Plasma total homocysteine, B vitamins, and risk of coronary atherosclerosis

Epidemiological research has shown that elevated plasma total homocysteine (tHcy) is a risk factor for atherosclerotic disease. In the present case-control study, we investigated whether fasting or postmethionine-loading tHcy was a stronger predictor of risk of severe coronary atherosclerosis. Furthermore, we studied levels of B vitamins, which are involved in homocysteine metabolism. Subjects were recruited from men and women, aged 25 to 65 years, who underwent coronary angiography between June 1992 and June 1994 in a hospital in Rotterdam, The Netherlands. Cases (n=131) were defined as those with > or =90% occlusion in one and > or =40% occlusion in a second coronary artery, while control subjects (n=88) had <50% occlusion in only one coronary vessel. In addition, a population-based control group free from clinical cardiovascular disease (n=101) was studied. Coronary patients were studied at least 2.5 months after angiography or other acute illness, such as myocardial infarction. After adjusting for age and sex differences between the groups, cases had 9% (P=.01) higher geometric mean fasting and 7% (P=.04) higher geometric mean postload tHcy than the combined control groups. Despite higher levels of tHcy for cases, their geometric mean levels of red cell folate and pyridoxal 5'-phosphate were higher than for control subjects, whereas plasma vitamin B12 was only slightly lower in cases. The frequency distribution of tHcy values in cases was slightly shifted toward the right, across the entire range, compared with the distribution in the combined control group. This was somewhat more obvious for fasting than postload tHcy levels. The odds ratio (OR) for severe coronary atherosclerosis (case status) for each 1 SD increase in fasting tHcy (5 micromol/L) was 1.3 (95% confidence interval [CI], 1.0-1.6), similar to the OR for each 1 SD increase (12 micromol/L) in postmethionine-loading tHcy (1.3 [95 CI, 1.0-1.7]), after adjustment for sex, age, and other potential confounders. Furthermore, there was a significant linear trend of increasing fasting tHcy with increasing number of occluded arteries (P=.01), correcting for sex, age, and other potential confounders. Our data show a positive association between plasma tHcy and risk of severe coronary atherosclerosis, of similar strength for fasting and postload tHcy levels. The data suggest that the association exists over a wide range of tHcy levels, without a clear cutoff point below which there is no increased risk.

Families and natural history of lipids in childhood: an 18-year follow-up study

The natural history of total cholesterol and lipoprotein cholesterol in offspring was studied in relation to total cholesterol levels in their parents in the Epidemiological Prevention Study of Zoetermeer (EPOZ). All residents of 5 or more years who were living in two districts in the Dutch town of Zoetermeer were invited to participate in a study on indicators for chronic diseases between 1975 and 1978. In a random sample of 483 youngsters who were 5-19 years old, yearly measurements of cardiovascular risk factors were performed during a follow-up period of 18 years (average follow-up, 13.8 years). Total and subfraction cholesterol levels in offspring during follow-up were studied by tertiles of age-adjusted total cholesterol in their parents. Total and low density lipoprotein (LDL) cholesterol levels measured from childhood into young adulthood differed significantly between offspring whose fathers were in the highest total cholesterol tertile compared with those whose fathers were in the lowest tertile, amounting to 0.4 mmol/liter for total cholesterol and 0.5 mmol/liter for LDL cholesterol. Offspring differences by maternal tertiles amounted to 0.5 mmol/liter for total cholesterol and 0.6 mmol/liter for LDL cholesterol. Offspring (n = 53) with both parents in the upper cholesterol tertile had almost 1 mmol/liter higher cholesterol levels compared with offspring (n = 51) with both parents in the lowest tertile, whereas offspring (n = 48) with both parents in the middle tertile had intermediate levels. Differences remained after adjustment for sex, Quetelet index, systolic and diastolic blood pressure, and use of alcohol, cigarettes, and oral contraceptives. Offspring group differences in total and LDL cholesterol were already present in childhood and persisted into young adulthood. There was no clear relation between offspring change in cholesterol levels and parental total cholesterol levels. For high density lipoprotein cholesterol and its subfractions, no relations with parental total cholesterol levels were found. Based on the evidence of a strong positive relation between total cholesterol levels in parents and offspring levels of total and LDL cholesterol measured from childhood into young adulthood, the authors conclude that total and LDL cholesterol levels in offspring may already be characterized from young age and beyond through cholesterol levels in their parents.

Long-term effects of neonatal sodium restriction on blood pressure

In 1980, a randomized trial was conducted among 476 Dutch newborn infants to study the effect of a low or normal sodium diet on blood pressure during the first 6 months of life. At the end of the trial, systolic blood pressure in the low sodium group (n = 231) was 2.1 mm Hg lower than in the control group (n = 245). To investigate whether contrasting levels of sodium intake in infancy are associated with blood pressure differences in adolescence, we measured blood pressure in 167 children from the original cohort (35%) after 15 years of follow-up. We assessed the differences in systolic and diastolic blood pressure levels between the diet groups using a multivariate regression model with adjustment for potential confounders. The adjusted systolic blood pressure at follow-up was 3.6 mm Hg lower (95% confidence interval, -6.6 to -0.5) and the diastolic pressure was 2.2 mm Hg lower (95% confidence interval, -4.5 to 0.2) in children who had been assigned to the low sodium group (n = 71) compared with the control group (n = 96). These findings suggest that sodium intake in infancy may be important in relation to blood pressure later in life.

