Sex differences in the association between body mass index and hypertension - a cross-sectional study in 717 812 adolescents.

In order to examine sex-specific differences in the association of body mass index (BMI) and hypertension, we conducted a retrospective, cross-sectional study of 717 812 (402 914 men and 314 898 women) Israeli Jewish adolescents aged 16.0-19.99 years medically screened for military service. A diagnosis of hypertension was established per history or if a mean of 10 separate blood pressure measurements exceeded 140/90, following an initial measurement higher than 140/90. Weight and height were measured. Prevalence of hypertension was 0.42% in men and 0.05% in women. In men, BMI was significantly associated with hypertension from the third decile (odds ratio [OR] 1.67, 1.06-2.65) up to the 10th decile (OR 30.17, 20.83-43.69). In women, we observed a significantly increased risk for hypertension in the ninth decile (OR 3.82, 1.42-10.22) and in the 10th decile (OR 18.92, 7.7-46.51), with no visible trend in lower deciles. BMI effects on hypertension prevalence are different in male and female adolescents.

Population-based trends in overweight and obesity: a comparative study of 2,148,342 Israeli male and female adolescents born 1950-1993.

BACKGROUND: The epidemic of obesity has been identified as a major source of morbidity, not just in developed countries but globally, in adults as well as at younger ages. OBJECTIVE: The aims of this study were to describe trends in obesity and overweight in Israeli adolescents and observe temporal changes and association by risk factors. METHODS: The research analyzed records of 2,148,342 Jewish adolescents, over a span of 44 years and included data for individual body measurements, place of residence, area of origin and education levels. Body mass index (BMI) was measured by professionals, calculated and categorized as overweight or obesity according to age- and gender-specific BMI curves established in recent years. We processed the data in multinomial logistic regression model and calculated odds ratios for various risk factors. RESULTS: Obesity and overweight are on the rise for male and female adolescents born from the mid-1960s onwards, and especially for men from the 1980s onwards. Risk factors for male adolescents include lower socioeconomic status, inferior education levels and Western origins (vs. Asian, African or Israeli origins). Risk modifiers for women were similar, except for African origins, which were associated with increased risk rather than decreased risk. Asian and Israeli origins were protective for both genders, and education was more strongly associated with obesity for women. CONCLUSIONS: We recommend stronger preventive efforts directed at adolescents as a whole, and particularly vulnerable groups with lower education levels and poverty, or those with specific geographical origins. Gender disparities are evident and should be considered in these efforts and in further research.

Mass casualty incident management, triage, injury distribution of casualties and rate of arrival of casualties at the hospitals: lessons from a suicide bomber attack in downtown Tel Aviv.

BACKGROUND: Terrorist attacks in Israel cause mass events with varying numbers of casualties. A study was undertaken to analyse the medical response to an event which occurred on 17 April 2006 near the central bus station, Tel Aviv, Israel. Lessons are drawn concerning the management of the event, primary triage, evacuation priorities and the rate and characteristics of casualty arrival at the nearby hospitals. METHODS: Data were collected both during and after the event in formal debriefings. Their analysis refers to medical response components, interactions and main outcomes. The event is described according to the DISAST-CIR methodology (Disastrous Incidents Systematic AnalysiS Through--Components, Interactions and Results). RESULTS: 91 casualties were reported in this event; 85 were evacuated from the scene including 3 already dead on arrival, 9 severely injured, 14 moderately injured and 59 mildly injured. Six were declared dead at the scene. Emergency medical service (EMS) vehicle accumulation was rapid. The casualties were distributed between five hospitals (three level 1 and two level 2 trauma centres). The first evacuated casualty arrived at the hospital within 20 min of the explosion and the last urgent victim was evacuated from the scene after 1 h 14 min. Evacuation occurred in two phases: the first, lasting 1 h 20 min, in which most of the patients with evident trauma were evacuated and the second, lasting 8 h 15 min, in which most patients presented with tinnitus and symptoms of somatisation. The most common injuries were upper and lower limb injuries, diagnosed in 37% of the total injuries, and stress-related disturbances (anxiety, tinnitus, somatisation) diagnosed in 41%. CONCLUSION: Rapid accumulation of EMS vehicles, effective primary triage between urgent and non-urgent casualties and primary distribution between five hospitals enabled rapid conclusion of the event, both at the scene and at the receiving hospitals.

