Serum folate and homocysteine and the incidence of acute coronary events: the Kuopio Ischaemic Heart Disease Risk Factor Study

BACKGROUND

Several, but not all, prospective studies have shown that low folate intakes, low circulating folate concentrations, or high plasma total homocysteine (tHcy) concentrations are associated with an increased risk of coronary artery disease (CAD).

OBJECTIVE

We examined the relations of both serum folate and serum tHcy concentrations with acute coronary events in middle-aged men from eastern Finland who had no CAD at baseline.

DESIGN

In a population-based prospective cohort study, 1027 men aged 46-64 y were examined in 1991-1993 as part of the Kuopio Ischaemic Heart Disease Risk Factor Study. During an average follow-up of 7.7 y (7900 person-years of follow-up), 114 acute coronary events were observed in 61 men who had no previous history of CAD (n = 810).

RESULTS

In a Cox model, compared with men whose serum folate concentrations were in the lowest tertile, those whose concentrations were in the highest tertile had a risk factor-adjusted relative risk of acute coronary events of 0.35 (95% CI: 0.17, 0.73; P = 0.005). Serum tHcy concentrations were not significantly associated with the risk of acute coronary events (for the highest tertile compared with the lowest, adjusted relative risk = 1.03; 95% CI: 0.57, 1.87; P = 0.932).

CONCLUSIONS

The results of this prospective cohort study do not support the hypothesis that a high circulating tHcy concentration is a risk factor for acute coronary events in a male population free of prior heart disease. However, they do suggest that moderate-to-high serum folate concentrations are associated with a greatly reduced incidence of acute coronary events.

Testosterone and sex hormone-binding globulin predict the metabolic syndrome and diabetes in middle-aged men

OBJECTIVE

In men, hypoandrogenism is associated with features of the metabolic syndrome, but the role of sex hormones in the pathogenesis of the metabolic syndrome and diabetes is not well understood. We assessed the association of low levels of testosterone and sex hormone-binding globulin (SHBG) with the development of the metabolic syndrome and diabetes in men.

RESEARCH DESIGN AND METHODS

Concentrations of SHBG and total and calculated free testosterone and factors related to insulin resistance were determined at baseline in 702 middle-aged Finnish men participating in a population-based cohort study. These men had neither diabetes nor the metabolic syndrome.

RESULTS

After 11 years of follow-up, 147 men had developed the metabolic syndrome (National Cholesterol Education Program criteria) and 57 men diabetes. Men with total testosterone, calculated free testosterone, and SHBG levels in the lower fourth had a severalfold increased risk of developing the metabolic syndrome (odds ratio [OR] 2.3, 95% CI 1.5-3.4; 1.7, 1.2-2.5; and 2.8, 1.9-4.1, respectively) and diabetes (2.3, 1.3-4.1; 1.7, 0.9-3.0; and 4.3, 2.4-7.7, respectively) after adjustment for age. Adjustment for potential confounders such as cardiovascular disease, smoking, alcohol intake, and socioeconomic status did not alter the associations. Factors related to insulin resistance attenuated the associations, but they remained significant, except for free testosterone.

CONCLUSIONS

Low total testosterone and SHBG levels independently predict development of the metabolic syndrome and diabetes in middle-aged men. Thus, hypoandrogenism is an early marker for disturbances in insulin and glucose metabolism that may progress to the metabolic syndrome or frank diabetes and may contribute to their pathogenesis.

Liquid chromatography method for plant and mammalian lignans in human urine

Recently new mammalian lignan precursors were identified but no analysis methods are available for assay of those compounds in human urine. Previously published methods were developed for GC-MS about only two plant lignans were included. Consequently, a method for HPLC equipped with a coulometric electrode array detector was developed to measure plant and mammalian lignans in human urine. The plant lignans, secoisolariciresinol (Seco), matairesinol (Mat), lariciresinol (Lar), pinoresinol (Pin), syringaresinol (Syr) and isolariciresinol (IsoL) were included into the new method together with two mammalian lignans, enterolactone (Enl) and enterodiol (End). Validation of the method demonstrated that it could be applied to normal urine containing low amounts of plant lignans and moderate amounts of mammalian lignans, but the method was also applicable for samples from study subjects in supplementation studies, i.e. sample with very high concentrations of mammalian lignans. The method was found to be a useful tool for studies on plant lignan intake and the activity of micro flora in the metabolism of plant lignans.

Sex hormones, inflammation and the metabolic syndrome: a population-based study

OBJECTIVE

Mild hypoandrogenism in men is associated with features of the metabolic syndrome, but the association with the metabolic syndrome itself using an accepted definition has not been described.