The association of dietary fat and fiber with coagulation factor VII in the elderly: the Rotterdam Study

Considerable evidence suggests that a high concentration of coagulation factor VII is a risk factor for ischemic heart disease. Factor VII is known to be influenced by dietary fat and probably by dietary fiber in young and middle-aged people. There are no data available in elderly people and the effects of different types of fat are unclear. This study examines the relation of factor VII activity (factor VIIc) with dietary fat and fiber in The Rotterdam Study. The Rotterdam Study is a population-based study among 7983 men and women aged > or = 55 y. Factor VIIc was measured in 3007 subjects (1730 women and 1277 men aged 67.3 +/- 7.8 and 66.3 +/- 7.0 y, respectively). Measurements included cardiovascular risk factors and habitual diet was assessed by a semiquantitative food-frequency questionnaire. Associations that were significant or nearly significant differed for some nutrients between men and women. Total fat intake showed a direct association with factor VIIc only in women (beta = 0.1%/g; 95% CI: 0.01, 0.20). Saturated fat intake was associated with factor VIIc in women (beta = 0.18%/g; 95% CI: 0.001, 0.36) and in men (beta = 0.11%/g; 95% CI: -0.06, 0.27). Monounsaturated fat was positively related to factor VIIc in women (beta = 0.17%/g; 95% CI: -0.05, 0.39) and polyunsaturated fat was inversely associated with factor VIIc in men (beta = -0.15%/g; 95% CI: -0.33, 0.03). Fiber intake was inversely associated with factor VIIc in both men (beta = -0.31%/g; 95% CI: -0.57, -0.06) and women (beta = -0.36%/g; 95% CI: -0.63, -0.09). No associations were found for energy intake. In elderly persons, factor VIIc is associated with fat and fiber intake. This suggests that factor VIIc is influenced by nutritional factors, even in old age.

Vitamin K status and bone mass in women with and without aortic atherosclerosis: a population-based study

Gammacarboxyglutamate (Gla) is an uncommon amino acid formed by vitamin K action. Increasing evidence indicates that Gla-proteins are involved in the regulation of calcification processes in both bone tissue and atherosclerotic vessel wall. In a population-based study we have previously shown that in a group of 113 postmenopausal women the presence of abdominal aortic calcifications is associated with a reduced vitamin K status. In the present study we investigated whether this reduced vitamin K status was also associated with differences in bone mass or circulating calciotropic hormone levels. Serum immunoreactive osteocalcin with low affinity for hydroxyapatite (irOCfree) was used as a marker for vitamin K status. After correction for age it was found that women with atherosclerotic calcifications had a 7% lower bone mass as measured by metacarpal radiogrammetry (mean difference: 3.2 mm2, 95% CI: -0. 2-6.5, P = 0.06). No differences between both groups of women were observed for serum intact parathyroid hormone (PTH) and serum 25-hydroxyvitamin D levels. In the atherosclerotic women (n = 34), markers for vitamin K status were inversely associated with bone mass (r = -0.47, P = 0.013), whereas no such association was found in the nonatherosclerotic women (n = 79). It is concluded that the atherosclerotic women in this study may be at higher risk for osteoporotic fractures as evidenced by their lower bone mass and higher serum irOCfree levels. The finding that in atherosclerotic women vitamin K status is associated with bone mass supports our hypothesis that vitamin K status affects the mineralization processes in both bone and in atherosclerotic plaques.

Dietary antioxidants and cognitive function in a population-based sample of older persons. The Rotterdam Study

Antioxidants have been implicated in processes related to atherosclerosis, aging, and selective neuronal damage, all of which may ultimately affect cognitive function. In a sample of older persons, the authors examined the cross-sectional relation between cognitive function and dietary intake of beta-carotene and vitamins C and E. The data were derived from 5,182 community participants aged 55-95 years in the population-based Rotterdam Study in the period 1990 to 1993. Dietary intake was estimated from a semi-quantitative food frequency questionnaire and categorized into five levels of intake. Cognitive function was measured with the 30-point Mini-Mental State Examination (MMSE) and characterized as unimpaired (> 25 points) or impaired (< or = 25 points). Logistic regression analysis was used to estimate the odds ratio (OR) and 95% confidence interval (CI) for cognitive impairment. After adjustment for age, education, sex, smoking, total caloric intake, and intake of other antioxidants, a lower intake of beta-carotene was associated with impaired cognitive function (< 0.9 mg vs. > or = 2.1 mg intake, OR = 1.9, 95% CI 1.2-3.1; p for trend < 0.04). There was no association between cognitive function and intake of vitamins C and E. These cross-sectional observations are compatible with the view that beta-carotene-rich foods may protect against cognitive impairment in older people. The finding could also reflect unmeasured confounding, measurement error, or a change in food habits that resulted from rather than preceded the onset of cognitive impairment.

