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Biomedical subjects

C Summerbell

Publications and source records attributed to C Summerbell.

At least 19 recordsLinked to original sources
PubMed2004

Low glycaemic index diets for coronary heart disease.

BACKGROUND: The glycaemic index (GI) is a physiological measure of the ability of a carbohydrate to affect blood glucose. Interest is growing in the low GI carbohydrate concept for the clinical management of people at risk of, or with established coronary heart disease. There is a need to review the current evidence from controlled trials in this area. OBJECTIVES: The primary objective is to review the current evidence from RCTs that assess the relationship between the consumption of low glycaemic index diets and the effects on coronary heart disease and on risk factors for coronary heart disease. SEARCH STRATEGY: We searched CENTRAL (Issue 4, 2003), MEDLINE (1966 to 2003), EMBASE (1980 to 2003) and CINAHL (1982 to 2003). We also contacted experts in the field. SELECTION CRITERIA: We selected randomised controlled trials that assessed the effects of low glycaemic index diets, over a minimum of 4 weeks, on coronary heart disease (CHD) and risk factors. Participants included were adults who carry at least one major risk factor for coronary heart disease such as abnormal lipids, diabetes or being overweight. DATA COLLECTION AND ANALYSIS: Two of our research team independently assessed trial quality and extracted data. Authors of the included studies were contacted for additional information when this was appropriate. MAIN RESULTS: Fifteen randomised controlled trials met the inclusion criteria. No studies found reported the effect of low glycaemic index diets on CHD mortality or CHD events and morbidity. All fifteen included studies report the effect of low glycaemic index diets on major risk factors for CHD. Meta-analysis detected limited and weak evidence of a relationship between low glycaemic index diets and slightly lower total cholesterol, compared with higher glycaemic index diets. There is also limited and weak evidence of a small reduction in HbA1c after 12 weeks on low glycaemic index diets but not at 4 to 5 weeks. There is no evidence that low glycaemic index diets have an effect on LDL cholesterol or HDL cholesterol, triglycerides, fasting glucose or fasting insulin levels. REVIEWERS' CONCLUSIONS: The evidence from randomised controlled trials showing that low glycaemic index diets reduces coronary heart disease and CHD risk factors is weak. Many of the trials identified were short-term, of poor quality and conducted on small sample sizes. There is a need for well designed, adequately powered, randomised controlled studies, of greater than 12 weeks duration to assess the effects of low glycaemic index diets for CHD.

Blood Glucose↗
PubMed2004

Hormonally impregnated intrauterine systems (IUSs) versus other forms of reversible contraceptives as effective methods of preventing pregnancy.

