Dietary intake in the diabetes prevention program cohort: baseline and 1-year post randomization

Effectiveness of comprehensive nursing intervention program (CNIP) on knowledge and practice regarding the prevention of non-insulin-dependent diabetes mellitus (NIDDM) among adults

BACKGROUND

There are estimated 72.96 million cases of diabetes in the adult population of India. The prevalence in urban areas ranges between 10.9% and 14.2%, and the prevalence in rural India ranges between 3.0% and 7.8% among the population aged 20 years and above with a much higher prevalence among individuals aged over 50 years. This study aimed to determine the effectiveness of comprehensive nursing intervention program (CNIP) on knowledge and practice regarding the prevention of non-insulin-dependent diabetes mellitus (NIDDM) among adults.

MATERIALS AND METHODS

A quasi-experimental one-group pretest-posttest design was chosen for the study. Adults were selected using a simple random sampling technique by the lottery method; of 120 eligible adults, 60 were selected to participate in the study. The study was conducted in an urban community, Bangalore, and data were collected from March 25, 2022, to April 23, 2022. CNIP consisted of education, demonstration of exercise, and information booklet. The pretest and posttest were collected using the structured knowledge questionnaire for assessing the level of knowledge and non-observational checklist for assessing the level of practice among adults. Data were analyzed by descriptive and inferential statistics.

RESULTS

There was significant improvement in the mean scores of knowledge from 52.3 to 82.2 and practice mean score from 45.5 to 68.4. The paired t-test value of knowledge was 3.88, and practice was 2.97, which was significant at P < 0.05 level.

CONCLUSIONS

The study concluded that CNIP had a great role in increasing the level of knowledge and practice among adults in the prevention of NIDDM.

Dietary intake during a pragmatic cluster-randomized weight loss trial in an underserved population in primary care

BACKGROUND

Currently there are limited data as to whether dietary intake can be improved during pragmatic weight loss interventions in primary care in underserved individuals.

METHODS

Patients with obesity were recruited into the PROPEL trial, which randomized 18 clinics to either an intensive lifestyle intervention (ILI) or usual care (UC). At baseline and months 6, 12, and 24, fruit and vegetable (F/V) intake and fat intake was determined. Outcomes were analyzed by repeated-measures linear mixed-effects multilevel models and regression models, which included random cluster (clinic) effects. Secondary analyses examined the effects of race, sex, age, and food security status.

RESULTS

A total of 803 patients were recruited. 84.4% were female, 67.2% African American, 26.1% received Medicaid, and 65.5% made less than $40,000. No differences in F/V intake were seen between the ILI and UC groups at months 6, 12, or 24. The ILI group reduced percent fat at months 6, 12, and 24 compared to UC. Change in F/V intake was negatively correlated with weight change at month 6 whereas change in fat intake was positively associated with weight change at months 6, 12, and 24 for the ILI group.

CONCLUSIONS

The pragmatic weight loss intervention in primary care did not increase F/V intake but did reduce fat intake in an underserved population with obesity. F/V intake was negatively associated with weight loss at month 6 whereas percent fat was positively correlated with weight loss throughout the intervention. Future efforts better targeting both increasing F/V intake and reducing fat intake may promote greater weight loss in similar populations.

TRIAL REGISTRATION

NCT Registration: NCT02561221.

Metabolomic Profile of the Healthy Eating Index-2015 in the Multiethnic Study of Atherosclerosis

BACKGROUND

Poor diet quality is a risk factor for type 2 diabetes and cardiovascular disease. However, knowledge of metabolites marking adherence to Dietary Guidelines for Americans (2015 version) are limited.

OBJECTIVES

The goal was to determine a pattern of metabolites associated with the Healthy Eating Index (HEI)-2015, which measures adherence to the Dietary Guidelines for Americans.

METHODS

The analysis examined 3557 adult men and women from the longitudinal cohort Multiethnic Study of Atherosclerosis (MESA), without known cardiovascular disease and with complete dietary data. Fasting serum specimens and diet and demographic questionnaires were assessed at baseline. Untargeted 1H 1-dimensional nuclei magnetic resonance spectroscopy (600 MHz) was used to generate metabolomics and lipidomics. A metabolome-wide association study specified each spectral feature as outcomes, HEI-2015 score as predictor, adjusting for age, sex, race, and study site in linear regression analyses. Subsequently, hierarchical clustering defined the discrete groups of correlated nuclei magnetic resonance features associated with named metabolites, and the linear regression analysis assessed for associations with HEI-2015 total and component scores.

RESULTS

The sample included 50% women with an mean age of 63 years, with 40% identifying as White, 23% as Black, 24% as Hispanic, and 13% as Chinese American. The mean HEI-2015 score was 66. The metabolome-wide association study identified 179 spectral features significantly associated with HEI-2015 score. The cluster analysis identified 7 clusters representing 4 metabolites; HEI-2015 score was significantly associated with all. HEI-2015 score was associated with proline betaine [β = 0.12 (SE = 0.02); P = 4.70 × 10-13] and was inversely related to proline [β = -0.13 (SE = 0.02); P = 4.45 × 10-14], 1,5 anhydrosorbitol [β = -0.08 (SE = 0.02); P = 4.37 × 10-7] and unsaturated fatty acyl chains [β = 0.08 (SE = 0.02); P = 8.98 × 10-7]. Intake of total fruit, whole grains, and seafood and plant proteins was associated with proline betaine.

CONCLUSIONS

Diet quality is significantly associated with unsaturated fatty acyl chains, proline betaine, and proline. Further analysis may clarify the link between diet quality, metabolites, and pathogenesis of cardiometabolic disease.

Differences in the Association of Select Dietary Measures With Risk of Incident Type 2 Diabetes

OBJECTIVE

To evaluate associations between a broad range of approaches to classifying diet and incident type 2 diabetes in the REasons for Geographic And Racial Differences in Stroke (REGARDS) study.

RESEARCH DESIGN AND METHODS

This study included 8,750 Black and White adults without diabetes at baseline. Diabetes was defined according to fasting glucose ≥70 mmol/L, random glucose ≥111 mmol/L, or use of diabetes medications. The exposures were diet scores for Mediterranean and Dietary Approaches to Stop Hypertension (DASH) diets and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND), dietary inflammatory index (DII), dietary inflammation score (DIS), and empirical dietary patterns (plant-based and Southern) determined using data collected with use of the Block98 food-frequency questionnaire. Modified Poisson regression was used to assess association of dietary measures with risk of incident type 2 diabetes, with models adjusted for total energy intake, demographics, lifestyle factors, and waist circumference.

RESULTS

There were 1,026 cases of incident type 2 diabetes during follow-up (11.7%). Adherence to the Southern dietary pattern was most strongly associated with risk of incident type 2 diabetes after adjustment for demographics and lifestyle (quintile [Q]5 vs. lowest Q1: risk ratio [RR] 1.95; 95% CI 1.57, 2.41). Of the diet scores, DIS (Q5 vs. Q1 RR 1.41) and MIND (Q1 vs. Q5 RR 1.33), demonstrated anti-inflammatory diets, had strongest associations with lower diabetes incidence.

CONCLUSIONS

We found associations of several dietary approaches with incident type 2 diabetes. Investigation into mechanisms driving the association with the Southern dietary pattern is warranted. Further research into use of DIS, DII, and MIND diet score should be considered for dietary recommendations for diabetes prevention.

What Is the Profile of Overweight Individuals Who Are Unsuccessful Responders to a Low-Energy Diet? A PREVIEW Sub-study

This study was performed to evaluate the profile of overweight individuals with pre-diabetes enrolled in PREVIEW who were unable to achieve a body weight loss of ≥8% of the baseline value in response to a 2-month low-energy diet (LED). Their baseline profile reflected potential stress-related vulnerability that predicted a reduced response of body weight to a LED programme. The mean daily energy deficit maintained by unsuccessful weight responders of both sexes was less than the estimated level in successful female (656 vs. 1,299 kcal, p < 0.01) and male (815 vs. 1,659 kcal, p < 0.01) responders. Despite this smaller energy deficit, unsuccessful responders displayed less favorable changes in susceptibility to hunger and appetite sensations. They also did not benefit from the intervention regarding the ability to improve sleep quality. In summary, these results show that some individuals display a behavioral vulnerability which may reduce the ability to lose weight in response to a diet-based weight loss program. They also suggest that this vulnerability may be accentuated by a prolonged diet restriction.

Evolving Concepts of Type 2 Diabetes Management

With the concept of patient-centered care in mind, this article outlines the current diabetes medications available for glucose lowering and the characteristics of each of these medications that need to be considered in shared decision-making for durable and effective therapy. Important patient characteristics such as weight, risk for hypoglycemia, cost, social determinants of health, and medical literacy need to be considered. The evidence-base informing the use of antihyperglycemic agents has changed dramatically due to 2008 FDA guidance for cardiovascular safety and cardiorenal protection with antihyperglycemic agents. New evidence supports an approach to diabetes management that addresses pre-existing cardiorenal disease.

Diet quality, weight loss, and diabetes incidence in the Diabetes Prevention Program (DPP)

BACKGROUND

We evaluated whether diet quality is a predictor of weight loss and reduced diabetes risk, independent of caloric intake in the Diabetes Prevention Program (DPP) cohort, a randomized clinical trial of adults at risk for diabetes.

METHODS

This secondary analysis included 2914 participants with available data (964 intensive lifestyle (ILS), 977 metformin, 973 placebo). Dietary intake was assessed using a 117-item food frequency questionnaire. Diet quality was quantified using the Alternative Healthy Eating Index 2010 (AHEI). AHEI ranges from 0 to 110, with higher scores corresponding to higher quality diets. ILS participants had greater improvement (p < 0.001) in AHEI over 1-year (4.2 ± 9.0) compared to metformin (1.2 ± 8.5) and placebo (1.4 ± 8.4). We examined the association between AHEI change and weight change from baseline to 1-year using linear regression, and that between 1-year AHEI change and incident diabetes, using hazard models over an average 3 years follow-up. Models were evaluated within treatment group and adjusted for relevant characteristics including caloric intake, physical activity, BMI and AHEI. Models testing incident diabetes were further adjusted for baseline fasting and 2 h glucose.