DESIGN

Men with the metabolic syndrome were identified and testosterone and sex hormone-binding globulin (SHBG) levels were determined in a population-based cohort of 1896 non-diabetic middle-aged Finnish men.

RESULTS

Calculated free testosterone and SHBG were 11% and 18% lower (P<0.001) in men with the metabolic syndrome (n=345, World Health Organisation definition). After categorisation by tertiles and adjusting for age and body mass index, total and free testosterone and SHBG were inversely associated with concentrations of insulin, glucose, triglycerides, C-reactive protein (CRP) and CRP-adjusted ferritin and positively associated with high-density lipoprotein cholesterol. Men with free testosterone levels in the lowest third were 2.7 (95% confidence interval (CI) 2.0-3.7) times more likely to have the metabolic syndrome in age-adjusted analyses, and 1.7 (95% CI 1.2-2.4) times more likely even after further adjusting for body mass index. Exclusion of men with cardiovascular disease did not alter the association. The inverse association of SHBG with the metabolic syndrome was somewhat stronger.

CONCLUSIONS

Low testosterone and SHBG levels were strongly associated not only with components of the metabolic syndrome, but also with the metabolic syndrome itself, independently of body mass index. Furthermore, sex hormones were associated with inflammation and body iron stores. Even in the absence of late-stage consequences such as diabetes and cardiovascular disease, subtle derangements in sex hormones are present in the metabolic syndrome, and may contribute to its pathogenesis.

Serum ferritin concentration is associated with plasma levels of cholesterol oxidation products in man

Cholesterol oxidation products, oxysterols, are thought to play a part in the initiation and development of human atherosclerotic lesions. Excessive body iron has been suggested to promote atherosclerosis and coronary heart disease through its pro-oxidative properties. In the present study, the associations between serum ferritin and plasma oxysterol concentrations were examined in 669 eastern Finnish men. Serum ferritin concentration had statistically significant (p <.05) direct correlations with most of the measured oxysterols. In multivariate adjusted regression models, serum ferritin concentration predicted significantly the levels of 27-hydroxycholesterol (beta = 0.13, p <.001), 7alpha-hydroxycholesterol (beta = 0.11, p =.005), 25-hydroxycholesterol (beta = 0.10, p =.007), 7-ketocholesterol (beta = 0.10, p =.009), and 7beta-hydroxycholesterol (beta = 0.10, p =.02). In conclusion, excess body iron, as assessed by serum ferritin, is associated with increased levels of circulating oxysterols, both of enzymatic and nonenzymatic origin, in man.

Exhaustive exercise increases plasma/serum total oxidation resistance in moderately trained men and women, whereas their VLDL + LDL lipoprotein fraction is more susceptible to oxidation

The purpose of this study was to evaluate the effects of exhaustive exercise (marathon run) on different lipid peroxidation measurements, including copper-induced serum lipids and VLDL + LDL oxidation susceptibility, and on plasma total antioxidative capacity (TRAP), muscular damage and plasma antioxidants in healthy moderately trained male (n = 21) and female (n = 25) volunteers. Blood samples were taken before and just after the 42-km run. In women, baseline levels of several antioxidative compounds (serum albumin and uric acid, plasma free thiols and blood glutathione) were lower, resulting in 21.5% lower plasma total antioxidative capacity and 70.3% higher serum oxidation susceptibility, compared to men. To compare effects in men and women, the exercise-induced variable changes were adjusted for their baseline levels. After this adjustment, there were no statistically significant differences between the genders in the extent of muscular damage (serum creatine kinase, (CK)), or in the change in serum lipids or VLDL + LDL oxidation susceptibility, or that of plasma antioxidative capacity. A possible beneficial effect of exercise was that serum HDL cholesterol levels increased significantly in both genders, but especially in women. In the group of pooled genders (n=46), the increases in serum CK and in plasma lactate were 190% (95% CI, 133% to 246%) and 109% (95% CI, 65% to 175%), respectively. On the basis of our lipid peroxidation and TRAP measurements, uric acid was observed to be the most important plasma antioxidant. The effect of exercise was to decrease the oxidation susceptibility of serum lipids by 24.8% (95% CI 13.4% to 36.2%) and to elevate plasma TRAP by 14.6% (95% CI, 11.4% to 17.7%). Nonetheless, the oxidation susceptibility of the VLDL + LDL fraction increased by 11.0% (95% CI, 1.9% to 20.2%). Our results suggest that there are no gender-based differences in exhaustive exercise-induced lipid peroxidation or muscular damage. Secondly, even though exhaustive exercise can increase plasma/serum total resistance towards oxidation, the oxidation resistance of the atherogenic lipoprotein fraction might be diminished. On the basis of these results, several in vitro measurements of lipid peroxidation assessing both water and lipid soluble plasma fractions are needed if a true perspective of the plasma redox status is to be obtained.

