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Biomedical subjects

A Hofman

Publications and source records attributed to A Hofman.

At least 433 records · Page 24Linked to original sources
PubMed1987

Selenium status and chronic disease mortality: Dutch epidemiological findings.

This paper summarizes Dutch epidemiological findings on the impact of a low selenium (Se) status on mortality from cardiovascular disease (CVD) and cancer. Se status parameters of Dutch subjects are compared to those from Finland and the USA, and the concept of a threshold effect for Se on disease risk is discussed. Case-control analyses of prospective data suggest that low serum Se (below 105 micrograms/l) is not clearly associated with an excess risk of CVD death (relative risk RR = 1.6, 90% confidence interval Cl = 0.9-2.9). Se cancer findings indicate a possible gender difference in risk (in males RR = 2.7, 90% Cl = 1.2-6.2; in females RR = 1.5, 90% Cl = 0.5-4.5). Larger studies, monitoring a combination of Se status parameters are recommended.

Cardiovascular Diseases↗
PubMed1987

Is serum selenium a risk factor for cancer in men only?

The association of serum selenium with the subsequent risk of death from cancer was investigated in a case-control study that was nested in a prospective nine-year follow-up study in the Netherlands. In 1975-1978, 10,532 persons in the Dutch town of Zoetermeer who were aged five years or more participated in a medical survey. Serum samples were collected and stored at -20 C. For the 82 persons who died of cancer since the baseline examination, 164 cohort members still alive by the end of 1983 were selected as controls and matched for age, sex, and smoking. Cancer deaths that occurred in the first year of follow-up were excluded, leaving 69 cases for statistical analyses. The mean serum selenium level of 116.7 +/- 4.0 micrograms/liter among male cancer deaths (n = 40) was significantly different (p = 0.04) from that in the control subjects (126.4 +/- 3.1 micrograms/liter). In females, selenium levels were similar among cases and controls. The adjusted risk of death from cancer for men in the lowest quintile of serum selenium (below 100.8 micrograms/liter) was more than twice that of subjects with higher levels (relative risk = 2.7,90% confidence interval = 1.2-6.2). These data support recent findings of an increased cancer risk associated with low serum selenium levels in men but not in women.

Epidemiologic Methods↗
PubMed1987

Serum lipids in young women before, during, and after pregnancy.

The associations between pregnancy and serum lipids were investigated in a cohort of 831 Dutch women, initially aged 5-19 years. These women were examined yearly from 1975 to 1985 for an average period of six years, as part of a longitudinal survey of risk factors for coronary heart disease. During this period, 62 women became pregnant, and their serum total and high density lipoprotein (HDL) cholesterol levels were compared with those of an age-matched reference series of nonpregnant women, derived from the same cohort. Pregnant women showed higher total cholesterol levels (235 +/- 7.4 mg/100 ml) than nonpregnant women (205 +/- 2.7 mg/100 ml). Pregnant women also had higher levels of HDL cholesterol (66 +/- 2.1 mg/100 ml) than their referents (57 +/- 1.0 mg/100 ml). Total and HDL cholesterol increased with duration of pregnancy. When serum lipid levels of pregnant women were compared with the levels one year before and one year after pregnancy, it was observed that the year after pregnancy, HDL cholesterol levels dropped below pre-pregnancy concentrations. At the final examination, women who had ever been pregnant showed lower HDL cholesterol levels than those who had never been pregnant. The difference was most marked in users of oral contraceptives. These observations suggest that serum total and HDL cholesterol levels are elevated during pregnancy, probably because of hormonal changes. Furthermore, they point to a possibly lowering effect of parity on HDL cholesterol. These findings may help to explain the reported positive association between parity and the occurrence of cardiovascular diseases.

Adolescent↗
PubMed1987

Dose related coronary and systemic haemodynamic effects of intravenous bepridil in patients with coronary artery disease.

