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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 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 p 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.

OBJECTIVE Across the Diabetes Prevention Program (DPP) follow-up, cumulative diabetes incidence remained lower in the lifestyle compared with the placebo and metformin randomized groups and could not be explained by weight. Collection of self-reported physical activity (PA) (yearly) with cross-sectional objective PA (in follow-up) allowed for examination of PA and its long-term impact on diabetes prevention. RESEARCH DESIGN AND METHODS Yearly self-reported PA and diabetes assessment and oral glucose tolerance test results (fasting glucose semiannually) were collected for 3,232 participants with one accelerometry assessment 11–13 years after randomization (n = 1,793). Mixed models determined PA differences across treatment groups. The association between PA and diabetes incidence was examined using Cox proportional hazards models. RESULTS There was a 6% decrease (Cox proportional hazard ratio 0.94 [95% CI 0.92, 0.96]; P < 0.001) in diabetes incidence per 6 MET-h/week increase in time-dependent PA for the entire cohort over an average of 12 years (controlled for age, sex, baseline PA, and weight). The effect of PA was greater (12% decrease) among participants less active at baseline ( CONCLUSIONS PA was inversely related to incident diabetes in the entire cohort across the study, with cross-sectional accelerometry results supporting these findings. This highlights the importance of PA within lifestyle intervention efforts designed to prevent diabetes and urges health care providers to consider both PA and weight when counseling high-risk patients.

Subclinical markers of atherosclerosis, including CAC, are less favorable in adults with IGT. In previous adult studies, higher PA has been associated with lower CAC with findings varying by age and sex. PA and CAC were examined by age and sex in the diverse Diabetes Prevention Program Outcomes Study (DPPOS) cohort with IGT who were randomized at baseline to lifestyle intervention, metformin, or placebo groups for a mean of 3.2 years, and subsequently observed in DPPOS for follow-up. PA was measured via questionnaire (annually); accelerometry once at 11-13yrs and CAC Agatston score (AS) using chest computed tomography at 13-15 yrs from randomization. The relationship between PA and CAC was examined using Tobit regression models in 1434 participants with valid PA and CAC data (mean age 63±9.5 yrs; 70% female; 54% with diabetes) adjusted for treatment group, age, sex, race/ethnicity, lipid medication use, diabetes status, and cumulative metformin exposure; pairwise and three-way interactions were examined. Accelerometry-assessed median (IQR) daily step counts and moderate+ PA (MVPA) minutes were 5302 (3576, 7104) and 21 (9, 41), respectively. Median (IQR) AS was 9 (0, 151). In fully adjusted models, each 1000 steps /day was associated with lower CAC (p=0.024). Results were examined by sex and age subgroups (0.05). Similarly, significant inverse associations between MVPA minutes and CAC AS were found in women ( Suggested sex differences in the PA-CAC association in adults with initial glucose intolerance was found and should be investigated in other studies. Disclosure B. Rockette-wagner: None. E. Horton: None. M. A. Hoskin: None. U. N. Ibebuogu: None. M. Schlögl: None. R. B. Goldberg: None. D. Research group: None. A. Kriska: None. N. Younes: None. S. Edelstein: None. T. J. Orchard: None. M. Armstrong: None. A. L. Brown: Research Support; Self; Medtronic, National Heart, Lung, and Blood Institute, National Institute of Diabetes and Digestive and Kidney Diseases. D. Dabelea: None. K. M. Gadde: Other Relationship; Self; AstraZeneca, Research Support; Self; BioKier, National Institute of Diabetes and Digestive and Kidney Diseases. Funding National Institute of Diabetes and Digestive and Kidney Diseases (U01DK048489)

Objective: Across the DPP follow-up, cumulative diabetes incidence remained lower in the lifestyle compared to placebo and metformin randomized groups and could not be explained by weight. Collection of self-reported PA (yearly) with cross-sectional objective PA (in follow-up) allowed for examination of PA and its long-term impact on diabetes prevention. Research Design and Methods: Yearly self-reported PA and diabetes assessment, OGTT, (fasting glucose semi-annually) was collected for 3232 participants with one accelerometry assessment 11-13 years after randomization (n=1,793). Mixed models determined PA differences across treatment groups. The association between PA and diabetes incidence was examined using Cox proportional hazards models. Results: There was a 6% decrease (Cox proportional HR 0.94 [0.92, 0.96]; P< 0.001) in diabetes incidence per 6 MET-hrs/week increase in time-dependent PA for the entire cohort over an average 12 years (controlled for age, sex, baseline PA and weight). The effect of PA was greater (12% decrease) among participants less active at baseline ( Conclusions: PA was inversely related to incident diabetes in the entire cohort across the study with cross-sectional accelerometry results supporting these findings. This highlights the importance of PA within lifestyle intervention efforts designed to prevent diabetes and urge health-care providers to consider both PA and weight when counseling high-risk patients.