BACKGROUND: In the 1970s a new approach to the delivery of hormonal contraception was researched and developed. It was suggested that the addition of a progestogen to a non-medicated contraceptive device improved its contraceptive action. An advantage of these hormonally impregnated intrauterine systems (IUS) is that they are relatively maintenance free, with users having to consciously discontinue using them to become pregnant rather than taking a proactive daily decision to avoid conception. OBJECTIVES: To assess the contraceptive efficacy, tolerability and acceptability of hormonally impregnated intrauterine systems (IUSs) in comparison to other reversible contraceptive methods. SEARCH STRATEGY: Literature was identified through database searches, reference lists and individuals/organisations working in the field. Searches covered the period from 1972 to November 2003. SELECTION CRITERIA: All randomised controlled trials comparing IUSs with other forms of reversible contraceptives and reporting on pre-determined outcomes in women of reproductive years. The primary outcomes were pregnancy due to method/user failure and continuation rate. DATA COLLECTION AND ANALYSIS: The quality assessment of studies and data extraction were completed independently by two blinded reviewers. A quality checklist was designed to identify general methodological and contraceptive specific factors which could bias results. Events per women months and single decrement life table rates were extracted where possible for pregnancy, continuation, adverse events and reasons for discontinuation. Events per total number of women at follow up were collected for hormonal side effects and menstrual disturbance. When appropriate, data were pooled at the same points of follow up to calculate rate ratios in order to determine the relative effectiveness of one method compared to another. For the single decrement life table rates, the rate differences were pooled to determine the absolute difference in effectiveness of one method compared to another. Interventions were only combined if the contraceptive methods were similar. Non-hormonal IUDs were divided into three categories for the purpose of comparison with IUSs: IUDs >250mm2 (i.e. CuT 380A IUD and CuT 380 Ag IUD), IUDs <=250mm2 (i.e. Nova-T, Multiload, CuT 200 and CuT 220 IUDs) and non-medicated IUDs. MAIN RESULTS: Twenty-one RCTs comparing hormonally impregnated IUSs to a reversible contraceptive method met the inclusion criteria and it was possible to include eight of these in the meta-analyses, four comparing LNG-20 IUSs with non-hormonal IUDs, one comparing the LNG-20 IUS with Norplant-2 and three comparing Progestasert with non-hormonal IUDs. No significant difference was observed between the pregnancy rates for the LNG-20 users and those for the IUD >250mm2 users. However, women using the LNG-20 IUS were significantly less likely to become pregnant than those using the IUD <=250mm2. Women using the LNG-20 IUS were more likely to experience amenorrhoea and device expulsion than women using IUDs >250mm2. LNG-20 users were significantly more likely than all the IUD users to discontinue because of hormonal side effects and menstrual disturbance, which on further breakdown of the data was due to amenorrhoea. When the LNG-20 IUS was compared to Norplant-2, the LNG-20 users were significantly more likely to experience amenorrhoea and oligomenorrhoea, but significantly less likely to experience prolonged bleeding and spotting. No other significant differences were observed. Progestasert users were significantly less likely to become pregnant and less likely to continue on the method than non-medicated IUD users after one year, but no significant difference was noted for these two outcomes when Progestasert users were compared to IUD<=250mm2 users. The only other significant differences found in the meta-analyses were that Progestasert users were less likely to expel the device and more likely to discontinue the method because of menstrual bleeding and pain than users of IUDs <=250mm2. REVIEWERS' CONCLUSIONl the device and more likely to discontinue the method because of menstrual bleeding and pain than users of IUDs <=250mm2. REVIEWERS' CONCLUSIONS: Current evidence suggests LNG-20 IUS users are no more or less likely to have unwanted pregnancies than IUD >250mm2 and Norplant-2 users. The LNG-20 IUS was more effective in preventing either intrauterine or extrauterine pregnancies than IUDs <=250mm2. The contraceptive effectiveness of Progestasert was significantly better than non-medicated IUDs, but no difference was observed when compared to IUDs<=250mm2. Continuation of LNG-20 IUS use was similar to continuation of the non-hormonal IUDs and Norplant-2. Amenorrhoea was the main reason for the discontinuation for the LNG-20 IUS and women should be informed of this prior to starting this method.

Contraceptive Agents, Female↗
PubMed2004

Dietary advice for treatment of type 2 diabetes mellitus in adults.

BACKGROUND: While initial dietary management immediately after formal diagnosis is an 'accepted' cornerstone of treatment of type 2 diabetes mellitus, a formal and systematic overview of its efficacy and method of delivery is not currently available. OBJECTIVES: To assess the effect of type and frequency of different types of dietary advice to all adults with type 2 diabetes on weight, measures of diabetic control, morbidity, total mortality and quality of life. SEARCH STRATEGY: We carried out a comprehensive search of The Cochrane Library (The Cochrane Library Issue 3, 2003), MEDLINE (1966 to October Week 1, 2003), EMBASE (1980 to Week 40, 2003), CINAHL (1982 to October Week 1, 2003), AMED (1985 to October 2003), bibliographies and contacted relevant experts. SELECTION CRITERIA: All randomised controlled trials, of six months or longer, in which dietary advice was the main intervention in adults with type 2 diabetes mellitus. DATA COLLECTION AND ANALYSIS: The lead investigator performed all data extraction and quality scoring with duplication being carried out by one of the other six investigators independently with discrepancies resolved by discussion and consensus. Authors were contacted for missing data. For continuous outcomes, endpoint data were preferred to change data. MAIN RESULTS: Thirty-six articles reporting a total of eighteen trials following 1467 participants were included. Dietary approaches assessed in this review were low-fat/high-carbohydrate diets, high-fat/low-carbohydrate diets, low-calorie (1000 kcal per day) and very-low-calorie (500 kcal per day) diets and modified fat diets. Two trials compared the American Diabetes Association exchange diet with a standard reduced fat diet and five studies assessed low-fat diets versus moderate fat or low-carbohydrate diets. Two studies assessed the effect of a very-low-calorie diet versus a low-calorie diet. Six studies compared dietary advice with dietary advice plus exercise and three other studies assessed dietary advice versus dietary advice plus behavioural approaches. The studies all measured weight and measures of glycaemic control although not all studies reported these in the articles published. Other outcomes which were measured in these studies included mortality, blood pressure, serum cholesterol (including LDL and HDL cholesterol), serum triglycerides, maximal exercise capacity and compliance. The results suggest that adoption of regular exercise is a good way to promote better glycaemic control in type 2 diabetic patients, however all of these studies were at high risk of bias. REVIEWERS' CONCLUSIONS: There are no high quality data on the efficacy of the dietary treatment of type 2 diabetes, however the data available indicate that the adoption of exercise appears to improve glycated haemoglobin at six and twelve months in people with type 2 diabetes. There is an urgent need for well-designed studies which examine a range of interventions, at various points during follow-up, although there is a promising study currently underway.

