Evaluation of a self-help dietary intervention in a primary care setting

Reduction in saturated fat intake for cardiovascular disease

BACKGROUND

Reducing saturated fat reduces serum cholesterol, but effects on other intermediate outcomes may be less clear. Additionally, it is unclear whether the energy from saturated fats eliminated from the diet are more helpfully replaced by polyunsaturated fats, monounsaturated fats, carbohydrate or protein.

OBJECTIVES

To assess the effect of reducing saturated fat intake and replacing it with carbohydrate (CHO), polyunsaturated (PUFA), monounsaturated fat (MUFA) and/or protein on mortality and cardiovascular morbidity, using all available randomised clinical trials.

SEARCH METHODS

We updated our searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid) and Embase (Ovid) on 15 October 2019, and searched Clinicaltrials.gov and WHO International Clinical Trials Registry Platform (ICTRP) on 17 October 2019.

SELECTION CRITERIA

Included trials fulfilled the following criteria: 1) randomised; 2) intention to reduce saturated fat intake OR intention to alter dietary fats and achieving a reduction in saturated fat; 3) compared with higher saturated fat intake or usual diet; 4) not multifactorial; 5) in adult humans with or without cardiovascular disease (but not acutely ill, pregnant or breastfeeding); 6) intervention duration at least 24 months; 7) mortality or cardiovascular morbidity data available.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed inclusion, extracted study data and assessed risk of bias. We performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity analyses, funnel plots and GRADE assessment.

MAIN RESULTS

We included 15 randomised controlled trials (RCTs) (16 comparisons, 56,675 participants), that used a variety of interventions from providing all food to advice on reducing saturated fat. The included long-term trials suggested that reducing dietary saturated fat reduced the risk of combined cardiovascular events by 17% (risk ratio (RR) 0.83; 95% confidence interval (CI) 0.70 to 0.98, 12 trials, 53,758 participants of whom 8% had a cardiovascular event, I² = 67%, GRADE moderate-quality evidence). Meta-regression suggested that greater reductions in saturated fat (reflected in greater reductions in serum cholesterol) resulted in greater reductions in risk of CVD events, explaining most heterogeneity between trials. The number needed to treat for an additional beneficial outcome (NNTB) was 56 in primary prevention trials, so 56 people need to reduce their saturated fat intake for ~four years for one person to avoid experiencing a CVD event. In secondary prevention trials, the NNTB was 53. Subgrouping did not suggest significant differences between replacement of saturated fat calories with polyunsaturated fat or carbohydrate, and data on replacement with monounsaturated fat and protein was very limited. We found little or no effect of reducing saturated fat on all-cause mortality (RR 0.96; 95% CI 0.90 to 1.03; 11 trials, 55,858 participants) or cardiovascular mortality (RR 0.95; 95% CI 0.80 to 1.12, 10 trials, 53,421 participants), both with GRADE moderate-quality evidence. There was little or no effect of reducing saturated fats on non-fatal myocardial infarction (RR 0.97, 95% CI 0.87 to 1.07) or CHD mortality (RR 0.97, 95% CI 0.82 to 1.16, both low-quality evidence), but effects on total (fatal or non-fatal) myocardial infarction, stroke and CHD events (fatal or non-fatal) were all unclear as the evidence was of very low quality. There was little or no effect on cancer mortality, cancer diagnoses, diabetes diagnosis, HDL cholesterol, serum triglycerides or blood pressure, and small reductions in weight, serum total cholesterol, LDL cholesterol and BMI. There was no evidence of harmful effects of reducing saturated fat intakes.

AUTHORS' CONCLUSIONS

The findings of this updated review suggest that reducing saturated fat intake for at least two years causes a potentially important reduction in combined cardiovascular events. Replacing the energy from saturated fat with polyunsaturated fat or carbohydrate appear to be useful strategies, while effects of replacement with monounsaturated fat are unclear. The reduction in combined cardiovascular events resulting from reducing saturated fat did not alter by study duration, sex or baseline level of cardiovascular risk, but greater reduction in saturated fat caused greater reductions in cardiovascular events.

Reduction in saturated fat intake for cardiovascular disease

BACKGROUND

Reducing saturated fat reduces serum cholesterol, but effects on other intermediate outcomes may be less clear. Additionally, it is unclear whether the energy from saturated fats eliminated from the diet are more helpfully replaced by polyunsaturated fats, monounsaturated fats, carbohydrate or protein.

OBJECTIVES

To assess the effect of reducing saturated fat intake and replacing it with carbohydrate (CHO), polyunsaturated (PUFA), monounsaturated fat (MUFA) and/or protein on mortality and cardiovascular morbidity, using all available randomised clinical trials.

SEARCH METHODS

We updated our searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid) and Embase (Ovid) on 15 October 2019, and searched Clinicaltrials.gov and WHO International Clinical Trials Registry Platform (ICTRP) on 17 October 2019.

SELECTION CRITERIA

Included trials fulfilled the following criteria: 1) randomised; 2) intention to reduce saturated fat intake OR intention to alter dietary fats and achieving a reduction in saturated fat; 3) compared with higher saturated fat intake or usual diet; 4) not multifactorial; 5) in adult humans with or without cardiovascular disease (but not acutely ill, pregnant or breastfeeding); 6) intervention duration at least 24 months; 7) mortality or cardiovascular morbidity data available.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed inclusion, extracted study data and assessed risk of bias. We performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity analyses, funnel plots and GRADE assessment.

MAIN RESULTS

We included 15 randomised controlled trials (RCTs) (16 comparisons, ~59,000 participants), that used a variety of interventions from providing all food to advice on reducing saturated fat. The included long-term trials suggested that reducing dietary saturated fat reduced the risk of combined cardiovascular events by 21% (risk ratio (RR) 0.79; 95% confidence interval (CI) 0.66 to 0.93, 11 trials, 53,300 participants of whom 8% had a cardiovascular event, I² = 65%, GRADE moderate-quality evidence). Meta-regression suggested that greater reductions in saturated fat (reflected in greater reductions in serum cholesterol) resulted in greater reductions in risk of CVD events, explaining most heterogeneity between trials. The number needed to treat for an additional beneficial outcome (NNTB) was 56 in primary prevention trials, so 56 people need to reduce their saturated fat intake for ~four years for one person to avoid experiencing a CVD event. In secondary prevention trials, the NNTB was 32. Subgrouping did not suggest significant differences between replacement of saturated fat calories with polyunsaturated fat or carbohydrate, and data on replacement with monounsaturated fat and protein was very limited. We found little or no effect of reducing saturated fat on all-cause mortality (RR 0.96; 95% CI 0.90 to 1.03; 11 trials, 55,858 participants) or cardiovascular mortality (RR 0.95; 95% CI 0.80 to 1.12, 10 trials, 53,421 participants), both with GRADE moderate-quality evidence. There was little or no effect of reducing saturated fats on non-fatal myocardial infarction (RR 0.97, 95% CI 0.87 to 1.07) or CHD mortality (RR 0.97, 95% CI 0.82 to 1.16, both low-quality evidence), but effects on total (fatal or non-fatal) myocardial infarction, stroke and CHD events (fatal or non-fatal) were all unclear as the evidence was of very low quality. There was little or no effect on cancer mortality, cancer diagnoses, diabetes diagnosis, HDL cholesterol, serum triglycerides or blood pressure, and small reductions in weight, serum total cholesterol, LDL cholesterol and BMI. There was no evidence of harmful effects of reducing saturated fat intakes.

AUTHORS' CONCLUSIONS

The findings of this updated review suggest that reducing saturated fat intake for at least two years causes a potentially important reduction in combined cardiovascular events. Replacing the energy from saturated fat with polyunsaturated fat or carbohydrate appear to be useful strategies, while effects of replacement with monounsaturated fat are unclear. The reduction in combined cardiovascular events resulting from reducing saturated fat did not alter by study duration, sex or baseline level of cardiovascular risk, but greater reduction in saturated fat caused greater reductions in cardiovascular events.

