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Biomedical subjects

C Nowson

Publications and source records attributed to C Nowson.

13 recordsLinked to original sources

Men and osteoporosis.

BACKGROUND: While strict criteria have been developed for defining osteoporosis in women (bone mineral density measurements more than 2.5 standard deviations below the mean for young adult normal women, i.e. t-score value < -2.5), there still remains a controversy regarding the definition in men. Spinal fractures occur in 5% and hip fractures in 6% of men older than 50 years. There are significant differences between men and women with respect to the pathogenesis of osteoporosis, underlying medical conditions and postfracture sequelae. OBJECTIVE: To provide an overview of the pathogenesis, diagnosis and prevention of osteoporosis in men. DISCUSSION: Osteoporosis is increasingly recognised. Data from the Dubbo Osteoporosis Epidemiology Study suggests that 30% of men in Australia aged over 60 years will suffer from an osteoporotic fracture. It is estimated that 30-60% of men presenting with spinal fractures will have another illness contributing to their bone loss. Osteoporotic fractures in men are associated with higher morbidity and mortality than in women. Lifestyle changes together with daily calcium supplementation should be implemented and vitamin D3 should be considered in men with osteopenia.

Bone Density↗

Guidelines for treatment of osteoporosis in men.

BACKGROUND: Osteoporosis is associated with significant morbidity and mortality in men. Published randomised controlled trials assessing the benefits of therapy in men with osteoporosis are limited, but those available need to be used to develop management guidelines. OBJECTIVE: To present evidence based guidelines for the treatment of osteoporosis in men. DISCUSSION: It is estimated that 30-60% of men presenting with spinal fractures have another illness contributing to their bone disease. Therefore assessment and treatment of coexisting medical conditions is a vital part of management of osteoporosis. While primary prevention of fractures remains crucial, treatment to ensure further fractures do not occur is equally important. Alendronate is the treatment of choice for men with osteoporosis and fractures, with cyclical etidronate an appropriate alternative and testosterone replacement therapy is indicated in hypogonadal men presenting with osteoporosis.

Calcitriol↗

Corticosteroid induced osteoporosis. Guidelines for treatment.

BACKGROUND: Last year, Australian Family Physician published 'Guidelines for Management of Postmenopausal Osteoporosis', which were developed by Osteoporosis Australia. Recently, significant advances in our understanding of the treatment of corticosteroid osteoporosis have occurred. OBJECTIVE: The following guidelines, also developed by Osteoporosis Australia, and supported by the National Asthma Campaign, are to help general practitioners identify those patients at risk of this problem and to provide information about current treatment strategies. DISCUSSION: Corticosteroids are widely used and effective agents for the control of many inflammatory diseases. Corticosteroid osteoporosis is a common problem associated with the long term high dose use of these medications.

Adrenal Cortex Hormones↗

Effect of calcium carbonate on blood pressure in normotensive and hypertensive people.

Forty-seven patients with mild hypertension and 48 normotensive patients entered a blinded, parallel study in which they received a placebo, 10 mmol/day calcium carbonate (CaCO3), or 20 mmol/day CaCO3. There were no significant differences in blood pressure changes among the groups. In the hypertensive group and in patients with the highest blood pressure there were individual falls in systolic pressure, particularly in the group receiving 10 mmol daily CaCO3. In the hypertensive group the changes were: with placebo, -3 +/- 2/-2 +/- 2 mm Hg; with CaCO3 (10 mmol), -7 +/- 3/-2 +/- 2 mm Hg; and with CaCO3 (20 mmol), -2 +/- 3/1 +/- 2 mm Hg. No change was significant, and no pressure changes of patients taking CaCO3 differed significantly from changes of patients taking placebo. Ten of 33 patients taking placebo, 11 of 31 taking 10 mmol/day CaCO3, and nine of 31 taking 20 mmol/day CaCO3 were classified as responders from their systolic blood pressure fall. These response rates did not differ. Eight patients had falls of systolic blood pressure greater than 15 mm Hg. Five were on 10 mmol/day CaCO3 and three on 20 mmol/day CaCO3. This response was significantly different from that with placebo. Univariate analyses failed to reveal any predictive dietary or biochemical parameter. After 3 months of not taking CaCO3, 12 patients classified as responders, including six of the eight with a fall of 15 mm Hg or more, were rerandomized to placebo or to 20 mmol/day CaCO3. In the rechallenge, responses to CaCO3 and placebo were similar, neither causing a significant pressure fall. Calcium carbonate did not reduce blood pressure. The apparent response in a few patients was not verified by rechallenge. The present study does not support calcium supplementation as a useful nonpharmacological measure for reducing elevated blood pressure.