Dietary electrolyte intake and blood pressure in older subjects: the Rotterdam Study

OBJECTIVE

To examine the relation between dietary electrolyte intake and blood pressure in older people.

METHODS

The study included 3239 participants of the Rotterdam Study (41% of the total cohort) who were aged over 55 years and had not been prescribed antihypertensive drugs. Their dietary intake was assessed by a semiquantitative food frequency questionnaire. The association of energy-adjusted intakes of potassium, magnesium and calcium with blood pressure was studied in a linear regression model with adjustment for age, sex, body mass index and alcohol intake.

RESULTS

An increase in potassium intake of 1 g/day was associated with a 0.9 mmHg lower systolic and a 0.8 mmHg lower diastolic blood pressure. An increase in magnesium intake of 100 mg was associated with a 1.2 mmHg lower systolic and a 1.1 mmHg lower diastolic blood pressure. Calcium intake was not independently related to blood pressure, except for a subgroup of 1360 hypertensive subjects in which a significant inverse association with diastolic blood pressure was observed.

CONCLUSIONS

Our findings support the view that an increase in the intake of foods rich in potassium and magnesium could lower blood pressure at older age.

Lipoproteins and apolipoproteins in the young and familial risk of coronary atherosclerosis

The aim of this study was to assess the predictive value of lipoproteins and apolipoproteins at a young age for the development of coronary artery disease at middle and older ages. Because children of coronary artery disease patients are at high risk themselves we compared lipoprotein and apolipoprotein levels between the offspring of parents with and without coronary artery disease. We selected a group of male patients (n = 90), who had severe coronary atherosclerosis at angiography, and a reference group of male controls (n = 62), who had no coronary atherosclerosis at angiography. Lipoprotein and apolipoprotein levels were determined in 115 sons and 73 daughters of the patients with severe coronary atherosclerosis. These were compared to levels in 68 sons and 47 daughters of controls. Additionally, lipoprotein and apolipoprotein levels were compared between patients and controls as well as between their spouses. In sons of patients, lower levels of HDL3 cholesterol (-0.07 mmol/1, standard error of the mean (SEM) 0.03, P < 0.05) and apolipoprotein A2 (-5.1 mg/dl (SEM, 1.4), P < 0.0001) were found compared to sons of controls. Similar differences were observed in daughters of such patients without, however, achieving statistical significance. No significant differences between the groups of offspring were found for total cholesterol, LDL cholesterol, HDL and HDL2 cholesterol, triglycerides and apolipoproteins A-I and B. Patients had higher levels of total (group difference 0.6 mmol/1 (SEM, 0.18), P < 0.001) and LDL cholesterol (0.6 mmol/1 (SEM, 0.17), P < 0.001), triglycerides (0.6 mmol/1 (SEM, 0.16), P < 0.001) and apolipoprotein B (21.2 mg/dl (SEM, 5.1), P < 0.001), and lower HDL cholesterol (0.1 mmol/1 (SEM, 0.04), P < 0.05) than controls. Spouses of patients had higher levels of triglycerides (0.23 mmol/1 (SEM, 0.11), P < 0.05). Our findings add to the growing evidence that predictors for atherosclerotic disease can be detected relatively early in life. It is concluded that reduced levels of HDL3 cholesterol and apolipoprotein A2 may be early risk indicators for coronary atherosclerosis later in life.

Low diastolic blood pressure and atherosclerosis in elderly subjects. The Rotterdam study

BACKGROUND

A low diastolic blood pressure has been associated with increased cardiovascular risk. The following proposed mechanisms underlie this phenomenon: a low diastolic pressure that compromises coronary blood flow, a low diastolic pressure that is due to deteriorating health, and a low diastolic pressure that is a consequence of stiffening of the large arteries. Atherosclerosis may be the link between stiffening of the arteries, a low diastolic pressure, and an increased cardiovascular risk.

OBJECTIVE

To study whether a low diastolic blood pressure in older subjects is a reflection of atherosclerosis.

METHODS

The Rotterdam (the Netherlands) Study is a population-based follow-up study of 7983 subjects (age, > or = 55 years) who are living in the suburb of Ommoord of Rotterdam. Baseline measurements included ultrasonographic evaluation of the carotid arteries, measurement of blood pressure, and determination of other cardiovascular risk factors. The main cross-sectional analyses were performed among 930 subjects who currently were not using blood pressure-lowering drugs.

RESULTS

A J-shaped association of the intima-media thickness of the common carotid artery with diastolic blood pressure was found with a nadir from 60 to 69 mm Hg. The intima-media thickness was increased in subjects with a diastolic pressure that was less than 60 mm Hg compared with that in subjects with a diastolic pressure that was between 60 and 69 mm Hg (a difference of 0.033 mm [95% confidence limits; 0.001, 0.065]). Beyond a diastolic pressure of 70 mm Hg, a gradual increase in the intima-media thickness was observed. The association was most pronounced among subjects with relatively high pulse pressures.

