Alcohol and blood pressure: the INTERSALT study.

OBJECTIVES--To assess the relation between alcohol intake and blood pressure in men and women and in men at younger and older ages; to examine the influence of amount and pattern of alcohol consumption, as well as of acute effects, taking into account body mass index, smoking, and urinary sodium and potassium excretion. DESIGN--Subjects reported alcohol consumption for each of seven days before standardised blood pressure measurement, and whether they had consumed any alcohol in the 24 hours before measurement. SETTING--50 centres worldwide. SUBJECTS--4844 men and 4837 women aged 20-59. MAIN OUTCOME MEASURES--Effect of alcohol on blood pressure estimated by taking a weighted average of regression coefficients from centres. Acute effect assessed by examining mean differences in blood pressure of non-drinkers and of heavy drinkers who had and had not consumed alcohol in the 24 hours before measurement. Effect of pattern of consumption assessed by examining mean differences in blood pressure of non-drinkers compared with drinkers (i) whose intake was concentrated in fewer days or who were drinking more frequently, and (ii) whose alcohol intake varied little over the seven days or varied more substantially, as indicated by the standard deviation of daily consumption. RESULTS--Of the 48 centres in which some people reported consuming at least 300 ml/week of alcohol, 35 had positive regression coefficients linking heavy alcohol consumption to blood pressure. Overall, alcohol consumption was associated with blood pressure, significantly at the highest intake. After account was taken of key confounders, men who drank 300-499 ml alcohol/week had systolic/diastolic blood pressure on average 2.7/1.6 mmHg higher than non-drinkers, and men who drank > or = 500 ml alcohol/week had pressures of 4.6/3.0 mmHg higher. For women, heavy drinkers (> or = 300 ml/week) had blood pressures higher by 3.9/3.1 mmHg than non-drinkers. Heavy drinking and blood pressure were strongly associated in both sexes, and in men at both younger (20-39 years) and older (40-59 years) ages. In men who were heavy drinkers, episodic drinkers (those with great variation in daily alcohol consumption) had greater differences in blood pressure compared with non-drinkers than did regular drinkers of relatively constant amounts. CONCLUSION--The significant relation of heavy drinking (3-4 or more drinks/day) to blood pressure, observed in both men and women, and in younger and older men, was independent of and added to the effect on blood pressure of body mass index and urinary excretion of sodium and potassium. The findings indicate the usefulness of targeting those at high risk as well as the general population to reduce the adverse effects of alcohol on blood pressure.     

Intersalt: an international study of electrolyte excretion and blood pressure. Results for 24 hour urinary sodium and potassium excretion. Intersalt Cooperative Research Group.

The relations between 24 hour urinary electrolyte excretion and blood pressure were studied in 10,079 men and women aged 20-59 sampled from 52 centres around the world based on a highly standardised protocol with central training of observers, a central laboratory, and extensive quality control. Relations between electrolyte excretion and blood pressure were studied in individual subjects within each centre and the results of these regression analyses pooled for all 52 centres. Relations between population median electrolyte values and population blood pressure values were also analysed across the 52 centres. Sodium excretion ranged from 0.2 mmol/24 h (Yanomamo Indians, Brazil) to 242 mmol/24 h (north China). In individual subjects (within centres) it was significantly related to blood pressure. Four centres found very low sodium excretion, low blood pressure, and little or no upward slope of blood pressure with age. Across the other 48 centres sodium was significantly related to the slope of blood pressure with age but not to median blood pressure or prevalence of high blood pressure. Potassium excretion was negatively correlated with blood pressure in individual subjects after adjustment for confounding variables. Across centres there was no consistent association. The relation of sodium to potassium ratio to blood pressure followed a pattern similar to that of sodium. Body mass index and heavy alcohol intake had strong, significant independent relations with blood pressure in individual subjects.     