Metabolic stress with a high carbohydrate diet increases adiponectin levels.

BACKGROUND: Adiponectin is an adipose tissue-specific protein, which possesses anti-atherogenic and antidiabetic properties, yet its plasma levels are decreased in subjects with metabolic syndrome. Although high fat diet has been linked to hypoadiponectinemia, the effect of high-carbohydrate diet on adiponectin levels is not known. Therefore, we studied the effect of high-carbohydrate diet on adiponectin levels in the rat models of hypertension and insulin resistance. METHODS: Rats were randomly assigned to the high carbohydrate diet [Sprague-Dawley rats with fructose enriched diet (SDR-F) and spontaneously hypertensive rats with sucrose enriched diet (SHR-S model)] or chow diet (Control group). Rats were followed for 6 weeks (SDR-F model) and 8 weeks (SHR-S model). Body weight, systolic blood pressure, plasma levels of glucose, insulin, triglycerides and adiponectin, were recorded. RESULTS: Both models were associated with features of the metabolic syndrome, namely, high insulin levels, increased blood pressure and triglyceride levels. Plasma adiponectin levels did not change in the control groups. In contrast, adiponectin levels increased by 39 and 30% compared to baseline following four and six weeks of fructose enriched diet in SDR (from 3.3+/-0.2 to 4.5+/-0.4 and 4.3+/-0.2 microg/ml, respectively, p<0.05). Likewise, five and eight weeks of sucrose enriched diet in SHR, induced a 54 and 81% increase in adiponectin levels compared to baseline (from 4.2+/-0.3 to 6.3+/-0.3 and 7.3+/-0.5 microg/ml, respectively, p<0.01). CONCLUSION: Metabolic stress with a high-carbohydrate diet increases plasma levels of adiponectin. Further studies will elucidate whether this is a transitory compensatory mechanism or a sign of target organ resistance to adiponectin.

Dietary electrolytes and hypertension in the elderly.

The effect of age on older hypertensive patient's blood pressure response to increased sodium intake is well known. Salt sensitivity which does increase with age and the decrease in renal function limiting the ability of aged kidney to excrete sodium load are major factors, responsible for rise in blood pressure during Na consumption in the elderly. Clinical studies encourage salt reduction with and without weight loss. Although potassium consumption is highly recommended, one should be aware of potassium overload in the elderly.

The relationship of physical fitness on pilot candidate selection in the Israel Air Force.

BACKGROUND: The purpose of this study was to examine whether physical fitness is an important component in the selection process of pilot candidates to the Israel Air Force (IAF) flight school. METHODS: There were 223 male pilot candidates who volunteered to participate in the study. All subjects were tested 1 - 12 wk prior to a week-long "bootcamp" for aerobic power (Astrand bicycle test), anaerobic power (vertical jump test), and percent body fat. In addition, an activity profile was established based on an activity history questionnaire. All fitness measures were correlated to a performance score based on the IAF selection criteria measure for each candidate. RESULTS: Candidates who were accepted to flight school had a higher aerobic capacity, anaerobic power output relative to body weight and a lower percent body fat than candidates who were not successful. Significant correlations were seen between the performance score and aerobic power (r = 0.31), anaerobic power (r = 0.17) and anaerobic power relative to body weight (r = 0.21). Linear regression analysis showed that aerobic power explained 9% of the variance in the performance score, while anaerobic power explained an additional 3%. The results of this study suggest that physical fitness has a positive influence on the success of pilot candidates in gaining admittance to the IAF flight school.

Stapedectomy in combat pilots.

