Impact of individual and environmental factors on dietary or lifestyle interventions to prevent type 2 diabetes development: a systematic review.

BACKGROUND: The variability in the effectiveness of type 2 diabetes (T2D) preventive interventions highlights the potential to identify the factors that determine treatment responses and those that would benefit the most from a given intervention. We conducted a systematic review to synthesize the evidence to support whether sociodemographic, clinical, behavioral, and molecular factors modify the efficacy of dietary or lifestyle interventions to prevent T2D. METHODS: We searched MEDLINE, Embase, and Cochrane databases for studies reporting on the effect of a lifestyle, dietary pattern, or dietary supplement interventions on the incidence of T2D and reporting the results stratified by any effect modifier. We extracted relevant statistical findings and qualitatively synthesized the evidence for each modifier based on the direction of findings reported in available studies. We used the Diabetes Canada Clinical Practice Scale to assess the certainty of the evidence for a given effect modifier. RESULTS: The 81 publications that met our criteria for inclusion are from 33 unique trials. The evidence is low to very low to attribute variability in intervention effectiveness to individual characteristics such as age, sex, BMI, race/ethnicity, socioeconomic status, baseline behavioral factors, or genetic predisposition. CONCLUSIONS: We report evidence, albeit low certainty, that those with poorer health status, particularly those with prediabetes at baseline, tend to benefit more from T2D prevention strategies compared to healthier counterparts. Our synthesis highlights the need for purposefully designed clinical trials to inform whether individual factors influence the success of T2D prevention strategies.

Clinical trials to prevent development of type 2 diabetes (T2D) that test dietary and lifestyle interventions have resulted in different results for different study participants. We hypothesized that the differing responses could be because of different personal, social and inherited factors. We searched different databases containing details of published research studies investigating this to look at the effect of these factors on prevention of the development of T2D. We found a small amount of evidence suggesting that those with poorer health, particularly those with a higher amount of sugar in their blood, tend to benefit more from T2D prevention strategies compared to healthier counterparts. Our results suggest that further clinical trials that are designed to examine the effect of personal and social factors on interventions for T2D prevention are needed to better determine the impact of these factors on the success of diet and lifestyle interventions for T2D.

Assessment of Placebo Response in Objective and Subjective Outcome Measures in Rheumatoid Arthritis Clinical Trials.

Importance: Large placebo responses in randomized clinical trials may keep effective medication from reaching the market. Primary outcome measures of clinical trials have shifted from patient-reported to objective outcomes, partly because response to randomized placebo treatment is thought to be greater in subjective compared with objective outcomes. However, a direct comparison of placebo response in subjective and objective outcomes in the same patient population is missing. Objective: To assess whether subjective patient-reported (pain severity) and objective inflammation (C-reactive protein [CRP] level and erythrocyte sedimentation rate [ESR]) outcomes differ in placebo response. Design, Setting, and Participants: The placebo arms of 5 double-blind, randomized, placebo-controlled clinical trials were included in this cross-sectional study. These trials were conducted internationally for 24 weeks or longer between 2005 and 2009. All patients with rheumatoid arthritis randomized to placebo (N = 788) were included. Analysis of data from these trials was conducted from March 27 to December 31, 2019. Intervention: Placebo injection. Main Outcomes and Measures: The difference (with 95% CIs) from baseline at week 12 and week 24 on a 0- to 100-mm visual analog scale to evaluate the severity of pain, CRP level, and ESR. Results: Of the 788 patients included in the analysis, 644 were women (82%); mean (SD) age was 51 (13) years. There was a statistically significant decrease in patient-reported pain intensity (week 12: -14 mm; 95% CI, -12 to -16 mm and week 24: -20 mm; 95% CI, -16 to -22 mm). Similarly, significant decreases were noted in the CRP level (week 12: -0.51 mg/dL; 95% CI, -0.47 to -0.56 mg/dL and week 24: -1.16 mg/dL; 95% CI, -1.03 to -1.30 mg/dL) and ESR (week 12: -11 mm/h; 95% CI, -10 to 12 mm/h and week 24: -25 mm/h; 95% CI, -12 to -26 mm/h) (all P < .001). Conclusions and Relevance: The findings of this study suggest that improvements in clinical outcomes among participants randomized to placebo were not limited to subjective outcomes. Even if these findings could largely demonstrate a regression to the mean, they should be considered for future trial design, as unexpected favorable placebo responses may result in a well-designed trial becoming underpowered to detect the treatment difference needed in clinical drug development.

Changes in BMI before and during economic development and subsequent risk of cardiovascular disease and total mortality: a 35-year follow-up study in China.

OBJECTIVE: It is unclear whether changes in BMI during rapid economic development influence subsequent mortality. RESEARCH DESIGN AND METHODS: We analyzed whether BMI in 1976 and 1994 and changes in BMI during 1976-1994 predict cardiovascular disease (CVD) and all-cause mortality in a 35-year follow-up cohort of 1,696 Chinese (1,124 men and 572 women, aged 35-65 years) in Xi'an, China. Participants were categorized as underweight (<18.5 kg/m(2)), normal weight (18.5-24.9 kg/m(2)), and overweight (≥25.0 kg/m(2)). RESULTS: During 51,611 person-years of follow-up, we identified 655 deaths from all causes and 234 from CVD. From 1976 to 1994, the prevalence of overweight rose from 9.2 to 27.8%. With each unit increment in 1976 BMI, multivariate hazard ratios (HRs) (95% CI) were 0.78 (0.72-0.84) for CVD and 0.91 (0.87-0.95) for all-cause mortality. In contrast, corresponding HRs were 1.14 (1.08-1.19) and 1.05 (1.01-1.08) in 1994 BMI. The HRs for each unit increment in BMI change from 1976 to 1994 were 1.35 (1.25-1.41) for CVD and 1.09 (1.05-1.13) for all-cause mortality. Compared with participants with stable normal weight in 1976 and 1994, HRs of all-cause mortality for those who had normal weight in 1976 but became overweight in 1994 and for those who were persistently overweight during 1976-1994 were 1.42 (1.12-1.80) and 1.80 (1.04-3.14), respectively. CONCLUSIONS: Gaining weight with increased BMI at middle age in Chinese during economic development was associated with elevated risks of all-cause and CVD mortality. Higher BMI measured before economic development was associated with lower mortality risk, whereas BMI measured afterward was associated with increased mortality.