Muscle strength and body composition as determinants of blood pressure in young men

The correlations of blood pressure to various indices of muscularity and fatness were studied in 183 young healthy men (mean age 19.7, SD 2.1 years). Systolic pressure showed significant positive correlations with body fat percentage, isometric strength of trunk extensors, body mass index, lean body mass, strength of leg extensors, heart rate, and the sum of four skinfolds. Diastolic pressure had significant positive correlations with body mass index, lean body mass, body fat percentage, sum of skinfolds, strength of leg extensors, strength of trunk extensors, and age. A stepwise selective multiple regression analysis for systolic pressure resulted in four significantly correlating variables: body fat percentage (p less than 0.001), heart rate (p less than 0.01), lean body mass (p less than 0.05), and strength of trunk extensors per kg body weight (p less than 0.05). For diastolic pressure the analysis resulted in two explaining variables: body mass index (p less than 0.001) and age (p less than 0.05). In a regression equation with 13 variables the strength of trunk flexors was negatively correlated with diastolic pressure. It is concluded that both fatness and muscularity are factors related to blood pressure in young men. The muscularity effect is more clearly associated with trunk and leg extensor strength.     

Sodium and potassium intake and blood pressure.

Sodium and potassium intakes were increased in normotensive volunteers to assess the effects on their blood pressures. An approximately threefold increase in sodium intake for eight days had no effect on the blood pressures of seven volunteers, while a two-stage increase in potassium intake, by about 40% for eight days and a further 55% for 14 days, had no effect on the blood pressures of 21 volunteers. Renal electrolyte excretions and the blood pressures of all 28 subjects showed no statistically significant correlations between either sodium or potassium excretion and blood pressure. A weak negative correlation was found between the sodium: potassium ratio and systolic pressure. The small reductions in sodium intake and increases in potassium intake that might be achieved through propaganda and changes in food processing are unlikely to lower mean blood pressure in Western societies.     

Intersalt revisited: further analyses of 24 hour sodium excretion and blood pressure within and across populations. Intersalt Cooperative Research Group.

OBJECTIVES--To assess further the relation in Intersalt of 24 hour urinary sodium to blood pressure of individuals and populations, and the difference in blood pressure from young adulthood into middle age. DESIGN--Standardised cross sectional study within and across populations. SETTING--52 population samples in 32 countries. SUBJECTS--10,074 men and women aged 20-59. MAIN OUTCOME MEASURES--Association of sodium and blood pressure from within population and cross population multiple linear regression analyses with multivariate correction for regression dilution bias. Relation of sample median daily urinary sodium excretion to difference in blood pressure with age. RESULTS--In within population analyses (n = 10,074), individual 24 hour urinary sodium excretion higher by 100 mmol (for example, 170 v 70 mmol) was associated with systolic/diastolic blood pressure higher on average by 3/0 to 6/3 mm Hg (with and without body mass in analyses). Associations were larger at ages 40-59. In cross population analyses (n = 52), sample median 24 hour sodium excretion higher by 100 mmol was associated with median systolic/diastolic pressure higher on average by 5-7/2-4 mm Hg, and estimated mean difference in systolic/diastolic pressure at age 55 compared with age 25 greater by 10-11/6 mm Hg. CONCLUSIONS--The strong, positive association of urinary sodium with systolic pressure of individuals concurs with Intersalt cross population findings and results of other studies. Higher urinary sodium is also associated with substantially greater differences in blood pressure in middle age compared with young adulthood. These results support recommendations for reduction of high salt intake in populations for prevention and control of adverse blood pressure levels.     

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.     

A possible role of atrial natriuretic peptide in ethanol-induced acute diuresis.

