Epidemiological study of the relationship between calcium and blood pressure.

During an epidemiological survey of 9321 male Belgian subjects, a highly significant positive correlation was found between the serum calcium level and blood pressure. The slope of the equation relating serum calcium level to blood pressure was higher in subjects who restricted their sodium intake than in subjects who did not. The slope was also significantly higher in subjects who did not take medication for hypertension compared to those who did. There was a significant and positive correlation between urinary calcium measured from 24-hour samples and blood pressure, both in the Belgian study and in a further epidemiological survey in Korea. In the Korean study, no significant correlation was found between 24-hour urinary magnesium excretion and blood pressure.

The relationship between cations and blood pressure in the People's Republic of China.

Blood pressure was measured in the north and in the south of the People's Republic of China in 1002 men and 1006 women. The 24-hour urinary excretion of sodium, potassium, calcium, magnesium, and creatinine was measured, and the relationship between urinary cations and blood pressure was studied. Blood pressure and 24-hour sodium excretion were higher in northern China than in southern China. With some exceptions, a positive correlation was found between urinary sodium and blood pressure and a negative one between 24-hour urinary potassium excretion and blood pressure. Urinary calcium correlated negatively and urinary magnesium did not correlate significantly with blood pressure. The sodium/potassium ratio correlated positively with blood pressure, and the calcium/magnesium ratio, negatively. This study confirms the positive within-population relationship between sodium intake and blood pressure in Oriental populations.

Intermittent aortic cross-clamping versus St. Thomas' Hospital cardioplegia in extensive aorta-coronary bypass grafting. A randomized clinical study.

Myocardial preservation was assessed in 72 patients undergoing extensive myocardial revascularization. The patients were allocated at random to three surgical techniques: Group 1, intermittent aortic cross-clamping at 32 degrees C; Group 2, intermittent aortic cross-clamping at 25 degrees C; and Group 3, St. Thomas' Hospital cardioplegia. As intraoperative markers of ischemic damage, adenosine triphosphate, creatine phosphate, and glycogen contents were determined in transmural left ventricular biopsy specimens taken at the beginning and at the end of cardiopulmonary bypass. Ultrastructure was studied in a similar pair of biopsy specimens. Release of myocardium-specific creatine kinase isoenzyme was determined intraoperatively and postoperatively. Functional recovery was assessed before and after weaning from cardiopulmonary bypass. The incidence of low cardiac output, myocardial infarction, and rhythm disturbances was compared between groups. Finally, actuarial survival and event-free curves were studied after 18 months' follow-up. The results show a better preservation of high-energy phosphates, glycogen, and ultrastructure in the cardioplegia group as compared to the two cross-clamp groups. However, severe myocardial damage was never observed. Release of MB creatine kinase isoenzyme was the same in all three groups. Functional recovery of the hearts immediately after cessation of cardiopulmonary bypass was better in the cardioplegia group, but the incidence of rhythm disturbances (atrioventricular conduction problems) was higher in the cardioplegia group than in the other two groups (p less than 0.05). Clinical outcome in terms of incidence of perioperative infarction, survival, and event-free follow-up was not different between groups. It is concluded that both techniques (aortic cross-clamping at 32 degrees C or 25 degrees C and St. Thomas' Hospital cardioplegia) offer good myocardial protection in extensive aorta-coronary bypass operations. St. Thomas' cardioplegia, however, in contrast to intermittent aortic cross-clamping, prevents the onset of ischemia-induced deterioration of cardiac metabolism, i.e., destruction of the adenine nucleotide pool.

Nifedipine as an adjunct to St. Thomas' Hospital cardioplegia. A double-blind, placebo-controlled, randomized clinical trial.