The acute coronary and systemic haemodynamic effects of intravenous bepridil were investigated in 27 patients with coronary artery disease; 13 (group 1) received 2 mg kg-1 and 14 (group 2) 4 mg kg-1 over 5 min. An immediate systemic and coronary vasodilation occurred in both groups during and immediately after the infusion. Changes were dose-related with a maximal decrease in left ventricular (LV) systolic pressure of 11% (group 1) and 18% (group 2), in mean aortic pressure of 11% (group 1) and 19% (group 2), and in coronary resistance of 23% (group 1) and 41% (group 2). Coronary flow increased by 17% (group 1) and 47% (group 2) (all changes significantly different from control (C) values and between groups). Cardiac output, measured immediately after bepridil, was unaltered, although in group 2 stroke volume index increased (14%) and systemic resistance decreased (16%), both P less than 0.05 vs C. In group 2, heart rate (HR) and contractility initially increased (8% and 10%, respectively, P less than 0.05 vs C), secondary to the greater fall in afterload, followed by a significant reduction at 5 and 10 min after bepridil (9% and 10%, respectively), accompanied by a 36% increase in LV enddiastolic pressure (P less than 0.05 vs C). No such changes were observed in group 1, apart from a simultaneous decrease in HR (9%, P less than 0.05 vs C). Thus, in humans, a dose-related, biphasic haemodynamic pattern is observed with intravenous bepridil, consisting of an acute, short-lasting vasodilation, followed by late negative chronotropic and inotropic effects, which, with longterm bepridil administration, may be beneficial during myocardial ischaemic.

Adult↗
PubMed1987

Acute antiischaemic properties of high dosages of intravenous diltiazem in humans in relation to its coronary and systemic haemodynamic effects.

The antiischaemic properties of intravenous diltiazem in recommended therapeutic doses are disputed. In 17 patients with coronary artery disease the systemic and coronary haemodynamic effects of diltiazem were assessed during a high-dose infusion (0.4 mg kg-1 per 5 min, followed by 0.4 mg kg-1 per 10 min). In addition, its potential antiischaemic properties were investigated during identical pacing stress tests, 30 minutes before (P1) and immediately after diltiazem administration (P2). Diltiazem reduced left ventricular systolic pressure from 133 +/- 5 to 116 +/- 5 mmHg (P less than 0.005, means +/- SEM), persisting until after P2. It decreased systemic and coronary resistance by 32% (P less than 0.001) and 29% (P less than 0.005), respectively, with a sustained increase in cardiac output from 5.9 +/- 0.4 to 7.3 +/- 0.6 l min-1 (P less than 0.01), but a brief 20% rise in coronary flow (P less than 0.05), after the bolus infusion only. Heart rate, contractility, left ventricular filling pressure and myocardial O2 consumption remained unchanged. Despite high plasma levels (673 +/- 81 micrograms l-1) diltiazem was well tolerated. During identical maximal pacing rates diltiazem considerably reduced myocardial O2 demand (double product: 16.3 +/- 0.8 (P2) vs 21.1 +/- 1.1 (P1), P less than 0.005), due to an 18% decrease in left ventricular systolic pressure, resulting in diminished coronary flow and myocardial O2 consumption during P2 (14% and 15%, respectively, P less than 0.05 vs P1). Diltiazem also significantly reduced pacing-induced ischaemia, indicated by normalization of myocardial lactate extraction (1 +/- 8% (P2) vs -41 +/- 12% (P1), P less than 0.05), and left ventricular filling pressure (13 +/- 2 (P2) vs 27 +/- 3 mmHg (P1), P less than 0.01), less ST-segment depression (0.12 +/- 0.01 (P2) vs 0.24 +/- 0.02 mV (P1), P less than 0.01) and improved contractility (Vmax 59 +/- 5 (P2) vs 48 +/- 3 s-1 (P1), P less than 0.05). Angina was absent or less in 15 patients during pacing after diltiazem. Thus, diltiazem, in high dosages, induces continuing systemic but short lasting coronary vasodilation, improves pump function without negative chronotropic and inotropic effects and has pronounced antiischaemic properties, predominantly due to diminished myocardial O2 demand.

Adult↗
PubMed1987

Sodium restriction and potassium supplementation in young people with mildly elevated blood pressure.