Culturally Competent Diabetes Education

Purpose

The purpose of this study was to test effects of a culturally competent, dietary self-management intervention on physiological outcomes and dietary behaviors for African Americans with type 2 diabetes.

Methods

A longitudinal experimental study was conducted in rural South Carolina with a sample of 97 adult African Americans with type 2 diabetes who were randomly assigned to either usual care or the intervention. The intervention consisted of 4 weekly classes in low-fat dietary strategies, 5 monthly peer-professional group discussions, and weekly telephone follow-up. The culturally competent approach reflected the ethnic beliefs, values, customs, food preferences, language, learning methods, and health care practices of southern African Americans.

Results

Body mass index and dietary fat behaviors were significantly lowered in the experimental group. At 6 months, weight decreased 1.8 kg (4 lb) for the experimental group and increased 1.9 kg (4.2 lb) for the control group, a net difference of 3.7 kg (8.2 lb). The experimental group reduced high-fat dietary habits to moderate while high-fat dietary habits of the control group remained essentially unchanged. A trend in reduction of A1C and lipids was observed.

Conclusions

Results suggest the effectiveness of a culturally competent dietary self-management intervention in improving health outcomes for southern African Americans, especially those at risk due to high-fat diets and body mass index ≥ 35 kg/mm2. Given the burgeoning problem of obesity in South Carolina and the nation, the time has come to focus on aggressive weight management. Diabetes educators are in pivotal positions to assume leadership in achieving this goal for vulnerable, rural populations.

Effects of total fat intake on body weight

BACKGROUND

In order to prevent overweight and obesity in the general population we need to understand the relationship between the proportion of energy from fat and resulting weight and body fatness in the general population.

OBJECTIVES

To assess the effects of proportion of energy intake from fat on measures of weight and body fatness (including obesity, waist circumference and body mass index) in people not aiming to lose weight, using all appropriate randomised controlled trials (RCTs) and cohort studies in adults, children and young people

SEARCH METHODS

We searched CENTRAL to March 2014 and MEDLINE, EMBASE and CINAHL to November 2014. We did not limit the search by language. We also checked the references of relevant reviews.

SELECTION CRITERIA

Trials fulfilled the following criteria: 1) randomised intervention trial, 2) included children (aged ≥ 24 months), young people or adults, 3) randomised to a lower fat versus usual or moderate fat diet, without the intention to reduce weight in any participants, 4) not multifactorial and 5) assessed a measure of weight or body fatness after at least six months. We also included cohort studies in children, young people and adults that assessed the proportion of energy from fat at baseline and assessed the relationship with body weight or fatness after at least one year. We duplicated inclusion decisions and resolved disagreement by discussion or referral to a third party.

DATA COLLECTION AND ANALYSIS

We extracted data on the population, intervention, control and outcome measures in duplicate. We extracted measures of weight and body fatness independently in duplicate at all available time points. We performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity and funnel plot analyses.

MAIN RESULTS

We included 32 RCTs (approximately 54,000 participants) and 30 sets of analyses of 25 cohorts. There is consistent evidence from RCTs in adults of a small weight-reducing effect of eating a smaller proportion of energy from fat; this was seen in almost all included studies and was highly resistant to sensitivity analyses. The effect of eating less fat (compared with usual diet) is a mean weight reduction of 1.5 kg (95% confidence interval (CI) -2.0 to -1.1 kg), but greater weight loss results from greater fat reductions. The size of the effect on weight does not alter over time and is mirrored by reductions in body mass index (BMI) (-0.5 kg/m(2), 95% CI -0.7 to -0.3) and waist circumference (-0.3 cm, 95% CI -0.6 to -0.02). Included cohort studies in children and adults most often do not suggest any relationship between total fat intake and later measures of weight, body fatness or change in body fatness. However, there was a suggestion that lower fat intake was associated with smaller increases in weight in middle-aged but not elderly adults, and in change in BMI in the highest validity child cohort.

AUTHORS' CONCLUSIONS

Trials where participants were randomised to a lower fat intake versus usual or moderate fat intake, but with no intention to reduce weight, showed a consistent, stable but small effect of low fat intake on body fatness: slightly lower weight, BMI and waist circumference compared with controls. Greater fat reduction and lower baseline fat intake were both associated with greater reductions in weight. This effect of reducing total fat was not consistently reflected in cohort studies assessing the relationship between total fat intake and later measures of body fatness or change in body fatness in studies of children, young people or adults.

Reduction in saturated fat intake for cardiovascular disease

BACKGROUND

Reducing saturated fat reduces serum cholesterol, but effects on other intermediate outcomes may be less clear. Additionally it is unclear whether the energy from saturated fats that are lost in the diet are more helpfully replaced by polyunsaturated fats, monounsaturated fats, carbohydrate or protein. This review is part of a series split from and updating an overarching review.

OBJECTIVES

To assess the effect of reducing saturated fat intake and replacing it with carbohydrate (CHO), polyunsaturated (PUFA) or monounsaturated fat (MUFA) and/or protein on mortality and cardiovascular morbidity, using all available randomised clinical trials.

SEARCH METHODS

We updated our searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid) and EMBASE (Ovid) on 5 March 2014. We also checked references of included studies and reviews.

SELECTION CRITERIA

Trials fulfilled the following criteria: 1) randomised with appropriate control group; 2) intention to reduce saturated fat intake OR intention to alter dietary fats and achieving a reduction in saturated fat; 3) not multifactorial; 4) adult humans with or without cardiovascular disease (but not acutely ill, pregnant or breastfeeding); 5) intervention at least 24 months; 6) mortality or cardiovascular morbidity data available.

DATA COLLECTION AND ANALYSIS

Two review authors working independently extracted participant numbers experiencing health outcomes in each arm, and we performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity analyses and funnel plots.

MAIN RESULTS

We include 15 randomised controlled trials (RCTs) (17 comparisons, ˜59,000 participants), which used a variety of interventions from providing all food to advice on how to reduce saturated fat. The included long-term trials suggested that reducing dietary saturated fat reduced the risk of cardiovascular events by 17% (risk ratio (RR) 0.83; 95% confidence interval (CI) 0.72 to 0.96, 13 comparisons, 53,300 participants of whom 8% had a cardiovascular event, I² 65%, GRADE moderate quality of evidence), but effects on all-cause mortality (RR 0.97; 95% CI 0.90 to 1.05; 12 trials, 55,858 participants) and cardiovascular mortality (RR 0.95; 95% CI 0.80 to 1.12, 12 trials, 53,421 participants) were less clear (both GRADE moderate quality of evidence). There was some evidence that reducing saturated fats reduced the risk of myocardial infarction (fatal and non-fatal, RR 0.90; 95% CI 0.80 to 1.01; 11 trials, 53,167 participants), but evidence for non-fatal myocardial infarction (RR 0.95; 95% CI 0.80 to 1.13; 9 trials, 52,834 participants) was unclear and there were no clear effects on stroke (any stroke, RR 1.00; 95% CI 0.89 to 1.12; 8 trials, 50,952 participants). These relationships did not alter with sensitivity analysis. Subgrouping suggested that the reduction in cardiovascular events was seen in studies that primarily replaced saturated fat calories with polyunsaturated fat, and no effects were seen in studies replacing saturated fat with carbohydrate or protein, but effects in studies replacing with monounsaturated fats were unclear (as we located only one small trial). Subgrouping and meta-regression suggested that the degree of reduction in cardiovascular events was related to the degree of reduction of serum total cholesterol, and there were suggestions of greater protection with greater saturated fat reduction or greater increase in polyunsaturated and monounsaturated fats. There was no evidence of harmful effects of reducing saturated fat intakes on cancer mortality, cancer diagnoses or blood pressure, while there was some evidence of improvements in weight and BMI.