Long-term combined supplementations with alpha-tocopherol and vitamin C have no detectable anti-inflammatory effects in healthy men

Inflammatory and oxidative stresses play a pivotal role in atherogenesis. Vitamin E and vitamin C are the two most important dietary antioxidants; moreover, vitamin E has anti-inflammatory effects. Combined supplementations with vitamin E and vitamin C twice daily for 3 y reduced lipid peroxidation and retarded the progression of common carotid atherosclerosis in healthy men in the Antioxidant Supplementation in Atherosclerosis Prevention (ASAP) study. To further elucidate the underlying mechanisms that retarded the progression of atherosclerosis in the ASAP study, we investigated the effect of a combined intake of vitamin E and vitamin C on inflammatory markers in vivo. Circulating levels of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and C reactive protein (CRP) were measured in 45- to 69-y-old men from the ASAP study with cholesterol >5.0 mmol/L before and after treatment with either placebo (n = 52) or a combined supplementation with 91 mg (136 IU) alpha-tocopherol and 250 mg of slow-release vitamin C twice a day (n = 55) for 3 y. Antioxidant treatment for 36 mo had no effect on circulating levels of TNF-alpha, IL-6 or CRP. In conclusion, long-term combined supplementations with alpha-tocopherol and vitamin C in reasonable doses have no detectable systemic anti-inflammatory effects in a healthy population of men with slight hypercholesterolemia and no overt signs of inflammation.

Six-year effect of combined vitamin C and E supplementation on atherosclerotic progression: the Antioxidant Supplementation in Atherosclerosis Prevention (ASAP) Study

BACKGROUND

Self-selected supplementation of vitamin E has been associated with reduced coronary events and atherosclerotic progression, but the evidence from clinical trials is controversial. In the first 3 years of the ASAP trial, the supplementation with 136 IU of vitamin E plus 250 mg of slow-release vitamin C twice daily slowed down the progression of carotid atherosclerosis in men but not women. This article examines the 6-year effect of supplementation on common carotid artery (CCA) intima-media thickness (IMT).

METHODS AND RESULTS

The subjects were 520 smoking and nonsmoking men and postmenopausal women aged 45 to 69 years with serum cholesterol > or =5.0 mmol/L (193 mg/dL), 440 (84.6%) of whom completed the study. Atherosclerotic progression was assessed ultrasonographically. In covariance analysis in both sexes, supplementation reduced the main study outcome, the slope of mean CCA-IMT, by 26% (95% CI, 5 to 46, P=0.014), in men by 33% (95% CI, 4 to 62, P=0.024) and in women by 14% (not significant). In both sexes combined, the average annual increase of the mean CCA-IMT was 0.014 mm in the unsupplemented and 0.010 mm in the supplemented group (25% treatment effect, 95% CI, 2 to 49, P=0.034). In men, this treatment effect was 37% (95 CI, 4 to 69, P=0.028). The effect was larger in subjects with either low baseline plasma vitamin C levels or CCA plaques. Vitamin E had no effect on HDL cholesterol.

CONCLUSIONS

These data replicate our 3-year findings confirming that the supplementation with combination of vitamin E and slow-release vitamin C slows down atherosclerotic progression in hypercholesterolemic persons.

Serum lycopene concentrations and carotid atherosclerosis: the Kuopio Ischaemic Heart Disease Risk Factor Study

BACKGROUND

Interest in lycopene is growing rapidly following the recent publication of epidemiologic studies in which high circulating lycopene concentrations were associated with reductions in cardiovascular disease. Lycopene is one of the major carotenoids in the Western diet and is probably one of the protective factors in a vegetable-rich diet.

OBJECTIVE

We studied the hypothesis that the intima-media thickness of the common carotid artery (CCA-IMT) would be greater in men with low serum lycopene concentrations.

DESIGN

We investigated the relation between serum lycopene concentration and CCA-IMT in 1028 middle-aged men (aged 46-64 y) in eastern Finland who were participants in the Kuopio Ischaemic Heart Disease Risk Factor study and who were examined in 1991-1993. The subjects were classified into quarters according to serum lycopene concentration.