Adult↗

The effect of a rechallenge with CaCO3 in patients who have been classified as responders to an initial challenge.

In a previous study 25 of 95 patients were identified as possibly having a fall in blood pressure with CaCO3 supplementation. After a 3-month period off calcium and on their usual diet, 12 of these were randomly assigned to receive placebo or CaCO3. Four crossed over to the alternate therapy after 2 months on the first agent. The change in blood pressure with placebo was 0.3 +/- 4.3/2.9 +/- 2.7 mmHg and the change in blood pressure with CaCO3 at 20 mmol/day was 1.3 +/- 4.8/-0.3 +/- 4.2 mmHg. These changes were not different from each other or from zero, and contrasted with the fall of 16.5 +/- 2.3/7.8 +/- 2.7 mmHg in the initial study. This study indicates that apparent individual falls in blood pressure with calcium supplementation need to be verified by rechallenge before such patients can be classified as responders. The absence of a predictable response, if applied to other studies, casts doubt on the conclusions made. Calcium supplementation cannot be recommended as a method of reducing blood pressure in people with mild hypertension.

Calcium Carbonate↗

Use of sodium restriction and enalapril in persons with moderate to severe hypertension.

One hundred and seventy-four patients who were receiving drug therapy for hypertension were asked to restrict their sodium intake for three months. At the end of that time their drug therapy was replaced with enalapril and the dose of the drug "titrated" to obtain a diastolic blood pressure of less than 90 mmHg. Sodium restriction caused a small fall in blood pressure and could be used as sole therapy in only 6% of patients. Enalapril therapy was instituted without problems and control of blood pressure below 90 mmHg was achieved in 62% of persons with monotherapy. The number of tablets of enalapril that were taken was reduced from 5.9 to 2.7; in most patients these were taken once a day. There were few side-effects and no depression of white cell count, no proteinuria and no deterioration of renal function. Seventy-six per cent of patients preferred the new regimen either because they felt better than with their previous therapy (52%) or because of the more simple regimen (24%). Enalapril was an effective, well tolerated antihypertensive agent and potentially has a major role to play in the management of patients with high blood pressure.

Antihypertensive Agents↗

The effect of perindopril on blood pressure in humans on different sodium intakes.

Perindopril is a new inhibitor of converting enzyme activity with a prolonged half-life. Thirty-two patients with essential hypertension and a diastolic blood pressure greater than 95 mm Hg were stratified into two groups according to their 24 h urine sodium excretion. They were randomized in a double-blind fashion to placebo or perindopril and a dose titration made in steps of 2, 4, 6, and 8 mg given once daily at weekly intervals. The goal diastolic blood pressure was 90 mm Hg. Goal blood pressure was achieved in 11 of 16 patients on perindopril and 3 of 6 patients on placebo. Perindopril caused a fall in BP of 22/11 (supine) and 27/14 (erect) mm Hg while the placebo group had falls of 3/2 (supine) and 3/0 (erect) mm Hg. Most of the blood pressure fall occurred in the first week of therapy with 2 mg/day. Side effects were few and occurred mainly in the placebo phase. There was no alteration in urine protein, white cell count, plasma urea, or creatinine. The fall in blood pressure achieved at the end of the titration or with 2 mg did not differ between the two groups. There was no correlation between blood pressure response and 24 h urine sodium or plasma renin activity. These results indicate that perindopril is an effective antihypertensive drug that appears to work equally well in patients on high or low sodium intake.

Aged↗

Comparative studies of reduced sodium and high potassium diet in hypertension.

A decrease in sodium intake or an increase in potassium intake reduces blood pressure (BP) in people with essential hypertension. Additional potassium prevents, in sodium-sensitive people and rats, the rise in BP caused by extra sodium chloride. In people with a diastolic BP between 90 and 100 mm Hg, dietary reduction of sodium to 80 mmol/day and dietary increase of potassium to 90 mmol/day caused a fall in BP of 5.1/4.2 and 3.6/3.1 mm Hg, respectively, greater than was observed in the control group. There was a negative interaction between the two diets when used together with a BP change of 4.0/3.6 mm Hg. The fall in BP with sodium restriction was not reversed by the addition of sodium chloride and a similar fall in BP was not achieved with potassium chloride. It is possible that the response is due to some other factor. A strong correlation existed between the change in urine Na:K and the fall in BP. This study indicates that a reduced sodium or an increased potassium diet will reduce BP and should be considered for the initial management of essential hypertension.

Blood Pressure↗

The role of sodium restriction in the management of hypertension.