RESULTS

An increase in AHEI score was associated with weight loss in ILS [β per 10-point increase (SE) -1.2 kg (0.3, p < 0.001)], metformin [- 0. 90 kg (0.2, p < 0.001)] and placebo [- 0.55 kg (0.2, p = 0.01)]. However, AHEI change was not associated with incident diabetes in any group before or after adjustment for weight change.

CONCLUSIONS

Controlling for weight, diet quality was not associated with diabetes incidence but helps achieve weight loss, an important factor in diabetes prevention.

Is a Higher Protein-Lower Glycemic Index Diet More Nutritious Than a Conventional Diet? A PREVIEW Sub-study

High protein diets and low glycemic index (GI) diets have been associated with improved diet quality. We compared the changes in nutrient intakes of individuals at high risk of developing type-2 diabetes over 3 y who followed either a higher protein-lower GI diet (HPLG) or a conventional moderate protein-moderate GI diet (MPMG). This post hoc analysis included 161 participants with overweight and pre-diabetes from the Australian cohort of the PREVIEW study (clinical trial registered in https://www.clinicaltrials.gov/ct2/show/NCT01777893?term=NCT01777893&draw=2&rank=1) who were randomly assigned to a HPLG diet (25% energy from protein, dietary GI ≤ 50, n = 85) or a MPMG diet (15% energy from protein, dietary GI ≥ 56, n = 76). Food records were collected at 0-mo (baseline) and at 6-, 12-, 24-, and 36-mo (dietary intervention period). Linear mixed models were used to compare the differences in total energy, macro- and micronutrients, dietary GI, glycemic load (GL) and body weight between the two diet groups at the 4 dietary intervention time points. At 3 y, 74% participants from the HPLG diet and 74% participants from the MPMG diet completed the trial. The HPLG group showed significantly higher protein intake and lower dietary GI and GL than the MPMG group (group fixed effect P < 0.001 for all three parameters). By 6-, 12-, 24-, and 36-mo there was a 3.0, 2.7, 2.2, and 1.4% point difference in protein intake and 6.2, 4.1, 4.8, and 3.9 GI unit difference between the groups. The intake of energy and saturated fat decreased (mostly in the first 6-mo), while the intake of dietary fiber increased (from mo-0 to mo-12 only) in both diets, with no significant differences between the diets. The dietary intakes of zinc (group fixed effect P = 0.05), selenium (P = 0.01), niacin (P = 0.01), vitamin B12 (P = 0.01) and dietary cholesterol (group by time fixed effect P = 0.001) were higher in the HPLG group than in the MPMG group. Despite both diets being designed to be nutritionally complete, a HPLG diet was found to be more nutritious in relation to some micronutrients, but not cholesterol, than a MPMG diet.

Enhanced long-term dietary change and adherence in a nutrigenomics-guided lifestyle intervention compared to a population-based (GLB/DPP) lifestyle intervention for weight management: results from the NOW randomised controlled trial

Background

Adherence to nutritional guidelines for chronic disease prevention and management remains a challenge in clinical practice. Innovative strategies are needed to help optimise dietary behaviour change.

Objective

The objective of this study was to determine if a nutrigenomics-guided lifestyle intervention programme could be used to motivate greater dietary adherence and change in dietary intake short-term, moderate-term and long-term compared to the gold-standard population-based weight management intervention (Group Lifestyle Balance (GLB)/Diabetes Prevention Programme (DPP)).

Design

The Nutrigenomics, Overweight/Obesity, and Weight Management (NOW) randomised controlled trial is a pragmatic, parallel-group, superiority clinical trial (n=140), which was conducted at the East Elgin Family Health Team (EEFHT). GLB weight management groups were prerandomised 1:1 to receive either the standard GLB programme or a modified GLB+nutrigenomics (GLB+NGx) programme. Three 24-hour recalls were collected at baseline, 3, 6 and 12 months using the validated multiple pass method. Research assistants collecting the three 24-hour recalls were blinded to the participants’ group assignments. Statistical analyses included split plot analyses of variance (ANOVAs), two-way ANOVAs, binary logistic regression, χ² and Fisher’s exact tests. Using the Theory of Planned Behaviour as guidance, key confounding factors of behaviour change were considered in the analyses. This study was registered with clinicaltrials.gov (NCT03015012).

Results

Only the GLB+NGx group significantly reduced their total fat intake from baseline to 12-month follow-up (from 36.0%±4.8% kcal to 30.2%±8.7% kcal, p=0.02). Long-term dietary adherence to total fat and saturated fat guidelines was also significantly (p<0.05) greater in the GLB+NGx group compared to the standard GLB group.

Conclusions

Weight management interventions guided by nutrigenomics can motivate long-term improvements in dietary fat intake above and beyond gold-standard population-based interventions.

Dietary characteristics associated with plasma concentrations of per- and polyfluoroalkyl substances among adults with pre-diabetes: Cross-sectional results from the Diabetes Prevention Program Trial

Diet is assumed to be the main source of exposure to per- and polyfluoroalkyl substances (PFAS) in non-occupationally exposed populations, but studies on the diet-PFAS relationship in the United States are scarce. We extracted multiple dietary variables, including daily intakes of food group, diet scores, and dietary patterns, from self-reported dietary data collected at baseline (1996-1999) from adults with pre-diabetes enrolled in the Diabetes Prevention Program, and used linear regression models to evaluate relationships of each dietary variable with plasma concentrations of six PFAS (perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), 2-(N-ethyl-perfluorooctane sulfonamido) acetic acid (EtFOSAA), 2-(N-methyl-perfluorooctane sulfonamido) acetic acid (MeFOSAA), perfluorononanoic acid (PFNA) adjusting for covariates. Participants (N = 941, 65% female, 58% Caucasian, 68% married, 75% with higher education, 95% nonsmoker) had similar PFAS concentrations compared to the general U.S. population during 1999-2000. Using a single food group approach, fried fish, other fish/shellfish, meat and poultry had positive associations with most PFAS plasma concentrations. The strongest effect estimate detected was between fried fish and PFNA [13.6% (95% CI: 7.7, 19.9) increase in median concentration per SD increase]. Low-carbohydrate and high protein diet score had positive association with plasma PFHxS. Some food groups, mostly vegetables and fruits, and the Dietary Approaches to Stop Hypertension diet score had inverse associations with PFOS and MeFOSAA. A vegetable diet pattern was associated with lower plasma concentrations of MeFOSAA, while high-fat meat and low-fiber and high-fat grains diet patterns were associated with higher plasma concentrations of PFOS, PFHxS, MeFOSAA and PFNA. We summarized four major dietary characteristics associated with variations in PFAS plasma concentrations in this population. Specifically, consuming more meat/fish/shellfish (especially fried fish, and excluding Omega3-rich fish), low-fiber and high-fat bread/cereal/rice/pasta, and coffee/tea was associated with higher plasma concentrations while dietary patterns of vegetables, fruits and Omega-3 rich fish were associated with lower plasma concentrations of some PFAS.

Nutrient intake and dietary quality changes within a personalized lifestyle intervention program for metabolic syndrome in primary care

A team-based 12-month lifestyle program for the treatment of metabolic syndrome (MetS) (involving physicians, registered dietitians (RDs), and kinesiologists) was previously shown to reverse MetS in 19% of patients (95% confidence interval, 14% to 24%). This work evaluates changes in nutrient intake and diet quality over 12 months (n = 205). Individualized diet counselling was provided by 14 RDs at 3 centres. Two 24-h recalls, the Canadian Healthy Eating Index (HEI-C), and the Mediterranean Diet Score (MDS) were completed at each time point. Total energy intake decreased by 145 ± 586 kcal (mean ± SD) over 3 months with an additional 76 ± 452 kcal decrease over 3–12 months. HEI-C improved from 58 ± 15 to 69 ± 12 at 3 months and was maintained at 12 months. Similarly, MDS (n = 144) improved from 4.8 ± 1.2 to 6.2 ± 1.9 at 3 months and was maintained at 12 months. Changes were specific to certain food groups, with increased intake of fruits, vegetables, and nuts and decreased intake of “other foods” and “commercial baked goods” being the most prominent changes. There was limited change in intake of olive oil, fish, and legumes. Exploratory analysis suggested that poorer diet quality at baseline was associated with greater dietary changes as assessed by HEI-C.

Novelty Multiple dietary assessment tools provided rich information on food intake changes in an intervention for metabolic syndrome. Improvements in diet were achieved by 3 months and maintained to 12 months. The results provide a basis for further dietary change implementation studies in the Canadian context.

Effects of dietary and physical activity interventions on the risk of type 2 diabetes in South Asians: meta-analysis of individual participant data from randomised controlled trials

AIMS/HYPOTHESIS

Individuals of South Asian origin have a high risk of type 2 diabetes and of dying from a diabetes-attributable cause. Lifestyle modification intervention trials to prevent type 2 diabetes in high-risk South Asian adults have suggested more modest effects than in European-origin populations. The strength of the evidence of individual studies is limited, however. We performed an individual participant data meta-analysis of available RCTs to assess the effectiveness of lifestyle modification in South Asian populations worldwide.

METHODS

We searched PubMed, EMBASE, Cochrane Library and Web of Science (to 24 September 2018) for RCTs on lifestyle modification interventions incorporating diet and/or physical activity in South Asian adults. Reviewers identified eligible studies and assessed the quality of the evidence. We obtained individual participant data on 1816 participants from all six eligible trials (four from Europe and two from India). We generated HR estimates for incident diabetes (primary outcome) and mean differences for fasting glucose, 2 h glucose, weight and waist circumference (secondary outcomes) using mixed-effect meta-analysis overall and by pre-specified subgroups. We used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system to rate the quality of evidence of the estimates. The study is registered with the International Prospective Register of Systematic Reviews ([PROSPERO] CRD42017078003).