Forty young subjects, aged 18 to 28 years, with mildly elevated blood pressure participated in a double-blind randomized three-period crossover study of the effect of sodium restriction with and without potassium supplementation on blood pressure. Dietary sodium intake was restricted for 18 weeks in which the patients received in random sequence 'slow-sodium' (90 mmol/day), 'slow-potassium' (72 mmol/day), and placebo tablets, each for 6 weeks. Mean urinary sodium excretion was 129 mmol/24 h in the slow-sodium period, 57 mmol/24 h during placebo, and 69 mmol/24 h during slow-potassium. Mean supine systolic blood pressure in the sixth week of the slow-potassium period was 3.3 mmHg lower than that at the end of the slow-sodium period (P less than 0.05). There was no significant difference in systolic or diastolic blood pressure between the placebo and the slow-sodium periods. The fall in systolic blood pressure in the low sodium/high potassium period was accompanied by a fall in cardiac index of 0.4 l/min per m2 body surface area (BSA) (P = 0.03). Our observations suggest a small hypotensive effect of moderate sodium restriction combined with high potassium intake in young hypertensive subjects. Sodium restriction alone has little effect on blood pressure in this group. The combination of a low sodium/high potassium diet may lower blood pressure by affecting cardiac output. Reducing the dietary sodium:potassium ratio may therefore be useful in the management of early primary hypertension.

Adolescent↗
PubMed1987

Determinants of rise in blood pressure in normotensive children.

Thirty-nine initially normotensive children (25 girls) with a large increase in systolic blood pressure (SBP) over a period of 7 years were compared with 78 children with a small increase, matched for age and gender. They were selected from a random sample of 596 Dutch children who were examined at an initial examination and 4 weeks later, and at yearly intervals thereafter. Body weight, height and Quetelet index at baseline were similar in children with a large rise in SBP and those with a small rise. Children with a large increase had a larger weight gain during follow-up than those with a small rise. Parental blood pressure (BP) and parental history of diabetes mellitus and cardiovascular diseases did not differ between the study groups. Cardiovascular reactivity as assessed by a cold-pressor test at baseline did not differ between the study groups, nor did urinary sodium excretion during follow-up. Total tobacco consumption was larger in those with a small increase. Children with a large rise in SBP experienced a larger fall in SBP from the initial to the 4-week examination. The individual variability of BP over the whole observation period did not differ between the study groups. These observations suggest that a fall in BP after a short follow-up period may be indicative of high BP in the years to come.

Adolescent↗
PubMed1987

Blood pressure and physical fitness in children.

The association between physical fitness and blood pressure was studied in 2061 children selected from all fourth graders in 44 elementary schools in the New York City area. Their blood pressure and physical fitness were measured on two consecutive examinations 1 year apart. Systolic and diastolic blood pressure were highest in children with poor physical fitness. The change in physical fitness between the 2 examination years was related to the change in systolic and diastolic blood pressure (i.e., children with a decline in physical fitness showed the largest rise in blood pressure). These observations suggest that the level of systolic and diastolic blood pressure in children is associated with the level of physical fitness. They also indicate that change in blood pressure in childhood may be related to change in physical fitness.

Blood Pressure↗
PubMed1987

Prevalence, incidence, prognosis and risk factors of dementia.

The epidemiological evidence on the dementing illnesses suggests that dementia poses an important public health problem. Estimates of the prevalence of dementia indicate that in the twelve countries of the European Community 1.5 to 2.5 million people may be suffering of the disease. The available data on the incidence suggest that in these countries 200,000 to 250,000 people are newly hospitalized yearly for dementia. Fruitful epidemiological approaches to identify preventable causes of the dementing illnesses may include incidence studies across populations, family studies, and risk factors studies using Creutzfeldt-Jakob disease as a model for dementia of the Alzheimer type.

Aged↗
PubMed1986

Effect of calcium supplementation on diastolic blood pressure in young people with mild hypertension.

In a double-blind trial 90 mildly hypertensive subjects aged 16-29 years were randomly assigned to 1 g calcium per day or placebo. Calcium supplementation did not affect systolic blood pressure, but at six and twelve weeks diastolic blood pressure had fallen by 3.1 (p = 0.04) and 2.4 (p = 0.11) mm Hg, respectively, more in the calcium group than it had in the placebo group. Subjects with a baseline plasma parathyroid hormone (PTH) higher than the median showed a 6.1 mm Hg (p = 0.01) greater fall in diastolic blood pressure after six weeks and 5.4 mm Hg (p = 0.01) after twelve than in the placebo group. The fall in diastolic blood pressure was greater in the calcium group than in the placebo group in subjects with a lower than median serum total calcium and in those with a large bodyweight. Calcium supplementation may lower blood pressure in young people with mildly raised blood pressure, particularly in those with high plasma PTH and/or low serum total calcium.