AUTHORS' CONCLUSIONS

The findings of this updated review are suggestive of a small but potentially important reduction in cardiovascular risk on reduction of saturated fat intake. Replacing the energy from saturated fat with polyunsaturated fat appears to be a useful strategy, and replacement with carbohydrate appears less useful, but effects of replacement with monounsaturated fat were unclear due to inclusion of only one small trial. This effect did not appear to alter by study duration, sex or baseline level of cardiovascular risk. Lifestyle advice to all those at risk of cardiovascular disease and to lower risk population groups should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturated fats. The ideal type of unsaturated fat is unclear.

Fat- and fiber-related diet behavior among type 2 diabetes patients from distinct regions

PURPOSE

Diet and eating habits are of key importance in patients with type 2 diabetes mellitus (T2DM). The purpose of this comparative study was to analyze fat- and fiber-related behavior (FFB) in patients with T2DM from distinct cultural areas.

PATIENTS AND METHODS

Observational study was carried out in the Czech Republic (CR) (n=200), the US (n=207), and Yemen (n=200). Patients completed the Fat- and Fiber-related Diet Behavior Questionnaire (FFBQ).

RESULTS

Differences in all aspects of FFB among countries were found (P<0.05). The best fat-related behavior reported was from patients from the CR. Patients from the US showed the worst fat-related behavior in total. On the other hand, patients from the US reported the best fiber-related behavior. Patients from Yemen reached the worst scores in all fat-related domains. Patients from all studied countries reported the best results in the "modify meat" and "avoid fat as flavoring" and the worst in the "substitute high fiber" subscales.

CONCLUSION

Professionals involved in the diet education of T2DM patients should be aware of the specificity of diet in their country when advising patients keeping general recommendations. We suggest them to be as specific as possible and concentrate on fiber-related behavior.

An analysis of fat-related and fiber-related behavior in men and women with type 2 diabetes mellitus: key findings for clinical practice

BACKGROUND

Despite the efforts of health care providers, adherence of patients with type 2 diabetes to the recommended diet is poor. The aim of this study was to describe the eating habits with emphasis on fat and fiber-related behavior (FFB) as well as the relationship between FFB behavior and parameters of diabetes control in men and women with type 2 diabetes mellitus.

METHODS

The subjects in this observational cross-sectional study were 200 patients (54.5% male, mean age 66.2 ± 10.1 years, mean Diabetes Control and Complications Trial [DDCT] glycosylated hemoglobin [HbA1c] 7.6% ± 1.7%) recruited from diabetes outpatient clinics in the Czech Republic. The subjects filled out the Fat- and Fiber-related Diet Behavior Questionnaire. The most recent patient data on diabetes control and drug therapy were derived from patient medical records.

RESULTS

Patients tend to modify the dishes they are used to, rather than remove them completely from their diet and replace them by other types of foods. It is easier to perform healthier fat-related behaviors than fiber-related ones. Women scored significantly better than men on the fat-related diet habits summary scale (P = 0.002), as well as on "modify meat" (P = 0.001) and "substitute specially manufactured low-fat foods" (P = 0.045) subscales. A better score on the fat-related diet habits summary scale was significantly associated with higher HbA1c (ρ = -0.248; P = 0.027) and higher waist circumference (ρ = -0.254; P = 0.024) in women.

CONCLUSION

Type 2 diabetes patients are likely to vary in their FFB behavior, and their dietary habits depend on gender. Health care professionals should pay attention to these facts when providing specific education. Emphasis should be placed on how to increase the fiber intake in diabetic patients.

Nurse delivered lifestyle interventions in primary health care to treat chronic disease risk factors associated with obesity: a systematic review

Nurses in primary health care (PHC) provide an increasing proportion of chronic disease management and preventive lifestyle advice. The databases MEDLINE, CINAHL, EMBASE and PsychINFO were searched and the articles were systematically reviewed for articles describing controlled adult lifestyle intervention studies delivered by a PHC nurse, in a PHC setting. Thirty-one articles describing 28 studies were analysed by comparison group which revealed: (i) no difference of effect when the same intervention was delivered by a PHC nurse compared to other health professionals in PHC (n = 2); (ii) the provision of counselling delivered by a PHC nurse was more effective than health screening (n = 10); (iii) counselling based on behaviour change theory was more effective than the same dose of non-behavioural counselling when at least three counselling sessions were delivered (n = 3). The evidence supports the effectiveness of lifestyle interventions delivered by nurses in PHC to affect positive changes on outcomes associated with the prevention of chronic disease including: weight, blood pressure, cholesterol, dietary and physical activity behaviours, patient satisfaction, readiness for change and quality of life. The strength of recommendations is limited by the small number of studies within each comparison group and the high risk of bias of the majority of studies.

Reduced or modified dietary fat for preventing cardiovascular disease

BACKGROUND

Reduction and modification of dietary fats have differing effects on cardiovascular risk factors (such as serum cholesterol), but their effects on important health outcomes are less clear.

OBJECTIVES

To assess the effect of reduction and/or modification of dietary fats on mortality, cardiovascular mortality, cardiovascular morbidity and individual outcomes including myocardial infarction, stroke and cancer diagnoses in randomised clinical trials of at least 6 months duration.

SEARCH METHODS

For this review update, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE, were searched through to June 2010. References of Included studies and reviews were also checked.

SELECTION CRITERIA

Trials fulfilled the following criteria: 1) randomised 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) adult humans with or without cardiovascular disease, 5) intervention at least six months, 6) mortality or cardiovascular morbidity data available.

DATA COLLECTION AND ANALYSIS

Participant numbers experiencing health outcomes in each arm were extracted independently in duplicate and random effects meta-analyses, meta-regression, sub-grouping, sensitivity analyses and funnel plots were performed.

MAIN RESULTS

This updated review suggested that reducing saturated fat by reducing and/or modifying dietary fat reduced the risk of cardiovascular events by 14% (RR 0.86, 95% CI 0.77 to 0.96, 24 comparisons, 65,508 participants of whom 7% had a cardiovascular event, I(2) 50%). Subgrouping suggested that this reduction in cardiovascular events was seen in studies of fat modification (not reduction - which related directly to the degree of effect on serum total and LDL cholesterol and triglycerides), of at least two years duration and in studies of men (not of women). There were no clear effects of dietary fat changes on total mortality (RR 0.98, 95% CI 0.93 to 1.04, 71,790 participants) or cardiovascular mortality (RR 0.94, 95% CI 0.85 to 1.04, 65,978 participants). This did not alter with sub-grouping or sensitivity analysis.Few studies compared reduced with modified fat diets, so direct comparison was not possible.

AUTHORS' CONCLUSIONS

The findings are suggestive of a small but potentially important reduction in cardiovascular risk on modification of dietary fat, but not reduction of total fat, in longer trials. Lifestyle advice to all those at risk of cardiovascular disease and to lower risk population groups, should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturates. The ideal type of unsaturated fat is unclear.

Reduced or modified dietary fat for preventing cardiovascular disease

BACKGROUND

Reduction and modification of dietary fats have differing effects on cardiovascular risk factors (such as serum cholesterol), but their effects on important health outcomes are less clear.

OBJECTIVES

To assess the effect of reduction and/or modification of dietary fats on mortality, cardiovascular mortality, cardiovascular morbidity and individual outcomes including myocardial infarction, stroke and cancer diagnoses in randomised clinical trials of at least 6 months duration.

SEARCH STRATEGY

For this review update, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE, were searched through to June 2010. References of Included studies and reviews were also checked.