RESULTS

Incident diabetes was observed in 12.6% of participants in the intervention groups and in 20.0% of participants in the control groups. The pooled HR for diabetes incidence was 0.65 (95% CI 0.51, 0.81; I² = 0%) in intervention compared with control groups. The absolute risk reduction was 7.4% (95% CI 4.0, 10.2), with no interactions for the pre-specified subgroups (sex, BMI, age, study duration and region where studies were performed). The quality of evidence was rated as moderate. Mean difference for lifestyle modification vs control groups for 2 h glucose was -0.34 mmol/l (95% CI -0.62, -0.07; I² = 50%); for weight -0.75 kg (95% CI -1.34, -0.17; I² = 71%) and for waist -1.16 cm (95% CI -2.16, -0.16; I² = 75%). No effect was found for fasting glucose. Findings were similar across subgroups, except for weight for European vs Indian studies (-1.10 kg vs -0.08 kg, p = 0.02 for interaction).

CONCLUSIONS/INTERPRETATION

Despite modest changes for adiposity, lifestyle modification interventions in high-risk South Asian populations resulted in a clinically important 35% relative reduction in diabetes incidence, consistent across subgroups. If implemented on a large scale, lifestyle modification interventions in high-risk South Asian populations in Europe would reduce the incidence of diabetes in these populations.

Per- and polyfluoroalkyl substances and blood lipid levels in pre-diabetic adults-longitudinal analysis of the diabetes prevention program outcomes study

Exposure to per- and polyfluoroalkyl substances (PFASs) may interfere with lipid regulation. However, most previous studies were cross-sectional with the risk of reverse causation, suggesting a need for long-term prospective studies. We examined the relationship of baseline plasma PFAS concentrations with repeated measures of blood lipids. We included 888 prediabetic adults from the Diabetes Prevention Program (DPP) and DPP Outcomes Study, who had measurements of 6 plasma PFAS concentrations at baseline (1996-1999) and repeated measures of blood lipids over 15 years of follow-up, and were initially randomized to placebo or a lifestyle intervention. We used linear regression to examine cross-sectional associations of PFAS concentrations and lipid levels at baseline, and evaluated prospective risks of hypercholesterolemia and hypertriglyceridemia using Cox proportional hazard models, and tested for effect modification by study arm. Participants (65.9% female, 57.0% White, 65.9% aged 40-59 years) had comparable PFAS concentrations [e.g., median (IQR) perfluorooctanoic acid (PFOA) 4.9 ng/mL (3.2)] with the general U.S. population in 1999-2000. We observed higher total cholesterol at baseline per doubling of PFOA (β: 6.1 mg/dL, 95% CI: 3.1, 9.04), perfluorohexane sulfonic acid (PFHxS, β: 2.2 mg/dL, 95% CI: 0.2, 4.3), and perfluorononanoic acid (PFNA, β: 2.9 mg/dL, 95% CI: 0.7, 5.0). Prospectively, baseline concentrations of several PFASs, including PFOA, PFOS, PFHxS and PFNA, predicted higher risks of incident hypercholesterolemia and hypertriglyceridemia, but only in the placebo group and not the lifestyle intervention group. For example, participants in the placebo group with PFOA concentration > median (4.9 ng/mL) were almost twice as likely (HR: 1.90, 95% CI: 1.25, 2.88) to develop hypertriglyceridemia compared to those ≤median. Findings suggest adverse effects of some PFASs on lipid profiles in prediabetic adults. However, the detrimental effect was attenuated with a lifestyle intervention.

Dietary changes in a diabetes prevention intervention among people with prediabetes: the Diabetes Community Lifestyle Improvement Program trial

AIMS

Diabetes prevention interventions have been less successful in Asian Indians compared to other populations, which may be due in part to dietary differences. The objective of this study was to determine the impact of a diabetes prevention intervention on diet and risk of diabetes in Asian Indians at high risk.

METHODS

Data were included from the Diabetes Community Lifestyle Improvement Program (D-CLIP), a randomized control trial to prevent diabetes in overweight/obese Asian Indian adults (20-65 years) with prediabetes. Respondents received standard treatment (control; n = 283) or a 6-month intervention (n = 295) that included education and support to reduce intakes of fat and total calories (kilocalories; kcal). Diet was ascertained using a food frequency questionnaire, and incident diabetes was determined from annual 2-h plasma glucose post-oral glucose tolerance test or biannual fasting plasma glucose.

RESULTS

There were 485 (control 240; intervention 245) respondents with complete diet data at baseline. At 6 months, the intervention was associated with decreased intake of total energy (- 185.6 kcal/day; 95% CI - 353.6, - 17.5 kcal/day) and refined cereals (- 7.2 g/1000 kcal; 95% CI - 12.7, - 1.7 g/1000 kcal), and increased intakes of fruits and vegetables (33.4 g/1000 kcal; 95% CI 16.0, 50.8 g/1000 kcal). The intervention group was half (HR 0.49; 95% CI 0.25, 0.94) as likely to develop diabetes at 1 year, and the hazard was significantly attenuated (12.2%; P = 0.015) with adjustment for fruits and vegetable intake.

CONCLUSION

The D-CLIP decreased the total energy intake and increased the intakes of fruits and vegetables, and reduced the 1-year incidence of diabetes by half.

TRIAL REGISTRATION

Clinicaltrails.gov # NCT01283308.

Long-term effects of increased protein intake after weight loss on intrahepatic lipid content and implications for insulin sensitivity: a PREVIEW study

The aim of this study was to assess the effects of a weight maintenance period comprising two diets differing in protein intake, after weight loss, on intrahepatic lipid content and implications for insulin sensitivity. A total of 25 participants [body mass index (BMI): 31.1 (3.5 kg/m²; intrahepatic lipid (IHL): 8.7 (8.3%; fasting glucose: 6.4 (0.6 mmol/l; homeostatic model assessment for insulin resistance (HOMA-IR): 3.7 (1.6; Matsuda index: 3.4 (2.9] started an 8-wk low-energy diet followed by a 2-yr weight maintenance period with either high protein or medium protein dietary guidelines. At baseline, after 6 mo, and after 2 yr, IHL, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) were determined by magnetic resonance spectroscopy/imaging. Glucose and insulin concentrations, determined during an oral glucose challenge, were used to assess the HOMA-IR and Matsuda insulin sensitivity index (ISI). Protein intake was measured with 24-h urinary nitrogen excretion. Protein intake, BMI, IHL, VAT, SAT, HOMA-IR, and ISI did not change differently between the groups during the intervention. In the whole group, BMI, IHL, VAT, SAT, HOMA-IR, and ISI were favorably changed at 6 mo and 2 yr compared with baseline ( P < 0.05). Mixed-model analysis showed that independent of BMI, protein intake (g/d) at 6 mo was inversely related to IHL (coefficient: -0.04; P < 0.05) and VAT (coefficient: -0.01; P < 0.05). Overall, IHL was positively related to HOMA-IR (coefficient: 0.10; P < 0.01) and inversely related to ISI (coefficient: -0.17; P < 0.01), independent of BMI. A 2-yr medium- to high-protein energy-restricted diet reduced IHL and VAT. Independently of changes in BMI, IHL was inversely related to insulin sensitivity.

Community involvement in design, implementation and evaluation of nutrition interventions to reduce chronic diseases in indigenous populations in the U.S.: a systematic review

Background

Indigenous peoples of the United States disproportionately experience chronic diseases associated with poor nutrition, including obesity and diabetes. While chronic disease related health disparities among Indigenous people are well documented, it is unknown whether interventions adequately address these health disparities. In addition, it is unknown whether and to what extent interventions are culturally adapted or tailored to the unique culture, worldview and nutrition environments of Indigenous people. The aim of this review was to identify and characterize nutrition interventions conducted with Indigenous populations in the US, and to determine whether and to what degree communities are involved in intervention design, implementation and evaluation.

Methods

Peer-reviewed articles were identified using MEDLINE. Articles included were published in English in a refereed journal between 2000 and 2015, reported on a diet-related intervention in Indigenous populations in the US, and reported outcome data. Data extracted were program objectives and activities, target population, geographic region, formative research to inform design and evaluation, partnership, capacity building, involvement of the local food system, and outcomes. Narrative synthesis of intervention characteristics and the degree and type of community involvement was performed.

Results

Of 1060 records identified, 49 studies were included. Overall, interventions were successful in producing changes in knowledge, behavior or health (79%). Interventions mostly targeted adults in the Western region and used a pre-test, post-test design. Involvement of communities in intervention design, implementation, and evaluation varied from not at all to involvement at all stages. Of programs reporting significant changes in outcomes, more than half used at least three strategies to engage communities. However, formative research to inform the evaluation was not performed to a great degree, and fewer than half of the programs identified described involvement of the local food system.

Conclusions

The extent of use of strategies to promote community engagement in programs reporting significant outcomes is notable. In planning interventions in Indigenous groups, researchers should consider ways to involve the community in intervention design, execution and evaluation. There is a particular need for studies focused on Indigenous youth in diverse regions of the US to further address diet-related chronic conditions.

Impact of lifestyle behavior change on glycemic control in youth with type 2 diabetes

BACKGROUND

Little is known about the feasibility and impact of lifestyle intervention, determined by change in diet and cardiovascular fitness (CRF), on glycemic control in youth who are overweight with type 2 diabetes. This was examined in the Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) clinical trial cohort from across 15 US centers.

SUBJECTS

TODAY enrolled 699 youth aged 10 to 17 years with type 2 diabetes <2 years and body mass index ≥85th percentile at baseline.