The acute effects of ethanol on plasma atrial natriuretic peptide levels were investigated in 4 clinically healthy males, aged 24-26 years, consumed either 750 ml of water as a control study, or the same beverage with 1 ml/kg alcohol added, which increased the plasma alcohol concentration to 99.12 +/- 15.10 mg/dl at 60 min. Plasma atrial natriuretic peptide levels were significantly higher in the alcohol study compared to the control study at each time point (10, 20, 30, 60, 120 min after drinking onset), and with a peak at 10 min. Atrial natriuretic peptide levels showed a positive significant correlation with plasma antidiuretic hormone in the control group, while no relationship was found between the two peptides in the alcohol study. Moreover, a significant correlation exists between plasma atrial natriuretic peptide levels and systolic arterial blood pressure, and heart rate, and between the variations in atrial natriuretic peptide values and the variations in plasma sodium, serum ethanol, and plasma osmolality in the alcohol study. Acute ethanol intake causes an increase in urinary volume, and a decrease in urinary potassium excretion and urinary osmolality, and no change in urinary sodium excretion. These data suggest that acute ethanol administration causes a rapid increase in plasma levels of atrial natriuretic peptide, which could be an important factor of ethanol-induced diuresis. The main mechanisms for increased atrial natriuretic peptide release from atria after acute ethanol ingestion seem to be atrial stretch, due to the increase in arterial blood pressure, in heart rate, in sympathetic tone, and in plasma osmolality, and to a direct secretory effect by antidiuretic hormone.     

Does gender influence human cardiovascular and renal responses to water immersion?

We hypothesized that women and men exhibit similar cardiovascular and renal responses to thermoneutral water immersion (WI) to the neck. Ten women and nine men underwent two sessions in random order: 1) seated nonimmersed for 5.5 h (control) and 2) WI for 3 h, with subjects seated nonimmersed for 1.5 h pre- and 1 h postimmersion. We measured left atrial diameter, heart rate, arterial pressure, urine volume and osmolality, and urinary endothelin, urodilatin, sodium, and potassium excretion. No significant difference existed between groups in cardiovascular responses. The groups also exhibited mostly similar renal responses to immersion after adjustment for body mass. However, female urodilatin excretion per kilogram during immersion was over twofold that of men, and the female kaliuretic response to immersion was delayed and less pronounced relative to that in men. Men may excrete more potassium than women during immersion because men possess greater lean body mass (potassium per kilogram). Results obtained in men during WI may be cautiously extrapolated to women, yet urodilatin and potassium responses exhibit gender differences.     

The population mean predicts the number of deviant individuals.

OBJECTIVE--To examine the relation between the prevalence of deviation and the mean for the whole population in characteristics such as blood pressure and consumption of alcohol. DESIGN--Re-examination of standardised data from the Intersalt study, an international, multicentre study on the determinants of blood pressure. SETTING AND SUBJECTS--Samples of adults representing 52 populations in 32 countries. MAIN OUTCOME MEASURES--The relations, expressed as correlation coefficients, between the mean population values for blood pressure, body mass index, alcohol consumption, and sodium intake and the prevalence of, respectively, hypertension (greater than or equal to 140 mm Hg), obesity (body mass index greater than or equal to 30 kg/m2), high alcohol intake (greater than or equal to 300 ml/week), and high sodium intake (greater than or equal to 250 mmol/day). RESULTS--There were close and independent associations between the population mean and the prevalence of deviance for each of the variables examined: correlation coefficients were 0.85 for blood pressure, 0.94 for body mass index, 0.97 for alcohol intake, and 0.78 for sodium intake. CONCLUSIONS--These findings imply that distributions of health related characteristics move up and down as a whole: the frequency of "cases" can be understood only in the context of a population''s characteristics. The population thus carries a collective responsibility for its own health and well being, including that of its deviants.     

Effects of alcohol and smoking on blood lead in middle-aged British men.

A survey of middle-aged men in 24 British towns showed a strong association between blood lead concentrations, alcohol consumption, and cigarette smoking. The association with alcohol persisted after age, social class, body mass index, cigarette smoking, water lead concentrations, and the town of residence had been taken into account. There was an independent but less pronounced association between cigarette smoking and blood lead concentrations after adjustment for the other factors. The possible mechanisms include a decreased excretion of lead due to alcohol-induced hepatic dysfunction and an increased lead intake from cigarette smoking. These findings have implications for widespread measurement of blood lead concentrations in adults in the community and for all studies attempting to relate blood lead concentrations to environmental exposure.     