SELECTION CRITERIA

Trials fulfilled the following criteria: 1) randomised 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) adult humans with or without cardiovascular disease, 5) intervention at least six months, 6) mortality or cardiovascular morbidity data available.

DATA COLLECTION AND ANALYSIS

Participant numbers experiencing health outcomes in each arm were extracted independently in duplicate and random effects meta-analyses, meta-regression, sub-grouping, sensitivity analyses and funnel plots were performed.

MAIN RESULTS

This updated review suggested that reducing saturated fat by reducing and/or modifying dietary fat reduced the risk of cardiovascular events by 14% (RR 0.86, 95% CI 0.77 to 0.96, 24 comparisons, 65,508 participants of whom 7% had a cardiovascular event, I(2) 50%). Subgrouping suggested that this reduction in cardiovascular events was seen in studies of fat modification (not reduction - which related directly to the degree of effect on serum total and LDL cholesterol and triglycerides), of at least two years duration and in studies of men (not of women). There were no clear effects of dietary fat changes on total mortality (RR 0.98, 95% CI 0.93 to 1.04, 71,790 participants) or cardiovascular mortality (RR 0.94, 95% CI 0.85 to 1.04, 65,978 participants). This did not alter with sub-grouping or sensitivity analysis.Few studies compared reduced with modified fat diets, so direct comparison was not possible.

AUTHORS' CONCLUSIONS

The findings are suggestive of a small but potentially important reduction in cardiovascular risk on modification of dietary fat, but not reduction of total fat, in longer trials. Lifestyle advice to all those at risk of cardiovascular disease and to lower risk population groups, should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturates. The ideal type of unsaturated fat is unclear.

Repeatability and validation of a short, semi-quantitative food frequency questionnaire designed for older adults living in Mediterranean areas: the MEDIS-FFQ

The aim of the present work was to evaluate the repeatability and the validity of a short food frequency questionnaire (FFQ) that could be used for older people living in Mediterranean areas. The semi-quantitative FFQ included questions regarding the frequency of consumption of the main food groups and beverages typically consumed in the Mediterranean areas as well as some questions regarding eating habits of older persons. During 2006-2007, for the repeatability assessment (within 10-30 days), 150 individuals (51 +/- 17 yrs, 40% males) were studied, while another 190 individuals (74 +/- 9 yrs, 52% males) were enrolled for the validation purposes. Agreement of the FFQ with the 3-day food records was evaluated using the Bland-Altman method and the Kendall's tau-b coefficient. Repeatability was tested using the Cohen's kappa coefficient. Between 3-day food records and the FFQ, good agreement for alcohol (tau-b = 0.64, p < 0.001) was found, while moderate agreement for food and beverage groups of greens (tau-b = 0.32, p < 0.001), fruits (tau-b = 0.35, p < 0.001), cereals (tau-b = 0.61, p < 0.001), sweets (tau-b = 0.51, p < 0.001), and coffee (tau-b = 0.58, p < 0.001) was observed. Low, but still significant, agreement for fish (tau-b = 0.21, p = 0.001), legumes (tau-b = 0.23, p < 0.001), vegetables (tau-b = 0.23, p < 0.001), pasta (tau-b = 0.25, p < 0.001), potatoes (tau-b = 0.17, p = 0.006) and meat consumption (tau-b = 0.14, p < 0.001) were also found. The FFQ was also valid regarding the estimation of macronutrients and energy intake. Sensitivity analyses by sex, age category (<or= or > 75 yrs), and education status showed similar validity of the FFQ in each subgroup, except for elders older than 75 years. The repeatability of the FFQ was fair in all foods tested (Cohen's kappa coefficients varied between 0.15-0.39, p-values < 0.05). The suggested FFQ seems to be a reasonably valid and repeatable measure of dietary intake and can be used in older persons living in the Mediterranean areas.

Features of the Chronic Care Model (CCM) associated with behavioral counseling and diabetes care in community primary care

BACKGROUND

The Chronic Care Model (CCM) was developed to improve chronic disease care, but it may also inform delivery of other types of preventive care. Using hierarchical analyses of service delivery to patients, we explored associations of CCM implementation with diabetes care and counseling for diet or weight loss and physical activity in community-based primary care offices.

METHODS

Secondary analysis focused on baseline data from 25 practices (with an average of 4 physicians per practice) participating in an intervention trial targeting improved colorectal cancer screening rates. This intervention made no reference to the CCM. CCM implementation was measured through staff and clinical management surveys and was associated with patient care indicators (chart audits and patient questionnaires).

RESULTS

Overall, practices had low levels of CCM implementation. However, higher levels of CCM implementation were associated with better diabetes assessment and treatment of patients (P = .009 and .015, respectively), particularly among practices open to "innovation." Physical activity counseling for obese and, particularly, overweight patients was strongly associated with CCM implementation (P = .0017), particularly among practices open to "innovation"; however, this association did not hold for overweight and obese patients with diabetes.

CONCLUSIONS

Very modest levels of CCM implementation in unsupported primary care practices are associated with improved care for patients with diabetes and higher rates of behavioral counseling. Incremental incorporation of CCM components is an option, especially for community practices with stretched resources and with cultures of "innovativeness."

Mediation of adult fruit and vegetable consumption in the National 5 A Day for Better Health community studies

BACKGROUND

The 5 A Day for Better Health community studies demonstrated in randomized trials the efficacy of population-based strategies to increase fruit and vegetable consumption in diverse geographic areas and settings.

PURPOSE

Mediation analysis can help to elucidate the theoretical basis of changing dietary habits. This is important for informing more powerful cancer prevention and control interventions to achieve broad public health impact.

METHODS

Five sites that focused on adults were included in mediation analyses to determine whether theoretically derived constructs assessed at baseline and follow-up contributed to explaining change in fruit and vegetable (F&V) consumption. These variables were knowledge, self-efficacy, and autonomy/responsibility. Stage of change also was considered as a potential moderating variable.

RESULTS

Self-efficacy and knowledge of the 5 A Day recommendation increased in those who received the interventions and were positively associated with higher F&V. Mediation of intervention effect was demonstrated for these variables. Autonomy/responsibility did not meet the criteria for mediation. There was no evidence of differential effect of mediators according to baseline stage.

CONCLUSIONS

The present study findings provide strong support for mediation of F&V consumption by two variables: self-efficacy and knowledge. The authors discuss the findings in relation to study limitations and future research directions.

Performance of a short percentage energy from fat tool in measuring change in dietary intervention studies

Measurement of percentage energy from fat is important in surveillance of populations and in epidemiologic studies examining relationships between diet and disease as well as for behavioral intervention studies seeking to change dietary behavior. The NCI percentage energy from fat screener (PFat) has adequately predicted percentage of energy from fat compared with 24-h recalls (24HR) in cross-sectional analyses. However, the instrument has not been evaluated for its ability to assess change of percentage energy from fat over time or in response to interventions to change dietary intake of fat. The objective of this analysis is to evaluate the performance of the PFat in assessing change in percentage energy intake from fat in a behavioral intervention setting. Four individual sites participating in the Behavior Change Consortium Nutrition Working Group administered both the PF at and multiple 24HR at baseline and follow-up to 278 participants. A measurement error model was used to assess agreement between the PFat and 24HR at baseline and follow-up. The PFat was consistent with 24HR in finding there was no significant change in percentage energy from fat as a result of the intervention. Both male and female participants in the intervention group demonstrated a significant increase in the correlation between PFat and 24HR from baseline to follow-up. Percentage energy from fat measured by PFat may be useful to provide estimates of change in mean intake of populations over time in longitudinal studies. Further methodologic research is called for in interventions producing significant changes and in diverse populations with adequate sample size.