Adult↗
PubMed2004

Dietary advice for treatment of type 2 diabetes mellitus in adults.

BACKGROUND: While initial dietary management immediately after formal diagnosis is an 'accepted' cornerstone of treatment of type 2 diabetes mellitus, a formal and systematic overview of its efficacy and method of delivery is not currently available. OBJECTIVES: To assess the effect of type and frequency of different types of dietary advice to all adults with type 2 diabetes on weight, measures of diabetic control, morbidity, total mortality and quality of life. SEARCH STRATEGY: We carried out a comprehensive search of The Cochrane Library (The Cochrane Library Issue 3, 2003), MEDLINE (1966 to October Week 1, 2003), EMBASE (1980 to Week 40, 2003), CINAHL (1982 to October Week 1, 2003), AMED (1985 to October 2003), bibliographies and contacted relevant experts. SELECTION CRITERIA: All randomised controlled trials, of six months or longer, in which dietary advice was the main intervention in adults with type 2 diabetes mellitus. DATA COLLECTION AND ANALYSIS: The lead investigator performed all data extraction and quality scoring with duplication being carried out by one of the other six investigators independently with discrepancies resolved by discussion and consensus. Authors were contacted for missing data. For continuous outcomes, endpoint data were preferred to change data. MAIN RESULTS: Thirty-six articles reporting a total of eighteen trials following 1467 participants were included. Dietary approaches assessed in this review were low-fat/high-carbohydrate diets, high-fat/low-carbohydrate diets, low-calorie (1000 kcal per day) and very-low-calorie (500 kcal per day) diets and modified fat diets. Two trials compared the American Diabetes Association exchange diet with a standard reduced fat diet and five studies assessed low-fat diets versus moderate fat or low-carbohydrate diets. Two studies assessed the effect of a very-low-calorie diet versus a low-calorie diet. Six studies compared dietary advice with dietary advice plus exercise and three other studies assessed dietary advice versus dietary advice plus behavioural approaches. The studies all measured weight and measures of glycaemic control although not all studies reported these in the articles published. Other outcomes which were measured in these studies included mortality, blood pressure, serum cholesterol (including LDL and HDL cholesterol), serum triglycerides, maximal exercise capacity and compliance. The results suggest that adoption of regular exercise is a good way to promote better glycaemic control in type 2 diabetic patients, however all of these studies were at high risk of bias. REVIEWERS' CONCLUSIONS: There are no high quality data on the efficacy of the dietary treatment of type 2 diabetes, however the data available indicate that the adoption of exercise appears to improve glycated haemoglobin at six and twelve months in people with type 2 diabetes. There is an urgent need for well-designed studies which examine a range of interventions, at various points during follow-up, although there is a promising study currently underway.

Adult↗
PubMed2003

Energy metabolism in Bardet-Biedl syndrome.