METHODS

Dietary data were collected by an interviewer-administered food frequency questionnaire; CRF was assessed using a submaximal cycle ergometer test. Change from baseline in these variables was analyzed using generalized linear mixed models for both continuous and categorical measures. Models were adjusted for age, baseline HbA1c, treatment group, and medication adherence. Data were collected at baseline, 6, and 24 months. Trial registration ClinicalTrials.gov NCT00081328.

RESULTS

At 6 months, ~25% of females and ~33% of males improved CRF. In males, this was related to a decreased HbA1c (P = .001) and a lower percent experiencing glycemic failure (HbA1c ≥8%; P = .007). Females who decreased their saturated fat intake and/or increased their fiber intake had lower HbA1c at month 24 (P = .01 and P = .007, respectively). Males who increased their sweetened beverage intake at 6-month follow-up were at a 1.6-fold higher risk of experiencing glycemic failure (P = .04).

CONCLUSIONS

Few youth improved fitness and/or diet over time, although those who did showed a beneficial impact on glycemic outcomes. Although lifestyle behaviors are difficult to change in youth with type 2 diabetes, interventions are needed that are feasible (in scope, complexity, and demands), sustainable, and clinically meaningful.

A High-Carbohydrate, High-Fiber, Low-Fat Diet Results in Weight Loss among Adults at High Risk of Type 2 Diabetes

Background: Weight loss is a key factor in reducing diabetes risk. The Diabetes Prevention Program (DPP) is a completed clinical trial that randomly assigned individuals at high risk of diabetes to a placebo (PLBO), metformin (MET), or intensive lifestyle intervention (ILS) group, which included physical activity (PA) and reduced dietary fat intake.Objective: We aimed to evaluate the associations between diet and weight at baseline and to identify specific dietary factors that predicted weight loss among DPP participants.Methods: Diet was assessed by a food frequency questionnaire. The associations between intakes of macronutrients and various food groups and body weight among DPP participants at baseline were assessed by linear regression, adjusted for race/ethnicity, age, sex, calorie intake, and PA. Models that predicted weight loss at year 1 were adjusted for baseline weight, change in calorie intake, and change in PA and stratified by treatment allocation (MET, ILS, and PLBO). All results are presented as estimates ± SEs.Results: A total of 3234 participants were enrolled in the DPP; 2924 had completed dietary data (67.5% women; mean age: 50.6 ± 10.7 y). Adjusted for calorie intake, baseline weight was negatively associated with carbohydrate intake (-1.14 ± 0.18 kg body weight/100 kcal carbohydrate, P < 0.0001) and, specifically, dietary fiber (-1.26 ± 0.28 kg/5 g fiber, P < 0.0001). Baseline weight was positively associated with total fat (1.25 ± 0.21 kg/100 kcal, P < 0.0001), saturated fat (1.96 ± 0.46 kg/100 kcal, P < 0.0001), and protein (0.21 ± 0.05 kg/100 kcal, P < 0.0001). For all groups, weight loss after 1 y was associated with increases in carbohydrate intake, specifically dietary fiber, and decreases in total fat and saturated fat intake.Conclusions: Higher carbohydrate consumption among DPP participants, specifically high-fiber carbohydrates, and lower total and saturated fat intake best predicted weight loss when adjusted for changes in calorie intake. Our results support the benefits of a high-carbohydrate, high-fiber, low-fat diet in the context of overall calorie reduction leading to weight loss, which may prevent diabetes in high-risk individuals. This trial was registered at clinicaltrials.gov as NCT00004992.

PREVIEW: Prevention of Diabetes through Lifestyle Intervention and Population Studies in Europe and around the World. Design, Methods, and Baseline Participant Description of an Adult Cohort Enrolled into a Three-Year Randomised Clinical Trial

Type-2 diabetes (T2D) is one of the fastest growing chronic diseases worldwide. The PREVIEW project has been initiated to find the most effective lifestyle (diet and physical activity) for the prevention of T2D, in overweight and obese participants with increased risk for T2D. The study is a three-year multi-centre, 2 × 2 factorial, randomised controlled trial. The impact of a high-protein, low-glycaemic index (GI) vs. moderate protein, moderate-GI diet in combination with moderate or high-intensity physical activity on the incidence of T2D and the related clinical end-points are investigated. The intervention started with a two-month weight reduction using a low-calorie diet, followed by a randomised 34-month weight maintenance phase comprising four treatment arms. Eight intervention centres are participating (Denmark, Finland, United Kingdom, The Netherlands, Spain, Bulgaria, Australia, and New Zealand). Data from blood specimens, urine, faeces, questionnaires, diaries, body composition assessments, and accelerometers are collected at months 0, 2, 6, 12, 18, 24, and 36. In total, 2326 adults were recruited. The mean age was 51.6 (SD 11.6) years, 67% were women. PREVIEW is, to date, the largest multinational trial to address the prevention of T2D in pre-diabetic adults through diet and exercise intervention. Participants will complete the final intervention in March, 2018.

Comparing methods of targeting obesity interventions in populations: An agent-based simulation

Social networks as well as neighborhood environments have been shown to effect obesity-related behaviors including energy intake and physical activity. Accordingly, harnessing social networks to improve targeting of obesity interventions may be promising to the extent this leads to social multiplier effects and wider diffusion of intervention impact on populations. However, the literature evaluating network-based interventions has been inconsistent. Computational methods like agent-based models (ABM) provide researchers with tools to experiment in a simulated environment. We develop an ABM to compare conventional targeting methods (random selection, based on individual obesity risk, and vulnerable areas) with network-based targeting methods. We adapt a previously published and validated model of network diffusion of obesity-related behavior. We then build social networks among agents using a more realistic approach. We calibrate our model first against national-level data. Our results show that network-based targeting may lead to greater population impact. We also present a new targeting method that outperforms other methods in terms of intervention effectiveness at the population level.

•

While behavioral interventions exist for obesity, uncertainty remains about how best to target those interventions to maximize population-level impact.

•

Agent-based models are simulation tools that can be used to evaluate different targeting strategies to help policy makers.

•

Targeting intervention resources using social networks may lead to greater population impact of behavioral interventions compared to traditional methods of targeting.

Replication of the Association of BDNF and MC4R Variants With Dietary Intake in the Diabetes Prevention Program

OBJECTIVE

Genomewide association studies (GWAS) have identified consistent associations with obesity, with a number of studies implicating eating behavior as a primary mechanism. Few studies have replicated genetic associations with dietary intake. This study evaluates the association between obesity susceptibility loci and dietary intake.

METHODS

Data were obtained as part of the Diabetes Prevention Program (DPP), a clinical trial of diabetes prevention in persons at high risk of diabetes. The association of 31 genomewide association studies identified obesity risk alleles with dietary intake, measured through a food frequency questionnaire, was investigated in 3,180 participants from DPP at baseline.

RESULTS

The minor allele at BDNF, identified as protective against obesity, was associated with lower total caloric intake (β = -106.06, SE = 33.13; p = .0014) at experimentwide statistical significance (p = .0016), whereas association of MC4R rs571312 with higher caloric intake reached nominal significance (β = 61.32, SE = 26.24; p = .0194). Among non-Hispanic white participants, the association of BDNF rs2030323 with total caloric intake was stronger (β = -151.99, SE = 30.09; p < .0001), and association of FTO rs1421085 with higher caloric intake (β = 56.72, SE = 20.69; p = .0061) and percentage fat intake (β = 0.37, SE = 0.08; p = .0418) was also observed.

CONCLUSIONS

These results demonstrate with the strength of independent replication that BDNF rs2030323 is associated with 100 to 150 greater total caloric intake per allele, with additional contributions of MC4R and, in non-Hispanic white individuals, FTO. As it has been argued that an additional 100 kcal/d could account for the trends in weight gain, prevention focusing on genetic profiles with high dietary intake may help to quell adverse obesity trends.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov,NCT00004992.

A Prospective Programmatic Cost Analysis of Fuel Your Life: A Worksite Translation of DPP

OBJECTIVE

An accounting of the resources necessary for implementation of efficacious programs is important for economic evaluations and dissemination.

METHODS

A programmatic costs analysis was conducted prospectively in conjunction with an efficacy trial of Fuel Your Life (FYL), a worksite translation of the Diabetes Prevention Program. FYL was implemented through three different modalities, Group, Phone, and Self-study, using a micro-costing approach from both the employer and societal perspectives.

RESULTS

The Phone modality was the most costly at $354.6 per participant, compared with $154.6 and $75.5 for the Group and Self-study modalities, respectively. With the inclusion of participant-related costs, the Phone modality was still more expensive than the Group modality but with a smaller incremental difference ($461.4 vs $368.1).

CONCLUSIONS

This level of cost-related detail for a preventive intervention is rare, and our analysis can aid in the transparency of future economic evaluations.

The Impact of a Home-Based Diabetes Prevention and Management Program on High-Risk American Indian Youth

PURPOSE

The purpose of this study was to examine the impact of a home-based diabetes prevention and management program on high-risk American Indian youth.

METHODS

Together on Diabetes (TOD) was designed via a participatory approach with 4 tribal communities in the southwestern United States. A multisite pre- and postevaluation design was used to evaluate the efficacy of the TOD intervention on improving youth's psychosocial, knowledge, behavioral, and physiological outcomes at 4 time points from baseline to 12 months postenrollment.

RESULTS

A total of 256 youth and 225 support persons were enrolled in the TOD program. At 12 months postenrollment, improvements were observed in youth's quality of life (P < .001), depressive symptoms (P < .001), knowledge related to TOD content (P < .001), standardized body mass index scores (P = .004), and hypertension (P = .026). Improvements in mean A1C were observed among diabetic youth with baseline A1C >6.5% (P = .036).

CONCLUSIONS

The TOD program was feasible, acceptable, and effective in lowering diabetes risk among reservation-based American Indian youth. It is the first efficacious youth-focused diabetes prevention and management program developed and implemented in partnership with tribal communities.