The cardioprotective effect of the addition of the slow calcium-channel blocker nifedipine to cardioplegic solution was tested in two double-blind placebo controlled randomized studies. The first study included 24 patients undergoing aortic-coronary bypass grafting, and the second included 24 patients undergoing aortic valve replacement. Nifedipine at a dose of 200 micrograms/L or placebo was added to St. Thomas' Hospital cardioplegic solution. The following markers of ischemia were used: adenosine triphosphate and its catabolites, creatine phosphate and inorganic phosphate, determined in transmural left ventricular biopsy specimens taken before, at the end of, and after aortic cross-clamping; hemodynamic recovery 15 minutes after cessation of cardiopulmonary bypass; clinical outcome in terms of the incidence of arrhythmias, low cardiac output, positive inotropic support immediately after operation, and follow-up at 15 months. The main difference between the two studies was that myocardial temperature during cross-clamping remained constant at 14 degrees C in coronary bypass grafting but increased to 25 degrees C in valve operations despite the application of the same amounts of cardioplegic solutions. This lower temperature resulted in better preservation of high-energy phosphates in coronary bypass operations as compared to the placebo group having valve replacement operations. According to analysis of variance, a drug effect could be demonstrated only in the aortic valve replacement study: Accumulation of breakdown products of the adenine nucleotide pool was less in the nifedipine group than in the placebo group (p less than 0.05). Adenosine triphosphate decreased only to 84% in the nifedipine group and to 72% in the placebo group. Despite this adenosine triphosphate-sparing effect, weaning from cardiopulmonary bypass was more difficult in the nifedipine group. Left ventricular stroke work index 15 minutes after bypass was decreased to 72% of the prebypass value in the nifedipine group (t test, p less than 0.01) and only to 86% in the placebo group (p = NS). In contrast, after the patients were admitted to the intensive care unit, the incidence of low cardiac output tended to be lower in the nifedipine group than in the placebo group: 33% versus 58% (p = NS). In conclusion, ischemia-induced degradation of nucleotides as it occurs when myocardial cooling is inadequate can be prevented by the addition of nifedipine to the St. Thomas' Hospital cardioplegic solution. This effect, however, is not associated with an improved clinical outcome.

Coffee consumption and serum cholesterol: an epidemiological study in Belgium.

In a Belgian population group of 15,954 male and 2116 female soldiers and their spouses the relationship between coffee drinking and serum cholesterol has been studied. A moderate but highly significant monotonic positive relationship between coffee drinking and both serum total and non-high density lipoprotein (HDL)-cholesterol was observed in men (p less than 0.001) even when adjusted for the confounding effects of age, body mass index, smoking, alcohol, and dietary fat and cholesterol intake. Men drinking at least three cups of coffee daily had a mean level of serum total cholesterol about 4 mg/dl and of non-HDL-cholesterol about 3 mg/dl higher than those who did not drink coffee. No significant effect of coffee drinking on HDL-cholesterol was observed in men. In women coffee-drinking did not influence any of the measured serum lipids.

Cardiovascular risk factor distribution above the age of 75 years in a Belgian community.

An elderly Belgian population group anno 1986 consisting of 53 men and 110 women above the age of 75 years with a mean age of 80 and 81 years, respectively, is characterized by relative obesity and low diastolic blood pressure, both in men and women. The SBP/DBP ratio is 1.91 in men and 1.88 in women. HDL-cholesterol levels are relatively high in men. Women still have slightly higher HDL-cholesterol levels than men, the difference between women and men being 3.4 mg/dl. In both sexes HDL-cholesterol correlates negatively with body weight. The 24-hour urinary sodium/potassium ratio is 2.9 in men and 2.5 in women. Factors significantly related to diastolic blood pressure in a multiple regression analysis included being on a low-salt diet, the level of 24-hour urinary potassium excretion and of 24-hour urinary creatinine excretion in men, and body weight, heart rate and the level of 24-hour urinary calcium excretion in women. It may be concluded that significant differences exist between the distribution of cardiovascular risk factors in older compared to middle-aged subjects.

Trends in stroke mortality and in antihypertensive treatment in Finland from 1972 to 1984 with special reference to North Karelia.