CONCLUSIONS

Results of the present study indicate the existence of a J-shaped association between carotid atherosclerosis and diastolic pressure. These findings support the hypothesis that in elderly subjects, a low diastolic pressure may be a reflection of widespread atherosclerosis.

Long-term moderate sodium restriction does not adversely affect the serum HDL/total cholesterol ratio

We examined the effect of long-term moderate sodium restriction on the HDL/total cholesterol ratio within a randomised trial of the effect of mineral salt on blood pressure (BP). Eighty nine untreated hypertensive men and women aged 55-75 years were included in the analysis. During 24 weeks, 46 subjects used a low sodium, high potassium, high magnesium salt and 43 controls used common salt. Serum cholesterol levels were measured at baseline and at the end of the trial. After 24 weeks, 24 h urinary sodium was decreased by 41 mmol (95% Cl 23-60 mmol, P < 0.0001) in the mineral salt group compared with the controls. Serum total cholesterol was decreased in both groups, but 0.45 mmol/l (95% Cl 0.12-0.78, P = 0.01) more in the controls than in the mineral salt group after adjustment for age, sex and changes in body weight, serum total protein and potassium excretion. Serum HDL-cholesterol was decreased by 0.07 mmol/l in the controls and increased by 0.06 mmol/l in the mineral salt group, yielding a difference of 0.14 mmol/l (95% Cl 0.05-0.22 mmol/l, P = 0.003). The change in HDL/total cholesterol ratio was more favourable in the mineral salt group than in the controls (0.014 and 0.004 units, respectively, P = 0.014). We conclude that long-term moderate sodium restriction does not adversely affect the serum HDL/total cholesterol ratio and is a safe dietary measure for lowering BP.

[Risk factors for cardiovascular diseases in the elderly; the ERGO study (Erasmus Rotterdam Health and the Elderly)]

OBJECTIVE

To determine the prevalence of risk factors for cardiovascular disease among elderly people.

DESIGN

Prospective cohort study.

SETTING

A district of Rotterdam, the Netherlands.

METHODS

As a part of the Rotterdam Study information about smoking habits, blood pressure, Quetelet index and serum cholesterol of 7,983 responding persons (78%) (3,105 men and 4,878 women) of 55 years and older was obtained by an interview and physical examination during two visits to a research center.

RESULTS

Among men and women there were 29.7% and 16.7% smokers and 60.1% and 25.9% ex-smokers, respectively. Among men the proportion of smokers decreased from 31.0% in the age category 55-59 years to 15.9% in de category > or = 85 years, among women from 28.0% to 2.7%. Systolic blood pressure increased with age in both sexes, while diastolic blood pressure hardly changed. Hypertension (systolic blood pressure 160 mmHg and/or diastolic blood pressure > or = 95 mmHg at a single measurement and/or use of antihypertensive drugs) occurred in 23.3% of men and 28.0% of women. In men, total serum cholesterol decreased gradually with age, whereas in women there was a slight increase up to the category 70-74 years. No evident change in HDL cholesterol with increasing age was observed in men, but in women a decrease was observed until the same level was reached as in men. Thirty-five per cent of men and 49.5% of women had an elevated level of serum cholesterol (> or = 6.5 mmol/l). The prevalence of obesity (Quetelet index > 25 kg/m2) was about 50% in both men and women but was less in the categories from 75 years onwards. Approximately 80% of men and women had at least one risk factor, while in almost half of them two or more risk factors were found.

CONCLUSION

Risk factors for cardiovascular disease are common among elderly people.

Vitamin K intake and osteocalcin levels in women with and without aortic atherosclerosis: a population-based study

Protein-bound gamma-carboxyglutamate (Gla) has been demonstrated in calcified atherosclerotic plaques. Vitamin K is required for the formation of Gla-residues. As the biological activity of Gla-proteins appears to be strictly dependent on the presence of the Gla-residues, vitamin K status may be an important factor in the development and progression of atherosclerotic calcifications. We studied the association of vitamin K status, as assessed by nutritional vitamin K intake and the measurements of two circulating immunoreactive osteocalcin (irOC) fractions, with aortic atherosclerosis in a population-based study of 113 postmenopausal women. Women with calcified lesions (n = 34) had a 42.9 micrograms lower mean age-adjusted dietary vitamin K intake/day (95% C.I. -6.6 to 92.5) than those without calcifications (n = 79). Atherosclerotic women had higher irOC levels with a low affinity for hydroxyapatite (irOCfree): age-adjusted difference of 0.32 ng/ml (95% C.I. 0.03 to 0.61). In addition, the high affinity irOC levels expressed as a percentage (hydroxyapatite binding capacity, HBC) were 5.12% (95% C.I. 1.32 to 8.92) lower in women with calcifications. Our study indicates that women with aortic atherosclerosis have an impaired vitamin K status as reflected by a lower nutritional vitamin K intake, an increased irOCfree level and a reduced HBC level. An impaired vitamin K status in subjects with atherosclerosis is compatible with the view that vitamin K or Gla-containing proteins are involved in the development of calcification of the vessel wall.

Physical activity, calcium intake, and bone mineral content in children in The Netherlands

STUDY OBJECTIVE

To examine the relation between physical activity, calcium intake, and bone mineral content in children.