INTRODUCTION: Obesity is a consistent presenting feature of the Bardet-Biedl syndrome (BBS), a hereditary disorder caused by a single gene defect. This contrasts sharply with general obesity which, despite a strong hereditary component, has a multifactorial aetiology. For BBS, the phenotypic characterisation of the components of energy balance and the implications for their management remains relatively uninvestigated. OBJECTIVE: A case-control study to determine whether energy metabolism in subjects with BBS differs from matched obese controls and to inform the clinical management of these patients. METHODS: A total of 20 overweight and obese subjects with BBS (11 females, 9 males) matched for age, gender and BMI to 20 subjects without BBS. Resting metabolic rate (RMR) was measured by indirect calorimetry, physical activity by CSA accelerometry, body composition by the deuterium dilution technique and dietary intake by 7-day food records. RESULTS: There was no significant difference between BBS and control subjects in body fat (male: % fat=38, s.d. 2.8 vs 34, s.d. 9.1, female: % fat=45, s.d. 5.9 vs 44, s.d. 8.1; P=0.46] or absolute RMR (male: 6.95, s.d. 1.55 MJ/day vs 7.19, s.d. 1.28 MJ/day; P=0.6). After adjustment for gender, age, fat-free mass and fat mass, there was no significant difference in RMR between BBS and control subjects (F(1, 30)=0.91; P=0.35). A lower level of physical activity was observed in BBS subjects (median cnts/min 259, IQR=153) compared to controls (median cnts/min=306, IQR=119, P=0.02). Reported energy intake, macronutrient composition and magnitude of under-reporting were comparable in both groups. CONCLUSION: This study reveals no evidence for systematic differences in energy metabolism in subjects with BBS relative to other obese individuals, suggesting that the genetic basis of BBS is not associated with specific abnormalities in energy metabolism. This is an important finding for clinical management and supports the use of energy prescriptions based on RMR for the general obese population plus an appropriate allowance for energy expended via physical activity. Further research is needed on physical activity in BBS.

Adult↗
PubMed2003

Should we recommend low-fat diets for obesity?

Dietary fat intake has been blamed for the increase in adiposity and has led to a worldwide effort to decrease the amount of fat in the diet. However, the comparative efficacy of this approach is debatable. Whilst short-term dietary intervention studies show that low-fat diets lead to weight loss in both healthy and overweight individuals, it is less clear if a reduction in fat intake is more efficacious than other dietary restrictions in the long term. The purpose of this systematic review was to determine the effectiveness of low-fat diets in achieving sustained weight loss when used for the express purpose of weight loss in obese or overweight people. A comprehensive search identified six studies that fulfilled our criteria for inclusion (randomized controlled trial, participants either overweight or obese, comparison of a low-fat diet with another type of weight-reducing diet, follow-up period that was at least 6 months in duration and inclusion of participants 18 years or older without serious disease). There were a total of 594 participants in the six trials. The duration of the intervention varied from 3 to 18 months with follow-up from 6 to 18 months. There were no significant differences between low-fat diets and other weight-reducing diets in terms of sustained weight loss. Furthermore, the overall weight loss at the 12-18-month follow-up in all studies was very small (2-4 kg). In overweight or obese individuals who are dieting for the purpose of weight reduction, low-fat diets are as efficacious as other weight-reducing diets for achieving sustained weight loss, but not more so.

Adolescent↗
PubMed2002

Advice on low-fat diets for obesity.