Impact of a two-city community cancer prevention intervention on African Americans

We report the first multisite, multicomponent community intervention trial to focus on cancer prevention in African Americans. The project explored the potential of historically black medical schools to deliver health information to their local communities and used a community-based participatory research approach. The intervention consisted of culturally sensitive messages at appropriate educational levels delivered over an 18-month period and tested in predominantly black census tracts in Nashville, TN and Atlanta, GA. Chattanooga, TN and Decatur, GA served as comparison cities. Results were evaluated by pre- and postintervention random-digit dial telephone surveys. The intervention cities showed an increase in reported contact with or knowledge of the project. There was little or no effect on knowledge or attitudes in the intervention cities. Compared to Chattanooga, Nashville showed an increase in percentage of women receiving Pap smears. Compared to Decatur, Atlanta showed an increase in percentage of age-appropriate populations receiving digital rectal exams, colorectal cancer screenings and mammograms. The results of this community intervention trial demonstrated modest success and are encouraging for future efforts of longer duration.

Validation of a Brief Diet Survey Instrument among Medical Students

Our objective was to assess the reproducibility and accuracy of fat and of fruit and vegetable items on a 43-item food frequency questionnaire (FFQ) previously self-administered by students at 16 US medical schools. Five in-person, 24-hour recalls were administered between two FFQ administrations to 88 medical students. Reported fat intake decreased from the first (34.7%) to the second (33.1%) FFQ administration ( P <.001); the reproducibility correlation was r =0.63. Fat intake from recalls (28.4%) was lower than that from the FFQ (33.8%, P <.001). The Pearson correlation was r =0.36. Fruit and vegetable servings per day were 3.9 and 3.7 from the first and second FFQ, respectively ( P =.5); the reproducibility correlation was r =0.77. Fruit and vegetable servings were marginally higher from recalls (4.3) than from the FFQ (3.8, P =.06). The Pearson correlation for fruit and vegetable servings was r =0.50. This brief FFQ provides acceptably reproducible and valid estimates of fruit and vegetable servings per day among most groups of medical students, but overestimates fat as a percentage of energy intake.

Randomized trial of a low-intensity dietary intervention in rural residents: the Rural Physician Cancer Prevention Project

BACKGROUND

Dietary behavior, specifically a low-fat, high-fiber diet, plays a role in the primary prevention of chronic diseases including cancer.

DESIGN

A community-based randomized trial to assess the impact of a low-intensity, physician-endorsed, self-help dietary intervention that provided tailored dietary feedback, and was designed to promote improved fat and fiber behavior in a rural, low-education/low-literacy, partly minority population. The data were collected from 1999 to 2003.

SETTING/PARTICIPANTS

A total of 754 patients from three physician practices in rural Virginia completed a baseline telephone survey assessing dietary and psychosocial information, and were then randomly assigned to the intervention or control condition. Follow-up telephone evaluation was based on 522 participants at 1 month, 470 at 6 months, and 516 participants at 12 months.

INTERVENTION

A series of tailored feedback, followed by brief telephone counseling and theory-based nutritional education booklets, provided by staggered delivery to the home.

MAIN OUTCOME MEASURES

Dietary fat and fiber behavior, dietary intentions to change, self-efficacy for dietary change, and fat and fiber knowledge.

RESULTS

The intervention group demonstrated significant improvement in dietary fat and fiber behaviors and intentions to change fat and fiber intake (p <0.05) at 1, 6, and 12 months.

CONCLUSIONS

The Rural Physician Cancer Prevention Project provides an effective model for achieving public health-level dietary health behavior changes among a rural, minority, and low-literacy/low-education population.

Minimal intervention programs for weight loss in heart transplant candidates: a preliminary examination

CONTEXT

Overweight can be a contraindication for cardiac transplantation, and empirical findings suggest that obesity may pose serious posttransplant health risks that can increase morbidity and mortality.

OBJECTIVE

This study assessed the relative effectiveness of 2 minimal intervention programs to assist weight loss in heart transplant candidates.

DESIGN

A randomized trial was employed to assess changes in body weight.

SETTING

A large, tertiary care hospital in a Southern locale.

PATIENTS

Forty-three heart transplant candidates (74% men, 79% married, 86% white), with a mean pretreatment body mass index of 32.4 (SD = 4.4).

INTERVENTIONS

Patients were randomly assigned to a bibliotherapy weight-loss program or a bibliotherapy plus telephone contact weight-loss program.

MAIN OUTCOME MEASURES

Change in body weight over 3 months and return rate of measures of program adherence (3-day food diaries and self-monitoring postcards).

RESULTS

An intent-to-treat analysis showed a significant weight loss at posttreatment for the sample as a whole. Within-group analyses indicated that a significant weight change (P < .05) in the telephone contact group (mean [SD] = -2.76 [4.96] kg) but not the bibliotherapy-only group (mean [SD] = -1.02 [2.97] kg). Participants in the telephone contact group returned more 3-day food diaries and self-monitoring postcards, with pounds lost significantly correlated with the number of completed self-monitoring postcards. These findings suggest that a minimal intervention program involving information plus limited professional contact may represent a viable approach to assisting overweight transplant candidates in weight management.

One-year results from a brief, computer-assisted intervention to decrease consumption of fat and increase consumption of fruits and vegetables

BACKGROUND

Current cancer prevention recommendations include reducing consumption of fat and increasing consumption of fruits and vegetables.

METHODS

Healthy women health maintenance organization members (n = 616) ages 40-70 were randomly assigned to either a nutrition intervention or a control intervention unrelated to diet. Intervention included two 45-min counseling sessions plus two brief follow-up telephone contacts. Counseling sessions included a 20-min, interactive, computer-based intervention using a touch-screen format. Intervention goals were reducing dietary fat and increasing fruit and vegetable consumption. Outcome measures included a food frequency questionnaire and the Fat and Fiber Behavior Questionnaire (FFBQ). Total serum cholesterol was also measured at baseline and 12 months.

RESULTS

Twelve-month follow-up data showed improvements on all dietary outcome variables. Compared to the control, intervention participants reported significantly less fat consumption (3.75 points less for percentage of energy from fat), significantly greater consumption of fruit and vegetables combined (0.93 more servings per day), and a significant reduction in a behavioral measure of fat consumption (0.20 point change in the FFBQ). Group differences in total serum cholesterol, while in the desired direction, were not significant.

CONCLUSIONS

In appropriate circumstances, moderate-intensity dietary interventions can show significant effects for periods of at least 1 year.

Validation of a short questionnaire to qualitatively assess the intake of total fat, saturated, monounsaturated, polyunsaturated fatty acids, and cholesterol

BACKGROUND

To validate a self-administered 20-item short questionnaire (SQ) for classifying individuals according to their intake of total fat, saturated (SFA), monounsaturated (MUFA), and polyunsaturated fatty acids (PUFA), as well as cholesterol.

METHODS

The SQ was sent to a randomly selected subsample of 300 participants of the European Prospective Investigation into Cancer and Nutrition (EPIC) in Heidelberg. The SQ was sent back by 244 participants (52.5% women, 47.5% men). Intake of total fat, SFA, MUFA, PUFA, and cholesterol was calculated from a 148-item food frequency questionnaire (FFQ). The intake was compared with the scores computed from the SQ.

RESULTS

Spearman's correlation coefficient between the intake estimated from the FFQ and the score from the SQ ranged from r = 0.29 (PUFA) to r = 0.56 (cholesterol). When the participants were assigned to quartiles of intake according to both methods 29-42% were classified into the same quartile, 1-7% of the participants were grossly misclassified.

CONCLUSIONS

The SQ demonstrated a good validity with respect to SFA and cholesterol and an acceptable validity with respect to total fat and MUFA, while the results are less good for PUFA. The SQ can be used to classify persons according to their intake into categories of intake.