DESIGN

Population based, cross sectional study.

SETTING

Primary schools in Zoetermeer, The Netherlands.

PARTICIPANTS

Altogether 1359 Dutch boys and girls, aged 7 to 11 years (response rate 88%).

MEASUREMENTS

Bone mineral content was measured by quantitative roentgen microdensitometry of the midphalanx of the second digit at the diaphyseal and metaphyseal site. Maximal exercise testing, according to the Bruce treadmill protocol, was used to assess physical fitness. Habitual physical activity was assessed by use of a questionnaire on physical activities. Daily calcium intake from dairy products was estimated by use of a semiquantitative food frequency questionnaire.

MAIN RESULTS

Bone mineral content in boys was not linearly associated with physical fitness after adjustments for differences in height, body weight, chronological age, and skeletal age. In girls a linear association was found at the metaphyseal site only. When extreme groups were compared, bone mineral content was found to be higher in "high fitness children" (upper decile) than "low fitness children" (lowest decile), with statistical significance reached in boys only. When analyses were performed in subgroups of skeletal age, a clear linear relation between physical fitness and bone mineral content was seen in the mature subgroup in both boys and girls. No linear association was found between habitual physical activity and bone mineral content, while the results in extreme groups (that is, upper versus lowest decile) and in subgroups of skeletal age were comparable to those on physical fitness in boys only. No association was found between daily calcium intake and bone mineral content in this age group.

CONCLUSIONS

This cross sectional study in children aged 7 to 11 years suggests that an increased bone mineral content is found only in those with a high level of physical activity. This association is most pronounced in the more mature children. No evidence was found for an association between daily calcium intake and bone mineral content in childhood.

Postprandial triglyceride response in young adult men and familial risk for coronary atherosclerosis

OBJECTIVE

To determine whether an increased familial risk for coronary artery disease in young adult men is related to changes in postprandial lipoprotein metabolism.

DESIGN

Cross-sectional study.

SETTING

Coronary angiography departments of four central general hospitals in the Netherlands.

PATIENTS

80 sons (mean age, 24.8 years) of men with severe coronary artery disease and 55 sons (mean age, 23.2 years) of controls.

MEASUREMENTS

Postprandial levels of serum triglycerides, retinyl palmitate, and total cholesterol were measured during a 12-hour period after a standardized oral lipid load.

RESULTS

Both groups showed a marked increase in levels of serum triglyceride and retinyl palmitate after lipid loading, reaching a maximum 4 to 6 hours postprandially. No changes in postprandial total cholesterol levels were observed in either group. Sons of men with coronary artery disease had prolonged postprandial hypertriglyceridemia when compared with sons of controls. Significant differences in postprandial triglyceride levels were found at 8 hours (difference, 0.35 mmol/L; 95% CI, 0.07 to 0.62 mmol/L), at 10 hours (difference, 0.21 mmol/L; CI, 0.06 to 0.36 mmol/L), and at 12 hours after lipid loading (difference, 0.13 mmol/L; CI, 0.01 to 0.26 mmol/L). Levels of postprandial retinyl palmitate were also slightly, but not statistically, different (mainly after 6 hours).

CONCLUSIONS

Healthy young adult sons, whose fathers have established coronary artery disease, have prolonged postprandial hypertriglyceridemia. Changes in postprandial lipoprotein metabolism appear to be associated with familial risk for coronary atherosclerosis.

Reduction in blood pressure with a low sodium, high potassium, high magnesium salt in older subjects with mild to moderate hypertension

OBJECTIVE

To examine the effect of a reduced sodium and increased potassium and magnesium intake on blood pressure.

DESIGN

Randomised double blind placebo controlled trial.

SETTING

General population of a suburb of Rotterdam.

SUBJECTS

100 men and women between 55 and 75 years of age with untreated mild to moderate hypertension.

INTERVENTIONS

During 24 weeks the intervention group received a mineral salt (sodium: potassium: magnesium 8:6:1) and foods prepared with the mineral salt. Controls received common salt and foods.

MAIN OUTCOME MEASURE

Change in blood pressure.

RESULTS

Complete follow up was achieved for 97 of the 100 randomised subjects. Systolic blood pressure (mean of measurements at weeks 8, 16, and 24) fell by 7.6 mm Hg (95% confidence interval 4.0 to 11.2) and diastolic blood pressure by 3.3 mm Hg (0.8 to 5.8) in the mineral salt group compared with the controls, with a 28% decrease in urinary sodium excretion and a 22% increase in urinary potassium excretion. Twenty five weeks after the study the difference in blood pressure between the groups was no longer detectable.

CONCLUSION

Replacing common sodium salt by a low sodium, high potassium, high magnesium mineral salt could offer a valuable non-pharmacological approach to lowering blood pressure in older people with mild to moderate hypertension.