Sodium and potassium intake and blood pressure change in childhood.

OBJECTIVE--To assess the association between sodium and potassium intake and the rise in blood pressure in childhood. DESIGN--Longitudinal study of a cohort of children with annual measurements during an average follow up period of seven years. SETTING--Epidemiological survey of the population of a suburban town in western Netherlands. SUBJECTS--Cohort of 233 children aged 5-17 drawn at random from participants in the population survey. MAIN OUTCOME MEASURES--At least six annual timed overnight urine samples were obtained. The mean 24 hour sodium and potassium excretion during the follow up period was estimated for each participant and the sodium to potassium ratio calculated. Individual slopes of blood pressure over time were calculated by linear regression analysis. RESULTS--No significant association was observed between sodium excretion and the change in blood pressure over time. The mean systolic blood pressure slopes, however, were lower when potassium intake was higher (coefficient of linear regression -0.045 mm Hg/year/mmol; 95% confidence interval -0.069 to -0.020), and the change in systolic pressure was greater when the urinary sodium to potassium ratio was higher (0.356 mm Hg/year/unit; 95% confidence interval 0.069 to 0.642). In relation to potassium this was interpreted as a rise in blood pressure that was on average 1.0 mm Hg (95% confidence interval -1.65 to -0.35) lower in children in the upper part of the distribution of intake compared with those in the lower part. The mean yearly rise in systolic blood pressure for the group as a whole was 1.95 mm Hg. Urinary electrolyte excretion was not associated with diastolic blood pressure. CONCLUSION--Dietary potassium and the dietary sodium to potassium ratio are related to the rise in blood pressure in childhood and may be important in the early pathogenesis of primary hypertension.     

Selected zinc metabolism parameters in relation to insulin, renin-angiotensin-aldosterone system, and blood pressure in healthy subjects

The relationship between the renin-angiotensin-aldosterone system and insulin concentration and selected zinc (Zn) metabolism parameters and arterial blood pressure in young healthy subjects of both sexes is presented in this study. The following parameters were measured: systolic and diastolic arterial blood pressure, total and ouabain-dependent efflux rate constants of Zn from lymphocytes, serum and lymphocyte Zn concentrations, serum aldosterone, angiotensin-converting enzyme, insulin, sodium and potassium concentrations, body mass index, and plasma rennin activity. The correlations among these parameters show gender-dependent differences, except for a negative correlation between serum Zn and ouabain-dependent Zn efflux rate constant and the serum level of angiotensin-converting enzyme, and a positive relationship between the total efflux rate constant of Zn from lymphocytes and the serum aldosterone levels, both of which were gender independent. The results led us to conclude that there is a gender-independent functional relation between Zn homeostasis and the renin-angiotensin-aldosterone system. Insulin does not appear to play a significant role in Zn homeostasis.     

Lifestyle modifications to prevent and control hypertension. 1. Methods and an overview of the Canadian recommendations. Canadian Hypertension Society,Canadian Coalition for High Blood Pressure Prevention and Control,Laboratory Centre for Disease Control at Health Canada,Heart and Stroke Foundation of Canada