BACKGROUND: Overweight and obesity are global health problems contributing to an ever increasing noncommunicable disease burden. Calorie restriction can achieve short-term weight loss but the weight loss has not been shown to be sustainable in the long-term. An alternative approach to calorie restriction is to lower the fat content of the diet. However, the long-term effects of fat-restricted diets on weight loss have not been established. OBJECTIVES: To assess the effects of advice on low-fat diets as a means of achieving sustained weight loss, using all available randomised clinical trials. This review focused primarily on participants who were overweight or clinically obese and were dieting for the purpose of weight reduction. Since we were particularly interested in the ability of participants to sustain weight loss over a longer period of time, we focused on studies of 'free living' men and women who were given dietary advice rather than provision of food or money to purchase food. SEARCH STRATEGY: We searched the Cochrane Library (issue 2, 2001), MEDLINE (up to February 20002), and EMBASE (up to February 20002). We also searched the Science Citation Index (up to January 2001) and bibliographies of studies identified. Date of latest search: February 2002. SELECTION CRITERIA: Trials were included if they fulfilled the following criteria: 1) they were randomised controlled clinical trials of low-fat diets versus other weight-reducing diets, 2) the primary purpose of the study was weight loss, 3) participants were followed for at least six months, 4) the study participants were adults (18 years or older) who were overweight or obese (BMI >25 kg/m2) at baseline. Studies including pregnant women or patients with serious medical conditions were excluded. Two people independently applied the inclusion criteria to the studies identified. Disagreement was resolved by discussion or by intervention of a third party. DATA COLLECTION AND ANALYSIS: Data were extracted by three independent reviewers and meta-analysis performed using a random effects model. Weighted mean differences of weight loss were calculated for treatment and control groups at 6, 12 and 18 months. MAIN RESULTS: Four studies were included at the six month follow-up, five studies at the 12 month follow-up and three studies at the 18 month follow-up. There was no significant difference in weight loss between the two groups at six months (WMD 1.7 kg, 95% CI -1.4 to 4.8 kg). The weighted sum of weight loss in the low fat group was -5.08 kg (95% CI -5.9 to -4.3 kg) and in the control group was -6.5 kg, (95% CI -7.3 to -5.7 kg). There was no significant difference in weight loss between the two groups at 12 months (WMD 1.1 kg, 95% CI -1.6 to 3.8 kg). The weighted sum of weight loss in the low fat group was -2.3 kg (95% CI -3.2 to -1.4 kg) and in the control group was -3.4 kg (95% CI -4.2 to -2.6 kg). There was no significant difference in weight loss between the two groups at 18 months (WMD 3.7 kg, 95% CI - 1.8 to 9.2). The weighted sum of weight loss in the control group was -2.3 kg (95% CI -3.5 to -1.2 kg) and in the low fat group there was a weight gain of 0.1 kg (95% CI -0.8 to 1 kg). There was significant heterogeneity in the results for weight loss at six months and 12 months. Apart from one study which showed a slight but statistically significant difference in total cholesterol in the low fat group at one year follow-up, there were no significant differences between the dietary groups for other outcome measures such as serum lipids, blood pressure and fasting plasma glucose. Studies measuring other factors such as perceived wellness and quality of life reported conflicting results. REVIEWER'S CONCLUSIONS: The review suggests that fat-restricted diets are no better than calorie restricted diets in achieving long term weight loss in overweight or obese people. Overall, participants lost slightly more weight on the control diets but this was not significantly different from the weight loss achieved through dietary fat restriction and was so small as to be clinically insignificant.

Diet, Fat-Restricted↗
PubMed2001

The design features and practicalities of conducting a pragmatic cluster randomized trial of obesity management in primary care.

The aim of this paper is to describe the design features and practicalities of conducting a cluster randomized trial of obesity management in primary care. The aim of the trial is to assess the effectiveness of an obesity management educational intervention delivered to staff within primary care practices (unit of randomization) in terms of change in body weight of their patients (unit of analysis) at one year. The design features which merit particular attention in this cluster randomized trial include standardization of intervention, sample size considerations, recruitment of patients prior to randomization of practices, method of randomization to balance control and intervention practices with respect to practice and patient level characteristics, and blinding of outcome assessment. The practical problems (and our solutions) associated with implementing these design features, particularly those that result in a time delay between baseline data collection, randomization and intervention, are discussed.

Adolescent↗
PubMed2001

Hormonally impregnated intrauterine systems (IUSs), versus other forms of reversible contraceptives as effective methods of preventing pregnancy.