Reduction of blood pressure with oral magnesium supplementation in women with mild to moderate hypertension

In a double-blind controlled trial, 91 middle-aged and elderly women with mild to moderate hypertension who were not on antihypertensive medication were randomly assigned to treatment with magnesium aspartate-HCl (20 mmol Mg/d) or placebo for 6 mo. Magnesium aspartate-HCl in the given dose was well-tolerated and was not associated with an increased frequency of diarrhea compared with placebo. At the end of the study, systolic blood pressure had fallen by 2.7 mm Hg (95% CI -1.2, 6.7; P = 0.18) and diastolic blood pressure by 3.4 mm Hg (1.3, 5.6; P = 0.003) more in the magnesium group than in the placebo group. Blood pressure response was not associated with baseline magnesium status, as measured by dietary magnesium intake and urinary magnesium excretion. Urinary magnesium excretion in the magnesium group increased by 50% during the intervention period. No changes were seen in other biochemical indexes, including serum concentrations of total and high-density-lipoprotein cholesterol. The findings suggest that oral supplementation with magnesium aspartate-HCl may lower blood pressure in subjects with mild to moderate hypertension.

J-shaped relation between change in diastolic blood pressure and progression of aortic atherosclerosis

The J-shaped relation between diastolic blood pressure and mortality from coronary heart disease continues to provoke controversy. We examined the association between diastolic blood pressure and progression of aortic atherosclerosis in a population-based cohort of 855 women, aged 45-64 years at baseline. The women were examined radiographically for calcified deposits in the abdominal aorta, which have been shown to reflect intimal atherosclerosis. After 9 years of follow-up, slight progression of atherosclerosis was noted in 19% of women and substantial progression in 16%. The age-adjusted relative risk of substantial atherosclerotic progression in women with a decrease in diastolic pressure of 10 mm Hg or more was 2.5 (95% CI 1.3-5.6), compared with the reference group of women who had a smaller decrease or no change. The excess risk in this group was confined to women whose increase in pulse pressure was above the median (3.9 [1.5-9.9] vs 1.1 [0.3-4.2] in women with an increase in pulse pressure below the median). The relative risks for women with rises in diastolic pressure of 1-9 mm Hg and 10 mm Hg or more were 2.2 (1.1-4.3) and 3.5 (1.6-8.0), respectively. These findings suggest that a decline in diastolic blood pressure indicates vessel wall stiffening associated with atherosclerotic progression. They support the hypothesis that in low-risk subjects progression of atherosclerosis may be accompanied by a decrease in diastolic blood pressure rather than the opposing idea that low diastolic blood pressure precipitates the occurrence of atherosclerotic events.

Cigarette smoking and the development and progression of aortic atherosclerosis. A 9-year population-based follow-up study in women

BACKGROUND

Cigarette smoking has been recognized as an important risk factor for cardiovascular disease in men and women. Whether the increased risk results from an atherogenic effect of smoking is still debated. We examined the relation between cigarette smoking and atherosclerotic changes in the abdominal aorta.

METHODS AND RESULTS

The association between cigarette smoking and atherosclerotic changes in the abdominal aorta was examined in a population-based cohort of 758 women, initially aged 45 to 64 years. All women were examined radiographically for calcified deposits in the abdominal aorta, which have been shown to represent intimal atherosclerosis. After 9 years of follow-up, atherosclerotic changes, indicating development or progression of plaques, could be demonstrated in 37% of women. A direct association was found between atherosclerotic change and number of cigarettes smoked per day. Compared with women who had never smoked, the relative risks of those who smoked 1 to 9, 10 to 19, and 20 or more cigarettes per day were 1.4 (95% confidence interval, 1.0 to 2.0), 2.0 (1.6 to 2.5), and 2.3 (1.8 to 3.0), respectively, after adjustment for age and other cardiovascular risk factors. Associations of atherosclerotic change with inhaling habit and duration of smoking were borderline significant after number of cigarettes smoked per day was taken into account. Among former smokers, the risk decreased with increasing duration of stopping but a significant excess risk was still observed after 5 to 10 years since quitting (relative risk, 1.6; 95% confidence interval, 1.1 to 2.2).

CONCLUSIONS

These follow-up data support the evidence for an effect of cigarette smoking on atherosclerosis. The findings suggest that the rate of atherosclerotic change may be reduced by cessation of smoking, but a residual effect appears to be present for at least 10 years.

Carotid intima-media wall thickness in elderly women with and without atherosclerosis of the abdominal aorta

In the present study the association was evaluated between non-invasively assessed atherosclerosis of the abdominal aorta and ultrasonographically measured intima-media wall thickness of the common carotid arteries in a population-based study of 41 elderly women. Atherosclerosis of the abdominal aorta was assessed in 1985 using a lateral X-ray of the lumbar spine, on which the presence of calcified deposits was determined. The carotid arteries were ultrasonographically evaluated in 1990 for presence of atherosclerotic plaques and intima-media wall thickness of the distal common carotid was measured off line using dedicated software. The age-adjusted mean intima-media wall thickness of the right common carotid artery was significantly higher in subjects with calcified deposits in the aorta (n = 16) compared with those without deposits (n = 25) with a mean difference of 0.15 mm (95% confidence interval (CI) 0.03, 0.26). For the left side similar results were observed. Mean common carotid intima-media wall thickness, ((left+right)/2), differed significantly across groups with a mean difference of 0.11 mm (95% CI 0.01, 021). Additional adjustment for differences across groups in body mass index, serum cholesterol, hypertension and smoking did not change the magnitude of the observed association: mean difference of 0.12 mm (95% CI -0.01, 0.25). The findings of the present study provide evidence that among subjects with atherosclerotic plaques in the abdominal aorta, the intima-media wall thickness of the distal common carotid arteries is increased.