Adolescent↗
PubMed1986

Does sodium restriction lower blood pressure?

Data from 13 randomised trials on the effect of sodium restriction on blood pressure were analysed. The hypotensive effect of sodium restriction was found to be small and restricted largely to systolic blood pressure, which fell by an average of 3.6 mm Hg (range 0.5-10.0 mm Hg). The reduction increased with age and in those with higher blood pressure. Sodium restriction therefore seems to be of limited use in those who are most eligible for non-pharmacological treatment of high blood pressure--namely, young patients with mild hypertension.

Adolescent↗
PubMed1986

Is the ratio of apo B/apo A-I an early predictor of coronary atherosclerosis?

It is unknown which lipoprotein in childhood is the best predictor of atherosclerosis later on in life. We measured serum triglycerides, total cholesterol, its subfractions (LDL, HDL, HDL2, HDL3) and apoproteins (A-I, A-II, B) in two groups of children. They were offspring of fathers who had severe coronary atherosclerosis or no coronary sclerosis, as determined by coronary angiography. Fasting blood lipids were measured in 49 children of fathers with severe sclerosis, and in 37 children of fathers without sclerosis. Sons of fathers with severe coronary atherosclerosis had higher levels of apo B and of the ratio apo B/apo A-I than sons of fathers free of atherosclerosis. No differences in lipid levels in daughters were observed. These observations suggest that apolipoproteins play a part in early atherogenesis. They further indicate that it may be possible to detect children who have a high probability of developing severe coronary atherosclerosis later in life.

Adolescent↗
PubMed1986

The effect of large doses of ethinylestradiol on apolipoprotein levels in excessively tall prepubertal girls.

Seventeen constitutionally tall prepubertal girls, aged 10 to 14 years, were treated with large doses of ethinyl estradiol (EE) to reduce their final height. The serum concentration of cholesterol, triglyceride, and apolipoproteins before and after four to 17 months of treatment were compared with the same variables in a reference group, initially matched for bone age and height. In the patients, cholesterol rose by 24% (1.1 +/- 0.8 mmol/L), triglyceride by 105% (0.97 +/- 0.70 mmol/L), LDL apo B by 48% (27 +/- 19 mg/dL), apo A-I by 45% (62 +/- 17 mg/dL), and apo A-II by 21% (12 +/- 11 mg/dL). In the reference group, none of these variables changed significantly. The ratio of LDL apo B/apo A-I remained constant in both groups.

Adolescent↗
PubMed1986

Intact parathyroid hormone (1-84) in primary hypertension.

Intact parathyroid hormone (1-84) (PTH) concentrations were measured in serum of 83 hypertensive and 83 normotensive subjects, aged 20 to 69 years, matched for age and gender, and selected from the same open population. No significant differences in serum intact-PTH levels were found between the total group nor between groups based on three age strata. However, PTH was negatively associated with body weight and after adjustment for differences in body weight, significantly higher intact-PTH levels were found in hypertensive than in normotensive subjects, aged 20-39 years, but not in those aged 40 to 69 years. Our findings suggest that body weight is a confounding variable when comparing differences in intact-PTH between groups. Intact-PTH levels may be increased in a subgroup of young primary hypertensive subjects.

Adult↗
PubMed1986

Non-pharmacological intervention in primary hypertension in childhood.

In children with blood pressure levels persistently in the upper part of the distribution and without evidence for known causes of hypertension, one may ask which approach should be used to lower blood pressure. In general, non-pharmacological intervention will be preferred over drug treatment as a first choice in children with primary hypertension. No specific non-pharmacological treatment is available for children with high blood pressure. The main objective of this review is to underscore the need for further intervention studies in hypertensive children. Although the scientific evidence is rather scanty, some general recommendations concerning body weight, physical activity and fitness, dietary intake of electrolytes and relaxation procedures can be made. In obese children, weight reduction, combined with increase of physical activity, is the measure of first choice to lower blood pressure. In children with a high sympathetic outflow, as evidenced by high levels of circulating catecholamines, increase of physical activity and use of relaxation procedures may be the first approach to lower blood pressure. In children with evidence for disturbances in electrolyte metabolism, as evidenced by high intralymphocytic sodium, low serum calcium, or high PTH, a dietary approach to high blood pressure may be used. In these children, an increase of potassium intake or calcium intake seems a promising way to lower blood pressure.

Body Weight↗