More than 50 studies have investigated the effect of altered sodium intake on blood pressure. A regression line drawn through the change in blood pressure and change in sodium intake indicates that blood pressure alters about 10 mmHg (1 mmHg = 133.322 Pa) for every 100 mmol/day alteration in sodium intake, a change similar to that observed in between-population "studies." The studies that have failed to show a change in blood pressure have usually been in people with a blood pressure less than 130/90 mmHg. Normotensive people appear to tolerate a higher intake of sodium before blood pressure rises, but if increased sufficiently, blood pressure rises in most people. Sodium restriction reduces blood pressure in people with severe hypertension, moderate hypertension and mild hypertension. It may be the cause of blood pressure increase associated with age and the reason for the higher prevalence of hypertension and vascular disease in Western communities. Sodium restriction should be used to treat people with elevated blood pressure.

Blood Pressure↗

Compliance and the elderly hypertensive.

In the control of chronic disease no therapeutic regimen is successful unless it is complied with. A number of studies have indicated that compliance with tablet-taking may be as low as 40%. Patients with hypertension are frequently on a number of different anti-hypertensive agents, and if they have other chronic disorders they may take as many as 10 different drugs and up to 40 tablets per day. It is therefore not surprising that compliance is poor. To achieve compliance requires education of the patient, reduction in the number of drugs and simplification of the drug regimen. Methyldopa was used in a crossover study on a once- or twice-daily basis. Blood pressure was measured at the same time each day 2 hours after the morning dose. Compliance was assessed by tablet count and by blood pressure control, which was better on once-a-day therapy. Over a 6-week period 95% of medication was taken on the once-daily compared with 84% on the twice-daily regimen. In a subsequent study atenolol once per day replaced propranolol given 3 times per day. Blood pressure was lower on atenolol and tablet compliance was 94% compared with 74% on thrice-daily propranolol therapy. In addition, many patients admitted not taking the midday dose. The effect of dietary advice was then monitored by 24-hour urine electrolytes. When advice was given superficially by the doctor, urine sodium fell from 186 mmol/day to 165 mmol/day. When seen on one occasion by a dietitian and given diet sheets, it fell from 182 to 135 mmol/day. When seen at repeated visits by the dietitian and the advice modified according to sodium excretion, urine sodium excretion fell from 188 to 83 mmol/day. Supplemental oral potassium is often given as antihypertensive medication and up to 6 tablets per day may be administered. Compliance decreased as the number of tablets increased. Compliance was 92% on 1 tablet, 83% on 2 tablets, 68% on 3 tablets, 75% on 4 tablets (usually taken as 2 tablets twice a day) and 58% when on 6 tablets per day. The compliance with diuretic-taking was 96%. When given amiloride/hydrochlorothiazide the compliance was 93% and this elevated plasma potassium more than high dose supplemental potassium. In a recent study people on 3 or more drugs for blood pressure control were placed on a low salt diet and their drugs replaced with enalapril.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenergic beta-Antagonists↗

Australian National Health and Medical Research Council dietary salt study in mild hypertension.

Two-hundred-and-twelve untreated subjects (mean age 52.3 +/- 0.8 years; 181 males and 31 females) with a diastolic blood pressure between 90 and 100 mmHg were recruited to the study. Subjects were seen fortnightly and, after 4 pre-diet visits, were randomized into a normal diet group (A, 55 subjects), a high-potassium diet group (B, 52 subjects receiving greater than 100 mmol K+/day) a reduced-sodium diet group (C, 52 subjects receiving 50-75 mmol Na+/day) or a high-potassium and low-sodium diet group (D, 53 subjects receiving same Na+ and K+ as groups B and C). Two-hundred subjects completed the diet phase of 12 weeks. Urine sodium fell to 86 +/- 7 mmol/day in group C and 73 +/- 6 mmol/day in group D, while daily potassium excretion rose to 96 +/- 5 mmol in group B and 87 +/- 4 mmol in group C. Systolic and diastolic blood pressure fell by 3.8 +/- 1.0 and 1.6 +/- 0.6 mmHg respectively in the normal diet group. The falls in systolic and diastolic blood pressures (mmHg) in the diet phase were 7.7 +/- 1.1 and 4.7 +/- 0.7 (B), 8.9 +/- 1.0 and 5.8 +/- 0.6 (C) and 7.9 +/- 0.9 and 4.2 +/- 0.7 (D). These falls were all greater than those in the control group on an intention-to-treat analysis (P less than 0.005) but did not differ from each other. Factorial analysis confirmed that the falls in pressure attributable to the low-sodium diet and high-potassium diet were not additive.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