OBJECTIVES: To assess the contraceptive efficacy, tolerability and acceptability of hormonally impregnated intrauterine systems (IUSs) in comparison to other reversible contraceptive methods. SEARCH STRATEGY: Literature was identified through database searches, reference lists and individuals/organisations working in the field. SELECTION CRITERIA: All randomised controlled trials comparing IUSs with other forms of reversible contraceptives and reporting on pre-determined outcomes in women of reproductive years. The primary outcomes were pregnancy due to method/user failure and continuation rate. DATA COLLECTION AND ANALYSIS: The quality assessment of studies and data extraction were completed independently by two blinded reviewers. A quality checklist was designed to identify general methodological and contraceptive specific factors which could bias results. Events per women months and single decrement life table rates were extracted where possible for pregnancy, continuation, adverse events and reasons for discontinuation. Events per total number of women at follow up were collected for hormonal side effects and menstrual disturbance. When appropriate, data were pooled at the same points of follow up to calculate rate ratios in order to determine the relative effectiveness of one method compared to another. For the single decrement life table rates, the rate differences were pooled to determine the absolute difference in effectiveness of one method compared to another. Interventions were only combined if the contraceptive methods were similar. Non-hormonal IUDs were divided into three categories for the purpose of comparison with IUSs: IUDs >250mm2 (i.e. CuT 380A IUD and CuT 380 Ag IUD), IUDs <=250mm2 (i.e. Nova-T, Multiload, CuT 200 and CuT 220 IUDs) and non-medicated IUDs. MAIN RESULTS: Nineteen RCTs comparing hormonally impregnated IUSs to a reversible contraceptive method met the inclusion criteria and it was possible to include eight of these in the meta-analyses, four comparing LNG-20 IUSs with non-hormonal IUDs, one comparing the LNG-20 IUS with Norplant-2 and three comparing Progestasert with non-hormonal IUDs. No significant difference was observed between the pregnancy rates for the LNG-20 users and those for the IUD >250mm2 users. However, women using the LNG-20 IUS were significantly less likely to become pregnant than those using the IUD <=250mm2. Women using the LNG-20 IUS were more likely to experience amenorrhoea and device expulsion than women using IUDs >250mm2. LNG-20 users were significantly more likely than all the IUD users to discontinue because of hormonal side effects and menstrual disturbance, which on further breakdown of the data was due to amenorrhoea. When the LNG-20 IUS was compared to Norplant-2, the LNG-20 users were significantly more likely to experience amenorrhoea and oligomenorrhoea, but significantly less likely to experience prolonged bleeding and spotting. No other significant differences were observed. Progestasert users were significantly less likely to become pregnant and less likely to continue on the method than non-medicated IUD users after one year, but no significant differences was noted for these two outcomes when Progestasert users were compared to IUD<=250mm2 users. The only other significant differences found in the meta-analyses were that Progestasert users were less likely to expel the device and more likely to discontinue the method because of menstrual bleeding and pain than users of IUDs <=250mm2. REVIEWER'S CONCLUSIONS: Current evidence suggests LNG-20 IUS users are no more or less likely to have unwanted pregnancies than IUD >250mm2 and Norplant-2 users. The LNG-20 IUS was more effective in preventing either intrauterine or extrauterine pregnancies than IUDs <=250mm2. The contraceptive effectiveness of Progestasert was significantly better than non-medicated IUDs, but no difference was observed when compared to IUDs<=250mm2. Continuation of LNG-20 IUS use was similar to continuation of the non-hormonal IUDs and Norplant-2. Amenorrhoea was the main reason for the discontinuation for the LNG-20 IUS and women should be informed of this prior to starting this method.

Contraceptive Agents, Female↗
PubMed2001

Interventions for preventing obesity in children.

BACKGROUND: The prevalence of obesity and overweight is increasing world-wide. Obesity in children impacts on their health in both the short and longer term. Obesity prevention strategies are poorly understood. OBJECTIVES: To assess the effectiveness of interventions designed to prevent obesity in childhood. SEARCH STRATEGY: Electronic databases were searched from 1985 to October 1999. SELECTION CRITERIA: Data from RCTs and non-randomised trials with concurrent control group were included. studies with follow up of one year minimum were selected, A priori, this was subsequently amended to include studies with minimum follow up of three months. The possible susceptibility of post hoc questions to bias is addressed. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data and assessed study quality. MAIN RESULTS: Seven studies were included, three long-term and four short- term. The studies included were diverse in terms of study design and quality, target population, theoretical underpinning of intervention approach, and outcome measures. As such, it was not possible to combine study findings using statistical methods. REVIEWER'S CONCLUSIONS: The findings of the review suggest that currently there is limited quality data on the effectiveness of obesity prevention programs and as such no generalisable conclusions can be drawn. The need for well-designed studies which examine a range of interventions remains a priority.

Adolescent↗
PubMed2001

Interventions for preventing obesity in childhood. A systematic review.