RESULTS

In a covariance analysis with adjustment for covariates, the men in the lowest quarter of serum lycopene concentration had a significantly higher mean CCA-IMT and maximal CCA-IMT (P = 0.005 and P = 0.001 for the difference, respectively) than did the other men. The mean and maximal CCA-IMT increased linearly across the quarters of serum lycopene concentration.

CONCLUSIONS

A low serum lycopene concentration is associated with a higher CCA-IMT in middle-aged men from eastern Finland. This finding suggests that the serum lycopene concentration may play a role in the early stages of atherosclerosis. Increased thickness of the intima-media has been shown to predict coronary events; thus, lycopene intakes and serum concentrations may have clinical and public health relevance.

Lycopene, atherosclerosis, and coronary heart disease

Diets rich in fruits and vegetables containing carotenoids have been of interest because of their potential health benefit against chronic diseases such as cardiovascular diseases (CVD) and cancer. Interest particularly in lycopene is growing rapidly following the recent publication of epidemiological studies that have associated high lycopene levels with reductions in CVD incidence. Two studies were conducted. In the first one, we examined the role of lycopene as a risk-lowering factor with regard to acute coronary events and stroke in the prospective Kuopio Ischemic Heart Disease Risk Factor (KIHD) Study. The subjects were 725 middle-aged men free of coronary heart disease and stroke at the study baseline. In a Cox's proportional hazards' model adjusting for covariates, men in the lowest quartile of serum levels of lycopene had a 3.3-fold (P < 0.001) risk of the acute coronary event or stroke as compared with others. In the second study, we assessed the association between plasma concentration of lycopene and intima-media thickness of the common carotid artery wall (CCA-IMT) in a cross-sectional analysis of the Antioxidant Supplementation in the Atherosclerosis Prevention (ASAP) study data in 520 asymptomatic men and women. In a covariance analysis adjusting for common cardiovascular risk factors, low plasma levels of lycopene were associated with an 18% increase of IMT in men as compared with men in whom plasma levels were higher than median (P = 0.003 for difference). In women, the difference did not remain significant after the adjustments. On the basis of these works, it is evident that the circulating levels of lycopene play some role with regard to cardiovascular health in Finland, at least in men. We conclude that circulating levels of lycopene, a biomarker of tomato-rich food, may play a role in early stages of atherogenesis and may have clinical and public health relevance.

Plasma vitamin C modifies the association between hypertension and risk of stroke

BACKGROUND AND PURPOSE

There are no prospective studies to determine whether plasma vitamin C modifies the risk of stroke among hypertensive and overweight individuals. We sought to examine whether plasma vitamin C modifies the association between overweight and hypertension and the risk of stroke in middle-aged men from eastern Finland.

METHODS

We conducted a 10.4-year prospective population-based cohort study of 2419 randomly selected middle-aged men (42 to 60 years) with no history of stroke at baseline examination. A total of 120 men developed a stroke, of which 96 were ischemic and 24 hemorrhagic strokes.

RESULTS

Men with the lowest levels of plasma vitamin C (<28.4 micromol/L, lowest quarter) had a 2.4-fold (95% CI, 1.4 to 4.3; P=0.002) risk of any stroke compared with men with highest levels of plasma vitamin C (>64.96 micromol/L, highest quarter) after adjustment for age and examination months. An additional adjustment for body mass index, systolic blood pressure, smoking, alcohol consumption, serum total cholesterol, diabetes, and exercise-induced myocardial ischemia attenuated the association marginally (relative risk, 2.1; 95% CI, 1.2 to 3.8; P=0.01). Adjustment for prevalent coronary heart disease and atrial fibrillation did not attenuate the association any further. Furthermore, hypertensive men with the lowest vitamin C levels (<28.4 micromol/L) had a 2.6-fold risk (95% CI, 1.52 to 4.48; P<0.001), and overweight men (> or =25 kg/m2) with low plasma vitamin C had a 2.7-fold risk (95% CI, 1.48 to 4.90; P=0.001) for any stroke after adjustment for age, examination months, and other risk factors.

CONCLUSIONS

Low plasma vitamin C was associated with increased risk of stroke, especially among hypertensive and overweight men.

Serum fatty acid composition predicts development of impaired fasting glycaemia and diabetes in middle-aged men

AIMS

Dietary fatty acid intake is reflected in serum fatty acid composition. Studies prospectively investigating serum fatty acids and development of impaired fasting glycaemia (IFG) or diabetes mellitus (DM) are largely lacking. We assessed the association of serum fatty acid composition with development of IFG or DM.