Association between body weight and composition and plasma 25-hydroxyvitamin D level in the Diabetes Prevention Program

OBJECTIVE

We examined associations between body weight and plasma 25-hydroxyvitamin D concentration (25OHD) in prediabetes and sought to estimate the impact of adiposity on these associations.

METHODS

The study was conducted in the placebo (n = 1082) and intensive lifestyle (n = 1079) groups of the Diabetes Prevention Program (DPP), a multicenter trial to prevent type 2 diabetes in adults with prediabetes. Weight and 25OHD were measured at baseline, month 6, years 1 and 2. In a subset (n = 584), visceral (VAT) and subcutaneous (SAT) adiposity were assessed by computed tomography at baseline and year 1.

RESULTS

In cross-sectional analyses, baseline body weight, total fat, VAT, and SAT were inversely associated with plasma 25OHD concentration after multivariable adjustment. VAT accounted for 40 % [95 % CI 11, 69] of the association of body weight with plasma 25OHD concentration. There was no significant contribution by total fat or SAT. Two-year changes in plasma 25OHD concentration varied inversely with changes in body weight (p < 0.0001). One-year changes in total fat, VAT, or SAT were not significant mediators of the association between change in plasma 25OHD concentration and body weight.

CONCLUSION

Our study found an inverse association between body weight and plasma 25OHD concentration at baseline and over a 2-year period in adults with prediabetes. These findings in the DPP, a weight loss intervention study, raise the possibility that weight loss increases plasma 25OHD concentration. Whether adiposity mediates this association remains inconclusive.

Partial Meal Replacement Plan and Quality of the Diet at 1 Year: Action for Health in Diabetes (Look AHEAD) Trial

BACKGROUND

Little is known about diet quality with a reduced-energy, low-fat, partial meal replacement plan, especially in individuals with type 2 diabetes. The Action for Health in Diabetes (Look AHEAD) trial implemented a partial meal replacement plan in the Intensive Lifestyle Intervention.

OBJECTIVE

To compare dietary intake and percent meeting fat-related and food group dietary recommendations in Intensive Lifestyle Intervention and Diabetes Support and Education groups at 12 months.

DESIGN

A randomized controlled trial comparing Intensive Lifestyle Intervention with Diabetes Support and Education at 0 and 12 months.

PARTICIPANTS/SETTING

From 16 US sites, the first 50% of participants (aged 45 to 76 years, overweight or obese, with type 2 diabetes) were invited to complete dietary assessments. Complete 0- and 12-month dietary assessments (collected between 2001 and 2004) were available for 2,397 participants (46.6% of total participants), with 1,186 randomized to Diabetes Support and Education group and 1,211 randomized to Intensive Lifestyle Intervention group.

MAIN OUTCOME MEASURES

A food frequency questionnaire assessed intake: energy; percent energy from protein, fat, carbohydrate, polyunsaturated fatty acids, and saturated fats; trans-fatty acids; cholesterol; fiber; weekly meal replacements; and daily servings from food groups from the Food Guide Pyramid.

STATISTICAL ANALYSES PERFORMED

Mixed-factor analyses of covariance, using Proc MIXED with a repeated statement, with age, sex, race/ethnicity, education, and income controlled. Unadjusted χ² tests compared percent meeting fat-related and food group recommendations at 12 months.

RESULTS

At 12 months, Intensive Lifestyle Intervention participants had a significantly lower fat and cholesterol intake and greater fiber intake than Diabetes Support and Education participants. Intensive Lifestyle Intervention participants consumed more servings per day of fruits; vegetables; and milk, yogurt, and cheese; and fewer servings per day of fats, oils, and sweets than Diabetes Support and Education participants. A greater percentage of Intensive Lifestyle Intervention participants than Diabetes Support and Education participants met fat-related and most food group recommendations. Within Intensive Lifestyle Intervention, a greater percentage of participants consuming two or more meal replacements per day than participants consuming less than one meal replacement per day met most fat-related and food group recommendations.

CONCLUSIONS

The partial meal replacement plan consumed by Intensive Lifestyle Intervention participants was related to superior diet quality.

Long-term changes in dietary and food intake behaviour in the Diabetes Prevention Program Outcomes Study

AIMS

To compare change in dietary intake, with an emphasis on food groups and food intake behaviour, over time across treatment arms in a diabetes prevention trial and to assess the differences in dietary intake among demographic groups within treatment arms.

METHODS

Data are from the Diabetes Prevention Program and Diabetes Prevention Program Outcomes Study. Participants were randomized to a lifestyle intervention (n = 1079), metformin (n = 1073) or placebo (n = 1082) for an average of 3 years, after which the initial results regarding the benefits of the lifestyle intervention were released and all participants were offered a modified lifestyle intervention. Dietary intake was assessed using a food frequency questionnaire at baseline and at 1, 5, 6 and 9 years after randomization.

RESULTS

Compared with the metformin and placebo arms, participants in the lifestyle arm maintained a lower total fat and saturated fat and a higher fibre intake up to 9 years after randomization and lower intakes of red meat and sweets were maintained for up to 5 years. Younger participants had higher intakes of poultry and lower intakes of fruits compared with their older counterparts, particularly in the lifestyle arm. Black participants tended to have lower dairy and higher poultry intakes compared with white and Hispanic participants. In the lifestyle arm, men tended to have higher grain, fruit and fish intakes than women.

CONCLUSIONS

Changes in nutrient intake among participants in the lifestyle intervention were maintained for up to 9 years. Younger participants reported more unhealthy diets over time and thus may benefit from additional support to achieve and maintain dietary goals.

Prevention of Diabetes Through the Lifestyle Intervention: Lessons Learned from the Diabetes Prevention Program and Outcomes Study and its Translation to Practice

A number of strategies have been used to delay or prevent the development of type 2 diabetes mellitus (T2D) in high-risk adults. Among them were diet, exercise, medications and surgery. This report focuses on the nutritional lessons learned from implementation of the Intensive Lifestyle Intervention (ILI) in the DPP and its follow-up DPPOS that looked at weight loss through modification of diet and exercise. The Diabetes Prevention Program (DPP) is a large clinical trial, sponsored by the National Institutes of Health, designed to look at several strategies to prevent conversion to type 2 diabetes (T2D) by adults with prediabetes (IGT/IFG) including an Intensive Lifestyle Intervention (ILI). The ∼3800 ethnically diverse participants (46% reported non-white race) were overweight, had impaired glucose tolerance (IGT) and impaired fasting glucose (IFG). Treatments were assigned randomly. The Diabetes Prevention Program Outcomes Study (DPPOS) is a follow up study evaluating the long-term outcomes of the clinical trial.

Fiber intake and plasminogen activator inhibitor-1 in type 2 diabetes: Look AHEAD (Action for Health in Diabetes) trial findings at baseline and year 1

Plasminogen activator inhibitor 1 (PAI-1) is elevated in obese individuals with type 2 diabetes and may contribute, independently of traditional factors, to increased cardiovascular disease risk. Fiber intake may decrease PAI-1 levels. We examined the associations of fiber intake and its changes with PAI-1 before and during an intensive lifestyle intervention (ILI) for weight loss in 1,701 Look AHEAD (Action for Health in Diabetes) participants with dietary, fitness, and PAI-1 data at baseline and 1 year. Look AHEAD was a randomized cardiovascular disease trial in 5,145 overweight/obese patients with type 2 diabetes, comparing ILI (goal of ≥7% reduction in baseline weight) with a control arm of diabetes support and education. ILI participants were encouraged to consume vegetables, fruits, and grain products low in sugar and fat. At baseline, median fiber intake was 17.9 g/day. Each 8.3 g/day higher fiber intake was associated with a 9.2% lower PAI-1 level (P=0.008); this association persisted after weight and fitness adjustments (P=0.03). Higher baseline intake of fruit (P=0.019) and high-fiber grain and cereal (P=0.029) were related to lower PAI-1 levels. Although successful in improving weight and physical fitness at 1 year, the ILI in Look AHEAD resulted in small increases in fiber intake (4.1 g/day, compared with -2.35 g/day with diabetes support and education) that were not related to PAI-1 change (P=0.34). Only 31.3% of ILI participants (39.8% of women, 19.1% of men) met daily fiber intake recommendations. Increasing fiber intake in overweight/obese individuals with diabetes interested in weight loss is challenging. Future studies evaluating changes in fiber consumption during weight loss interventions are warranted.

The influence of rare genetic variation in SLC30A8 on diabetes incidence and β-cell function

CONTEXT/OBJECTIVE

The variant rs13266634 in SLC30A8, encoding a β-cell-specific zinc transporter, is associated with type 2 diabetes. We aimed to identify other variants in SLC30A8 that increase diabetes risk and impair β-cell function, and test whether zinc intake modifies this risk. DESIGN/OUTCOME: We sequenced exons in SLC30A8 in 380 Diabetes Prevention Program (DPP) participants and identified 44 novel variants, which were genotyped in 3445 DPP participants and tested for association with diabetes incidence and measures of insulin secretion and processing. We examined individual common variants and used gene burden tests to test 39 rare variants in aggregate.

RESULTS

We detected a near-nominal association between a rare-variant genotype risk score and diabetes risk. Five common variants were associated with the oral disposition index. Various methods aggregating rare variants demonstrated associations with changes in oral disposition index and insulinogenic index during year 1 of follow-up. We did not find a clear interaction of zinc intake with genotype on diabetes incidence.

CONCLUSIONS

Individual common and an aggregate of rare genetic variation in SLC30A8 are associated with measures of β-cell function in the DPP. Exploring rare variation may complement ongoing efforts to uncover the genetic influences that underlie complex diseases.

