The impact of interventions to promote healthier ready-to-eat meals (to eat in, to take away or to be delivered) sold by specific food outlets open to the general public: a systematic review

INTRODUCTION

Ready-to-eat meals sold by food outlets that are accessible to the general public are an important target for public health intervention. We conducted a systematic review to assess the impact of such interventions.

METHODS

Studies of any design and duration that included any consumer-level or food-outlet-level before-and-after data were included.

RESULTS

Thirty studies describing 34 interventions were categorized by type and coded against the Nuffield intervention ladder: restrict choice = trans fat law (n = 1), changing pre-packed children's meal content (n = 1) and food outlet award schemes (n = 2); guide choice = price increases for unhealthier choices (n = 1), incentive (contingent reward) (n = 1) and price decreases for healthier choices (n = 2); enable choice = signposting (highlighting healthier/unhealthier options) (n = 10) and telemarketing (offering support for the provision of healthier options to businesses via telephone) (n = 2); and provide information = calorie labelling law (n = 12), voluntary nutrient labelling (n = 1) and personalized receipts (n = 1). Most interventions were aimed at adults in US fast food chains and assessed customer-level outcomes. More 'intrusive' interventions that restricted or guided choice generally showed a positive impact on food-outlet-level and customer-level outcomes. However, interventions that simply provided information or enabled choice had a negligible impact.

CONCLUSION

Interventions to promote healthier ready-to-eat meals sold by food outlets should restrict choice or guide choice through incentives/disincentives. Public health policies and practice that simply involve providing information are unlikely to be effective.

A systematic review of the effectiveness of individual, community and societal-level interventions at reducing socio-economic inequalities in obesity among adults

BACKGROUND

Socioeconomic inequalities in obesity are well established in high-income countries. There is a lack of evidence of the types of intervention that are effective in reducing these inequalities among adults.

OBJECTIVES

To systematically review studies of the effectiveness of individual, community and societal interventions in reducing socio-economic inequalities in obesity among adults.

METHODS

Nine electronic databases were searched from start date to October 2012 along with website and grey literature searches. The review examined the best available international evidence (both experimental and observational) of interventions at an individual, community and societal level that might reduce inequalities in obesity among adults (aged 18 years or over) in any setting and country. Studies were included if they reported a body fatness-related outcome and if they included a measure of socio-economic status. Data extraction and quality appraisal were conducted using established mechanisms and narrative synthesis was conducted.

RESULTS

The 'best available' international evidence was provided by 20 studies. At the individual level, there was evidence of the effectiveness of primary care delivered tailored weight loss programmes among deprived groups. Community based behavioural weight loss interventions and community diet clubs (including workplace ones) also had some evidence of effectiveness-at least in the short term. Societal level evaluations were few, low quality and inconclusive. Further, there was little evidence of long term effectiveness, and few studies of men or outside the USA. However, there was no evidence to suggest that interventions increase inequalities.

CONCLUSIONS

The best available international evidence suggests that some individual and community-based interventions may be effective in reducing socio-economic inequalities in obesity among adults in the short term. Further research is required particularly of more complex, multi-faceted and societal-level interventions.

Technology-based dietary assessment: development of the Synchronised Nutrition and Activity Program (SNAP)

BACKGROUND

Accurate, reliable and feasible methods of dietary intake and physical activity assessment are required to improve our understanding of the associations between energy balance-related behaviours and health.

METHODS

The Synchronised Nutrition and Activity Program (SNAP) was developed to enhance recall in children by integrating new and established methods of dietary intake and physical activity recall. A list of commonly consumed foods (n = 40), drinks (n = 9) and physical activities (n = 29) was used in SNAP. All foods and drinks were analysed by count (i.e., the number of times a particular food was selected), as a proxy indicator of dietary behaviours. All reported physical activities were assigned an intensity code [in metabolic equivalents (METs)] to determine minutes of moderate-vigorous activity (MVPA; ≥3 METs).

RESULTS

Most participants completed a whole day's recall (both dietary intake and physical activities) in less than 25 min. SNAP was compared against 24-h multiple pass questionnaire and accelerometry in 121 children (aged 7-15 years old). For dietary variables, the accuracy of SNAP(™) (mean difference) was within ±1 count for the majority of food groups. The proportion of the sample with a between-method agreement within ±1 count ranged from 0.40 to 0.99. For MVPA, there was no substantial fixed or proportional bias, with a mean difference between methods (SNAP) - accelerometry) of -9 min of MVPA. Qualitatively, participants have indicated that they find SNAP easy and fun to use.

CONCLUSIONS

SNAP was developed to be a simple, quick and engaging method of assessing energy balance-related behaviours at a group or population level and succeeded because it can collect a whole day's recall (dietary intake and physical activities) in less than 25 min to a reasonable and acceptable degree of accuracy.

Characterizing the EPODE logic model: unravelling the past and informing the future

EPODE ('Ensemble Prévenons l'Obésité De Enfants' or 'Together let's Prevent Childhood Obesity') is a large-scale, centrally coordinated, capacity-building approach for communities to implement effective and sustainable strategies to prevent childhood obesity. Since 2004, EPODE has been implemented in over 500 communities in six countries. Although based on emergent practice and scientific knowledge, EPODE, as many community programs, lacks a logic model depicting key elements of the approach. The objective of this study is to gain insight in the dynamics and key elements of EPODE and to represent these in a schematic logic model. EPODE's process manuals and documents were collected and interviews were held with professionals involved in the planning and delivery of EPODE. Retrieved data were coded, themed and placed in a four-level logic model. With input from international experts, this model was scaled down to a concise logic model covering four critical components: political commitment, public and private partnerships, social marketing and evaluation. The EPODE logic model presented here can be used as a reference for future and follow-up research; to support future implementation of EPODE in communities; as a tool in the engagement of stakeholders; and to guide the construction of a locally tailored evaluation plan.

Evidence-based recommendations for the development of obesity prevention programs targeted at preschool children

The ToyBox intervention was developed using an evidence-based approach, using the findings of four reviews. These reviews included three critical and narrative reviews of educational strategies and psychological approaches explaining young children's acquisition and formation of energy-balance related behaviours, and the management of these behaviours, and also a systematic review of behavioural models underpinning school-based interventions in preschool and school settings for the prevention of obesity in children aged 4-6 years. This paper summarises and translates the findings from these reviews into practical evidence based recommendations for researchers and policy-makers to consider when developing and implementing interventions for the prevention of overweight and obesity in young (aged 4-6 years) children. The recommendations focus on two behaviours, physical activity and sedentary behaviour, and healthy eating, and include general recommendations, intervention approaches, interventions content, and simple messages. The review also briefly examines the role that the commercial sector plays in hindering or facilitating attempts to create healthy food environments for children. This paper also recognises that childhood obesity is not an issue for the education sector alone; it needs to be tackled at a multi sectoral level, recognizing the particularly important role of local governments, nongovernment organizations and the media.