BACKGROUND: The prevalence of obesity and overweight is increasing worldwide. Obesity in children impacts on their health in both short- and long-term. Obesity prevention strategies are poorly understood. OBJECTIVE: To assess the effectiveness of interventions designed to prevent obesity in childhood. SEARCH STRATEGY: Electronic databases were searched from January 1985 to October 1999. SELECTION CRITERIA: Data from randomized control trials and non-randomized trials with concurrent control group were included. A priori, studies with follow up of 1 year minimum were selected however, this was subsequently amended to include studies with a minimum follow up of three months. DATA COLLECTION & ANALYSIS: Two reviewers independently extracted data and assessed study quality. MAIN RESULTS: Seven studies were included, three long-term (> 1 years) and four short-term (> 3 months and < 1 years). The studies included were diverse in terms of study design and quality, target population, theoretical underpinning of intervention approach, and outcome measures. As such, it was not appropriate to combine study findings using statistical methods. CONCLUSIONS: Two of the long-term studies (one focused on dietary education and physical activity vs. control, and the other only on dietary education vs. control), resulted in a reduction in the prevalence on obesity, but the third, which focused on dietary education and physical activity, found no effect. Of the four short-term studies, three focused simply on physical activity/reduction of sedentary behavious vs. control. Two of these studies resulted in a reduction in the prevalence of obesity in intervention groups compared with control groups, and another study found a non-significant reduction. The fourth study focused on dietary education and physical activity, and did not find an effect on obesity, but did report a reduction in fat intake. Overall, the findings of the review suggest that currently there is limited quality data on the effectiveness of obesity prevention programmes and as such no generalizable conclusions can be drawn. The need for well-designed studies that examine a range of interventions remains a priority.

Child↗
PubMed2000

Dieting to reduce body weight for controlling hypertension in adults.

OBJECTIVES: Evaluate whether weight-loss diets are more effective than regular diets or other antihypertensive therapies in controlling blood pressure and preventing morbidity and mortality in hypertensive adults. SEARCH STRATEGY: MEDLINE and The Cochrane Library were searched through November 1997. Trials known to experts in the field were included through June 1998. SELECTION CRITERIA: For inclusion in the review, trials were required to meet each of the following criteria: 1) randomized controlled trials with one group assigned to a weight-loss diet and the other group assigned to either normal diet or antihypertensive therapy; 2) ambulatory adults with a mean blood pressure of at least 140 mm Hg systolic and/or 90 mm Hg diastolic; 3) active intervention consisting of a calorie-restricted diet intended to produce weight loss (excluded studies simultaneously implementing multiple lifestyle interventions where the effects of weight loss could not be disaggregated); and 4) outcome measures included weight loss and blood pressure. DATA COLLECTION AND ANALYSIS: Studies were dual abstracted by two independent reviewers using a standardized form designed specifically for this review. The primary mode of analysis was qualitative; graphs of effect sizes for individual studies were also used. MAIN RESULTS: Eighteen trials were found. Only one small study of inadequate power reported morbidity and mortality outcomes. None addressed quality of life or general well being issues. In general, participants assigned to weight-reduction groups lost weight compared to control groups. Six trials involving 361 participants assessed a weight-reducing diet versus a normal diet. The data suggested weight loss in the range of 4% to 8% of body weight was associated with a decrease in blood pressure in the range of 3 mm Hg systolic and diastolic. Three trials involving 363 participants assessed a weight-reducing diet versus treatment with antihypertensive medications. These suggested that a stepped-care approach with antihypertensive medications produced greater decreases in blood pressure (in the range of 6/5 mm Hg systolic/diastolic) than did a weight-loss diet. Trials that allowed adjustment of participants' antihypertensive regimens suggested that patients required less intensive antihypertensive drug therapy if they followed a weight-reducing diet. Data was insufficient to determine the relative efficacy of weight-reduction versus changes in sodium or potassium intake or exercise. REVIEWER'S CONCLUSIONS: Weight-reducing diets in overweight hypertensive persons can affect modest weight loss in the range of 3-9% of body weight and are probably associated with modest blood pressure decreases of roughly 3 mm Hg systolic and diastolic. Weight-reducing diets may decrease dosage requirements of persons taking antihypertensive medications.