Plasma 25-hydroxyvitamin D and risk of metabolic syndrome: an ancillary analysis in the Diabetes Prevention Program

BACKGROUND/OBJECTIVES

Low blood levels of 25-hydroxyvitamin D (25OHD) have been associated with cardiometabolic disease but results are inconsistent. The objective of the study was to investigate the association of 25OHD with metabolic syndrome in a population at increased risk for diabetes.

SUBJECTS/METHODS

Using baseline data from the placebo and lifestyle intervention arms of the Diabetes Prevention Program (N=2000), multivariable logistic regression models were used to estimate the odds of prevalent metabolic syndrome and each of its individual components across 25OHD tertiles. Multivariable linear regression was used to estimate the adjusted mean difference of insulin secretion and sensitivity across the same 25OHD tertiles. In participants free of metabolic syndrome at baseline (N=546), incident metabolic syndrome in the first 2 years of follow-up was assessed using discrete-time proportional hazards regression to test its association with 25OHD concentration.

RESULTS

After multivariate adjustment, participants in the highest tertile of 25OHD had lower odds of prevalent metabolic syndrome (odds ratio=0.62; 95% confidence interval (CI)=0.45-0.84), smaller waist circumference, higher high-density lipoprotein and lower fasting plasma glucose compared with participants in the lowest tertile of 25OHD. Higher plasma 25OHD concentration was associated with greater insulin sensitivity and lower insulin secretion. After multivariate adjustment, there was a nonsignificant lower risk of metabolic syndrome in the highest tertile of 25OHD (hazard ratio=0.79; 95% CI=0.48-1.32) compared with the lowest tertile.

CONCLUSIONS

In a population at increased risk for diabetes, higher plasma 25OHD concentration was inversely associated with prevalent metabolic syndrome and nonsignificantly with incident metabolic syndrome.

Short and long-term lifestyle coaching approaches used to address diverse participant barriers to weight loss and physical activity adherence

Background

Individual barriers to weight loss and physical activity goals in the Diabetes Prevention Program, a randomized trial with 3.2 years average treatment duration, have not been previously reported. Evaluating barriers and the lifestyle coaching approaches used to improve adherence in a large, diverse participant cohort can inform dissemination efforts.

Methods

Lifestyle coaches documented barriers and approaches after each session (mean session attendance = 50.3 ± 21.8). Subjects were 1076 intensive lifestyle participants (mean age = 50.6 years; mean BMI = 33.9 kg/m²; 68% female, 48% non-Caucasian). Barriers and approaches used to improve adherence were ranked by the percentage of the cohort for whom they applied. Barrier groupings were also analyzed in relation to baseline demographic characteristics.

Results

Top weight loss barriers reported were problems with self-monitoring (58%); social cues (58%); holidays (54%); low activity (48%); and internal cues (thought/mood) (44%). Top activity barriers were holidays (51%); time management (50%); internal cues (30%); illness (29%), and motivation (26%). The percentage of the cohort having any type of barrier increased over the long-term intervention period. A majority of the weight loss barriers were significantly associated with younger age, greater obesity, and non-Caucasian race/ethnicity (p-values vary). Physical activity barriers, particularly thought and mood cues, social cues and time management, physical injury or illness and access/weather, were most significantly associated with being female and obese (p < 0.001 for all). Lifestyle coaches used problem-solving with most participants (≥75% short-term; > 90% long term) and regularly reviewed self-monitoring skills. More costly approaches were used infrequently during the first 16 sessions (≤10%) but increased over 3.2 years.

Conclusion

Behavioral problem solving approaches have short and long term dissemination potential for many kinds of participant barriers. Given minimal resources, increased attention to training lifestyle coaches in the consistent use of these approaches appears warranted.

Predictors of sustained reduction in energy and fat intake in the Diabetes Prevention Program Outcomes Study intensive lifestyle intervention

BACKGROUND

Few lifestyle intervention studies examine long-term sustainability of dietary changes.

OBJECTIVE

To describe sustainability of dietary changes over 9 years in the Diabetes Prevention Program and its outcomes study, the Diabetes Prevention Program Outcomes Study, among participants receiving the intensive lifestyle intervention.

DESIGN

One thousand seventy-nine participants were enrolled in the intensive lifestyle intervention arm of the Diabetes Prevention Program; 910 continued participation in the Diabetes Prevention Program Outcomes Study. Fat and energy intake derived from food frequency questionnaires at baseline and post-randomization Years 1 and 9 were examined. Parsimonious models determined whether baseline characteristics and intensive lifestyle intervention session participation predicted sustainability.

RESULTS

Self-reported energy intake was reduced from a median of 1,876 kcal/day (interquartile range [IQR]=1,452 to 2,549 kcal/day) at baseline to 1,520 kcal/day (IQR=1,192 to 1,986 kcal/day) at Year 1, and 1,560 kcal/day (IQR=1,223 to 2,026 kcal/day) at Year 9. Dietary fat was reduced from a median of 70.4 g (IQR=49.3 to 102.5 g) to 45 g (IQR=32.2 to 63.8 g) at Year 1 and increased to 61.0 g (IQR=44.6 to 82.7 g) at Year 9. Percent energy from fat was reduced from a median of 34.4% (IQR=29.6% to 38.5%) to 27.1% (IQR=23.1% to 31.5%) at Year 1 but increased to 35.3% (IQR=29.7% to 40.2%) at Year 9. Lower baseline energy intake and Year 1 dietary reduction predicted lower energy and fat gram intake at Year 9. Higher leisure physical activity predicted lower fat gram intake but not energy intake.

CONCLUSIONS

Intensive lifestyle intervention can result in reductions in total energy intake for up to 9 years. Initial success in achieving reductions in fat and energy intake and success in attaining activity goals appear to predict long-term success at maintaining changes.

Variation at the melanocortin 4 receptor gene and response to weight-loss interventions in the diabetes prevention program

OBJECTIVE

To assess associations and genotype × treatment interactions for melanocortin 4 receptor (MC4R) locus variants and obesity-related traits.

DESIGN AND METHODS

Diabetes prevention program (DPP) participants (N = 3,819, of whom 3,356 were genotyped for baseline and 3,234 for longitudinal analyses) were randomized into intensive lifestyle modification (diet, exercise, weight loss), metformin or placebo control. Adiposity was assessed in a subgroup (n = 909) using computed tomography. All analyses were adjusted for age, sex, ethnicity and treatment.

RESULTS

The rs1943218 minor allele was nominally associated with short-term (6 month; P = 0.032) and long-term (2 year; P = 0.038) weight change. Eight SNPs modified response to treatment on short-term (rs17066856, rs9966412, rs17066859, rs8091237, rs17066866, rs7240064) or long-term (rs12970134, rs17066866) reduction in body weight, or diabetes incidence (rs17066829) (all Pinteraction < 0.05).

CONCLUSION

This is the first study to comprehensively assess the role of MC4R variants and weight regulation in a weight loss intervention trial. One MC4R variant was directly associated with obesity-related traits or diabetes; numerous other variants appear to influence body weight and diabetes risk by modifying the protective effects of the DPP interventions.

Self-reported dietary intake of youth with recent onset of type 2 diabetes: results from the TODAY study

Despite the widely recognized importance of diet in managing diabetes, few studies have documented usual dietary intake in young people with type 2 diabetes. The objectives of our study were to assess dietary intake among a large, ethnically diverse cohort of young people with type 2 diabetes and compare intake to current recommendations. The Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) study is a multicenter randomized clinical trial of 699 youth aged 10 to 17 years. At baseline, following a run-in period that included standard diabetes education, diet was assessed using a food frequency questionnaire between 2004 and 2009. Analysis of variance and nonparametric tests were used to compare mean and median nutrient intakes; logistic regression was used to compare the odds of meeting predefined dietary intake recommendation cutpoints between subgroups of age, sex, and race-ethnicity. Percent of energy from saturated fat was consistently 13% to 14% across all subgroups-substantially exceeding national recommendations. Overall, only 12% of youth met Healthy People 2010 guidelines for intake of <10% of energy from saturated fat and only 1% of youth met American Diabetes Association recommendations for intake of <7% of energy from saturated fat. Dietary intake fell substantially below other Healthy People 2010 targets; only 3% met calcium intake goals, 11% met fruit consumption goals, 5% met vegetable consumption goals, and 67% met grain intake goals. Overall, dietary intake in this large cohort of young people with type 2 diabetes fell substantially short of recommendations, in ways that were consistent by sex, age, and race-ethnicity. The data suggest a critical need for better approaches to improve dietary intake of these young people.

Longitudinal changes in dietary fat intake and associated changes in cardiovascular risk factors in adults with type 2 diabetes: the ACCORD trial

AIMS

To measure dietary fat intake using the Puget Sound Eating Patterns (PEP) questionnaire, a validated 19-item food questionnaire, and to quantify how reduced dietary fat intake affects cardiovascular risk factors in adults with type 2 diabetes.

METHODS

Randomized controlled trial including a subsample of 1781 Action to Control Cardiovascular Risk in Diabetes (ACCORD) participants. Participants received dietary counseling to consume a reduced-fat diet. Outcome measures included HbA1c, fasting lipid profile, blood pressure, and weight. Longitudinal linear regression analyses were used to evaluate relationships between baseline and follow-up PEP scores and cardiovascular risk factors.

RESULTS

PEP scores decreased significantly from baseline to 12-month follow up with a mean difference of -0.09 ± 0.39, P<0.001. All of the fat intake subscales showed significant improvement at 12 months from baseline. White race, female gender, and more hours per week of physical activity were correlated with a decline in PEP scores at 1-year. A longitudinal decrease in dietary fat intake was associated with significantly less weight gain at 12- and 36-months and lower serum triglycerides at 1 year.

CONCLUSIONS

Reduced fat intake as measured by a brief questionnaire was associated with significant improvement in some cardiovascular risk factors (triglycerides and weight), but not in others.