Critical narrative review to identify educational strategies promoting physical activity in preschool

The aim of this narrative review is critically to evaluate educational strategies promoting physical activity that are used in the preschool setting in the context of obesity prevention programmes. Literature search was conducted between April and August 2010 in English and German databases (PubMED, PsychINFO, PSYNDEX, ERIC, FIS Bildung). Outcomes considered were time and intensity of physical activity, motor skills or measures of body composition. A total of 19 studies were included. Ten studies added physical activity lessons into their curriculum, one study provided more time for free play, eight studies focused on the social and play environment. Studies reporting positive outcomes implemented physical activity sessions that lasted at least 30 min d(-1). Several studies showed that children are most active in the first 10-15 min. The existence or installation of playground markings or fixed play equipment had no effect, whereas the presence or addition of portable play equipment was positively correlated with moderate-to-vigorous physical activity. Teacher training may be a key element for successful interventions. To overcome time constraints, a suggested solution is to integrate physical activity into daily routines and other areas of the preschool curriculum.

Identifying effective behavioural models and behaviour change strategies underpinning preschool- and school-based obesity prevention interventions aimed at 4-6-year-olds: a systematic review

The aim of this comprehensive systematic review was to identify the most effective behavioural models and behaviour change strategies, underpinning preschool- and school-based interventions aimed at preventing obesity in 4-6-year-olds. Searching was conducted from April 1995 to April 2010 using MEDLINE, EMBASE, CINAHL, PsycINFO and The Cochrane Library. Epidemiological studies relevant to the research question with controlled assignment of participants were included in the review, if they had follow-up periods of 6 months or longer. Outcomes included markers of weight gain; markers of body composition; physical activity behaviour changes and dietary behaviour changes. Twelve studies were included in the review. The most commonly used model was social cognitive theory (SCT)/social learning theory (SLT) either as a single model or in combination with other behavioural models. Studies that used SCT/SLT in the development of the intervention had significant favourable changes in one, or more, outcome measures. In addition, interventions that (i) combined high levels of parental involvement and interactive school-based learning; (ii) targeted physical activity and dietary change; and (iii) included long-term follow-up, appeared most effective. It is suggested that interventions should also be focused on developing children's (and parents') perceived competence at making dietary and physical changes.

A narrative review of psychological and educational strategies applied to young children's eating behaviours aimed at reducing obesity risk

Strategies to reduce risk of obesity by influencing preschool children's eating behaviour are reviewed. The studies are placed in the context of relevant psychological processes, including inherited and acquired preferences, and behavioural traits, such as food neophobia, 'enjoyment of food' and 'satiety responsiveness'. These are important influences on how children respond to feeding practices, as well as predictors of obesity risk. Nevertheless, in young children, food environment and experience are especially important for establishing eating habits and food preferences. Providing information to parents, or to children, on healthy feeding is insufficient. Acceptance of healthy foods can be encouraged by five to ten repeated tastes. Recent evidence suggests rewarding healthy eating can be successful, even for verbal praise alone, but that palatable foods should not be used as rewards for eating. Intake of healthier foods can be promoted by increasing portion size, especially in the beginning of the meal. Parental strategies of pressuring to eat and restriction do not appear to be causally linked to obesity, but are instead primarily responses to children's eating tendencies and weight. Moderate rather than frequent restriction may improve healthy eating in children. Actively positive social modelling by adults and peers can be effective in encouraging healthier eating.

Objectively measured habitual physical activity in a highly obesogenic environment

BACKGROUND

While the prevalence of overweight and obesity among children continues to grow nationally, prevalence in the North-East of England is among the highest in the UK. The objective of this study was to investigate the habitual physical activity levels in a particularly obesogenic environment in the North-East of England.

METHODS

Eight primary schools were selected using a stratified random sampling frame ranking average deprivation levels. Participating children (n = 246, mean age 10 years) wore an accelerometer (Actigraph, GT-256) over five consecutive days (weekend plus three weekdays). Total daily moderate-to-vigorous intensity physical activity was calculated using thresholds by Puyau and colleagues.

RESULTS

Only 7% (17/246) of children were sufficiently active. Boys were more physically active than girls (766 +/- 268 vs. 641 +/- 202 counts/min, 95% CI for the difference 63-186 cpm.). Total physical activity was not influenced significantly by deprivation levels or weight status, and there were no significant differences in physical activity between school or weekend days.

CONCLUSIONS

The North-East of England is a recognized 'hot spot' for paediatric obesity and the present study shows that low levels of habitual physical activity are typical. Choice of accelerometry threshold affects both the apparent amount of physical activity and the ability to detect groups with particularly low levels of physical activity.

The impact of maternal BMI status on pregnancy outcomes with immediate short-term obstetric resource implications: a meta-analysis

Obesity is rising in the obstetric population, yet there is an absence of services and guidance for the management of maternal obesity. This systematic review aimed to investigate relationships between obesity and impact on obstetric care. Literature was systematically searched for cohort studies of pregnant women with anthropometric measurements recorded within 16-weeks gestation, followed up for the term of the pregnancy, with at least one obese and one comparison group. Two researchers independently data-extracted and quality-assessed each included study. Outcome measures were those that directly or indirectly impacted on maternity resources. Primary outcomes included instrumental delivery, caesarean delivery, duration of hospital stay, neonatal intensive care, neonatal trauma, haemorrhage, infection and 3rd/4th degree tears. Meta-analysis shows a significant relationship between obesity and increased odds of caesarean and instrumental deliveries, haemorrhage, infection, longer duration of hospital stay and increased neonatal intensive care requirement. Maternal obesity significantly contributes to a poorer prognosis for mother and baby during delivery and in the immediate post-partum period. National clinical guidelines for management of obese pregnant women, and public health interventions to help safeguard the health of mothers and their babies are urgently required.

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 effects of type and frequency of different types of dietary advice for adults with type 2 diabetes.

SEARCH STRATEGY

We carried out a comprehensive search of The Cochrane Library, MEDLINE, EMBASE, CINAHL, AMED, bibliographies and contacted relevant experts.

SELECTION CRITERIA

All randomised controlled trials, of six months or longer, in which dietary advice was the main intervention.

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.

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.

AUTHORS' 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.

Wholegrain cereals for coronary heart disease

BACKGROUND

There is increasing evidence from observational studies that wholegrains can have a beneficial effect on risk factors for coronary heart disease (CHD).

OBJECTIVES

The primary objective is to review the current evidence from randomised controlled trials (RCTs) that assess the relationship between the consumption of wholegrain foods and the effects on CHD mortality, morbidity and on risk factors for CHD, in participants previously diagnosed with CHD or with existing risk factors for CHD.

SEARCH STRATEGY

We searched CENTRAL (Issue 4, 2005), MEDLINE (1966 to 2005), EMBASE (1980 to 2005), CINAHL (1982 to 2005), ProQuest Digital Dissertations (2004 to 2005). No language restrictions were applied.

SELECTION CRITERIA

We selected randomised controlled trials that assessed the effects of wholegrain foods or diets containing wholegrains, over a minimum of 4 weeks, on CHD and risk factors. Participants included were adults with existing CHD or who had at least one risk factor for CHD, such as abnormal lipids, raised blood pressure 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 where this was appropriate.