High blood pressure and the incidence of non-insulin dependent diabetes mellitus: findings in a 11.5 year follow-up study in The Netherlands

To examine the contribution of cardiovascular risk factors to the development of non-insulin dependent diabetes mellitus, a prospective follow-up study was performed of a cohort, initially examined in a population survey on cardiovascular risk factors. The survey was conducted from 1975 to 1978 in the Netherlands among 5700 men and women aged 20 to 65. In 1988 a questionnaire on the prevalence of chronic diseases, including diabetes mellitus, was sent to all living participants of the initial survey. The general practitioners of the persons who indicated to have diabetes mellitus were asked to confirm the diagnosis. Diabetes mellitus was defined as current use of oral hypoglycemic drugs or insulin. After exclusion of the prevalent cases at the initial survey, 65 incident confirmed cases remained. All others responding to the questionnaire served as controls. The incidence of diabetes mellitus was associated with body mass index, use of diuretics, systolic and diastolic blood pressure. After adjustment for age and body mass index systolic and diastolic blood pressure were still associated with the incidence of non-insulin dependent diabetes mellitus in men; relative risks 1.28 (95% confidence interval 1.06-1.54) and 1.40 (95% CI 1.06-1.85) per 10 mmHg respectively. For women, only the relative risk associated with the use of diuretics remained statistically significant (2.26, 95% CI 1.04-4.90). This probably reflects the risk of (treated) hypertension: adjusted for blood pressure, the relative risk lost statistical significance. These findings suggest that elevated blood pressure is a risk for the development of non-insulin dependent diabetes mellitus (NIDDM). This supports the view that NIDDM and hypertension may have a similar origin.

Aortic calcified plaques and cardiovascular disease (the Framingham Study)

The relation between the presence of calcified plaques in the thoracic aorta, as detected on chest x-rays, and the development of cardiovascular disease is examined during 12 years of follow-up of the Framingham cohort (n = 5,209). The prevalence of aortic calcified plaques approximately doubled with each decade of age, with only a trivial male predominance. Its presence was associated with a twofold increase in risk of cardiovascular death in men and women younger than age 65, even after other risk factors were taken into account. Similar increases in risk were found for coronary artery disease, stroke and intermittent claudication among middle-aged women. In middle-aged men these risks were less marked. The predictive value of aortic calcified plaques generally diminished with age. Risk of sudden coronary death in men with calcified plaques in the thoracic aorta ranged from a sevenfold increase at age 35 to no excess risk at age 70 years. These results support the view that atherosclerosis is a generalized process. The finding of aortic calcified plaques in a relatively young subject on a routine chest x-ray should be regarded as a sign for potential development of clinically manifest atherosclerotic disease in the cardiac, cerebral and peripheral arterial circulation.

Relation of moderate alcohol consumption and risk of systemic hypertension in women

The relation between alcohol consumption and the risk of development of hypertension was studied among 58,218 US female registered nurses aged 39 to 59 years who were free of diagnosed systemic hypertension and other major diseases. In 1980, all of these women completed an independently validated dietary questionnaire, which included use of alcoholic beverages. During 4 years of follow-up, 3,275 women reported an initial diagnosis of hypertension; validity of the self-report measure was demonstrated in a subsample. When compared to nondrinkers, women drinking 20 to 34 g of alcohol per day (about 2 or 3 drinks) had a significantly elevated relative risk of 1.4; the 95% confidence interval (CI) was 1.2 to 1.7 after adjustment for age and Quetelet's index. For women consuming greater than 35 g/day, the relative risk was 1.9 (95% CI 1.6 to 2.2). Adjustment for smoking and dietary variables did not alter these results. Independent significant associations were observed for the consumption of beer, wine and liquor. These prospective data suggest that alcohol intake of up to about 20 g/day does not increase the risk of hypertension among women, but beyond this level, the risk increases progressively.

A prospective study of nutritional factors and hypertension among US women

The relation of various nutritional factors with hypertension was examined prospectively among 58,218 predominantly white US female registered nurses, aged 34-59 years. In 1980, all women completed an independently validated dietary questionnaire. During 4 years of follow-up, 3,275 women reported a diagnosis of hypertension; the validity of the self-report was shown in a subsample. Age, relative weight, and alcohol consumption were the strongest predictors for the development of hypertension. Dietary calcium and magnesium had independent and significant inverse associations with hypertension. For women with a calcium intake of at least 800 mg/day, the relative risk of hypertension was 0.78 (95% confidence interval, 0.69-0.88) when compared with an intake of less than 400 mg/day. The relative risk for magnesium intake of 300 mg/day or more compared with an intake of less than 200 mg/day was 0.77 (95% confidence interval, 0.67-0.88). For women with high intakes of both calcium and magnesium compared with those having low intakes of both, the relative risk of hypertension was 0.65 (95% confidence interval, 0.53-0.80). No independent associations with hypertension were observed for intakes of potassium, fiber, and saturated and polyunsaturated fatty acids. These prospective findings add to the growing evidence to support the need for randomized trials to determine whether there is a protective role of dietary calcium and magnesium in the regulation of blood pressure.