Between 1977 and 1995, nine stapedectomies using the Robinson-vein graft technique were performed in six high-performance airplane pilots diagnosed with otosclerosis. All of them returned to full active duty after stapedectomy without any vestibular symptoms. These cases illustrate that it can be safe for fighter or test pilots to return to full flight status after stapedectomy. These cases also suggest that full flight status can be reinstated as soon as 3 months after stapedectomy without endangering flight safety.

Felodipine in the treatment of severe refractory hypertension.

The efficacy of felodipine and tolerance of this drug was examined in 52 patients, 23 men and 29 women, 18-76 years of age, in whom it either replaced previous therapies of nifedipine and other vasodilators, or was added to a constant dose of beta blockers and diuretics or another previous therapy, which was unchanged. Felodipine significantly reduced blood pressure (BP), from 192.3 +/- 31.9/114.3 +/- 18.0 to 155.7 +/- 19.5/93.8 +/- 11.5 mm Hg, with no change in pulse rate. There were no significant biochemical changes, renal deterioration or blood sugar disequilibrium. Adverse reactions including flushes and leg edema could be tolerated by most of the patients, however six patients dropped out. Orthostasis dictated a decrease in felodipine dosage. Felodipine appears to be a highly potent, well tolerated drug and offers a substitute treatment for severe hypertensives refractory to other vasodilators.

Mefloquine versus doxycycline for malaria prophylaxis in intermittent exposure of Israeli Air Force aircrew in Rwanda.

BACKGROUND: The issue of the best chemoprophylaxis agent for aircrew to use against malaria is still not settled. METHOD: We studied the patterns of use of both doxycycline and mefloquine in aviators and other aircrew for 2 mo during biweekly flights from Israel to Rwanda with a few hours' visits. Some 28 aviators and 15 non-aviator aircrew were treated with doxycycline and mefloquine, respectively, less than 12 h before the first flight and up to 4 wk after the last return. RESULTS: No case of malaria occurred within or after the operational period. Compliance was better for mefloquine than for doxycyline for the full period of the operation (100% vs. 75%, respectively). The rate of side effects, mostly gastrointestinal, was higher for doxycycline (39% vs. 13%, respectively) and was related mainly to the frequency of administration (daily vs. weekly). CONCLUSION: In situations involving frequent intermittent short-term visits to areas with substantial risk of acquiring malaria, we conclude that aircrew can safely take weekly mefloquine as prophylaxis.

Effects of high gravity on cardiac dimensions in trained air crew.

We conclude that there is no difference in LV wall thickness, dimensions, or functional parameters between air crew members who fly high + Gz aircraft and those who fly other types of aircraft. No differences were detected between high +Gz air crew personnel and others in development of structural and functional changes over the short-term course of a flying career.

Twenty-four-hour blood pressure monitoring during treatment with extended-release felodipine versus slow-release nifedipine: cross-over study.

The lack of comparative studies of nifedipine and felodipine using 24-h blood pressure (BP) monitoring in the same patients led to the present study evaluating the antihypertensive efficacy and side effects of treatment with slow-release (SR) nifedipine (20 mg twice daily) and extended-release (ER) felodipine (10 mg once daily). In the double-blind study, subjects were randomly assigned to one of two treatment groups: 6 weeks of nifedipine SR (20 mg twice daily) followed by 6 weeks of felodipine (ER) (10 mg once daily with evening matched placebo), or vice versa. Twenty-four-hour ambulatory BP monitoring showed no significant differences in systolic BP (SBP) during the day. There were no significant differences in diastolic BP (DBP) throughout the 24 h, although the frequency of DBP recordings > 90 mm Hg was greater during nifedipine (33.1%) than felodipine (27.75%) treatment. The most common side effects were flushing, palpitations, headaches, and ankle edema; there were no adverse effect on lipid profile or glucose level.

Altered circadian rhythm of blood pressure in shift workers.