MAIN RESULTS

Ten trials met the inclusion criteria. None of the studies found reported the effect of wholegrain diets on CHD mortality or CHD events or morbidity. All 10 included studies reported the effect of wholegrain foods or diets on risk factors for CHD. Studies ranged in duration from 4 to 8 weeks. In eight of the included studies, the wholegrain component was oats. Seven of the eight studies reported lower total and low density lipoproteins (LDL) cholesterol with oatmeal foods than control foods. When the studies were combined in a meta-analysis lower total cholesterol (-0.20 mmol/L, 95% confidence interval (CI) -0.31 to -0.10, P = 0.0001 ) and LDL cholesterol (0.18 mmol/L, 95% CI -0.28 to -0.09, P < 0.0001) were found with oatmeal foods. However, there is a lack of studies on other wholegrains or wholegrain diets.

AUTHORS' CONCLUSIONS

Despite the consistency of effects seen in trials of wholegrain oats, the positive findings should be interpreted cautiously. Many of the trials identified were short term, of poor quality and had insufficient power. Most of the trials were funded by companies with commercial interests in wholegrains. There is a need for well-designed, adequately powered, longer term randomised controlled studies in this area. In particular there is a need for randomised controlled trials on wholegrain foods and diets other than oats.

Trends in maternal obesity incidence rates, demographic predictors, and health inequalities in 36,821 women over a 15-year period

OBJECTIVE

The aim of this study was to identify trends in maternal obesity incidence over time and to identify those women most at risk and potential-associated health inequalities.

DESIGN

Longitudinal database study.

SETTING

James Cook University Hospital maternity unit, Middlesbrough, UK.

SAMPLE

A total of 36 821 women from 1 January 1990 to 31 December 2004.

METHODS

Trends in maternal obesity incidence over time were analysed using chi-square test for trend. Demographic predictor variables were analysed using multivariate logistic regression, adjusting for confounding factors after testing for multicollinearity. National census data were used to place the regional data into the context of the general population.

MAIN OUTCOME MEASURE

Trends in maternal obesity incidence. Demographic predictor variables included ethnic group, age, parity, marital status, employment and socio-economic disadvantage.

RESULTS

The proportion of obese women at the start of pregnancy has increased significantly over time from 9.9 to 16.0% (P<0.01). This is best described by a quadratic model (P<0.01) showing that the rate is accelerating; by 2010, the rate will have increased to 22% of this population if the trend continues. There is also a significant relationship with maternal obesity and mothers' residing in areas of most deprivation (odds ratio [OR]=2.44, 95% CI=1.98, 3.02, P<0.01), with increasing age (OR=1.04, 95% CI=1.04, 1.05, P<0.01), and parity (OR=1.17, 95% CI=1.12, 1.21, P<0.01).

CONCLUSIONS

The incidence of maternal obesity at the start of pregnancy is increasing and accelerating. Predictors of maternal obesity are associated with health inequalities, particularly socio-economic disadvantage.

Obesity in pregnancy: a study of the impact of maternal obesity on NHS maternity services

OBJECTIVE

To gain a detailed understanding of healthcare professionals' perceptions of the impact that caring for obese pregnant women has on maternity services.

DESIGN

Qualitative interview study using purposeful sampling and face-to-face interviews.

SETTING

Sixteen maternity units in NHS Trusts in the North East Government Office Region of England, UK.

SAMPLE

Thirty-three maternity and obstetric healthcare professionals with personal experience of managing the care of obese pregnant women.

METHODS

Semi-structured interviews with healthcare professionals representing each maternity unit in the region. Transcripts were analysed using systematic content analysis.

MAIN OUTCOME MEASURES

Views on the impact maternal obesity has on maternity services, the facilities required to care for obese mothers in pregnancy, and existing services directed towards maternal obesity.

RESULTS

Five dominant themes relating to service delivery emerged; booking appointments, equipment, care requirements, complications and restrictions, and current and future management of care. Many of the issues identified were associated with managing the care of obese women in pregnancy safely, resources and cost issues to be able to do this, multidisciplinary care requirements because of coexisting morbidities when the mother is obese, and restricted care options and patient choice.

CONCLUSIONS

Healthcare professionals in the North East of England feel that maternal obesity has a major impact on services and resource, on the health of both the mother and child, and on the psychological wellbeing of the mother.

Obesity and disability - a short review

The prevalence of both obesity and disability is increasing globally and there is now growing evidence to suggest that these two health priorities may be linked. This paper explores the evidence linking obesity to muscular-skeletal conditions, mental health disorders and learning disabilities in both adult and child populations. The impact of obesity on the four most prevalent disabling conditions in the UK (arthritis, mental health disorders, learning disabilities and back ailments) has been examined through novel data analysis of the 2001 Health Survey for England and UK Back Exercise And Manipulation trial data. Together these analyses strongly suggest that whether the cause or result of disability, obesity is undeniably implicated, thus presenting a serious public health priority. Future research efforts are required to strengthen the evidence base examining obesity in back disorders, mental health and learning disabilities, in order to improve current clinical management.

Independent associations between weight status and disability in adults: Results from the health survey for England

OBJECTIVES

While direct links between obesity and some illnesses are well-established, there is a relative paucity of research on associations between obesity and disabilities. The aim of this study was to test for significant associations between overweight and obesity and the presence of a wide range of disabling conditions in adults, controlling for sex, age, education, social class, income, cigarette smoking status and alcohol consumption.

STUDY DESIGN

Data were extracted from the Health Survey for England (2001); a cross-sectional survey of the community-dwelling population. In total, 8613 adult participants were included in the analysis.

METHODS

Multivariate logistic regression was employed to test whether the odds of having a range of disabling conditions are higher in the overweight and obese populations compared with those in the ideal weight range.

RESULTS

The risk of nearly all disabling conditions tested was elevated in the obese and morbidly obese groups. Of great importance for public health, the risks of musculoskeletal illness, arthritis and rheumatism, and personal care disability were significantly elevated, even in those in the overweight category (currently about half of the adult population living in the UK).

CONCLUSIONS

Obesity is independently associated with a range of disabling conditions in adults. The present study highlights the need for further research into the mechanisms by which these associations occur.

The Cochrane Library: more systematic reviews on nutrition needed

The knowledge and relevance of nutrition as well as the demand for well-funded advices increase. The Cochrane Collaboration plays a leading role within the evidence-based medicine and practice. We advocate therefore more specialized nutritional interest within the Cochrane Collaboration. In case 'Nutrition' needs more attention within the Cochrane Library, one of the first priorities is deciding about whether to include non-randomized studies into the Specialized Register and generating lists of journals to handsearch for such a Specialized Register. Preparatory to these activities an inventory of Nutritional content within the Cochrane Library is needed. We estimate that reviews directly related to nutrition and those of borderline interest to nutrition represent less than 4% of all published reviews in The Cochrane Library.

Interventions for preventing obesity in children

BACKGROUND

Obesity prevention is an international public health priority. The prevalence of obesity and overweight is increasing in child populations throughout the world, impacting on short and long-term health. Obesity prevention strategies for children can change behaviour but efficacy in terms of preventing obesity remains poorly understood.

OBJECTIVES

To assess the effectiveness of interventions designed to prevent obesity in childhood through diet, physical activity and/or lifestyle and social support.

SEARCH STRATEGY

MEDLINE, PsycINFO, EMBASE, CINAHL and CENTRAL were searched from 1990 to February 2005. Non-English language papers were included and experts contacted.