METHODS

Middle-aged normoglycaemic men (n = 895) participating in a prospective cohort study were followed up after 4 years.

RESULTS

At baseline proportions of serum esterified and non-esterified saturated fatty acids were increased and polyunsaturated fatty acids decreased in men who after 4 years had developed IFG (n = 56) or DM (n = 34). No differences in dietary fatty acid composition as recorded in 4-day dietary records were noted. In logistic regression analyses adjusting for age; obesity; and fasting lipid, glucose and insulin concentrations, men with proportions of non-esterified and esterified linoleate in the upper third had nearly half the risk for IFG or DM compared with the lower third. In covariate analyses, baseline non-esterified linoleate proportions were associated with changes in fasting insulin and glucose concentrations over the 4-year follow-up. Baseline esterified fatty acid composition was also associated with changes in insulin.

CONCLUSIONS

High serum linoleate proportions decreased the risk of developing IFG or DM in middle-aged men over a 4-year follow-up, possibly mediated in part by insulin resistance. These findings support recommendations to substitute vegetable fat for animal and dairy fat in the prevention of disturbances of glucose and lipid metabolism.

Supplementation with vitamin E but not with vitamin C lowers lipid peroxidation in vivo in mildly hypercholesterolemic men

Although the use of vitamin E supplements has been associated with a reduction in coronary events, assumed to be due to lowered lipid peroxidation, there are no previous long-term clinical trials into the effects of vitamin C or E supplementation on lipid peroxidation in vivo. Here, we have studied the long-term effects of vitamins C and E on plasma F2-isoprostanes, a widely used marker of lipid peroxidation in vivo. As a study cohort, a subset of the "Antioxidant Supplementation in Atherosclerosis Prevention" (ASAP) study was used. ASAP is a double-masked placebo-controlled randomized clinical trial to study the long-term effect of vitamin C (500 mg of slow release ascorbate daily), vitamin E (200 mg of D-alpha-tocopheryl acetate daily), both vitamins (CellaVie), or placebo on lipid peroxidation, atherosclerotic progression, blood pressure and myocardial infarction (n = 520 at baseline). Lipid peroxidation measurements were carried out in 100 consecutive men at entry and repeated at 12 months. The plasma F2-isoprostane concentration was lowered by 17.3% (95% CI 3.9-30.8%) in the vitamin E group (p = 0.006 for the change, as compared with the placebo group). On the contrary, vitamin C had no significant effect on plasma F2-isoprostanes as compared with the placebo group. There was also no interaction in the effect between these vitamins. In conclusion, long-term oral supplementation of clinically healthy, but hypercholesterolemic men, who have normal vitamin C and E levels with a reasonable dose of vitamin E lowers lipid peroxidation in vivo, but a relatively high dose of vitamin C does not. This observation may provide a mechanism for the observed ability of vitamin E supplements to prevent atherosclerosis.

Leucine7 to proline7 polymorphism in the preproneuropeptide Y is associated with the progression of carotid atherosclerosis, blood pressure and serum lipids in Finnish men

A rather common leucine7-to-proline7 (Leu7Pro) polymorphism in the preproneuropeptide Y (prepro-NPY) gene signal peptide may be important in blood pressure regulation, cholesterol metabolism and the pathogenesis of atherosclerosis in humans. We examined the associations of the Leu7Pro polymorphism with carotid atherosclerotic progression, blood pressure and serum lipids in a population-based sample of 966 men aged 42-60 years in Finland. The Pro7 substitution (carrier frequency 12.2%) was associated with accelerated four-year increase in the mean (P=0.01) and maximal (P=0.007) common carotid intima-media thickness (IMT) and with slightly increased systolic (P=0.03) and diastolic (P=0.02) blood pressures, adjusted for other major risk factors. Men with Pro7 substitution had 30.6% (95% CI 6.9-54.0%) greater increase in the mean IMT and 20.0% (95% CI 5.3-34.4%) greater increase in the maximal IMT than men with Leu7/Leu7 genotype. The Pro7 substitution was also related to increased serum total cholesterol (P=0.01) and LDL cholesterol (P=0.02) in obese (body mass index (BMI)>30 kg/m(2)) men. This study provides important evidence suggesting that the Pro7 substitution in the prepro-NPY is an important risk factor for accelerated atherosclerotic progression, increased blood pressure and increased serum cholesterol in humans.