Racial/ethnic differences in sex hormone levels among postmenopausal women in the diabetes prevention program

CONTEXT

Sex hormones may differ by race/ethnicity in postmenopausal women. Whether racial/ethnic differences also exist among those who are overweight and glucose intolerant is not clear.

OBJECTIVES

The objective of the study was to compare sex hormones by race/ethnicity [non-Hispanic white (NHW), Hispanic, African-American (AA)] in overweight, glucose-intolerant, postmenopausal women.

DESIGN

This was a secondary analysis of a randomized controlled trial.

PARTICIPANTS

Participants included postmenopausal glucose-intolerant women participating in the Diabetes Prevention Program.

INTERVENTIONS

Interventions included intensive lifestyle modification (consisting of diet and physical activity) or metformin 850 mg twice a day vs. placebo.

MAIN OUTCOME MEASURES

Baseline levels and 1-yr intervention-related changes in SHBG, total and bioavailable estradiol (E2), total and bioavailable testosterone, and dehydroepiandrosterone were measured.

RESULTS

At baseline, among women not using estrogen (n = 370), NHW had higher total and bioavailable E2 and testosterone levels than Hispanics independent of age, type of menopause, waist circumference, alcohol intake, and current smoking. NHW also had higher levels of bioavailable E2 and lower levels of SHBG than AA. At baseline, among estrogen users (n = 310), NHW had higher total and bioavailable E2 than Hispanics and higher levels of SHBG than AA after adjustment. At 1 yr, among women not using estrogen, NHW had larger declines in total E2 and bioavailable E2 levels than AA after adjustment for the above covariates, changes in waist circumference, and randomization arm. At 1 yr, among estrogen users, sex hormone changes did not differ by race/ethnicity.

CONCLUSIONS

Among postmenopausal women, there were significant race/ethnicity differences in baseline sex hormones and changes in sex hormones.

Genetic modulation of lipid profiles following lifestyle modification or metformin treatment: the Diabetes Prevention Program

Weight-loss interventions generally improve lipid profiles and reduce cardiovascular disease risk, but effects are variable and may depend on genetic factors. We performed a genetic association analysis of data from 2,993 participants in the Diabetes Prevention Program to test the hypotheses that a genetic risk score (GRS) based on deleterious alleles at 32 lipid-associated single-nucleotide polymorphisms modifies the effects of lifestyle and/or metformin interventions on lipid levels and nuclear magnetic resonance (NMR) lipoprotein subfraction size and number. Twenty-three loci previously associated with fasting LDL-C, HDL-C, or triglycerides replicated (P = 0.04–1×10⁻¹⁷). Except for total HDL particles (r = −0.03, P = 0.26), all components of the lipid profile correlated with the GRS (partial |r| = 0.07–0.17, P = 5×10⁻⁵–1×10⁻¹⁹). The GRS was associated with higher baseline-adjusted 1-year LDL cholesterol levels (β = +0.87, SEE±0.22 mg/dl/allele, P = 8×10⁻⁵, P_interaction = 0.02) in the lifestyle intervention group, but not in the placebo (β = +0.20, SEE±0.22 mg/dl/allele, P = 0.35) or metformin (β = −0.03, SEE±0.22 mg/dl/allele, P = 0.90; P_interaction = 0.64) groups. Similarly, a higher GRS predicted a greater number of baseline-adjusted small LDL particles at 1 year in the lifestyle intervention arm (β = +0.30, SEE±0.012 ln nmol/L/allele, P = 0.01, P_interaction = 0.01) but not in the placebo (β = −0.002, SEE±0.008 ln nmol/L/allele, P = 0.74) or metformin (β = +0.013, SEE±0.008 nmol/L/allele, P = 0.12; P_interaction = 0.24) groups. Our findings suggest that a high genetic burden confers an adverse lipid profile and predicts attenuated response in LDL-C levels and small LDL particle number to dietary and physical activity interventions aimed at weight loss.

The study included 2,993 participants from the Diabetes Prevention Program, a randomized clinical trial of intensive lifestyle intervention, metformin treatment, and placebo control. We examined associations between 32 gene variants that have been reproducibly associated with dyslipidemia and concentrations of lipids and NMR lipoprotein particle sizes and numbers. We also examined whether genetic background influences a person's response to cardioprotective interventions on lipid levels. Our analysis, which focused on determining whether common genetic variants impact the effects of cardioprotective interventions on lipid and lipoprotein particle size, shows that in persons with a high genetic risk score the benefit of intensive lifestyle intervention on LDL and small LDL particle levels is substantially diminished; this information may be informative for the targeted prevention of dyslipidemia, as it suggests that genetics might help identify persons in whom lifestyle intervention is likely to be an effective treatment for elevated lipids and lipoproteins. The NMR subfraction analyses provide novel insight into the biology of dyslipidemia by illustrating how numerous genetic variants that have previously been associated with lipid levels also modulate NMR lipoprotein particle sizes and number. This information may be informative for the targeted prevention of cardiovascular disease.

Plasma 25-hydroxyvitamin D and progression to diabetes in patients at risk for diabetes: an ancillary analysis in the Diabetes Prevention Program

OBJECTIVE

To investigate the association between vitamin D status, assessed by plasma 25-hydroxyvitamin D, and risk of incident diabetes.

RESEARCH DESIGN AND METHODS

Prospective observational study with a mean follow-up of 2.7 years in the Diabetes Prevention Program (DPP), a multicenter trial comparing different strategies for prevention of diabetes in patients with prediabetes. We assessed the association between plasma 25-hydroxyvitamin D, measured repeatedly during follow-up, and incident diabetes in the combined placebo (n = 1,022) and intensive lifestyle (n = 1,017) randomized arms of the DPP. Variables measured at multiple study time points (25-hydroxyvitamin D, BMI, and physical activity) entered the analyses as time-varying "lagged" covariates, as the mean of the previous and current visits at which diabetes status was assessed.

RESULTS

After multivariate adjustment, including for the DPP intervention, participants in the highest tertile of 25-hydroxyvitamin D (median concentration, 30.1 ng/mL) had a hazard ratio of 0.72 (95% CI 0.56-0.90) for developing diabetes compared with participants in the lowest tertile (median concentration, 12.8 ng/mL). The association was in the same direction in placebo (0.70; 0.52-0.94) versus lifestyle arm (0.80; 0.54-1.17).

CONCLUSIONS

Higher plasma 25-hydroxyvitamin D, assessed repeatedly, was associated with lower risk of incident diabetes in high-risk patients, after adjusting for lifestyle interventions (dietary changes, increased physical activity, and weight loss) known to decrease diabetes risk. Because of the observational nature of the study, the potential association between vitamin D and diabetes needs to be confirmed in intervention studies.

Associations of dairy intake with CT lung density and lung function

OBJECTIVE

Dairy products contain vitamin D and other nutrients that may be beneficial for lung function, but they are also high in fats that may have mixed effects on lung function. However, the overall associations of dairy intake with lung density and lung function have not been studied.

METHODS

We examined the cross-sectional relationships between dairy intake and computed tomography (CT) lung density and lung function in the Multi-Ethnic Study of Atherosclerosis (MESA). Total, low-fat, and high-fat dairy intakes were quantified from food frequency questionnaire responses of men and women who were ages 45-84 years and free of clinical cardiovascular disease. The MESA-Lung Study assessed CT lung density from cardiac CT imaging and prebronchodilator spirometry among 3965 MESA participants.

RESULTS

Total dairy intake was inversely associated with apical-basilar difference in percent emphysema and positively associated with forced vital capacity (FVC) (the multivariate-adjusted mean difference between the highest and lowest quintiles of total dairy intake was -0.92 [p for trend = 0.04] for apical-basilar difference in percent emphysema and 72.0 mL [p = 0.01] for FVC). Greater low-fat dairy intake was associated with higher alpha (higher alpha values indicate less emphysema) and lower apical-basilar difference in percent emphysema (corresponding differences in alpha and apical-basilar difference in percent emphysema were 0.04 [p = 0.02] and -0.98 [p = 0.01] for low-fat dairy intake, respectively). High-fat dairy intake was not associated with lung density measures. Greater low- or high-fat dairy intake was not associated with higher forced expiratory volume in 1 second (FEV(1)), FVC, and FEV(1)/FVC.

CONCLUSIONS

Higher low-fat dairy intake but not high-fat dairy intake was associated with moderately improved CT lung density.

Are the benefits of the 'Healthy Start' food support scheme sustained at three months postpartum? Results from the Sheffield 'before and after' study

Early results examining nutritional behaviour of Caucasian, English-speaking, postpartum women living in Sheffield, who were beneficiaries or eligible for the Welfare Food Scheme (WFS) or the Healthy Start (HS) scheme, suggested significant between-groups differences. The aim of this study was to examine whether differences observed at 4 weeks postpartum were sustained over time. Eighty-six WFS and 64 HS participants were recruited at baseline and, thereafter, 53 WFS and 33 HS participants at week 8, and 47 WFS and 39 HS participants at week 12. Dietary intakes were assessed by an interviewer-administered, semi-quantified food frequency questionnaire. At 4 weeks, HS women had higher energy intakes compared to WFS women, (9.7 MJ and 8.1 MJ, respectively). Differences were also sustained at 8 weeks, (8.8 MJ and 7.2 MJ) and 12 weeks (9.4 MJ and 7.6 MJ) for the HS and WFS participants, respectively. Within-groups, energy and most of nutrient intakes did not change appreciably over time. Consumption of fruit and vegetables at baseline, were significantly higher (P = 0.023) for participants under the HS scheme (3.4 portions) compared to WFS participants (2.7 portions). Differences were sustained over time as HS women reported consuming 4.1 and 3.7 portions/day respectively at 8 and 12 weeks, as opposed to 2.8 and 2.7 portions/day reported by WFS women. The study findings provided evidence of the potential effectiveness of the HS scheme in a population subgroup at risk of dietary deficiencies. Early findings could provide a useful snapshot of the diet of such mobile population and should be further exploited.