SELECTION CRITERIA

Randomised controlled trials and controlled clinical trials with minimum duration twelve weeks.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed study quality.

MAIN RESULTS

Twenty-two studies were included; ten long-term (at least 12 months) and twelve short-term (12 weeks to 12 months). Nineteen were school/preschool-based interventions, one was a community-based intervention targeting low-income families, and two were family-based interventions targeting non-obese children of obese or overweight parents. Six of the ten long-term studies combined dietary education and physical activity interventions; five resulted in no difference in overweight status between groups and one resulted in improvements for girls receiving the intervention, but not boys. Two studies focused on physical activity alone. Of these, a multi-media approach appeared to be effective in preventing obesity. Two studies focused on nutrition education alone, but neither were effective in preventing obesity. Four of the twelve short-term studies focused on interventions to increase physical activity levels, and two of these studies resulted in minor reductions in overweight status in favour of the intervention. The other eight studies combined advice on diet and physical activity, but none had a significant impact. The studies were heterogeneous in terms of study design, quality, target population, theoretical underpinning, and outcome measures, making it impossible to combine study findings using statistical methods. There was an absence of cost-effectiveness data.

AUTHORS' CONCLUSIONS

The majority of studies were short-term. Studies that focused on combining dietary and physical activity approaches did not significantly improve BMI, but some studies that focused on dietary or physical activity approaches showed a small but positive impact on BMI status. Nearly all studies included resulted in some improvement in diet or physical activity. Appropriateness of development, design, duration and intensity of interventions to prevent obesity in childhood needs to be reconsidered alongside comprehensive reporting of the intervention scope and process.

Use of surgery to aid weight reduction-experience of two regions of Northern England: a database study

OBJECTIVE

To determine the usage of surgery in the management of obesity.

DESIGN

Analysis of routine statistics.

DATA SOURCES

Hospital Episode Statistics extract held by Public Health Observatories. GEOGRAPHICAL AREAS: Two Government Office Regions in England with a population of 7.6 million. TIME PERIOD: Data analysed in the study covered the 6 y 1996/1997-2001/2002.

RESULTS

The availability and uptake of surgery for obesity in the two regions was hugely variable. The overall utilisation of the procedures examined (OPCS operation codes: G30.1, G30.2, G32.10, G61.00) was 5.6 per million per annum, but ranged by Primary Care Trust from zero (the case in eight of the 50 PCTs in the two regions) to 24.0 operations per million per year. The rates of access to this surgery differed over six-fold between the two regions (1.4 operations per year per million population to 7.9 operations per year per million population). The PCTs with the highest rates of surgery, were those closest to the large providers of service.

CONCLUSIONS

Access to this intervention is highly variable. Primary Care Trusts in England and service providers need to ensure that there is appropriate access to this effective procedure in carefully selected cases. The surgical expertise required for these operations could be concentrated in fewer centres.

Omega 3 fatty acids for prevention and treatment of cardiovascular disease

BACKGROUND

It has been suggested that omega 3 (W3, n-3 or omega-3) fats from oily fish and plants are beneficial to health.

OBJECTIVES

To assess whether dietary or supplemental omega 3 fatty acids alter total mortality, cardiovascular events or cancers using both RCT and cohort studies.

SEARCH STRATEGY

Five databases including CENTRAL, MEDLINE and EMBASE were searched to February 2002. No language restrictions were applied. Bibliographies were checked and authors contacted.

SELECTION CRITERIA

RCTs were included where omega 3 intake or advice was randomly allocated and unconfounded, and study duration was at least six months. Cohorts were included where a cohort was followed up for at least six months and omega 3 intake estimated.

DATA COLLECTION AND ANALYSIS

Studies were assessed for inclusion, data extracted and quality assessed independently in duplicate. Random effects meta-analysis was performed separately for RCT and cohort data.

MAIN RESULTS

Forty eight randomised controlled trials (36,913 participants) and 41 cohort analyses were included. Pooled trial results did not show a reduction in the risk of total mortality or combined cardiovascular events in those taking additional omega 3 fats (with significant statistical heterogeneity). Sensitivity analysis, retaining only studies at low risk of bias, reduced heterogeneity and again suggested no significant effect of omega 3 fats. Restricting analysis to trials increasing fish-based omega 3 fats, or those increasing short chain omega 3s, did not suggest significant effects on mortality or cardiovascular events in either group. Subgroup analysis by dietary advice or supplementation, baseline risk of CVD or omega 3 dose suggested no clear effects of these factors on primary outcomes. Neither RCTs nor cohorts suggested increased relative risk of cancers with higher omega 3 intake but estimates were imprecise so a clinically important effect could not be excluded.

REVIEWERS' CONCLUSIONS

It is not clear that dietary or supplemental omega 3 fats alter total mortality, combined cardiovascular events or cancers in people with, or at high risk of, cardiovascular disease or in the general population. There is no evidence we should advise people to stop taking rich sources of omega 3 fats, but further high quality trials are needed to confirm suggestions of a protective effect of omega 3 fats on cardiovascular health. There is no clear evidence that omega 3 fats differ in effectiveness according to fish or plant sources, dietary or supplemental sources, dose or presence of placebo.

Controlled clinical trial of two weight reducing diets in a NHS hospital dietetic outpatient clinic - a pilot study

BACKGROUND

Outpatient dietary weight reduction for obesity is unsatisfactory. The objective of this study was to compare the efficacy of an energy prescription diet with usual care (a healthy eating diet) in adult overweight patients referred to a NHS hospital dietetic outpatient clinic, in terms of weight change over 12 weeks.

METHODS

Controlled clinical trial (systematic allocation).

RESULTS

Of the 53 patients who attended their first appointment, 27 completed the trial. Mean weight loss (kg) after 12 weeks was 4.2 (sd 3.8) on the energy prescription diet (n = 16) and 6.0 (sd 2.8) on the healthy eating diet (n = 11).

CONCLUSIONS

Patients on a weight reducing diet based on energy prescription or healthy eating lost, on average, clinically significant amounts of body weight by 12 weeks. Mean weight loss was greater by about 50% in the healthy eating group and supports the development of a larger trial to estimate true effect [corrected].

Review of methods used to estimate non-milk extrinsic sugars

BACKGROUND

Those sugars in foods, which are potentially damaging to dental health, were classified by the Committee on Medical Aspects of Food Policy (COMA) as non-milk extrinsic sugars (NMES). The NMES include sugars outside the cellular structure of a food, excluding the sugars naturally present in milk and milk products. The NMES should contribute no more than 10% of energy intake (Department of Health, 1991). A number of studies have been published where NMES content of foods has been estimated. The purpose of this study was to carry out a comprehensive literature review using a methodical search strategy in order to identify the different methods that have been used for NMES estimation.

METHODS

Databases searched were MEDLINE, EMBASE, Health-CD and Health Management Information Consortium (HMIC) (as sources of UK government and other official publications).

RESULTS

In total, 32 publications were found in which NMES values were reported and five different methods to estimate NMES were identified. No published method provided sufficient information to clearly differentiate between methods and inadequate detail was given to support replication of any of the methods. Of these five methods, The Ministry of Agriculture, Fisheries and Food (MAFF) have published three different descriptions of methods of NMES estimation used in UK national dietary surveys published since 1989. However, one method has been described consistently in the National Diet and Nutrition surveys published since 1994.