Trends in antihypertensive treatment and stroke mortality were analysed in the province of North Karelia where the first systematic hypertension control programme in Finland was started in 1972. Surveys carried out in random samples of the middle-aged population of North Karelia showed that the control of hypertension was better than in the reference area, especially from 1972 to 1977. From 1972 to 1984, mortality from stroke fell on average 6.3% and 7.6% per annum, in North Karelian men and women aged 35-64 years. These declines were steeper than those observed in the rest of Finland. In the age group of 65-74 years the decline in stroke mortality was also steeper in North Karelia. From 1978 to 1984 the self-reported awareness of hypertension and the proportion of people receiving antihypertensive drug treatment decreased in the middle-aged population in Finland, suggesting lesser efforts at detection and treatment. During the same period, the steep national decline in stroke mortality levelled off, but the mortality rate remained higher than in the USA and in other Western European countries. Prevention of stroke through hypertension control in the community still remains a major challenge for health care.

Nutrition and cancer.

Although no absolute certainty exists about the role of nutrition in the etiology of cancer, many facts in favor of the relationship became available during the last decades. Correlation studies, experimental work and to a lesser extent case-control studies made it possible to clarify the role of certain nutrients and foods in carcinogenesis. The most important cancer sites where nutrition could play a role are esophagus, stomach, colon, rectum, prostate and breast. Esophageal cancer is of a very complex etiology, in which alcohol intake plays an important role, at least in western countries. The cancer-promoting properties of alcohol intake are enhanced by smoking. Three factors from nutrition are probably related to stomach cancer, namely salt, nitrate/nitrite and vitamin C. Salt is caustic to the stomach mucosa, resulting in atrophic gastritis. Salt is also co-carcinogenic and stomach cancer-promoting in experimental animals. Nitrate is probably important at the stage of atrophic gastritis, where bacterial overgrowth, due to the high pH, converts nitrates in nitrites, making the loco synthesis possible of potent nitrosocarcinogens. Vitamin C inhibits the latter step. The epidemiological evidence for the role of those factors is provided. The most important among them is the strong and consistent association of stomach cancer mortality with stroke. Rectum, colon, prostate and breast cancer are related in some way to fat intake. They all seem positively related to saturated fat intake, whereas breast cancer is probably also promoted by polyunsaturated fat intake. However, polyunsaturated fat seems to be without effect on rectum cancer. Colon and prostate cancer are probably also influenced by polyunsaturated fat but to a lesser degree than breast cancer. An important argument for this are the positive ecological correlations between changes in rectum, colon and breast cancer mortality from 1968 on, and changes occurring in coronary heart diseases, stroke and diabetes mortality. Those six types of mortality are decreasing, or only slightly increasing in the USA, Belgium, France, the Netherlands, etc. They are strongly increasing in East European countries. The intake of saturated fat has generally decreased in the first group of countries, and has markedly increased in the second group.(ABSTRACT TRUNCATED AT 400 WORDS)

Ankle-foot orthosis has limited effect on walking test parameters among patients with peripheral ankle dorsiflexor paresis.

The aim of this study was to determine the relationship between ankle dorsiflexor strength and performances on several walking tests and to determine the effect of ankle-foot orthosis (AFO) use on walking tests. The following tests were used: 10-metre walking test (with and without three stairs), a complex walking task (6-minute walk with cognitive loading) and a subjective evaluation (SIP68 mobility scale and questionnaire). Isometric strength of the ankle dorsiflexors was measured. All walking tests were performed with and without AFO in random order. When relating torque values to walking performances, the highest correlation was found with the "10 metre" and "10 metre with stairs" test (r = -0.51, i.e. an inverse relationship). No threshold in the degree of paresis was found below which walking disability suddenly increased. No significant improvement could be demonstrated from AFO use on the 10-metre tests. Improvement on the 6-minute test was nearly significant (p = 0.06), the questionnaire revealed a positive opinion on AFO use related to overall walking function and effort. Thus, we have to conclude that these walking tests do not aid the clinician in estimating the severity of (progression of) the paresis nor to detect differences in degree of paresis between subjects.