Low serum lycopene concentration is associated with an excess incidence of acute coronary events and stroke: the Kuopio Ischaemic Heart Disease Risk Factor Study

A number of epidemiological studies have shown an association between beta-carotene and the risk of cardiovascular diseases, whereas only a few studies are available concerning the association of lycopene with the risk of coronary events, and no studies have been undertaken concerning lycopene and stroke. Thus, we tested the hypothesis that low serum levels of lycopene are associated with increased risk of acute coronary events and stroke in middle-aged men previously free of CHD and stroke. The subjects were 725 men aged 46-64 years examined in 1991-3 in the Kuopio Ischaemic Heart Disease Risk Factor Study. Forty-one men had either a fatal or a non-fatal acute coronary event or a stroke by December 1997. In a Cox' proportional hazard's model adjusting for examination years, age, systolic blood pressure and three nutritional factors (serum folate, beta-carotene and plasma vitamin C), men in the lowest quarter of serum lycopene levels (< or =0.07 micromol/l) had a 3.3-fold (95 % CI 1.7, 6.4, risk of acute coronary events or stroke compared with the others. Our study suggests that a low serum level of lycopene is associated with an increased risk of atherosclerotic vascular events in middle-aged men previously free of CHD and stroke.

An insertion/deletion polymorphism in the alpha2B-adrenergic receptor gene is a novel genetic risk factor for acute coronary events

OBJECTIVES

Our aim was to study whether an insertion/deletion (I/D) polymorphism in the alpha2B-adrenoceptor gene is associated with the risk for cardiovascular diseases.

BACKGROUND

alpha2-adrenoceptors mediate contraction of vascular smooth muscle and induce coronary vasoconstriction in humans. The alpha2-adrenoceptor subtype B mediates vasoconstriction in mice. A variant of the human alpha2B-adrenoceptor gene that encodes a D of three residues in an intracellular acidic motif has been shown to confer decreased receptor desensitization. This receptor variant could, therefore, be involved in diseases associated with enhanced vasoconstriction.

METHODS

This study was part of a prospective population-based study investigating risk factors for cardiovascular diseases in a cohort of middle-aged men from eastern Finland. Nine hundred twelve men aged 46 to 64 years were followed for an average time of 4.5 years.

RESULTS

In this study population, 192 men (21%) had the D/D genotype; 256 (28%) had the I/I genotype, and 464 (51%) had a heterozygous genotype. In a Cox model adjusting for other coronary risk factors, men with the D/D genotype had 2.2 times (95% confidence interval: 1.1 to 4.4, p = 0.02) the risk to experience an acute coronary event (n = 15 for D/D, 10 for I/I and 12 for I/D) compared with men carrying either of the other two genotypes. The alpha2B-adrenoceptor genotype was not associated with hypertension in this study population.

CONCLUSIONS

The D/D genotype of the alpha2B-adrenoceptor is a novel genetic risk factor for acute coronary events, but not for hypertension.

Low plasma lycopene concentration is associated with increased intima-media thickness of the carotid artery wall

Although a number of epidemiological studies have evaluated the association between ss-carotene and the risk of cardiovascular diseases, there has been little research on the role of lycopene, an acyclic form of ss-carotene, with regard to the risk of cardiovascular disease. We investigated the relationship between plasma concentrations of lycopene and intima-media thickness of the common carotid artery wall (CCA-IMT) in 520 middle-aged men and women (aged 45 to 69 years) in eastern Finland. They were examined from 1994 to 1995 at the baseline of the Antioxidant Supplementation in Atherosclerosis Prevention (ASAP) study, a randomized trial concerning the effect of vitamin E and C supplementation on atherosclerotic progression. The subjects were classified into 2 categories according to the median concentration of plasma lycopene (0.12 micromol/L in men and 0.15 micromol/L in women). Mean CCA-IMT of the right and left common carotid arteries was 1.18 mm in men and 0.95 mm in women with plasma lycopene levels lower than the median and 0.97 mm in men (P:<0.001 for difference) and 0.89 mm in women (P:=0.027 for difference) with higher levels of plasma lycopene. In ANCOVA adjusting for cardiovascular risk factors and intake of nutrients, in men, low levels of plasma lycopene were associated with a 17.8% increment in CCA-IMT (P:=0.003 for difference). In women, the difference did not remain significant after the adjustments. We conclude that low plasma lycopene concentrations are associated with early atherosclerosis, manifested as increased CCA-IMT, in middle-aged men living in eastern Finland.

Fish oil-derived fatty acids, docosahexaenoic acid and docosapentaenoic acid, and the risk of acute coronary events: the Kuopio ischaemic heart disease risk factor study

BACKGROUND

Previous findings concerning the serum levels of fish-derived (n-3) fatty acids and coronary heart disease are inconsistent. The purpose of this study was to investigate the association between the serum n-3 end-product fatty acids docosahexaenoic acid (DHA), docosapentaenoic acid (DPA), and eicosapentaenoic acid and the risk of acute coronary events in middle-aged men.