CONCLUSIONS

A single, uniform approach to the estimation of NMES for application in nutritional surveys is essential for cross-comparison between surveys. The results show that there is a clear need for one standardized approach for the estimation of NMES in foods.

Interventions for treating obesity in children

BACKGROUND

The prevalence of overweight and obesity is increasing in child populations throughout the world. Obesity in children has significant short and long term health consequences.

OBJECTIVES

To assess the effects of a range of lifestyle interventions designed to treat obesity in childhood.

SEARCH STRATEGY

We searched CCTR, MEDLINE, EMBASE, CINAHL, PsychLIT, Science Citation Index, Social Science Citation Index. Each database was searched from 1985 to July 2001. We also contacted experts in child obesity treatment.

SELECTION CRITERIA

We selected randomised controlled trials of lifestyle interventions for treating obesity in children with a minimum of six months duration. Examples of lifestyle interventions include dietary, physical activity and/or behavioural therapy interventions, with or without the support of associated family members. Interventions from any setting and delivered by any professional were considered. However, interventions that specifically dealt with the treatment of eating disorders were excluded.

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 where this was appropriate.

MAIN RESULTS

We included 18 randomised controlled trials with 975 participants. Many studies were run from a specialist obesity clinic within a hospital setting. Five studies (n=245 participants) investigated changes in physical activity and sedentary behaviour. Two studies (n=107 participants) compared problem-solving with usual care or behavioural therapy. Nine studies (n=399 participants) compared behavioural therapy at varying degrees of family involvement with no treatment or usual care or mastery criteria and contingent reinforcement. Two studies (n=224 participants) compared cognitive behavioural therapy with relaxation.Most of the studies included in this review were too small to have the power to detect the effects of the treatment. We did not conduct a meta-analysis since so few of the trials included the same comparisons and outcomes. Therefore, we synthesised the results in a narrative format.

REVIEWER'S CONCLUSIONS

Although 18 research studies were found, most of these were very small studies drawn from homogenous, motivated groups in hospital settings and so generalisable evidence from them is limited. In conclusion, there is a limited amount of quality data on the components of programs to treat childhood obesity that favour one program over another. Further research that considers psychosocial determinants for behaviour change, strategies to improve clinician-family interaction, and cost-effective programs for primary and community care is required. We conclude that no direct conclusions can be drawn from this review with confidence.

Dietitians' views of overweight and obese people and reported management practices

OBJECTIVES

To examine dietitians' views of overweight and obese people, to explore the role of level of severity on these perceptions (overweight vs. obesity), and to explore the relationship between dietitians' views and their reported weight management practices.

DESIGN

An independent measures survey, questioning dietitians about either overweight or obese people.

PARTICIPANTS

One-hundred and eighty-seven members of the British Dietetic Association.

MEASUREMENTS

A questionnaire exploring beliefs about the causes, attitudes, perceptions of responsibility and reported weight management practices.

RESULTS

Physical inactivity was identified as an important causative factor for both overweight and obesity. Mood, eating too much of the wrong foods, repeated dieting and interpersonal factors were also seen as relatively important for both groups. Attitudes were mixed, but were generally neutral to positive. The most negative attitudes were described in terms of perceived reduced self-esteem, sexual attractiveness and health. Dietitians rated obese people more negatively than overweight people. They viewed both overweight and obese people as being responsible for their excess weight. They also reported very similar management practices for overweight and obese people. Beliefs about the causes of overweight explained more of the variance in practice than dietitians' attitudes towards or perceived responsibility of overweight and obese people. However, these associations were not consistent and strong, and other factors not investigated here are likely to have a greater influence on weight management practices.

Obesity: diagnosis, prevention, and treatment; evidence based answers to common questions

Paediatric obesity is now common in the UK, as in other developed countries. A literature search was conducted and evidence based answers to five frequently answered questions sought. Recommendations for diagnosis are given. Although there is no conclusive evidence that the condition is preventable, a number of treatment approaches are promising.

An updated systematic review of interventions to improve health professionals' management of obesity

The objective of this article was twofold (1) to determine the existence and effectiveness of interventions to improve health professionals' management of obesity or the organization of care for overweight and obese people; and (2) to update a previous systematic review on this topic with new or additional studies. The study design was a systematic review of intervention studies, undertaken according to standard methods developed by the Cochrane Effective Practice and Organization of Care (EPOC) Group. Participants were trained health care professionals and overweight and obese patients. The measurements were objective measures of health professionals' practice and behaviours, and patient outcomes including satisfaction, behaviour, psychological factors, disease status, risk factors and measures of body weight, fat, or body mass index (BMI). Twelve studies were included in the original review. A further six were included in this update. Six of the 18 studies were randomized controlled trials of health professional-oriented interventions (such as the use of reminders and training) and one was a controlled before-and-after study to improve collaboration between a hospital clinic and general practitioners (GPs). Ten randomized controlled trials and two controlled clinical trials of interventions comparing either the deliverer of weight-loss interventions or the setting of the delivery of the intervention, were identified. The heterogeneity and generally limited quality of identified studies make it difficult to provide recommendations for improving health professionals' obesity management. To conclude, at present, there are few solid leads about improving obesity management, although reminder systems, brief training interventions, shared care, inpatient care and dietitian-led treatments may all be worth further investigation. Therefore, decisions for the improvement of provision of services must be based on the existing evidence on interventions with patients and good clinical judgement. Further research is needed to identify cost-effective strategies for improving the management of obesity. A full version of this review (including detailed descriptions of the included studies and their methodological quality, and results and excluded studies tables) is available in the Cochrane Library. The Cochrane Library is a database of systematic review and other evidence on the effects of health care, continuously updated as new information emerges. It is available on CD ROM from Update Software. For further information see: http://www.update-software.com/cochrane.

Dietary fat intake and prevention of cardiovascular disease: systematic review

OBJECTIVE

To assess the effect of reduction or modification of dietary fat intake on total and cardiovascular mortality and cardiovascular morbidity.

DESIGN

Systematic review.

DATA SOURCES

Cochrane Library, Medline, Embase, CAB abstracts, SIGLE, CVRCT registry, and biographies were searched; trials known to experts were included.

INCLUDED STUDIES

Randomised controlled trials stating intention to reduce or modify fat or cholesterol intake in healthy adult participants over at least six months. Inclusion decisions, validity, and data extraction were duplicated. Meta-analysis (random effects methodology), meta-regression, and funnel plots were performed.

RESULTS

27 studies (30 902 person years of observation) were included. Alteration of dietary fat intake had small effects on total mortality (rate ratio 0.98; 95% confidence interval 0.86 to 1.12). Cardiovascular mortality was reduced by 9% (0.91; 0.77 to 1.07) and cardiovascular events by 16% (0.84; 0.72 to 0.99), which was attenuated (0.86; 0.72 to 1.03) in a sensitivity analysis that excluded a trial using oily fish. Trials with at least two years' follow up provided stronger evidence of protection from cardiovascular events (0.76; 0.65 to 0.90).

CONCLUSIONS

There is a small but potentially important reduction in cardiovascular risk with reduction or modification of dietary fat intake, seen particularly in trials of longer duration.