Counseling to promote a healthy diet in adults: a summary of the evidence for the U.S. Preventive Services Task Force

OBJECTIVE

The purpose of this study was to examine the effectiveness of counseling to promote a healthy diet among patients in primary care settings.

DESIGN AND DATA SOURCES

We conducted a MEDLINE search from 1966 to December 2001.

STUDY SELECTION

We included randomized controlled trials of at least 3 months' duration with measures of dietary behavior that were conducted in patient populations similar to those found in primary care practices. We excluded studies that reported only biochemical or anthropomorphic endpoints, had dropout rates greater than 50%, or enrolled patients based on the presence of a chronic disease.

DATA EXTRACTION

One author extracted relevant data from each included article into evidence tables. Using definitions developed by the research team, two authors independently rated each study in terms of its effect size, the intensity of its intervention, the patient risk level, and the use of well-proven counseling techniques.

DATA SYNTHESIS

We identified 21 trials for use in this review. Dietary counseling produces modest changes in self-reported consumption of saturated fat, fruits and vegetables, and possibly dietary fiber. More-intensive interventions were more likely to produce important changes than brief interventions, but they may be more difficult to apply to typical primary care patients. Interventions using interactive health communications, including computer-generated telephone or mail messages, can also produce moderate dietary changes.

CONCLUSIONS

Moderate- or high-intensity counseling interventions, including use of interactive health communication tools, can reduce consumption of saturated fat and increase intake of fruit and vegetable. Brief counseling of unselected patients by primary care providers appears to produce small changes in dietary behavior, but its effect on health outcomes is unclear.

The efficacy of behavioral interventions to modify dietary fat and fruit and vegetable intake: a review of the evidence

BACKGROUND

The evidence suggesting that nutrition, particularly dietary saturated fat and fruit and vegetable intake, is related to chronic disease risk has prompted considerable research on behavioral interventions focusing on dietary change. No clear understanding has emerged, however, of the degree to which these interventions can materially influence dietary change, or the types of intervention that are most effective and for whom. Therefore, the primary objective of the current study was to evaluate the overall effectiveness of behavioral dietary interventions in promoting dietary change related to chronic disease risk reduction. A secondary goal was to explore the relative effectiveness of specific intervention features and among different population subgroups.

METHODS

We conducted an evidence-based review and secondary analysis of existing literature. Our data sources included reports of randomized controlled trials and other study designs identified from multiple searches of MEDLINE, EMBASE, PsycINFO, CINAHL, AGELINE, and AGRICOLA. We included all studies on humans (including children, adolescents, and adults) published in English since 1975 that had been conducted in North America, Europe, or Australia; that had sample sizes of at least 40 subjects at follow-up; that were not based on controlled diets; and that otherwise met inclusion criteria. Through dual review, we abstracted detailed information on study characteristics, methodology, and outcomes relating to consumption of fruits, vegetables, and fats.

RESULTS

From 907 unduplicated articles originally identified, we retained 104 articles reporting on 92 independent studies. The studies were similarly successful in reducing intake of total and saturated fat, and increasing fruit and vegetable intake. More than three-quarters of the studies (17 of the 22 reporting results for fruit and vegetable intake) reported significant increases in fruit and vegetable intake, with an average increase of 0.6 servings per day. Similar consistent decreases were seen in intake of saturated fat and total fat (7.3% reduction in the percentage of calories from fat). Interventions appeared to be more successful at positively changing dietary behavior among populations at risk of (or diagnosed with) disease than among general, healthy populations. Two intervention components seemed to be particularly promising in modifying dietary behavior-goal setting and small groups.

CONCLUSIONS

The majority of the interventions reviewed resulted in meaningful improvements in dietary factors behaviors associated with the prevention of chronic disease, particularly among individuals at elevated disease risk. The lack of similarity across studies in outcome measures, study design, analysis strategy, and intervention technique hampered our ability to draw broad conclusions about the most effective behavioral dietary interventions, but our findings offer insight into intervention components that may hold promise for future research efforts.

Randomized trial of a brief dietary intervention to decrease consumption of fat and increase consumption of fruits and vegetables

PURPOSE

This study tested the efficacy of a computer-assisted counseling intervention to reduce diet-related cancer risk.

DESIGN

Randomized controlled trial.

SUBJECTS

Healthy women HMO members (n = 616) aged 40 to 70.

INTERVENTION

Participants were randomly assigned to nutrition intervention or an attention-control intervention unrelated to diet. Intervention consisted of two 45-minute counseling sessions plus two 5- to 10-minute follow-up telephone contacts. Counseling sessions included a 20-minute, interactive, computer-based intervention using a touchscreen format. Intervention goals were reducing dietary fat and increasing consumption of fruit, vegetables, and whole grains.

MEASURES

Twenty-four hour diet recalls and the Fat and Fiber Behavior Questionnaire (FFB).

RESULTS

Four-month follow-up data were collected from 94% of the intervention participants and 91% of the controls. Testing with a multivariate general linear models analysis showed improvements on all dietary outcome variables. Compared to the control, intervention participants reported significantly less fat consumption (2.35 percentage points less for percentage of energy from fat), significantly greater consumption of fruit and vegetables combined (1.04 servings per day), and a significant reduction in a behavioral measure of fat consumption (.24 point change in the FFB).

CONCLUSIONS

These 4-month results are comparable to several other moderate-intensity studies showing that, in the appropriate circumstances, moderate-intensity dietary interventions can be efficacious. Study limitations include the short follow-up period and the use of self-reported outcome measures.

A randomized trial of a brief intervention to increase fruit and vegetable intake: a replication study among callers to the CIS

BACKGROUND

Results are reported from a large randomized trial designed to increase fruit and vegetable consumption among callers to the National Cancer Institute's Cancer Information Service (CIS) (n = 1,717).

METHODS

CIS callers assigned to the intervention group (n = 861) received a brief proactive educational intervention over the telephone at the end of usual service, with two follow-up mailouts. Key educational messages and print material derived from the NCI 5 A Day for Better Health program were provided to intervention participants. Participants were interviewed by telephone at 4 weeks (n = 1,307), 4 months (n = 1,180), and 12 months for follow-up (n = 1,016).

RESULTS

Results obtained from a single-item measure of fruit and vegetable consumption indicate a significant intervention effect of 0.88 servings per day at 4 weeks follow-up (P < 0.001), 0.63 servings per day at 4 months follow-up (P < 0.001), and 0.43 servings per day at 12 months follow-up (P < 0.001). Using a 7-item food frequency measure, an intervention effect of 0.63 servings per day was obtained at 4 weeks follow-up (P < 0.001), compared with 0.39 servings per day at 4 months follow-up (P = 0.002) and 0.44 servings per day at 12 months follow-up (P = 0.002). A 24-h recall assessment included in the 4-month interviews also yielded a significant intervention effect of 0.67 servings per day (P = 0.015). The vast majority of callers (90%) endorsed the strategy of providing 5 A Day information proactively within the CIS.

CONCLUSIONS

This brief educational intervention was associated with higher levels of self-reported fruit and vegetable intake at both short- and long-term follow-up. Additional research is recommended to test this or a similar intervention in diverse populations.

Nutrition and physical activity interventions to reduce cardiovascular disease risk in health care settings: a quantitative review with a focus on women

The authors conducted a quantitative literature review of the impact of 32 diet and physical activity (PA) interventions delivered in health care settings on cardiovascular disease risk factors. Intervention effects were relatively modest but statistically significant for PA, body mass index or weight, dietary fat, blood pressure, and total and low-density lipoprotein serum cholesterol. Intervention effects were generally larger for samples with a mean age >50 years and for studies with <6 months follow-up. Type of comparison group, type of intervention, and use of a behavior theory did not have a consistent impact on intervention effects. Few studies focused on persons of color, although the results from these studies are promising.

