HDL was lower than in Dutch male patients (0.94 vs. 1.08 mmol/l; p = 0.04). The total/HDL-cholesterol ratio in Turkish and Dutch diabetics was equal (5.4 vs. 5.4). Less Turkish than Dutch females smoked (9% vs. 23%; p<0.01). The 10-year absolute risk for a coronary event in both Turkish and Dutch male patients was 24%; the risk in Turkish vs. Dutch females was 13% vs. 15% (not significant).

CONCLUSION

The absolute risk for a coronary event in Turkish type 2 diabetes patients is similar to the risk in Dutch diabetes patients, although important differences in the risk profile exist, in particular, the lipid profile and smoking habits differ.

Risk determination of dyslipidemia in populations characterized by low levels of high-density lipoprotein cholesterol

BACKGROUND

Current guidelines for managing dyslipidemia qualify patients for treatment based on low-density lipoprotein cholesterol (LDL-C) levels and other risk factors for coronary heart disease (CHD). However, when LDL-C is the sole lipid criterion for initiating therapy, patients with levels below the treatment initiation threshold who are at high risk because of low levels (<40 mg/dL) of high-density lipoprotein cholesterol (HDL-C) might not be identified. Twenty percent of male patients with CHD in the United States fall into this category. The total cholesterol/HDL-C (TC/HDL-C) ratio predicts CHD risk regardless of the absolute LDL-C and HDL-C.

METHODS

We compared guidelines based on TC/HDL-C and LDL-C with those recommended by the National Cholesterol Education Program Adult Treatment Panel III (ATP III). Both sets of guidelines were applied to 9837 adults (>20 years of age) in the Turkish Heart Study, which has shown that 75% of men and 50% of women in Turkey have HDL-C <40 mg/dL.

RESULTS

ATP III guidelines identified 14% of Turkish adults, 20 years or older, as candidates for lifestyle treatment only and an additional 18% for drug treatment. In conjunction with ATP III LDL-C thresholds, the TC/HDL-C ratio (>3.5, patients with CHD; > or =6.0, 2+ risk factors, > or =7.0, 0 to 1 risk factor) assigned lifestyle therapy alone to 18% and drug treatment to an additional 36%. Among primary prevention subjects at high risk because of age (men > or =45 years; women > or =55 years), both sets of guidelines prescribed lifestyle therapy for only 5%; however, drug treatment was recommended for an additional 13% by ATP III guidelines and an additional 18% by TC/HDL-C and LDL-C.

CONCLUSIONS

In populations at risk for CHD caused by low HDL-C, qualification of subjects for treatment based on either the TC/HDL-C ratio or LDL-C thresholds identifies more high-risk subjects for treatment than LDL-C threshold values alone, and use of the ratio, instead of risk tables, simplifies the approach for physicians.

Risk factors and cardiovascular disease in Turkey

Cardiovascular risk factors as well as morbidity and mortality from coronary heart disease among Turkish adults are herein reviewed. Lipids and lipoproteins are in focus, but other relevant risk factors are also discussed. Turks have distinctively low levels of total and high-density lipoprotein (HDL)-cholesterol, associated with high levels of hepatic lipase and fasting triglycerides. In addition, physical inactivity is common in both genders; close to 60% of men have the smoking habit, while obesity is common among Turkish women leading to a high prevalence of hypertension and diabetes in them. These factors probably account for the unanticipated fact that Turkish adults have the pattern of causes of death similar to a developed population, although the process of industrialization is ongoing, the structure of its population is young and overall cholesterol levels are comparatively low. The age-standardized coronary heart disease death rate is estimated to rank among the highest in Europe. The leading independent predictors of coronary events and death [systolic blood pressure, total/HDL-cholesterol ratio, followed by diabetes and (central) obesity] are related to the metabolic syndrome, estimated to prevail in 3-4% of adults aged 30 or over, and to underlie one-eighth of cases of coronary disease. Since several adverse factors exhibit a rising trend, primary and secondary prevention of cardiovascular disease must assume a much higher priority in various issues in Turkey than it currently does.

Elevated systolic blood pressure and risk of cardiovascular and renal disease: overview of evidence from observational epidemiologic studies and randomized controlled trials

The effect of elevated blood pressure on risk of cardiovascular and renal disease has been documented in both observational epidemiologic studies and clinical trials. However, these studies have traditionally concentrated on diastolic blood pressure to characterize the risk associated with hypertension. We reviewed evidence from prospective studies and randomized controlled trials to quantify the risk associated with systolic blood pressure. Prospective studies and randomized controlled clinical trials that were published in English-language journals were retrieved using MEDLINE, bibliographies, and the authors' reference files. All retrieved publications were reviewed and information on sample size, duration, study design, antihypertensive medication, participant characteristics, and outcomes was abstracted for randomized controlled trials that reported systolic blood pressure reduction during intervention. Several prospective studies indicate that the association between systolic blood pressure and risk of coronary heart disease, stroke, and end-stage renal disease is continuous, graded, and independent. Furthermore, they suggest that the association of systolic blood pressure with these outcomes is stronger than that of diastolic blood pressure. Pooling of the data available from randomized controlled trials indicates that an average reduction of 12 to 13 mm Hg in systolic blood pressure over 4 years of follow-up is associated with a 21% reduction in coronary heart disease, 37% reduction in stroke, 25% reduction in total cardiovascular mortality, and 13% reduction in all-cause mortality rates. These data indicate that systolic blood pressure is an independent and strong predictor for risk of cardiovascular and renal disease.