Reduced or modified dietary fat for preventing cardiovascular disease

BACKGROUND

Reduction or modification of dietary fat can improve total cholesterol levels, but may also have a variety of effects, both positive and negative, on other cardiovascular risk factors.

OBJECTIVES

The aim of this systematic review was to assess the effect of reduction or modification of dietary fats on total and cardiovascular mortality and cardiovascular morbidity over at least 6 months, using all available randomized clinical trials.

SEARCH STRATEGY

The Cochrane Library, MEDLINE, EMBASE, CAB Abstracts, CVRCT registry and related Cochrane Groups' trial registers were searched through spring 1998, SIGLE to January 1999. Trials known to experts in the field and biographies were included through May 1999.

SELECTION CRITERIA

Trials fulfilled the following criteria: 1) randomized with appropriate control group, 2) intention to reduce or modify fat or cholesterol intake (excluding exclusively omega-3 fat interventions), 3) not multi factorial, 4) healthy adult humans, 5) intervention at least six months, 6) mortality or cardiovascular morbidity data available. Inclusion decisions were duplicated, disagreement resolved by discussion or a third party.

DATA COLLECTION AND ANALYSIS

Rate data were extracted by two independent reviewers and meta-analysis performed using random effects methodology. Meta-regression and funnel plots were used.

MAIN RESULTS

Twenty seven studies were included (40 intervention arms, 30,901 person-years). There was no significant effect on total mortality (rate ratio 0.98, 95% CI 0.86 to 1.12), a trend towards protection form cardiovascular mortality (rate ratio 0.91, 95% CI 0.77 to 1.07), and significant protection from cardiovascular events (rate ratio 0.84, 95% CI 0.72 to 0.99). The latter became non-significant on sensitivity analysis. Trials where participants were involved for more than 2 years showed significant reductions in the rate of cardiovascular events and a suggestion of protection from total mortality. The degree of protection from cardiovascular events appeared similar in high and low risk groups, but was statistically significant only in the former.

REVIEWER'S CONCLUSIONS

The findings are suggestive of a small but potentially important reduction in cardiovascular risk in trials longer than two years. Lifestyle advice to all those at high risk of cardiovascular disease (especially where statins are unavailable or rationed), and to lower risk population groups, should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturates.

Dietary advice given by a dietitian versus other health professional or self-help resources to reduce blood cholesterol

BACKGROUND

The average level of blood cholesterol is an important determinant of the risk of coronary heart disease. Blood cholesterol can be reduced by dietary means. Although dietitians are trained to provide dietary advice, for practical reasons it is also given by other health professionals and occasionally through the use of self-help resources.

OBJECTIVES

To assess the effects of dietary advice given by a dietitian compared with another health professional, or the use of self-help resources, in reducing blood cholesterol in adults.

SEARCH STRATEGY

We searched The Cochrane Library (to Issue 2 1999), MEDLINE (1966 to January 1999), EMBASE (1980 to December 1998), Cinahl (1982 to December 1998), Human Nutrition (1991 to 1998), Science Citation Index, Social Sciences Citation Index, hand searched conference proceedings on nutrition and heart disease, and contacted experts in the field.

SELECTION CRITERIA

Randomised trials of dietary advice given by a dietitian compared with another health professional or self-help resources. The main outcome was difference in blood cholesterol between dietitian groups compared with other intervention groups.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed study quality.

MAIN RESULTS

Eleven studies with 12 comparisons were included, involving 704 people receiving advice from dietitians, 486 from other health professionals and 551 people using self-help leaflets. Four studies compared dietitian with doctor, seven with self-help resources, and one compared dietitian with nurse. Participants receiving advice from dietitians experienced a greater reduction in blood cholesterol than those receiving advice only from doctors (-0.25 mmol/L (95% CI -0.37, -0.12 mmol/L)). There was no statistically significant difference in change in blood cholesterol between dietitians and self-help resources (-0.10 mmol/L (95% CI -0.22, 0.03 mmol/L)). No statistically significant differences were detected for secondary outcome measures between any of the comparisons with the exception of dietitian versus nurse for HDLc, where the dietitian groups showed a greater reduction (-0.06 mmol/L (95% CI -0.11, -0.01)). No significant heterogeneity between the studies was detected.

REVIEWER'S CONCLUSIONS

Dietitians were better than doctors at lowering blood cholesterol in the short to medium term, but there was no evidence that they were better than self-help resources. The results should be interpreted with caution as the studies were not of good quality and the analysis was based on a limited number of trials. More evidence is required to assess whether change can be maintained in the longer term. There was no evidence that dietitians provided better outcomes than nurses.

Improving health professionals' management and the organisation of care for overweight and obese people

BACKGROUND

Obesity is increasing throughout the industrialised world. If left unchecked it will have major implications for both population health and costs to health services. Health professionals have a key role to play in tackling the obesity problem, but little is known about how they may be encouraged to work more effectively with overweight and obese people.

OBJECTIVES

The main objective was to determine whether health professionals' management or the organisation of care for overweight and obese people could be improved.

SEARCH STRATEGY

We searched the specialised registers of the Cochrane Effective Practice and Organisation of Care Group (May 1997), the Cochrane Depression, Anxiety and Neurosis Group (August 1997), the Cochrane Diabetes Group (August 1997), the Cochrane Controlled Trials Register (September 1997), MEDLINE to January 1998, EMBASE to December 1997, Cinahl (1982 to November 1997), PsycLit (1974 to December 1997), Sigle (1980 to November 1997), Sociofile (1974 to October 1997), Dissertation Abstracts (1861 to January 1998), Conference Papers Index (1973 to January 1998), Resource Database in Continuing Medical Education. We also hand searched seven key journals and contacted experts in the field.

SELECTION CRITERIA

Randomised trials, controlled before-and-after studies and interrupted time series analyses of providers' management of obesity or the organisation of care to improve provider practice or patient outcomes. We addressed three a priori comparisons and a fourth post hoc comparison. 1. Interventions aimed at improving health professionals' management or the delivery of health care for overweight/obese patients are more effective than usual care. 2. Interventions aimed at redressing negative attitudes and related practices towards overweight/obese patients are more effective than usual care. 3. Organisational interventions designed to change the structure of services for overweight/obese people are more effective than educational or behavioural interventions for health professionals. 4. Comparisons of different organisational interventions.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed study quality.

MAIN RESULTS

Twelve studies were included involving more than 393 providers and 3392 patients. Four studies were identified for comparison 1. Three were professional-oriented interventions (the use of reminders and training) and the fourth was a study of professional and organisational interventions of shared care. No studies were identified for comparisons 2 or 3. Eight studies were identified for post hoc comparison 4. These compared either the deliverer of weight loss interventions or the setting of interventions. The included studies were heterogeneous and of generally poor quality.

REVIEWER'S CONCLUSIONS

At present, decisions about improving provision of services must be based on the evidence of patient interventions and good clinical judgement. Further research is needed to identify cost effective strategies for improving the management of obesity.

A systematic review of interventions to improve health professionals' management of obesity

OBJECTIVE

To determine the existence and effectiveness of interventions to improve health professionals' management of obesity or the organisation of care for overweight and obese people.