Nutrition and cardiovascular mortality in Belgium. For the B.I.R.N.H. Study Group.

Significant differences in nutrition exist between the northern and the southern regions of Belgium. The most important differences are a lower saturated fat intake, a higher polyunsaturated fat intake and a higher P/S ratio in the north. Total protein, animal and vegetal protein, salt from processed foods and fiber intake are also higher in the north. The intake of butter is higher in the south and the intake of total and dietetic margarine and of fish are higher in the north. All causes, total cardiovascular, IHD (only in men), stroke and residual cardiovascular mortality are higher in the south, consistent with the regional distribution of fat intake. However, within each region there is no correlation between these mortality patterns and fat intake. This phenomenon can be explained by the presence of confounding factors: salt intake from processed foods, fish, alcohol intake and smoking habits, all of them having a different and sometimes inverse distribution among the counties. The geographical association of fat intake and cardiovascular mortality is strengthened by a similar association between trends in fat intake and trends in cardiovascular mortality. From 1968 onwards until about 1975 a decrease in saturated fat and a marked increase in polyunsaturated fat occurred together with a decreasing dietary cholesterol and salt intake. An important decrease in IHD occurred in Belgium, particularly between 1972 and 1979, and is still the highest in Europe (1968-1984). Belgium is ranked among the five top countries of Europe where stroke mortality (age 45-74 years) is declining most. The nutritional situation of Belgium and the level of mortality, though improving, are still far from ideal. The total fat, saturated fat and salt intake are much higher than recommended by W.H.O. Continued vigorous action will be necessary in order to achieve the W.H.O. goals. A comparison of what occurred in Belgium and in other countries with regard to cardiovascular mortality and nutrition underlines the role of nutrition as a key factor in public health.

[Epidemiology of rectal cancer: current findings]. / Epidémiologie du cancer du rectum: données récentes.

The exact incidence of rectal cancer in Belgium is not known, due to the absence of an operational national cancer registry. Mortality data however are well documented by death certificates. Annual rectal cancer death rates reach 20 and 13 per 100,000 for men and women respectively in the age category from 45 to 74 years (data from 1981). When similar data obtained for the years 1968 to 1983 are being compared, a significant decrease of rectal cancer mortality can be observed, at a rate of 2.6% annually. Such a decrease is not seen for colon cancer, of which the respective annual death rates are 41 and 33 per 100,000. Absolute figures for the whole Belgian population in 1984 were 3204 deaths due to colorectal cancer, with 2307 cases for colon and 897 cases for rectal cancer. In regions where incidence data are available, it is found that the cumulative risk of colorectal cancer between birth and the age of 75 can reach more than 5% in industrialized countries. Recent incidence data confirm the significant decrease in rectal cancer occurrence.

Primary prevention of hypertension in Belgium--lessons from regional differences.

Circumstantial evidence is provided for the influence of nutritional changes such as less salt, less saturated fat and more polyunsaturated fat on blood pressure and on mortality from stroke and stomach cancer in Belgium. Nutritional differences exist between the two major regions, the North and the South of Belgium. The South has a high intake of saturated fats whereas in the North the intake of polyunsaturated fat is higher. Probably less salt is used in the South compared to the North. The observed nutritional differences correlate well with the observed changes in mortality for stroke and stomach cancer.

On the within-population relationship between dietary habits and serum lipid levels in Belgium.

In a Belgian population group of 15,954 male and 2116 female subjects, an epidemiological survey has been conducted to investigate the relationship between dietary fat intake and serum total and HDL-cholesterol. The study has established, both in men and in women, a significant positive relationship between serum total cholesterol and the dietary intake of saturated fat and a significant negative one between serum total cholesterol and the intake of polyunsaturated fat and the P/S-ratio of the diet. At equal levels of consumption, polyunsaturated fat has a decreasing effect on serum total cholesterol which is about half the increasing effect due to saturated fat. Polyunsaturated fat and the P/S-ratio decrease the HDL-cholesterol value but only with borderline significance. The present study demonstrates the importance of dietary fat as a determinant of the serum lipid level within a population.