The health information brochure: a useful tool for chiropractic practice?

BACKGROUND

It has been suggested that clinicians should be looking at new ways to enhance their patients' self-care. Patient education is one strategy that primary providers may use.

OBJECTIVE

This study investigates the format in which patients would like to pursue their health education within the chiropractic clinic.

METHODS

An exploratory study of chiropractic patients was undertaken to investigate patients' preferred health education formats, their commitment to pursuing health objectives, and their literacy level. Purposive sampling of 9 Australian chiropractic clinics was undertaken. Convenience sampling of patients attending these clinics resulted in 102 patients participating. Participants completed a questionnaire. A research assistant was available to clarify any questions. Data were collected and collated. A Likert scale was used to capture responses to questions ascertaining patient opinions.

RESULTS

Patients considered health the most important of the life objectives listed; however, they preferred spending time with family to undertaking health- and fitness-promoting activity. More chiropractic patients opted for health information brochures than health promotion classes, personally supervised self-care programs, or practitioner-supervised self-care contracts. Patient literacy levels varied within and between clinics.

CONCLUSIONS

Brochures may provide a definitive health information tool for chiropractors who limit their clinical role to primary contact and a helpful adjunct to patient education for chiropractors committed to a primary care role. However, care should be taken to select brochures consistent with the patients' literacy level. Tips for selecting and preparing suitable brochures are provided. The discrepancy between how greatly patients value health and how they prefer spending their time may have implications for successful behavior change. Brochures may not alone constitute adequate practitioner involvement.

Self-help in the long-term treatment of obesity

Despite the short-term success of professional behavioural techniques for obesity, weight losses are typically regained following treatment. The long-term maintenance of treatment effects will probably require ongoing, continuing care. Continuing care may be economically feasible when administered through self-help treatment modalities. Self-help confers a number of psychological benefits, such as self-reliance and an increased sense of empowerment. The effectiveness and cost-effectiveness of various modalities of self-help are reviewed, including purely self-prompted help, self-administered manuals, computer-assisted therapy, professionally assisted correspondence courses, and non-profit and commercial self-help groups. Stepped-care models suggest using a combination of these approaches when appropriate. However, logistical difficulties present themselves in stepped-care approaches with obesity, such as the complicating effects of severity and comorbidity on stepped-care status. Self-help groups are a promising venue for the provision of continuing care and as an adjunct to more intensive, specialty therapies.

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.

Implementing a dietary intervention in primary care practice: a process evaluation

OBJECTIVES

Physicians acknowledge the need to advise their patients about dietary habits, but they may not have the training or tools to do this efficiently. In the context of a randomized trial, we investigated the feasibility of enlisting physicians to implement a dietary intervention in the primary care setting.

METHODS

Physicians from 14 primary care practices were assigned via randomization to introduce a self-help booklet to promote dietary change at routine appointments. Delivery of the booklet was recorded by these intervention physicians at the clinic appointment; intervention participants were asked 3 months later in a telephone interview about whether they received and used the booklet.

RESULTS

According to physician documentation, 95% of intervention participants who kept an appointment (n = 935) received the booklet; among participants completing a 3-month interview (n = 890), 96% reported the same. However, only about 50% of participants reported receiving the booklet from their physician; the remainder received the booklet from other clinic staff. Overall, 93% reported reading at least part of the booklet. Use of the booklet varied little whether it was delivered by a physician or staff person, but it was more likely to be read as time spent discussing the booklet increased.

CONCLUSIONS

Physician cooperation and evidence of intervention effectiveness support the use of primary care for the delivery of interventions to change diet; training the entire health team and repeating dietary advice at subsequent visits may improve the success of such interventions.

A randomized trial of a tailored, self-help dietary intervention: the Puget Sound Eating Patterns study

BACKGROUND

This study evaluated a tailored, multiple-component self-help intervention designed to promote lower fat and higher fruit and vegetable consumption.

METHODS

Participants were 1,459 adults selected at random, stratified by sex and age (18-34, 35-54, 55-69), from enrollees of a large health maintenance organization. After completing a baseline telephone survey, participants were randomized to receive the intervention (consisting of a computer-generated personalized letter, a motivational phone call, a self-help manual, a package of supplementary materials, computer-generated behavioral feedback based on a self-administered food frequency questionnaire, and newsletters) or to receive no materials. Evaluation was based on 1,205 (86.5%) participants who completed both a 3- and a 12-month follow up survey.

RESULTS

The intervention effect +/- SE for fat, based on a diet habits questionnaire, was -0.10 +/- 0.02 (P < 0.001), corresponding to a reduction of approximately 0.8 percentage points of percentage energy from fat. For fruits and vegetables, the intervention effect was 0.47 +/- 0.10 servings/day (P < 0.001). Intervention effects were similar across age and sex groups.

CONCLUSIONS

Tailored, self-help interventions can effectively promote dietary change among both men and women and among younger as well as older adults.

Mediating factors in dietary change: understanding the impact of a worksite nutrition intervention

This report, based on 1,795 participants in the Next Step Trial, examines how a dietary intervention program affected mediating factors for dietary change. The model tested whether intervention increased predisposing (skills, knowledge, and beliefs) and enabling (social support and norms) factors for change and advanced participants into action and maintenance stages of change. The intervention significantly increased both predisposing factors for dietary change and the likelihood of moving into or remaining in action and maintenance stages of change. Changes in predisposing and enabling factors and stage of change at follow-up (regardless of stage at baseline) were associated with significant dietary change. Changes in mediating variables explained between 34% and 55% of the effects of the dietary intervention. These results support the value of measuring mediating factors as part of dietary intervention evaluations and suggest that interventions that target norms and eating environments in addition to skills and knowledge may further increase intervention effectiveness.

If diabetes is a public health problem, why not treat it as one? A population-based approach to chronic illness

It is increasingly acknowledged that diabetes and other chronic illnesses are major public health problems. Medicare and many managed health care organizations have recognized the enormous personal and societal costs of uncontrolled diabetes in terms of complications, patient quality of life, and health care system resources. However, the current system of reactive acute-episode focused disease care practiced in many settings does not adequately address this public health problem. An alternative proactive, population-based approach to chronic illnesses such as diabetes is proposed and illustrated. This multilevel systems approach addresses supportive and inhibitory social-environmental factors at multiple levels (personal, family, health care team, work, neighborhood, community). Key disciplines contributing to a population-based approach to diabetes include epidemiology, behavioral science, health care services, public health, health economics, and quality of life professions. Current and potential contributions of each of these disciplines are illustrated and an integrative, population-based systems approach to diabetes management and prevention of complications is proposed. This approach is also seen as applicable to other chronic illnesses.

Stages of change for increasing fruit and vegetable consumption among adults and young adults participating in the national 5-a-Day for Better Health community studies

Higher fruit and vegetable consumption is associated with a reduced risk of certain cancers and chronic diseases. The 5-a-Day for Better Health community studies are evaluating population-based strategies to achieving dietary behavior change using the stages-of-change model and associated theories. The authors present baseline comparisons of stages of change for fruit and vegetable consumption among adults and young adults in eight study sites representing diverse regions of the United States and diverse populations and settings. Three dominant stages, precontemplation, preparation, and maintenance, were found across sites. Women and those with college degrees were more likely to be in action/maintenance. Fruit and vegetable consumption, self-efficacy, and knowledge of the 5-a-Day recommendation were positively associated with more advanced stages of change in all study sites. The authors discuss the findings in relation to possible limitations of this and other dietary stages-of-change measures and suggest directions for future research.