A web-based survey of pediatric care providers revealed differences in their preference for clinical charts that monitor growth in children with obesity. These findings are attributed to pediatric specialty training. Very few providers believe the currently available Centers for Disease Control and Prevention 2000 body mass index-for-age charts adequately track growth in children with obesity.

We evaluated whether dietary quality is a predictor of reduced diabetes risk and/or weight loss, independent of caloric intake in the diverse DPP cohort, a randomized clinical trial of adults at risk for diabetes. This secondary analysis included the 2920 participants (90.3% of randomized) with complete baseline and 1-year data (967 intensive lifestyle (ILS), 979 metformin, 974 placebo). Dietary intake was assessed using a 117-item food frequency questionnaire. Dietary quality was quantified using the Alternative Healthy Eating Index 2010 (AHEI), which ranges from 0 to 110 with higher scores corresponding to healthier diets. Participants were 50.8 ±10.6 years, 67.5% female, 44.7% minority race/ethnicity and baseline AHEI was 44.2 ±10.4. ILS participants had greater improvement (p Disclosure B. Allaire: None. A.H. Tjaden: None. J.W. Apolzan: None. D. Dabelea: None. L.M. Delahanty: Advisory Panel; Self; Jana Care Inc., Omada Health, Inc., Weight Watchers International, Inc. S. Edelstein: None. M.A. Hoskin: None. L.M. Jaacks: None. K.A. Temple: None. E.M. Venditti: None. J. Wylie-Rosett: None. DPP Research Group: None. Funding National Institute of Diabetes and Digestive and Kidney Diseases

Weight loss prevents progression to diabetes but long term effects on lean mass are unknown. We determined if intensive lifestyle modification (ILS), metformin (MET) or placebo (PLB) treatment in the Diabetes Prevention Program (DPP) had differential effects on appendicular lean mass (ALM) and sarcopenic-obesity (SO) ∼16 years after DPP randomization in the DPP Outcome Study (DPPOS). During DPP, 3234 participants at high risk for diabetes were randomized to ILS, MET or PLB; 2779 continued in DPPOS and were offered modified group ILS. During DPPOS, ILS was offered additional lifestyle reinforcement semi-annually and MET received unmasked metformin. This analysis includes 1374 DPPOS participants who had dual-energy X-ray absorptiometry scans at year 12 for ALM (sum of lean mass in arms and legs). Low ALM was defined as ALM/BMI 30. Prevalence of low ALM and SO was compared across the 3 groups using Pearson’s chi-squared test. Logistic regression models determined the associations between treatment and low ALM or SO and between weight loss and low ALM or SO. Mean age at Y12 was 66.5 (±9.5) years. Mean time since DPP baseline was 15.6 (±0.7) years. Weight loss (DPP baseline to DPPOS Y12) did not differ by group (-4.4 kg ILS; -3.5 kg MET; -3.1 kg PLB; p=0.114). Prevalence of low ALM differed by group in men (35.7% ILS, 28.3% MET, 22.5% PLB; p=0.049) but not women (20.9% ILS, 24.8% MET, 24.1% PLB; p=0.482). In men, low ALM prevalence was higher in ILS compared with PLB (P=0.024) but not in MET vs. PLB. Prevalence of SO did not differ across groups in men (23.1% ISL, 22.0% MET, 14.1% PLB; p=0.112) or women (17.3% ILS, 20.9% MET, 20.3% PLB; p=0.492). SO prevalence was not different in ILS vs. PLB or in MET vs. PLB in men or women. More weight loss was associated with higher risk of low ALM and SO in women and men (p Disclosure A.V. Schwartz: None. Q. Pan: None. H.P. Hazuda: None. E. Horton: Advisory Panel; Self; PTS Diagnostics, Merck & Co., Inc., Theracos, Inc.. M.A. Hoskin: None. R. Rastogi Kalyani: None. W.C. Knowler: None. A. Kriska: None. M. Schlögl: None. H. Florez: Advisory Panel; Self; Sanofi. D. Research Group: None.

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.

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.

Following unblinding of the Diabetes Prevention Program (DPP) results, a 16-session lifestyle intervention program was offered to all study participants, including those who had initially been randomized to lifestyle treatment. This study compares the effects of the lifestyle program between participants who had previous exposure and those who had not. A 16-session behavioral intervention was conducted in groups at each of the 27 DPP sites during a transitional (bridge) period from the DPP trial to the DPP Outcomes Study (DPPOS). Session participation for this 6-month behavioral weight loss program was confirmed by originally randomized treatment groups. Independently assessed weight measurements were available within a 7-month period before and after the program for 2808 ethnically diverse participants. Participants from the lifestyle group in the DPP were the least likely to attend a repeat offering of a 16-session behavioral weight loss program conducted in groups. Weight loss during the transitional lifestyle program was strongly related to the duration of attendance in the three groups that were participating in the program for the first time (metformin, placebo and troglitazone), but not related to amount of earlier weight loss. Individuals who were naive to the behavioral program lost a greater amount of weight and this was strongly related to their degree of participation. A second exposure to a behavioral weight loss program resulted in unsatisfactory low attendance rates and weight loss.