Salt and hypertension.

The salt hypothesis states that salt is a necessary condition for the genesis of essential hypertension; however, it is not a sufficient condition. Other factors---primarily genetics--are necessary for the expression of the disease. The arguments in favor of this still controversial subject originate from pathophysiology, evolution, history, pharmacology, experimental and clinical medicine, and epidemiology. Epidemiologic observations favoring the hypothesis mostly relate to comparisons between populations, and much less to comparisons within populations. The arguments against this hypothesis are related mostly to the well known difficulties of proving a within-population relationship of a relatively homogeneously distributed variable to an age-related variable (blood pressure). Mortality data derived from stomach cancer and stroke, compared within and between populations, provide only circumstantial, but nevertheless important, evidence in favor of the salt hypothesis. The strong, consistent, and independent association between stomach cancer and stroke mortality is best explained by the level of salt intake in the population. The observations made in Belgium over the last years are consistent with the salt hypothesis. A decrease in salt intake at the population level correlated with a marked decrease in stroke and stomach cancer mortality, larger than in any other European country, except Finland.

Nutrition and gastric cancer.

Gastric cancer (Gc) is generally conceived as having a multifactorial origin. Different genetic factors, soil, nutritional and socioeconomic factors have all been mentioned in the literature as possible causes. Further research on the causation of Gc has, in fact, been hampered by the large number of hypotheses. A strong geographic association between gastric cancer and stroke mortality was found by chance in 1964; this association could be spurious, but the quantitative analysis of the data showed similar relationships both between countries and within countries (e.g., in countries as different as the US and Japan), a very unlikely situation if due to chance. The same quantitative relationship was maintained using multiple regression analysis of stroke mortality. All this was observed for each sex separately and for both sexes combined. The working hypothesis was set forth in 1965 that salt intake was the predominant linking factor for both types of mortality. Stroke would then be influenced by the relationship between salt and blood pressure; Gc would result from the delaying and caustic properties of a hypertonic stomach content. The latter condition could produce atrophic gastritis, a common problem in Japan, Chile and Columbia. Atrophic gastritis favors the synthesis of endogenous nitrites and, henceforth, of nitroso-carcinogens. The salt hypothesis can give an explanation for the geographical and time behavior of Gc and stroke mortality and for the socioeconomic gradient of both diseases. Gc mortality can also be used to provide a rough estimate of the salt intake in a given country and year. The hypothesis was tested in Belgium through a deliberate attempt to lower the salt intake of the population. The observed decreases in Gc and stroke mortality were consistent with the measured decrease in salt excretion. Further research is urgently needed through the monitoring of 24-hour salt and creatinine excretion in different countries and over many years.

On the within-population relationship between nutrition and serum lipids: the B.I.R.N.H. study.

A randomized study was performed in Belgium concerning the relationship between diet and serum lipids in 5485 men and 4856 women with a mean age of 49 years. In men 17.3% of total energy was provided by saturated fat, 15.2% by monounsaturated fat and 7.5% by polyunsaturated fat. The fat intake in women was very similar. The P/S ratio was 0.51 in men and 0.52 in women. The alcohol intake was significantly higher in men (5.2% of total energy) than in women (2% of total energy). In men and women total serum cholesterol increased with saturated fat intake (p less than 0.001) and decreased with polyunsaturated fat intake (p less than 0.01). Saturated fat intake raised the HDL-cholesterol level in men and women (p less than 0.001) and monounsaturated fat raised it in men only (p less than 0.01). Dietary cholesterol increased the HDL-cholesterol level in women only (p less than 0.01). HDL-cholesterol increased with alcohol consumption (p less than 0.001) and decreased with cigarette smoking (p less than 0.001). All these changes were adjusted for differences in age, height and weight. The study confirms the existence, within a population, of a significant relationship between fat intake and serum lipid levels.