OBJECTIVE: To provide updated, evidence-based recommendations for health care professionals on lifestyle changes to prevent and control hypertension in otherwise healthy adults (except pregnant women). OPTIONS: For people at risk for hypertension, there are a number of lifestyle options that may avert the condition--maintaining a healthy body weight, moderating consumption of alcohol, exercising, reducing sodium intake, altering intake of calcium, magnesium and potassium, and reducing stress. Following these options will maintain or reduce the risk of hypertension. For people who already have hypertension, the options for controlling the condition are lifestyle modification, antihypertensive medications or a combination of these options; with no treatment, these people remain at risk for the complications of hypertension. OUTCOMES: The health outcomes considered were changes in blood pressure and in morbidity and mortality rates. Because of insufficient evidence, no economic outcomes were considered. EVIDENCE: A MEDLINE search was conducted for the period January 1996 to September 1996 for each of the interventions studied. Reference lists were scanned, experts were polled, and the personal files of the authors were used to identify other studies. All relevant articles were reviewed, classified according to study design and graded according to level of evidence. VALUES: A high value was placed on the avoidance of cardiovascular morbidity and premature death caused by untreated hypertension. BENEFITS, HARMS AND COSTS: Lifestyle modification by means of weight loss (or maintenance of healthy body weight), regular exercise and low alcohol consumption will reduce the blood pressure of appropriately selected normotensive and hypertensive people. Sodium restriction and stress management will reduce the blood pressure of appropriately selected hypertensive patients. The side effects of these therapies are few, and the indirect benefits are well known. There are certainly costs associated with lifestyle modification, but they were not measured in the studies reviewed. Supplementing the diet with potassium, calcium and magnesium has not been associated with a clinically important reduction in blood pressure in people consuming a healthy diet. RECOMMENDATIONS: (1) It is recommended that health care professionals determine the body mass index (weight in kilograms/[height in metres]2) and alcohol consumption of all adult patients and assess sodium consumption and stress levels in all hypertensive patients. (2) To reduce blood pressure in the population at large, it is recommended that Canadians attain and maintain a healthy body mass index. For those who choose to drink alcohol intake should be limited to 2 or fewer standard drinks per day (maximum of 14/week for men and 9/week for women). Adults should exercise regularly. (3) To reduce blood pressure in hypertensive patients, individualized therapy is recommended. This therapy should emphasize weight loss for overweight patients, abstinence from or moderation in alcohol intake, regular exercise, restriction of sodium intake and, in appropriate circumstances, individualized cognitive behaviour modification to reduce the negative effects of stress. VALIDATION: The recommendations were reviewed by all of the sponsoring organizations and by participants in a satellite symposium of the fourth international Conference on Preventive Cardiology. They are similar to those of the World Hypertension League and the Joint National committee, with the exception of the recommendations on stress management, which are based on new information. They have not been clinically tested. SPONSORS: The Canadian Hypertension Society, the Canadian Coalition for High Blood Pressure Prevention and Control, the Laboratory Centre for Disease Control at health Canada, and the Heart and Stroke Foundation of Canada.     

Low sodium intake does not impair renal compensation of hypoxia-induced respiratory alkalosis.

Acute hypoxia causes hyperventilation and respiratory alkalosis, often combined with increased diuresis and sodium, potassium, and bicarbonate excretion. With a low sodium intake, the excretion of the anion bicarbonate may be limited by the lower excretion rate of the cation sodium through activated sodium-retaining mechanisms. This study investigates whether the short-term renal compensation of hypoxia-induced respiratory alkalosis is impaired by a low sodium intake. Nine conscious, tracheotomized dogs were studied twice either on a low-sodium (LS = 0.5 mmol sodium x kg body wt-1 x day-1) or high-sodium (HS = 7.5 mmol sodium x kg body wt-1 x day-1) diet. The dogs breathed spontaneously via a ventilator circuit during the experiments: first hour, normoxia (inspiratory oxygen fraction = 0.21); second to fourth hour, hypoxia (inspiratory oxygen fraction = 0.1). During hypoxia (arterial PO2 34.4 +/- 2.1 Torr), plasma pH increased from 7.37 +/- 0.01 to 7.48 +/- 0.01 (P < 0.05) because of hyperventilation (arterial PCO2 25.6 +/- 2.4 Torr). Urinary pH and urinary bicarbonate excretion increased irrespective of the sodium intake. Sodium excretion increased more during HS than during LS, whereas the increase in potassium excretion was comparable in both groups. Thus the quick onset of bicarbonate excretion within the first hour of hypoxia-induced respiratory alkalosis was not impaired by a low sodium intake. The increased sodium excretion during hypoxia seems to be combined with a decrease in plasma aldosterone and angiotensin II in LS as well as in HS dogs. Other factors, e.g., increased mean arterial blood pressure, minute ventilation, and renal blood flow, may have contributed.     