DESIGN

A systematic review of intervention studies, undertaken according to standard methods developed by the Cochrane Effective Practice and Organisation of Care (EPOC) Group.

PARTICIPANTS

Trained health care professionals and overweight and obese patients.

MEASUREMENTS

Objective measures of health professionals' practice and behaviours, and patient outcomes including satisfaction, behaviour, psychological factors, disease status, risk factors, and measures of body weight, fat, or BMI.

RESULTS

Twelve studies that met all the review inclusion criteria were identified. Three were randomised controlled trials of health professional-oriented interventions (such as the use of reminders and training) and one was a controlled before and after study to improve collaboration between a hospital clinic and GPs. A further eight randomised controlled trials were identified of interventions comparing either the deliverer of weight loss interventions or the setting of the delivery of the intervention. The heterogeneity and generally limited quality of identified studies make it difficult to provide recommendations for improving health professionals' obesity management.

CONCLUSIONS

At present, decisions about improving the provision of services for overweight and obese people must be based on the evidence from patient interventions and good clinical judgement. Future research is required to identify cost-effective strategies for improving health professionals' management and the organisation of care for overweight and obese people.

Childhood predictors of adult obesity: a systematic review

OBJECTIVE

To identify factors in childhood which might influence the development of obesity in adulthood.

BACKGROUND

The prevalence of obesity is increasing in the UK and other developed countries, in adults and children. The adverse health consequences of adult obesity are well documented, but are less certain for childhood obesity. An association between fatness in adolescence and undesirable socio-economic consequences, such as lower educational attainment and income, has been observed, particularly for women. Childhood factors implicated in the development of adult obesity therefore have far-reaching implications for costs to the health-services and economy.

SEARCH STRATEGY

In order to identify relevant studies, electronic databases--Medline, Embase, CAB abstracts, Psyclit and Sport Discus-were searched from the start date of the database to Spring 1998. The general search structure for electronic databases was (childhood or synonyms) AND (fatness or synonyms) AND (longitudinal or synonyms). Further studies were identified by citations in retrieved papers and by consultation with experts.

INCLUSION CRITERIA

Longitudinal observational studies of healthy children which included measurement of a risk factor in childhood (<18 y), and outcome measure at least 1 y later. Any measure of fatness, leanness or change in fatness or leanness was accepted. Measures of fat distribution were not included. Only studies with participants from an industrialized country were considered, and those concerning minority or special groups, e.g. Pima Indians or children born preterm, were excluded.

FINDINGS

Risk factors for obesity included parental fatness, social factors, birth weight, timing or rate of maturation, physical activity, dietary factors and other behavioural or psychological factors. Offspring of obese parent(s) were consistently seen to be at increased risk of fatness, although few studies have looked at this relationship over longer periods of childhood and into adulthood. The relative contributions of genes and inherited lifestyle factors to the parent-child fatness association remain largely unknown. No clear relationship is reported between socio-economic status (SES) in early life and childhood fatness. However, a strong consistent relationship is observed between low SES in early life and increased fatness in adulthood. Studies investigating SES were generally large but very few considered confounding by parental fatness. Women who change social class (social mobility) show the prevalence of obesity of the class they join, an association which is not present in men. The influence of other social factors such as family size, number of parents at home and childcare have been little researched. There is good evidence from large and reasonably long-term studies for an apparently clear relationship for increased fatness with higher birth weight, but in studies which attempted to address potential confounding by gestational age, parental fatness, or social group, the relationship was less consistent. The relationship between earlier maturation and greater subsequent fatness was investigated in predominantly smaller, but also a few large studies. Again, this relationship appeared to be consistent, but in general, the studies had not investigated whether there was confounding by other factors, including parental fatness, SES, earlier fatness in childhood, or dietary or activity behaviours. Studies investigating the role of diet or activity were generally small, and included diverse methods of risk factor measurement. There was almost no evidence for an influence of activity in infancy on later fatness, and inconsistent but suggestive evidence for a protective effect of activity in childhood on later fatness. No clear evidence for an effect of infant feeding on later fatness emerged, but follow-up to adulthood was rare, with only one study measuring fatness after 7y. Studies investigating diet in childhood were limited and inconc

Randomised controlled trial of novel, simple, and well supervised weight reducing diets in outpatients

OBJECTIVES

To investigate the contribution of novelty and simplicity to compliance with a low energy diet among obese outpatients.

DESIGN

Three arm randomised trial for 16 weeks.

SETTING

NHS hospital obesity clinic.

SUBJECTS

45 patients aged over 17 years with a body mass index >27 who were not diabetic, pregnant, or lactating.

INTERVENTIONS

Conventional 3.4 MJ diet (control), isoenergetic novel diet of milk only, or milk plus one designated food daily. Follow up visit every 4 weeks.

MAIN OUTCOME MEASURE

Weight loss.

RESULTS

Mean weight loss (kg) after 16 weeks on control, milk only, and milk plus diets was 1.7 (95% confidence interval 0.3 to 3.7), 9.4 (5.9 to 12.9), and 7.0 (2.7 to 11.3) respectively. Weight loss on the novel diets was significantly greater than on the control diet.

CONCLUSIONS

Dietary treatment can achieve as much weight loss in obese outpatients over 16 weeks as has been reported for the most successful drug treatment, but compliance with the prescribed diet is poor unless the diet is novel and simple.

Psyllium-enriched cereals lower blood total cholesterol and LDL cholesterol, but not HDL cholesterol, in hypercholesterolemic adults: results of a meta-analysis

We conducted a meta-analysis to determine the effect of consumption of psyllium-enriched cereal products on blood total cholesterol (TC), LDL cholesterol (LDL-C) and HDL cholesterol (HDL-C) levels and to estimate the magnitude of the effect among 404 adults with mild to moderate hypercholesterolemia (TC of 5.17-7.8 mmol/L) who consumed a low fat diet. Studies of psyllium cereals were identified by a computerized search of MEDLINE and Current Contents and by contacting United States-based food companies involved in psyllium research. Published and unpublished studies were reviewed by one author and considered eligible for inclusion in the meta-analysis if they were conducted in humans, were randomized, controlled experiments, and included a control group that ate cereal providing </=3 g soluble fiber/d. Eight published and four unpublished studies, conducted in four countries, met the criteria. Analysis of a linear model was performed, controlling for sex and age. Female subjects were divided into two groups to provide a rough estimate of the effect of menopausal status (premenopausal = <50 y, postmenopausal = >/=50 y) on blood lipids. The meta-analysis showed that subjects who consumed a psyllium cereal had lower TC and LDL-C concentrations [differences of 0.31 mmol/L (5%) and 0.35 mmol/L (9%), respectively] than subjects who ate a control cereal; HDL-C concentrations were unaffected in subjects eating psyllium cereal. There was no effect of sex, age or menopausal status on blood lipids. Results indicate that consuming a psyllium-enriched cereal as part of a low fat diet improves the blood lipid profile of hypercholesterolemic adults over that which can be achieved with a low fat diet alone.

Relationship between feeding pattern and body mass index in 220 free-living people in four age groups

OBJECTIVE

To assess the relationship between feeding pattern and body mass index in free-living humans.