METHODS AND RESULTS

We studied this association in the Kuopio Ischaemic Heart Disease Risk Factor Study, a prospective population study in Eastern Finland. Subjects were randomly selected and included 1871 men aged 42 to 60 years who had no clinical coronary heart disease at baseline examination. A total of 194 men had a fatal or nonfatal acute coronary event during follow-up. In a Cox proportional hazards' model adjusting for other risk factors, men in the highest fifth of the proportion of serum DHA+DPA in all fatty acids had a 44% reduced risk (P=0.014) of acute coronary events compared with men in the lowest fifth. Men in the highest fifth of DHA+DPA who had a low hair content of mercury (</=2.0 microgram/g) had a 67% reduced risk (P=0.016) of acute coronary events compared with men in the lowest fifth who had a high hair content of mercury (>2.0 microgram/g). There was no association between proportion of eicosapentaenoic acid and the risk of acute coronary events.

CONCLUSIONS

Our data provide further confirmation for the concept that fish oil-derived fatty acids reduce the risk of acute coronary events. However, a high mercury content in fish could attenuate this protective effect.

Antioxidant Supplementation in Atherosclerosis Prevention (ASAP) study: a randomized trial of the effect of vitamins E and C on 3-year progression of carotid atherosclerosis

OBJECTIVES

To study the efficacy of vitamin E and C supplementation on the progression of carotid atherosclerosis, hypothesizing an enhanced preventive effect in men and in smokers and synergism between vitamins.

DESIGN AND SUBJECTS

Double-masked two-by-two factorial trial, randomization in four strata (by gender and smoking status) to receive twice daily either 91 mg (136 IU) of d-alpha-tocopherol, 250 mg of slow-release vitamin C, a combination of these or placebo for three years. A randomized sample of 520 smoking and nonsmoking men and postmenopausal women aged 45-69 years with serum cholesterol >/= 5.0 mmol L-1 were studied.

SETTING

The population of the city of Kuopio in Eastern Finland.

INTERVENTION

Twice daily either a special formulation of 91 mg of d-alpha-tocopherol, 250 mg of slow-release vitamin C, a combination of these (CellaVie(R)) or placebo for three years.

MEASUREMENTS

Atherosclerotic progression, defined as the linear regression slope of ultrasonographically assessed common carotid artery mean intima-media thickness (IMT), was calculated over semi-annual assessments.

RESULTS

The average increase of the mean IMT was 0.020 mm year-1 amongst men randomized to placebo and 0.018 mm year-1 in vitamin E, 0.017 mm year-1 in vitamin C and 0.011 mm year-1 in the vitamin combination group (P = 0.008 for E + C vs. placebo). The respective means in women were 0.016, 0.015, 0.017 and 0.016 mm year-1. The proportion of men with progression was reduced by 74% (95% CI 36-89%, P = 0.003) by supplementation with the formulation containing both vitamins, as compared with placebo.

CONCLUSIONS

Our study shows that a combined supplementation with reasonable doses of both vitamin E and slow-release vitamin C can retard the progression of common carotid atherosclerosis in men. This may imply benefits with regard to other atherosclerosis-based events.

Antioxidative efficacy of parallel and combined supplementation with coenzyme Q10 and d-alpha-tocopherol in mildly hypercholesterolemic subjects: a randomized placebo-controlled clinical study

It has been claimed that coenzyme Q10 (Q10) would be an effective plasma antioxidant since it can regenerate plasma vitamin E. To test separate effects and interaction between Q10 and vitamin E in the change of plasma concentrations and in the antioxidative efficiency, we carried out a double-masked, double-blind clinical trial in 40 subjects with mild hypercholesterolemia undergoing statin treatment. Subjects were randomly allocated to parallel groups to receive either Q10 (200 mg daily), d-alpha-tocopherol (700 mg daily), both antioxidants or placebo for 3 months. In addition we investigated the pharmacokinetics of Q10 in a separate one-week substudy. In the group that received both antioxidants, the increase in plasma Q10 concentration was attenuated. Only vitamin E supplementation increased significantly the oxidation resistance of isolated LDL. Simultaneous Q10 supplementation did not increase this antioxidative effect of vitamin E. Q10 supplementation increased and vitamin E decreased significantly the proportion of ubiquinol of total Q10, an indication of plasma redox status in vivo. The supplementations used did not affect the redox status of plasma ascorbic acid. In conclusion, only vitamin E has antioxidative efficiency at high radical flux ex vivo. Attenuation of the proportion of plasma ubiquinol of total Q10 in the vitamin E group may represent in vivo evidence of the Q10-based regeneration of the tocopheryl radicals. In addition, Q10 might attenuate plasma lipid peroxidation in vivo, since there was an increased proportion of plasma ubiquinol of total Q10.