Abdominal adipose tissue distribution,obesity, and risk of cardiovascular disease and death: 13 year follow up of participants in the study of men born in 1913.

In a prospective study of risk factors for ischaemic heart disease 792 54 year old men selected by year of birth (1913) and residence in Gothenburg agreed to attend for questioning and a battery of anthropometric and other measurements in 1967. Thirteen years later these baseline findings were reviewed in relation to the numbers of men who had subsequently suffered a stroke, ischaemic heart disease, or death from all causes. Neither quintiles nor deciles of initial indices of obesity (body mass index, sum of three skinfold thickness measurements, waist or hip circumference) showed a significant correlation with any of the three end points studied. Statistically significant associations were, however, found between the waist to hip circumference ratio and the occurrence of stroke (p = 0.002) and ischaemic heart disease (p = 0.04). When the confounding effect of body mass index or the sum of three skinfold thicknesses was accounted for the waist to hip circumference ratio was significantly associated with all three end points. This ratio, however, was not an independent long term predictor of these end points when smoking, systolic blood pressure, and serum cholesterol concentration were taken into account. These results indicate that in middle aged men the distribution of fat deposits may be a better predictor of cardiovascular disease and death than the degree of adiposity.     

Ten-Year-Replicated Circadian Profiles for 36 Physiological, Serological and Urinary Variables in Healthy Men

At 3-hr intervals over a 24-hr span, 36 systemic, serologic and urinary variables were examined in 7 men in their mid 20's in the Spring of 1969, and again in the same 7 men in the Spring of 1979 under a similar chronobiologic protocol, using the same chemical and numerical analytical procedures. The variables examined for rhythms by cosinor were: vital signs--blood pressure (systolic, diastolic, pulse pressure and mean arterial pressure), heart rate, intraocular pressure (left and right), oral temperature; serum components--albumin, albumin/globulin ratio, total bilirubin, calcium, carbon dioxide, chlorides, bilirubin, cholesterol, globulin, glucose, potassium, sodium, sodium/potassium ratio, transaminase, triglycerides, total protein, urea nitrogen; and urine components--calcium, calcium/magnesium ratio, creatinine, magnesium, pH, potassium, sodium, sodium/potassium ratio, urea clearance, urea nitrogen, volume and zinc. Although all subjects appeared clinically healthy in 1969 and in 1979, certain inter-study differences were observed in a number of rhythm parameters of different variables. Statistically significant increases in mesor for the group as a whole were observed for serum Ca, cholesterol, Cl, CO2, K, Na, and while statistically significant mesor decreases for a group as a whole were noted in serum glucose and transaminase. Statistically significant increases in amplitude for the group as a whole were observed in serum chloride and urinary Na/K ratio, while statistically significant decreases were observed in amplitude for blood pressure, heart rate, serum albumin, A/G ratio, globulin, glucose, protein, sodium and transaminase.(ABSTRACT TRUNCATED AT 250 WORDS)     

The Kenyan Luo migration study: observations on the initiation of a rise in blood pressure.

OBJECTIVE--To demonstrate the magnitude, timing, and cause of changes in blood pressure that occur in migrants from a low blood pressure population on moving to an urban area. DESIGN--A controlled longitudinal observational study of migrants as soon after migration as possible and follow up at three, six, 12, 18, and 24 months after migration. A cohort of controls living in a rural area who were matched for age, sex, and locality were also observed at the same periods. SETTING--35 Villages on the northern shores of Lake Victoria in western Kenya and Nairobi. PARTICIPANTS--325 Members of the Luo tribe aged 15 to 34 years who had migrated to Nairobi and 267 controls living in villages. The numbers of both groups reduced during follow up such that only 63 migrants and 143 controls were followed up for two years. MAIN OUTCOME MEASURES--A medical questionnaire and three 24 hour diet histories were completed by migrants and controls. Height, weight, pulse, and blood pressure were measured. Three 12 hour overnight urine samples were collected from all participants and analysed for sodium, potassium, and creatinine concentrations. RESULTS--The mean systolic blood pressure of migrants was significantly higher than that of controls throughout the study, and the distribution of blood pressure was shifted to the right compared with controls. The mean diastolic blood pressure of the two groups diverged over time. Blood pressure differences were not due to selective migration. The migrants'' mean urinary sodium:potassium ratio was higher than that of controls (p less than 0.001) throughout, and weight and pulse rate were also higher among migrants, although differences diminished with time. CONCLUSIONS--Urinary sodium:potassium ratio, pulse rate, and weight are important predictors of increased blood pressure among migrants from a low blood pressure community and may also be implicated in the initiation of essential hypertension.     