DESIGN AND SUBJECTS

Feeding pattern was assessed from 220 7-day weighed dietary records. 187 records were obtained from three separate existing studies, and reanalysed. These studies contained data on three age groups in the British population; Elderly group (n = 88), Middle-aged group (n = 40), Working age group (n = 59). A separate study of 13-14 year olds living in Croydon was conducted from which 33 usable diet records were collected to produce a fourth, Adolescent group.

RESULTS

'Nibbling' and greater energy intakes at breakfast were associated with a lower body mass index (BMI) in the Adolescent group. In the Middle-aged group, greater energy intakes at breakfast and lower energy intakes during the evening were associated with a lower BMI. However, when diet records which produced unreasonably low energy intakes were removed from the analysis, these relationships disappeared except for energy intakes at breakfast and BMI in the Adolescent group.

CONCLUSION

It is suggested that the relationship between feeding pattern and BMI observed in the Adolescent and Middle-aged groups was caused by underestimation of 'habitual' energy intake from snacks and the omission of breakfast by females and those who were overweight. The lack of relationship in the Working age group was attributed to the fact that more individuals in this group appeared to report valid diet records. Reported energy intake was directly related to BMI in the Working age group, but was not related to BMI in the other three age groups. It is concluded that feeding pattern is not a major factor in determining BMI in humans. Also, since snacks have a relatively high sugar and low fat composition compared with meals, it is suggested that biased under-reporting of snacks by the obese could produce spurious results from free-living studies which show that obesity is related to the proportion of energy from fat in the diet.

Minisatellites corresponding to the human polycore probes 33.6 and 33.15 in the genome of the most 'primitive' known eukaryote Giardia lamblia

DNA fingerprinting has been widely used for genetic characterization and individual recognition in a range of species, from man and other mammals down the evolutionary scale to some lower eukaryotic parasites. These techniques utilise repetitive elements first characterised in the human genome, known as minisatellites, which display extensive allelic variability. Few biological or biochemical characteristics have been found that distinguish isolates of Giardia lamblia (Gl), or their apparent variations in virulence. We have characterized 21 Gl isolates in axenic culture using DNA fingerprinting with the human minisatellite probes, 33.6 and 33.15. Up to 12 variable bands per isolate were recognized in the size range of 2.5 to 15 kb by Southern blot hybridization of restriction endonuclease-digested Gl DNA. Most isolates demonstrated a distinct banding pattern or DNA fingerprint. The results suggest that this method may provide a basis for the detailed genotypic characterization of Gl which will be amenable to computer and statistical analysis for use in studies of virulence and epidemiology. Also, as Gl occupies a unique phylogenetic position as a member of the earliest known divergence from the eukaryotic line of descent, this study may provide a useful model for the study of other important eukaryotic pathogens, as it is rapidly becoming apparent that minisatellites are ubiquitous components of eukaryotic genomes.

Meta-analysis: effect of exercise, with or without dieting, on the body composition of overweight subjects

OBJECTIVE

To determine if physical training conserves fat-free mass (FFM) in overweight men or women during weight loss.

DESIGN

Journals published between 1966 and 1993 were searched by MEDLINE and by handsearch to obtain all reports on human subjects in which the effect of exercise on body composition was studied in at least two concurrent treatment groups, of which at least one group did, and one group did not, undergo an exercise programme designed to promote fat loss. The relation between loss of weight, and loss of FFM, was examined by linear regression analysis among exercising and non-exercising groups of men or women.

SUBJECTS

Twenty-eight publications reported results on 226 sedentary men in 13 groups, 233 exercising men in 14 groups, 199 sedentary women in 23 groups, and 258 exercising women in 28 groups.

RESULTS

Aerobic exercise without dietary restriction among men caused a weight loss of 3 kg in 30 weeks compared with sedentary controls, and 1.4 kg in 12 weeks among women, but there was little effect on FFM. Resistance exercise had little effect on weight loss, but increased FFM by about 2 kg in men and 1 kg in women. Regression analysis shows that for a weight loss of 10 kg by diet alone the expected loss of FFM is 2.9 kg in men and 2.2 kg in women. When similar weight loss is achieved by exercise combined with dietary restriction the expected loss of FFM is reduced to 1.7 kg in men, and women. It is probable that the FFM conserved by exercise during weight loss contains more water and potassium than average FFM. The subjects studied were not severely obese.

CONCLUSIONS

Aerobic exercise causes a modest loss in weight without dieting. Exercise provides some conservation of FFM during weight loss by dieting, probably in part by maintaining glycogen and water.

Sources of energy from meals versus snacks in 220 people in four age groups

OBJECTIVES

To assess meals versus snacks in terms of their contribution to total daily energy intake (TDI), macronutrient composition, and food commodity profile.

DESIGN AND SUBJECTS

Meals and snacks were assessed from 220 7-day weighed dietary records. 187 records were obtained from three separate existing studies, and reanalysed. These studies contained data on three different age groups in the British population; elderly group (n = 88), middle-aged group (n = 40), young adult group (n = 59). A separate study of 13-14-year-olds living in Croydon was conducted from which 33 usable diet records were collected (adolescent group).

RESULTS

Boys in the adolescent group consumed more of their TDI as snacks (29.0%) compared with men in the young adult (18.9%) and elderly groups (16.6%), but not the middle-aged group (25.8%). Females consumed about the same percentage of their TDI as snacks; adolescent group 23.6%, young adult group 19.4%, middle-aged group 21.4%, elderly group 17.9%. Meals were higher in protein and fat, and lower in total sugars, compared with snacks. Chocolate confectionery, crisps and fizzy drinks and squashes were popular snack foods in the adolescent group. Unlike snacks, the food commodity profiles of meals were similar in all age groups.

CONCLUSIONS

This study shows that foods and drinks consumed as snacks by the British public, including the elderly, have a relatively high total sugar composition. These results add to the concern relating snack foods with dental caries.

Nutritional advice and support for individuals with incurable diseases

Having an incurable illness raises a number of special nutritional issues for both the patient and the health professional. This review covers two of these issues: the use of unproven dietary products to improve immune function, and the role of nutritional support in palliative care. The usage of unproven dietary strategies, particularly vitamin and mineral supplements, is extremely popular in patients with incurable diseases such as HIV infection. A daily multivitamin and mineral supplement plus an additional supplement of beta-carotene may be beneficial in terms of slowing progression to AIDS, but megadosing of vitamins, minerals and Chinese herbs, and the use of 'special diets' should be cautioned against. The two main areas where nutritional support appears to be important in palliative care are symptom control and aggressive feeding as a means of stabilising body weight. The psychological benefits of appropriate nutritional advice and support are highlighted.

Causes of weight loss in human immunodeficiency virus infection

The medical records of all 420 patients attending an outpatient clinic between June 1990 and June 1991 were retrospectively reviewed for causes of weight loss. Of the 121 (29%) patients who had lost weight, the majority had a clear contributing cause; opportunistic infections (n = 57), psychosocial factors (n = 20), drug related problems (n = 9). Unexplained weight loss (n = 35) was more likely to have occurred in those patients with a better preserved immune system and most of these had symptoms suggestive of an unconfirmed infection or had local oral lesions associated with a loss of appetite. Unexplained weight loss associated with HIV infection is uncommon.