Adult↗
PubMed1999

Contribution of diet, tumour volume and patient-related factors to weight loss in patients with colorectal liver metastases.

BACKGROUND: One of the difficulties in assessing the contribution of tumour-related factors to cancer cachexia is measurement of the extent of disease where dissemination to multiple organ sites has occurred. METHODS: In this study the extent of tumour (both tumour volume and increase in marker levels), diet and patient-related factors (appetite, metabolic hormones, immune activation, liver function and quality of life) were compared in patients with colorectal liver metastases who had lost at least 1 kg in body-weight (weight loss) and patients who had not lost 1 kg in body weight (stable weight) during the preceding month. RESULTS: Forty patients (22 men; 14 with weight loss) were studied. Liver metastasis volume was significantly greater in patients who lost weight than in those whose weight was stable (median (interquartile range) 1179 (245-1517) versus 119 (23-523) ml; P = 0.003). The prevalence of patients with raised levels of serum immune products was significantly greater in the weight loss group for soluble interleukin (IL) 2 receptor alpha (sIL2ralpha) (P = 0.03) and IL-6 (P = 0.05), but not for soluble tumour necrosis factor receptor 1 (sTNFr1) or neopterin. There were significant correlations between serum C-reactive protein and sIL2ralpha (rs = 0.68, P < 0.0001) and IL-6 (rs = 0.46, P = 0.008) but not sTNFr1 or neopterin levels. Significant differences in appetite, nausea, diet, energy intake, liver function tests and serum levels of metabolic hormones were not detected. CONCLUSION: Weight loss in patients with colorectal liver metastases was not explained by changes in diet, quality of life, or hormones, but activation of the innate and incomplete activation of the acquired immune systems may be involved. Agents that attenuate either the acute-phase inflammatory response or T lymphocyte IL-2 receptor upregulation might reduce weight loss in patients with metastatic disease.

Appetite↗
PubMed1997

Feeding frequency and BMI among teenagers aged 16-17 years.

The aim of this study was to examine the relationship between feeding frequency (FFQ) and body mass index (BMI) in a free-living group of teenagers, since recent evidence suggests that this may be an artifact of under-reporting. The data was cross-sectional, and a sample of 731 respondents (M = 298, F = 433) from the 1970 Longitudinal Birth Cohort Study were investigated. An initial significant relationship between FFQ and BMI was found for both males and females. However, the removal of overweight males who were dieting and a group of non-dieting females with BMI < 25 who perceived themselves to be overweight negated this relationship for males and females respectively. In conclusion, the apparent relationship between FFQ and BMI observed in this and other free-living studies appears to be an artifact of dieting and dietary restraint rather than simply under-reporting.

Adolescent↗
PubMed1997

Enteropathy in Zambians with HIV related diarrhoea: regression modelling of potential determinants of mucosal damage.

BACKGROUND: AIDS is characterised by small intestinal mucosal damage, but its aetiopathogenesis is poorly understood. Enteric infections in Africa differ from those in northern countries, where protozoan infections have been associated with severe enteropathy in AIDS patients. AIMS: To characterise enteropathy in Zambian AIDS patients compared with local controls, and to assess relative contributions of enteric infection, nutritional impairment, and immune dysfunction. METHODS: Computer aided mucosal morphometry of small intestinal biopsy specimens from 56 HIV infected Zambians with persistent diarrhoea and 26 diarrhoea free controls, followed by regression modelling. RESULTS: Patients with HIV related diarrhoea had reduced villous height and increased crypt depth compared with controls. There was no difference between HIV positive and negative controls. In regression models applied to AIDS mucosal measurements, villous height and crypt depth were related to nutritional parameters and to serum soluble tumour necrosis factor receptor p55 concentration. Crypt depth was also related to lamina propria plasma cell count. Intestinal infection was found in 79%, which consisted predominantly of microsporidia in 34%, Isospora belli in 24%, and Cryptosporidium parvum in 21%, but detection of these enteropathogens was not related to severity of enteropathy. CONCLUSIONS: Nutritional and immune disturbances were associated with enteropathy, accounting for over one third of the variation in mucosal morphometric parameters.

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