Long-term effects of vitamin E, vitamin C, and combined supplementation on urinary 7-hydro-8-oxo-2'-deoxyguanosine, serum cholesterol oxidation products, and oxidation resistance of lipids in nondepleted men

We studied the long-term effects of vitamins E and C and their combination on lipid peroxidation in vivo and in vitro. The Antioxidant Supplementation in Atherosclerosis Prevention (ASAP) trial is a double-masked placebo-controlled randomized clinical trial to study the effects of vitamin C (500 mg of slow release ascorbate per day), vitamin E (182 mg of RRR-alpha-tocopherol acetate per day), and the combination of both antioxidants. Lipid peroxidation measurements were carried out for 48 male participants at entry and at 12 and 36 months. Compared with placebo, vitamin E and the vitamin combination increased plasma lipid-standardized alpha-tocopherol during the first 12 months by 68.2% and 65.2% (P:<0. 001 for both), respectively, and reduced serum 7beta-hydroxycholesterol by 50.4% (P:=0.013) and 44.0% (P:=0.041), respectively. The net change of lipid standardized alpha-tocopherol was 63.8% after 36 months of vitamin E supplementation and 43.3% for the combination. Vitamin C supplementation elevated plasma total ascorbate level by 30.1% (P:=0.043) in 12 months and by 91.1% (P:=0. 001) in 36 months. Neither vitamin E, vitamin C, nor the combination influenced the urinary excretion rate of 7-hydro-8-oxo-2'-deoxyguanosine or the antioxidative capacity of plasma. Vitamin E and the combination of vitamins E and C enhanced the oxidation resistance of isolated lipoproteins and total serum lipids. Our data indicate that long-term supplementation of nondepleted men with a reasonable dose of vitamin E alone or in combination with slow release vitamin C reduces lipid peroxidation in vitro and in vivo, whereas a relatively high dose of vitamin C alone does not.

Effect of supplementation with organic selenium on mercury status as measured by mercury in pubic hair

The purpose of this study was to evaluate the effect of four months of yeast-based selenium supplementation on selenium and mercury status in subjects with low serum selenium. The study was carried out in Rakvere, Estonia. Pubic hair mercury, serum selenium and blood selenium concentrations in 23 subjects (serum selenium < 90 micrograms/l) were investigated before and after selenium supplementation. Thirteen subjects were randomized into the selenium supplementation group and ten into the placebo group. The selenium supplementation group received daily 100 micrograms of selenomethionine. Selenium supplementation reduced pubic hair mercury level by 34% (p = 0.005) and elevated serum selenium by 73% and blood selenium by 59% in the supplemented group (p < 0.001 for both). The study indicates that mercury accumulation in pubic hair can be reduced by dietary supplementation with small daily amounts of organic selenium in a short range of time.

Measurement and stability of plasma reduced, oxidized and total coenzyme Q10 in humans

There are findings indicating that a decreased ratio of plasma coenzyme Q10 (Q10) to LDL cholesterol could be associated with an increased risk of atherosclerosis. Furthermore, the proportion of plasma Q10H2 (reduced Q10, ubiquinol) of total Q10 has been shown to be attenuated in major diseases, such as hyperlipidemia and coronary artery disease. These observations suggest that measurement of plasma total Q10 and the proportion of plasma Q10H2 of total Q10 would be of clinical significance. However, epidemiological studies addressing this issue require large numbers of subjects, and measurements from unfrozen samples are unfeasible. For this reason, we evaluated the stability of Q10 samples during sample storage and processing. We also compared solid phase and hexane pre-treatments prior to high-performance liquid chromatographic determination of Q10. Our results indicate that samples for plasma total Q10 measurement can be pre-treated in normal laboratory lighting conditions, thawed and frozen several times, and stored deep frozen for a couple of years without changes in measured Q10 values. If purification of the samples by silica and C18 is needed, the best reproducibility tends to be achieved with powder treatment (not with cartridges). However, to measure successfully the proportion of plasma ubiquinol of total Q10, samples must be thawed, extracted, and analysed one at a time and quickly to ensure minimal ubiquinol oxidation during the measurement process.