The effect of shift work on the circadian rhythm of blood pressure (BP) was studied in male bakery workers. The study group consisted of 28 men, blue collar non-rotating shift workers, 20-60 years of age, and the control group comprised 30 men, blue collar, day workers in the same age group. BP was evaluated in all subjects by 24h BP monitoring. Day workers showed typical circadian rhythm with a drop in both systolic and diastolic BP at night. This pattern was reversed in night workers. The peak SBP for night workers was at 11 pm and among day workers at 4 pm. Peak DBP was recorded among night workers at 10 pm and among day workers at 3 pm. All subjects showed a highly significant cyclic variation in BP. Whereas the range for SBP was similar in these two age groups (P > 0.05), the amplitude of DBP tended to be smaller in young workers. Therapeutic decisions for night shift workers with hypertension should take into account their altered BP cycle.

The effect of enalapril with and without hydrochlorothiazide on insulin sensitivity and other metabolic abnormalities of hypertensive patients with NIDDM.

The effect of 20 mg of enalapril with and without 12.5 mg of hydrochlorothiazide on glucose metabolism insulin sensitivity and lipids was evaluated in hypertensive non-insulin-dependent diabetes. Ten mild to moderate hypertensive patients with non-insulin-dependent diabetes mellitus were treated for 8 weeks with 20 mg enalapril once a day, and then divided into two groups of 5 patients each for a second 8 weeks of treatment with enalapril alone or in combination with hydrochlorothiazide, 12.5 mg once a day. Blood pressure, fasting plasma glucose, lipids and insulin, glycosylated hemoglobin, and insulin sensitivity were measured at baseline and after 8 and 16 weeks. Results were analyzed by the ANOVA test for repeated measures and all values are given as mean +/- SD. Diastolic blood pressure decreased significantly after the first and second period of enalapril and after the combination of enalapril and hydrochlorothiazide. Glycosylated hemoglobin dropped significantly after the first and second period of enalapril monotherapy. Plasma triglycerides and fasting plasma insulin decreased significantly after the 16 weeks of enalapril. Insulin-mediated glucose uptake increased significantly after 8 and 16 weeks of monotherapy with enalapril. No significant difference was observed in any of the metabolic characteristics, including insulin sensitivity, between the values after 8 weeks of enalapril alone and the final values of the enalapril-treated and the enalapril/hydrochlorothiazide-treated groups. It is concluded that enalapril improves some of the metabolic parameters, including insulin sensitivity, of hypertensive diabetic patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic and humoral effects of the angiotensin II antagonist losartan in essential hypertension.

Losartan (DuP 753) is a novel orally active angiotensin II antagonist that lowers blood pressure. The present study evaluates the hemodynamic and humoral effects of losartan in essential hypertension. Fifteen patients (12 men, 3 women; mean age, 46 +/- 2 years; range, 33 to 64 years) with a diastolic blood pressure (DBP) between 95 and 115 mm Hg after 2 weeks of placebo participated in the study. Initially the patients were treated with losartan (50 mg) once daily for 1 month. Then, if the trough DBP was > or = 93 mm Hg, hydrochlorothiazide (HCTZ), 6.25 to 12.5 mg daily, and nifedipine, 30 to 60 mg daily, were added as needed. Ten patients completed 12 months of treatment. Trough blood pressure, heart rate, plasma creatinine, potassium, uric acid, cholesterol, renin activity (PRA), aldosterone, and norepinephrine were measured at baseline and after 1 and 12 months of treatment. Losartan lowered mean arterial pressure significantly from 119 +/- 2 mm Hg at baseline to 113 +/- 2 mm Hg (P < .05) after 1 month of treatment. Coadministration of HCTZ and nifedipine further decreased the mean arterial pressure to 103 +/- 2 mm Hg after 12 months of treatment. Plasma levels of creatinine, potassium, uric acid, cholesterol, and norepinephrine remained unchanged. PRA increased and plasma aldosterone decreased significantly (P < .05). The decrease in mean arterial pressure was related to baseline PRA (r = 0.53, P < .05). and to the change in PRA (r = 0.52, P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical pharmacokinetics of ramipril.