Waist circumference and waist-to-hip ratio in Turkish adults: interrelation with other risk factors and association with cardiovascular disease

OBJECTIVE

To investigate the distribution of waist circumference (WC) and waist-to-hip ratio (WHR), their relationships with a number of established risk factors and their relevance to cardiovascular morbidity in a random sample of Turkish general adult population.

DESIGN

Cross-sectional population-based study.

SUBJECTS

The subjects comprised 958 men and 1014 women, aged 25-74 years.

MEASUREMENTS

Waist circumference was measured midway between the lower rib and iliac crest while that of the hip at the level of trochanters. Mean of two blood pressure measurements was used for analysis. Plasma total cholesterol (Cho) and triglyceride (Trg) concentrations were measured by the enzymatic dry method with a Reflotron apparatus.

RESULTS

Overall mean WC measured 93+/-12 cm in men, and 88.6+/-13 cm in women. Mean WHR was 0.919+/-0.077 and 0.823+/-0.074, respectively, and a rise by about 0.001 was associated with each year of age. In multiple regression analysis a model was utilized that included age, body mass index (BMI), systolic and diastolic blood pressure (BP), plasma total Cho and Trg and category of smoking. This revealed age, BMI, and Trg as independent determinants of WHR in both genders, and diastolic BP in women alone. Age, BMI, and diastolic BP proved to be independently associated with WC in both genders, while Cho did so in men alone, Trg and systolic BP in women alone. Partial correlation coefficients on univariate analysis between all four variables of blood pressure and plasma lipids and either WC or WHR, controlled for age, were highly significant though moderately weak in both genders. These were stronger in men than in women, and stronger with respect to WC than to WHR. Cigarette smoking men and women had significantly lower WC or WHR than nonsmokers and ex-smokers, though these associations did not prove to be independent. When the relevance of WC and WHR to CHD risk was tested in this cohort (for the age bracket 45-74 years) comprising 138 cases with a clinical diagnosis of CHD, only WHR in women proved to be significantly associated. Odds ratio for a value of >0.845 was 1.6.

CONCLUSION

WC and WHR are strongly associated with BMI and age as well as with parameters reflecting insulin resistance such as diastolic blood pressure and plasma triglycerides. WHR was significantly associated with coronary heart disease in Turkish women.

Methylene tetrahydrofolate reductase genotype and the risk and extent of coronary artery disease in a population with low plasma folate

OBJECTIVE

To determine the effects of the thermolabile methylene tetrahydrofolate reductase (MTHFR) mutation on the presence and extent of coronary atherosclerosis in a population with low plasma folate.

METHODS

242 consecutive patients undergoing coronary angiography were prospectively evaluated for conventional risk factors, plasma homocysteine, vitamin B-12, and folate, and MTHFR genotype. The severity of coronary atherosclerosis was determined by the Leaman score.

RESULTS

Mean (SD) plasma homocysteine was 15.6 (10) micromol/l in controls and 18.5 (11) micromol/l in patients with coronary artery disease (p > 0.05). Plasma homocysteine concentrations above 15 micromol/l were a risk factor for coronary artery disease (p = 0.03, risk ratio 2.1, 95% confidence interval (CI) 1.07 to 4.4). Homocysteine remained an independent risk factor on multivariate analysis when conventional risk factors were taken into account (p = 0.04). Homocysteine concentrations above 15 micromol/l were correlated with the extent of atherosclerosis (p = 0. 04, risk ratio 3.2, 95% CI 1.3 to 8.2). Homocysteine had no effect on other lipid variables (p > 0.05). Plasma folate was 15.8 (7.2) nmol/l in controls and 11.5 (2.9) nmol/l in patients with coronary artery disease. Plasma folate concentrations below 12.9 nmol/l (5.7 ng/ml) conferred a risk for coronary artery disease (p = 0.03, risk ratio 2.42, 95% CI 1.05 to 5.59). When the MTHFR genotype was determined, the TT genotype was present in 7.4% of patients and 5.2% of controls (p > 0.05). The prevalence of alleles was within the Hardy-Weinberg equilibrium (TT 7, CT 40, CC 53, chi2 = 2.3, p = 0.3). The highest homocysteine concentrations were found in patients with the TT genotype and folate below the median of the population (p = 0. 01). The extent of coronary atherosclerosis judged by the Leaman score was significantly higher in patients with the TT genotype (p = 0.03).

CONCLUSIONS

Plasma homocysteine over 15 micromol/l was a significant risk factor for the presence and extent of coronary artery disease. The mean plasma folate of the population was low and correlated negatively with homocysteine. Although TT genotype was not an independent predictor of coronary artery disease, it was an important predictor of the extent of coronary atherosclerosis and plasma homocysteine, especially in the presence of plasma folate values below the median of the population. These findings may have important implications for folate replacement in patients with the TT genotype.