Increased risk of atherosclerosis in women after the menopause

An increase in the incidence of cardiovascular disease has generally been observed in postmenopausal women, but there have been few studies of the association between menopausal state and atherosclerosis. In this study 294 premenopausal and 319 postmenopausal women aged 45 to 55 were examined radiographically for calcified deposits in the abdominal aorta, which have been shown to represent intimal atherosclerosis. Aortic atherosclerosis was present in eight (3%) of the premenopausal women and in 38 (12%) of the postmenopausal women. After adjustments for age and other indicators of cardiovascular risk women with a natural menopause had a 3.4 times greater risk of atherosclerosis than premenopausal women (95% confidence interval 1.2 to 9.7; p less than 0.05); women who had had a bilateral oophorectomy had a 5.5 times greater risk (1.9 to 15.8; p less than 0.005). No excess risk of atherosclerosis was observed among women who had had a hysterectomy without removal of both ovaries. These results suggest that when oestrogen production stops, either naturally or after surgery, the risk of atherosclerosis is increased.

Low vitamin B6 status in patients with acute myocardial infarction

The vitamin B6 status of 84 patients with acute myocardial infarction was compared with that of 84 control subjects. Pyridoxal and pyridoxal 5'-phosphate (PLP) in plasma and erythrocytes, as well as the basal and total potential activity of the PLP-dependent enzyme aspartate aminotransferase in erythrocytes, were measured for a comprehensive assessment of vitamin B6 status. The mean levels of all vitamin B6 indexes (except pyridoxal) were lower in the patients than in the control subjects. The differences were statistically significant, except for erythrocyte PLP and total potential enzyme activity. The adjusted relative odds of a myocardial infarction for subjects in the lowest quartile of plasma PLP was about 5 times higher when compared with those in the highest quartile (relative odds = 5.2, 95% confidence interval = 1.4 to 18.9). Similar findings were found with the other vitamin B6 indexes. No significant association between infarct size, as estimated by creatine kinase level, and the vitamin B6 indexes was observed.

Decreased selenium levels in acute myocardial infarction

To study the association between selenium status and the risk of myocardial infarction, we compared plasma, erythrocyte, and toenail selenium levels and the activity of erythrocyte glutathione peroxidase among 84 patients with acute myocardial infarction and 84 population controls. Mean concentrations of all selenium measurements were lower in cases than controls. The differences were statistically significant, except for the plasma selenium level. A positive trend in the risk of acute myocardial infarction from high to low toenail selenium levels was observed, which persisted after adjustment for other risk factors for myocardial infarction. In contrast, erythrocyte glutathione peroxidase activity was significantly higher in cases than controls (31.3 +/- 8.4 U/g of hemoglobin and 28.0 +/- 8.1 U/g of hemoglobin, respectively). Because the toenail selenium level reflects blood levels up to one year before sampling, these findings suggest that a low selenium status was present before the infarction and, thus, may be of etiologic relevance. The higher glutathione peroxidase activity in the cases may be interpreted as a defense against increased oxidant stress either preceding or following the acute event.

Aortic calcification as a predictor of cardiovascular mortality

Since aortic calcification is seen on X-rays of the prelumbar region in many patients, its relation with cardiovascular disease (CVD) was investigated in a prospective study in The Netherlands. X-rays were taken of 1359 men and 1598 women, in 1975-78. In the subsequent 9 years, 50 men and 33 women died from CVD. The prevalence of aortic calcification was about 10% in middle-aged subjects and rose with age to a maximum of 45% in men and 75% in women. Aortic calcification was associated with a six-fold increased risk of CVD death in men aged 45 years, independent of major CVD risk factors. For each year of age over 45, risk associated with the presence of aortic calcification declined by 6%. Death rates in middle-aged women were too small for risk analysis. These results suggest that atherosclerosis in other than coronary or cerebral vessels may have predictive relevance for CVD death: its diagnosis indicates intervention on present CVD risk factors.

Noncontraceptive hormones and rheumatoid arthritis in perimenopausal and postmenopausal women

The use of noncontraceptive hormones before onset of joint disease was compared between 490 perimenopausal and postmenopausal women with rheumatoid arthritis and a control group of 659 women with soft-tissue rheumatologic disorders and/or osteoarthritis. Both groups were sampled randomly from the attendees of five rheumatologic clinics. A negative association was found between the onset of rheumatoid arthritis and the previous use of noncontraceptive hormones (odds ratio, 0.32; 95% confidence interval, 0.16 to 0.64). This association persisted on univariate and multivariate control of potentially confounding variables and on subgroup analysis. The protective effect of oral contraceptives on the development of rheumatoid arthritis was confirmed.