Type 2 diabetes mellitus (T2DM) affects more than 7% of adults in the US and leads to substantial personal and economic burden. In prediabetic states insulin secretion and action--potential targets of preventive interventions--are impaired. In trials lifestyle modification (i.e. weight loss and exercise) has proven effective in preventing incident T2DM in high-risk groups, although weight loss has the greatest effect. Various medications (e.g. metformin, thiazolidinediones and acarbose) can also prevent or delay T2DM. Whether diabetes-prevention strategies also ultimately prevent the development of diabetic vascular complications is unknown, but cardiovascular risk factors are favorably affected. Preventive strategies that can be implemented in routine clinical settings have been developed and evaluated. Widespread application has, however, been limited by local financial considerations, even though cost-effectiveness might be achieved at the population level.

In Brief Given that a physically active lifestyle is important to health and quality of life, health care professionals are faced with the challenge of guiding individuals as they attempt to increase their level of physical activity. To provide some insight into this challenge, several lifestyle interventionists (many of whom were part of the Diabetes Prevention Program) have shared stories of participants and patients whom they have encountered through the years. This collection of “fishing tips”is meant to help in the challenge of hooking an active, healthy lifestyle.

Objective The Diabetes Prevention Program (DPP) showed that intensive lifestyle intervention reduced the risk of diabetes by 58%. This paper examines demographic, psychosocial, and behavioral factors related to achieving weight loss and physical activity goals in the DPP lifestyle participants. Research methods and procedures Lifestyle participants (n = 1079; mean age = 50.6, BMI = 33.9, 68% female, and 46% from minority groups) had goals of 7% weight loss and 150 min/wk of physical activity. Goal achievement was assessed at the end of the 16-session core curriculum (approximately week 24) and the final intervention visit (mean = 3.2 years) as a function of demographic, psychosocial, and behavioral variables. Results Forty-nine percent met the weight loss goal and 74% met the activity goal initially, while 37% and 67%, respectively, met these goals long-term. Men and those with lower initial BMI were more likely to meet activity but not weight loss goals. Hispanic, Asian, and Native Americans were more likely to meet the long-term activity goals, and whites were more likely to meet the initial weight loss goal. In multivariate analyses, meeting the long-term weight loss goal and both activity goals increased with age, while psychosocial and depression measures were unrelated to goal achievement. Dietary self-monitoring was positively related to meeting both weight loss and activity goals, and meeting the activity goal was positively related to meeting the weight loss goal. Participants who met initial goals were 1.5 to 3.0 times more likely to meet these goals long-term. Discussion Success at meeting the weight loss and activity goals increased with age. Initial success predicted long-term success. Self-monitoring and meeting activity goals were related to achieving and sustaining weight loss.

A pilot trial was conducted to test adherence to specific lifestyle interventions among Pima Indians of Arizona, and to compare them for changes in risk factors for diabetes mellitus. Ninety-five obese, normoglycaemic men and women, aged 25-54 years, were randomized to treatments named 'Pima Action' (Action) and 'Pima Pride' (Pride), which were tested for 12 months. Action involved structured activity and nutrition interventions, and Pride included unstructured activities emphasizing Pima history and culture. Adherence to interventions, changes in self-reported activity and diet, and changes in weight, glucose concentrations, and other risk factors were assessed regularly. Thirty-five eligible subjects who had declined randomization were also followed as an 'observational' group and 22 members of this group were examined once at a median of 25 months for changes in weight and glucose concentration. After 12 months of intervention, members of both intervention groups reported increased levels of physical activity (median: Action 7.3 h month(-1), Pride 6.3 h month(-1), p < 0.001 for each), and Pride members reported decreased starch intake (28 g, p = 0.008). Body mass index, systolic and diastolic blood pressures, weight, 2-h glucose and 2-h insulin had all increased in Action members (p < 0.003 for each), and waist circumference had decreased in Pride members (p = 0.05). Action members gained more weight than Pride members (2.5 kg vs 0.8 kg, p = 0.06), and had a greater increase in 2-h glucose than Pride members (1.33 mM vs 0.03 mM, p = 0.007). Members of the observational group gained an average of 1.9 kg year(-1) in weight and had an increase of 0.36 mM year(-1) in 2-h glucose. Sustaining adherence in behavioural interventions over a long term was challenging. Pimas may find a less direct, less structured, and more participative intervention more acceptable than a direct and highly structured approach.