Ramipril is a long-acting nonsulfhydryl angiotensin converting enzyme (ACE) inhibitor introduced for clinical use about a decade ago. Ramipril is a prodrug that undergoes de-esterification in the liver to form ramiprilat, its active metabolite. Ramipril rapidly distributes to all tissues, with the liver, kidneys and lungs showing markedly higher concentrations of the drug than the blood. After absorption from the gastrointestinal tract, rapid hydrolysis of ramipril occurs in the liver. In the therapeutic concentration range, protein binding of ramipril and ramiprilat is 73 and 56%, respectively. Ramiprilat binds to ACE with high affinity at concentrations similar to that of the enzyme and establishes equilibrium slowly. Although ramipril is metabolised by hepatic and renal mechanisms to both a glucuronate conjugate and a diketopiperazine derivative, most of the drug is excreted in the urine as ramiprilat and the glucuronate conjugate of ramiprilat. Elimination from the body is characterised by a relatively rapid initial phase with a half-life of 7 hours and a late phase with a half-life of about 120 hours. No clinically significant pharmacokinetic interactions between ramipril and other drugs have been reported. The drug has been generally well tolerated with the most prevalent adverse effects being dizziness (3.4%), headache (3.2%), weakness (1.9%) and nausea (1.7%). Ramipril is an effective and well tolerated drug for the treatment of hypertension and congestive heart failure in all patients, including those with renal or hepatic dysfunction, and the elderly.

Acute hypertensive response to +Gz acceleration in mildly hypertensive pilots.

Two fighter pilots with mild hypertension and a mildly hypertensive response to exercise underwent ambulatory blood pressure monitoring during a routine flight that included a brief exposure to +4 Gz stress. They exhibited an acute elevation of both systolic and diastolic blood pressures during +4 Gz stress: from 140/90 and 135/90 mm Hg to 179/139 and 180/140 mm Hg, respectively. Heart rate reached 182 and 132 beats/min. These responses of hypertensives may reflect exaggerated baroreceptor and sympathetic responses which cause a pronounced over-shoot of blood pressure. The findings demonstrate the value of 24-h ambulatory blood pressure monitoring for documenting episodic elevations of blood pressure that do not influence the "normal" average blood pressure, but may nevertheless have important clinical implications.

The role of atrial natriuretic peptide in the diuretic effect of Ca2+ entry blockers.

The effect of three calcium entry blockers--verapamil, nifedipine and felodipine--on diuresis, natriuresis, the renin-aldosterone axis, and atrial natriuretic peptide (ANP) levels was studied in 30 previously untreated patients with mild to moderate essential hypertension. All three blockers produced significant antihypertensive effects after 2 and after 24 h. Heart rate tended to decrease, but did not change significantly after verapamil, but increased significantly 1-2 h after nifedipine and felodipine. Plasma renin activity (PRA) did not change significantly with any treatment, and plasma aldosterone decreased with all three agents. ANP levels did not change significantly after verapamil, but increased significantly after nifedipine and felodipine. There was a significant positive correlation between the maximal change in ANP level and urinary sodium after nifedipine and felodipine. The increase in urinary sodium after verapamil was not significant. The role of the direct renal effect of calcium entry blockers in their persistent natriuretic action is discussed, as well as their short-term enhancement of ANP levels, which may account for the initial diuretic and natriuretic effects seen with this class of dihydropiridines.

The role of atrial natriuretic peptide in natriuresis of fasting.

OBJECTIVE: To examine the relation between plasma atrial natriuretic peptide (ANP) and the natriuresis of fasting. DESIGN: ANP, aldosterone and renin were examined during natriuresis of fasting in 25 obese essential hypertensive patients and nine overweight normotensive subjects placed on a supervised 500-KCal diet composed of 50% carbohydrates, 30% fat and 20% protein, and unlimited salt. Twenty-four-hour urinary electrolytes were measured on days 0, 4, 7 and 10 of the diet. RESULTS: Urinary sodium concentration nearly doubled in the patients on day 4, and increased 1.4-fold in the normotensive controls. Plasma ANP rose nearly threefold in the hypertensives on day 4 and nearly doubled in the normotensives. Patients and controls showed similar patterns of natriuresis and ANP secretion during the diet. CONCLUSIONS: We conclude that there is a clear association between ANP levels and natriuresis of fasting.