Nutrient intakes and dysglycaemia in populations of West African origin

Examining the relationship between glucose intolerance and dietary intake in genetically similar populations with different dietary patterns and rates of type 2 diabetes may provide important insights into the role of diet in the pathogenesis of this disease. The objective of the present study was to assess the relationship between dietary variables and dysglycaemia/type 2 diabetes among three populations of African origin. The study design consists of a cross-sectional study of men and women of African descent aged 24-74 years from Cameroon (n 1790), Jamaica (n 857) and Manchester, UK (n 258) who were not known to have diabetes. Each participant had anthropometric measurements and underwent a 2 h 75 g oral glucose tolerance test. Habitual dietary intake was estimated with quantitative FFQ, developed specifically for each country. The age-adjusted prevalence of undiagnosed type 2 diabetes in Cameroon was low (1·1 %), but it was higher in Jamaica (11·6 %) and the UK (12·6 %). Adjusted generalised linear and latent mixed models used to obtain OR indicated that each 1·0 % increment in energy from protein, total fat and saturated fats significantly increased the odds of type 2 diabetes by 9 (95 % CI 1·02, 1·16) %, 5 (95 % CI, 1·01, 1·08) % and 16 (95 % CI 1·08, 1·25) %, respectively. A 1 % increase in energy from carbohydrates and a 0·1 unit increment in the PUFA:SFA ratio were associated with significantly reduced odds of type 2 diabetes. The results show independent effects of dietary factors on hyperglycaemia in African origin populations. Whether modifying intake of specific macronutrients helps diabetes prevention needs testing in randomised trials.

Type 2 diabetes in Indigenous populations: quality of intervention research over 20 years

BACKGROUND

A robust evidence base is needed to reduce the disproportionately high rates of diabetes-related mortality and complications among Indigenous peoples.

OBJECTIVE

This study aimed to evaluate the quantity and methodological quality of published intervention research on Type 2 and gestational diabetes in the Indigenous populations of Australia, Canada, New Zealand, and the United States from 1989 to 2008. A robust evidence base is needed to reduce the disproportionately high rates of diabetes-related mortality and complications among Indigenous peoples.

METHODS

Systematic searches of Medline, Embase, and EBM Reviews identified publications focused on Type 2 or gestational diabetes in Indigenous peoples published between 1 January 1989 and 31 December 2008. Total publication number and proportion of research involving interventions over time were examined. The quality of intervention studies was evaluated using Cochrane's Effective Practice and Organisation of Care (EPOC) criteria.

RESULTS

Total publication number increased significantly over the 20 years (p<0.004). Research was predominantly descriptive (87%), with the proportion of research involving interventions increasing from 3% in 1989-1993 to 12% in 2003-2008 (χ(2)=12.42, df=3, p=0.006). However, only 25% (95%CI: 9-41%) of intervention studies met the EPOC methodological quality criteria; other studies lacked sufficient controls or measurements over time.

CONCLUSIONS

Increases in the amount of high-quality intervention research for prevention and treatment of Type 2 and gestational diabetes among Indigenous populations of these countries are needed.

Effect of a continuous diabetes lifestyle intervention program on male workers in Korea

AIMS

This study was conducted to compare the effects of two years of lifestyle intervention to no intervention or one year of intervention on diabetes risk factors in male workers with impaired fasting glucose (IFG) or diabetes.

METHODS

We conducted a randomized lifestyle intervention trial designed to alter personal lifestyles among 123 industrial male workers (CG; control group, n=75; OIG; one-year intervention group, n=23; TIG; two-year intervention group, n=25). The intervention consisted of two parts, the main program (face-to-face counseling five times/12 weeks) and a follow-up program (e-mail counseling ten times/30 weeks). Assessments included biochemical characteristics, anthropometry and nutrient intake at baseline and after two years.

RESULTS

After two years, systolic blood pressure, HOMA-IR, HDL cholesterol and total energy intake (p<0.05) were reduced in the OIG group, while weight, body mass index, waist circumference, blood pressure, fasting plasma glucose (FPG), HbA1c and nutrient intake (total energy, carbohydrate, protein and sodium) were significantly decreased (p<0.05, respectively) in the TIG group. When compared to the CG, subjects in OIG and TIG showed significant improvements in the level of FPG and HbA1c (p<0.05).

CONCLUSIONS

Continuous lifestyle intervention for two years is more effective at improving diabetes risk factors than OIG.

Adherence and success in long-term weight loss diets: the dietary intervention randomized controlled trial (DIRECT)

BACKGROUND

Data are limited as to whether participants in diet trials truly adhere to their assigned diet and the factors that affect their adherence.

METHODS

We evaluated success and adherence in a two-year dietary intervention randomized controlled trial (DIRECT) in which 322 moderately obese participants (mean age 52 yrs, mean body-mass-index (BMI) 31 kg/m(2), 86% men) were randomized to one of three groups: low-fat, Mediterranean, or low-carbohydrate diets.

RESULTS

Overall compliance at month-24 was 85%, with 90% in low-fat, 85% in Mediterranean, and 78% in low-carbohydrate diet (p = .042 between groups). Attrition was higher in women (29% vs. 14% men, p = .001) and current smokers (25% vs. 14% among maintainers, p = 0.04). In a multivariate model, independent predictors of dropping-out were: higher baseline BMI (OR = 1.11; CI: 1.03-1.21) and less weight loss at month-6 (OR = 1.20; CI: 1.1-1.3). In a multivariate model, greater weight loss achieved at month-6 was the main predictor associated with success in weight loss (> 5%) over 2 years (OR = 1.5; CI: 1.35-1.67). Self-reported complete adherence score to diet was greater on low-carbohydrate diet (p < .05 compared to low-fat) until month-6, but dropped overall from 81% at month-1 to 57% at month-24. Holidays were a trigger to a significant decrease in adherence followed by a partial rebound. Changes in diet composition from month-1 to month-12 were more pronounced in the multi-stage low-carbohydrate diet-group (p < .05). Generally, the most irresistible restricted food items were cookies (45% of dieters) and fruits (30%). Among the physically active (n = 107), 44% reported a tendency to eat less after exercising compared to 10% who tended to eat more.

CONCLUSION

Initial 6-month reduction in weight is the main predictor of both long-term retention and success in weight loss. Special attention is needed for women, current smokers, and during holidays. Physical activity is associated with subsequent reduction in energy intake.

Dietary strategies for patients with type 2 diabetes in the era of multi-approaches; review and results from the Dietary Intervention Randomized Controlled Trial (DIRECT)

Dietary intervention is recognized as a key component in prevention and management of type 2 diabetes (T2DM) and the debate persists: which dietary strategy is most effective. In the Dietary Intervention Randomized Controlled Trial (DIRECT) 322 moderately obese participants were randomized for 2 years to one of three diet groups: low-fat, Mediterranean and low-carbohydrate. Differential effects were observed in the sub-group of patients with T2DM at 24 months: participants randomized to the Mediterranean diet, which had the highest intake of dietary fibers and unsaturated to saturated fat ratio, achieved greater significant improvements in fasting plasma glucose and insulin levels. Patients who were randomized to the low-carbohydrate diet, which had the minimal intake of carbohydrates, achieved a significant reduction of hemoglobin A1C. Although improvements were observed in all groups, the low-fat diet was likely to be less beneficial in terms of glycemic control and lipid metabolism. Interpretation of results from different studies on dietary strategies may be complex since there is often no consistency in diet compositions, calorie restriction, intensity of intervention, dietary assessment or extent of adherence in the trial. Nevertheless, it seems that low fat restricted calorie diets are effective for weight loss and are associated with some metabolic benefits; however, some recent trials have shown that low carbohydrate diets are as efficient in inducing weight loss and in some metabolic measures such as serum triglycerides and HDL-cholesterol may be even superior to low fat diets. When addressing the issue of diet quality rather than quantity applying the glycemic index may have some added benefits. Furthermore special features of the Mediterranean diet have apparent additional favorable effects for patients with T2DM.

Alcohol consumption and diabetes risk in the Diabetes Prevention Program

BACKGROUND

Moderate alcohol consumption is associated with a decreased risk of type 2 diabetes in the general population, but little is known about the effects in individuals at high risk of diabetes.

OBJECTIVES

The objectives were to determine associations between alcohol consumption and diabetes risk factors and whether alcohol consumption was a predictor of incident diabetes in individuals enrolled in the Diabetes Prevention Program (DPP).

DESIGN

DPP participants (n = 3175) had impaired glucose tolerance (2-h glucose: 7.8-11.1 mmol/L), elevated fasting glucose (5.3-7.0 mmol/L), and a body mass index (in kg/m(2)) > or =24. Participants were randomly assigned to placebo, metformin, or lifestyle modification and were followed for a mean of 3.2 y. Alcohol intake was assessed at baseline and year 1 by using a semiquantitative food-frequency questionnaire. Diabetes was diagnosed by annual oral-glucose-tolerance testing and semiannual fasting plasma glucose measurement.

RESULTS

Participants who reported higher alcohol consumption tended to be male, older, white, and less obese and to have a higher calorie intake and a higher HDL-cholesterol concentration. Higher alcohol consumption was associated with lower insulin secretion at any level of insulin sensitivity. We found lower incidence rates of diabetes with higher alcohol consumption in the metformin (P < 0.01 for trend) and lifestyle modification (P = 0.02 for trend) groups, which remained significant after adjustment for multiple baseline covariates. No similar association was observed in the placebo group.

CONCLUSIONS

Despite overall low rates of alcohol consumption, there was a reduced risk of incident diabetes in those who reported modest daily alcohol intake and were assigned to metformin or lifestyle modification. Moderate daily alcohol intake is associated with lower insulin secretion-an effect that warrants further investigation. This trial was registered at clinicaltrials.gov as NCT00038727.