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., Author Summary 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.

Numerous observational studies have reported decreased cancer incidence and cancer-related mortality in patients with diabetes receiving standard doses of metformin. A recent meta-analysis of these studies suggested a 31% reduction in overall cancer incidence, summary relative risk (0.69; 95% confidence interval, 0.52-0.90), in subjects taking metformin as compared with other antidiabetic drugs. Separate meta-analyses of studies that adjusted for BMI or time-related bias suggested an attenuation of this signal, but still showed a significant reduction in cancer incidence. However, studies published to date are limited by the observational nature of the data and the randomized controlled trials that have been used to examine metformin's potential as an anti-cancer agent in patients with diabetes have had insufficient follow-up for cancer endpoints. These data also do not address the cancer risk in non-diabetic populations, in which the cancer preventive potential of metformin is unknown. The Diabetes Prevention Program (DPP) was a national multi-center, randomized, placebo-controlled clinical trial, which enrolled 3234 participants between 1996 and 1999, designed to investigate whether intensive lifestyle modification or treatment with metformin (850mg twice a day) delayed or prevented the onset of type 2 diabetes in a high risk population. The DPP and its follow up study, the Diabetes Prevention Program Outcomes Study (DPPOS), provide a unique opportunity to examine the role of metformin and lifestyle intervention in reducing cancer incidence in an overweight adult population with impaired glucose regulation, before the onset of diabetes. The National Cancer Institute Division of Cancer Prevention, in collaboration with the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and the DPPOS investigators, proposed a study to examine the hypothesis that metformin and/or lifestyle intervention can modify total cancer incidence and/or obesity-related cancer incidence (breast, colorectal, endometrium, pancreas, lower esophagus, gall-bladder, and kidney) in DPP/DPPOS participants. The DPPOS protocol and consent were modified to allow collection of data to support the inclusion of cancer incidence as an endpoint of interest in the study. Participants complete a cancer risk questionnaire that includes family history of cancer, cancer screening activities, and use of aspirin and NSAIDs including dose and frequency. The participants who previously reported a cancer diagnosis, through the SAE reporting process and/or an annual questionnaire, or during a subsequent follow-up visit, are asked to provide physician information to obtain medical records for case adjudication. This protocol will allow for the examination of the effect of metformin and lifestyle intervention on cancer incidence in an initially pre-diabetic population potentially through a median of 20 years of follow-up. Data from this study will compare incidence of total and obesity-related cancers between the original treatment groups; assess cancer (total and obesity-related) incidence by metformin exposure across all treatment groups, using a “met-years” variable, and explore subgroups to investigate effect modification by sex, age group, race/ethnicity, diabetes status, or weight loss at 1 year or mean weight loss since study baseline. Citation Format: Brandy M. Heckman-Stoddard, Jill P. Crandall, Sharon L. Edelstein, Richard F. Hamman, Philip C. Prorok, Anne Ryan, Dana Dabelea, Helen P. Hazuda, Edward Horton, Mary A. Hoskin, Susan Jeffries, William C. Knowler, Kieren J. Mather, Susana M. Shapiro, Farzana L. Walcott, Leslie G. Ford. Cancer outcomes in the diabetes prevention program outcomes study. [abstract]. In: Proceedings of the Thirteenth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2014 Sep 27-Oct 1; New Orleans, LA. Philadelphia (PA): AACR; Can Prev Res 2015;8(10 Suppl): Abstract nr A23.

OBJECTIVE—Diabetes Prevention Program (DPP) participants randomized to the intensive lifestyle intervention (ILS) had significantly reduced risk of diabetes compared with placebo participants. We explored the contribution of changes in weight, diet, and physical activity on the risk of developing diabetes among ILS participants. RESEARCH DESIGN AND METHODS—For this study, we analyzed one arm of a randomized trial using Cox proportional hazards regression over 3.2 years of follow-up. RESULTS—A total of 1,079 participants were aged 25–84 years (mean 50.6 years, BMI 33.9 kg/m2). Weight loss was the dominant predictor of reduced diabetes incidence (hazard ratio per 5-kg weight loss 0.42 [95% CI 0.35–0.51]; P < 0.0001). For every kilogram of weight loss, there was a 16% reduction in risk, adjusted for changes in diet and activity. Lower percent of calories from fat and increased physical activity predicted weight loss. Increased physical activity was important to help sustain weight loss. Among 495 participants not meeting the weight loss goal at year 1, those who achieved the physical activity goal had 44% lower diabetes incidence. CONCLUSIONS—Interventions to reduce diabetes risk should primarily target weight reduction.

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 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.