Long-term effects and costs of brief behavioural dietary intervention for patients with diabetes delivered from the medical office

This study evaluated the 12-month follow-up results and costs of a personalized, medical office-based intervention focused on behavioral issues related to dietary self-management. Two hundred and six adults having diabetes attending an internal medicine outpatient clinic visit were randomized to either Usual Care or to Brief Intervention. The single session intervention involved touchscreen computer-assisted assessment that provided immediate feedback on key barriers to dietary self-management, goal setting and problem-solving counselling. Follow-up components included phone calls and videotape intervention relevant to each participant. Brief Intervention produced significantly greater improvement than Usual Care on multiple measures of change in dietary behaviour (e.g., covariate adjusted difference of 2.2% of calories from fat; p = 0.023) and on serum cholesterol levels (covariate adjusted difference of 15 mg/dl; p = 0.002) at 12-month follow-up. There were also significant differences favouring intervention on patient satisfaction (p < 0.02) but not on HbA1c levels. The costs of intervention ($137 per patient) were modest relative to many commonly used practices.

Behavioral research contributions and needs in cancer prevention and control: dietary change

This paper summarizes key behavioral research contributions to the promotion of healthful diets and identifies the outstanding behavioral research needs that could lead to positive dietary changes in the United States. Nutrition plays an important role in the initiation, promotion, and progression of cancer. Dietary guidelines for health promotion and cancer prevention recommend diets that are lower in fat and higher in fiber, fruits, and vegetables. Behavioral research on dietary change has become more rigorous and sophisticated in the past decade, with noteworthy contributions in four areas: behavioral research within clinical trials, self-help or minimal contact intervention strategies, school nutrition programs and services, and advances in the development of measures. Work in progress includes large-scale randomized intervention trials, with the majority of funding for studies to increase fruit and vegetable consumption. There are many needs for further research. Six priority areas for behavioral research are identified and discussed: (1) determinants of dietary behavior and change processes; (2) policy, environmental, and organizational interventions; (3) studies of dietary change and exercise and interventions with persons at high risk for diet-related cancers; (4) methodological research; (5) research on diffusion and dissemination; and (6) systematic behavioral research on dietary change in clinical trials. A concerted research effort in the area of dietary change has great potential benefits for cancer prevention and control and for public health in general.

Can dietary interventions change diet and cardiovascular risk factors? A meta-analysis of randomized controlled trials

OBJECTIVES

This study evaluated the effectiveness of dietary advice in primary prevention of chronic disease.

METHODS

A meta-analysis was conducted of 17 randomized controlled trials of dietary behavior interventions of at least 3 months' duration. Results were analyzed as changes in reported dietary fat intakes and biomedical measures (serum cholesterol, urinary sodium, systolic and diastolic blood pressure) in the intervention group minus changes in the control group at 3 to 6 months and 9 to 18 months of follow-up.

RESULTS

After 3 to 6 months, mean net changes in each of the five outcomes favored intervention. For dietary fat as a percentage of food energy, the change was -2.5% (95% confidence interval [CI] = -3.9%, -1.1%). Mean net changes over 9 to 18 months were as follows: serum cholesterol, -0.22 (95% CI = -0.39, -0.05) mmol/L; urinary sodium, -45.0 (95% CI = -57.1, -32.8) mmol/24 hours; systolic blood pressure, -1.9 (95% CI = -3.0, 0.8) mm Hg; and diastolic blood pressure, -1.2 (95% CI = -2.6, 0.2) mm Hg.

CONCLUSIONS

Individual dietary interventions in primary prevention can achieve modest improvements in diet and cardiovascular disease risk status that are maintained for 9 to 18 months.

A dietary intervention in primary care practice: the Eating Patterns Study

OBJECTIVES

This study evaluated the effectiveness of a low-intensity dietary intervention in primary care practice in lowering dietary fat intake and raising dietary fiber intake.

METHODS

A randomized controlled trial of 28 physician practices in six primary care clinics enrolled, by telephone, adult patients who had appointments for nonurgent nonacute visits. Of 3490 eligible patients contacted, 2111 completed baseline interview; 86.1% also completed a 12-month follow-up. Physicians gave intervention participants a self-help booklet and a brief motivational message. Changes in fat and fiber from baseline to 12-month follow-up were evaluated.

RESULTS

Intervention and control groups both reported a decrease in fat intake and an increase in fiber intake. The differential change and 95% confidence interval (CI) for the percentage of energy obtained from fat was -1.2 (CI = -0.71, -1.7) (P = .0015), for grams fiber/1000 kcal 0.32 (CI = -0.066, 0.71) (P = .086), for fat score -0.044 (CI = -0.016, -0.072) (P = .010), and for fiber score 0.036 (CI = 0.011, 0.061) (P = .014), with greater reductions in fat and greater increase in fiber in the intervention group.

CONCLUSIONS

This low-intensity intervention was effective in dietary behavior change.

Worksite cancer screening and nutrition intervention for high-risk auto workers: design and baseline findings of the Next Step Trial

BACKGROUND

This article describes the design and baseline findings of The Next Step Trial, a health promotion intervention targeting automobile industry employees at increased colorectal cancer risk. The intervention encouraged colorectal cancer screening participation and adoption of low-fat, high-fiber diets.

METHODS

Twenty-eight worksites (n = 5,042) were randomized to control (a company-sponsored screening program) or intervention (an enhanced screening program including a personalized educational booklet and motivational telephone call and diet-change program including nutrition classes, self-help materials, and computer-generated personalized feedback). Outcomes included screening compliance and fat and fiber intake.

RESULTS

Pretrial data indicated targeted employees were predominantly older, well educated, married, Caucasian men. Sixty-one percent (SE = 2) participated in the screening program in the preceding 2 years, and 24% (SE = 1) reported a history of colorectal polyps or cancer. Fifty-eight percent of the cohort responded to the baseline questionnaire; respondents were older and more educated; more were married, retired, and Caucasian than nonrespondents. Mean dietary intakes were 36.9% energy from fat (SE = 0.21), 8.8 g fiber/1000 kcal (SE = 0.07), and 3.4 servings of fruits and vegetables per day (SE = 0.04).

CONCLUSIONS

Baseline data show moderate screening participation and dietary intakes that did not meet guidelines; hence intervention efforts were warranted. Data from this trial will support a rigorous test of whether this high-risk employee population is responsive to targeted health promotion, early cancer detection, and prevention interventions.

Are community health interventions evaluated appropriately? A review of six journals

OBJECTIVES

To determine if Randomized Controlled Trial (RCT) methodology was used appropriately in community health, we: (1) determined the proportion of non-randomized studies that should have been RCTs, and (2) assessed the quality of the RCTs.

METHODS

The 1992 issues of six community health journals were manually searched. Intervention studies were analyzed. Studies that did not use randomization were analyzed for feasibility and practicality of RCT methods; RCTs were analyzed for quality using a checklist. RCTs were compared with community health RCTs from The New England Journal of Medicine. The proportion of studies meeting each criterion was determined.

RESULTS

Fourteen percent of 603 studies were interventions and 4% were RCTs. Of those not using randomization, 42% should have. Mean RCT scores were significantly lower for the community health journals than for The New England Journal of Medicine. Many criteria important to quality scored poorly.

CONCLUSIONS

RCTs are underused and lack methodologic rigor in community health. Conclusions regarding the effectiveness of interventions are therefore suspect.

Effects of Orem-based nursing intervention on nutritional self-care of myocardial infarction patients

The purpose of the study was to investigate the effect of nursing care based on Orem's nursing theory on nutritional self-care of myocardial infarction patients. Self-efficacy was explored as a disposition which may motivate behavioral change. One hundred and four subjects were randomly assigned to treatment or control groups. The nursing intervention, which took place during the first 6 weeks following hospital discharge, was effective in supporting healthy low-fat eating behavior. Nursing care influenced patients' self-care agency but lacked impact on self-efficacy for healthy eating.