Nutritional management of hypertension: past, present, and future

A succinct overview of the nutritional management of hypertension, past, present, and future is presented. Prior to 1945, the low sodium diet and the rice-fruit diet were shown to be effective in reducing the blood pressure to normal levels in 35-40% of hypertensive patients. Between 1945 and the present, many studies were made on the effects of alcohol, water hardness, obesity, moderate restriction of sodium with increased potassium intake, increased dietary calcium, low animal and high unsaturated fat intake, and increased amounts of fiber in the diet. Criticisms are made of the very small magnitude, even if statistically significant, of blood pressure decreases and the too-short control periods in many instances, and also concerning the assumption of use of 24-h urinary sodium as an accurate index of the sodium intake, and of urinary creatinine as a physiological reference standard against the excretion of sodium. The author mentions, for possible future research, long-term studies of the effects of diets moderately restricted in sodium and high in potassium, of reducing weight and increasing physical activity in obese hypertensives, and of low animal and high polyunsaturated fat diets in patients with mild essential hypertension.     

Body weight: implications for the prevention of coronary heart disease,stroke, and diabetes mellitus in a cohort study of middle aged men.

OBJECTIVE: To determine the body mass index associated with the lowest morbidity and mortality. DESIGN: Prospective study of a male cohort. SETTING: One general practice in each of 24 British towns. SUBJECTS: 7735 men aged 40-59 years at screening. MAIN OUTCOME MEASURES: All cause death rate, heart attacks, and stroke (fatal and non-fatal) and development of diabetes, or any of these outcomes (combined end point) over an average follow up of 14.8 years. RESULTS: There were 1271 deaths from all causes, 974 heart attacks, 290 strokes, and 245 new cases of diabetes mellitus. All cause mortality was increased only in men with a body mass index (kg/m2) < 20 and in men with an index > or = 30. However, risk of cardiovascular death, heart attack, and diabetes increased progressively from an index of < 20 even after age, smoking, social class, alcohol consumption, and physical activity were adjusted for. For the combined end point the lowest risks were seen for an index of 20.0-23.9. In never smokers and former smokers, deaths from any cause rose progressively from an index of 20.0-21.9 and for the combined end point, from 20.0-23.9. Age adjusted levels of a wide range of cardiovascular risk factors rose or fell progressively from an index < 20. CONCLUSION: A healthy body mass index in these middle aged British men seems to be about 22.     

Alcohol and ischaemic heart disease in middle aged British men.

The relation between alcohol intake and ischaemic heart disease was examined in a large scale prospective study of middle aged men drawn from general practices in 24 British towns. After an average follow up of 6.2 years 335 of the 7729 men had experienced a myocardial infarction (fatal or non-fatal) or sudden cardiac death. No significant relation was found between reported alcohol intake and the incidence of such events. Though the group of light daily drinkers had the lowest incidence of ischaemic heart disease events, it also contained the lowest proportion of current smokers, had the lowest mean blood pressure, had the lowest mean body mass index, and contained the lowest proportion of manual workers. These characteristics are more likely to account for the apparent protective effect of alcohol against ischaemic heart disease than a direct effect of alcohol. Compared with the effects of established risk factors alcohol seems to be quite unimportant in the development of ischaemic heart disease.