Dietary pattern and diversity analysis using DietDiveR in R: a cross-sectional evaluation in the National Health and Nutrition Examination Survey.

BACKGROUND: There are few resources available for researchers aiming to conduct 24-h dietary record and recall analysis using R. OBJECTIVES: We aimed to develop DietDiveR, which is a toolkit of functions written in R for the analysis of recall or record data collected with the Automated Self-Administered 24-h Dietary Assessment Tool or 2-d 24-h dietary recall data from the National Health and Nutrition Examination Survey (NHANES). The R functions are intended for food and nutrition researchers who are not computational experts. METHODS: DietDiveR provides users with functions to 1) clean dietary data, 2) analyze 24-h dietary intakes in relation to other study-specific metadata variables, 3) visualize percentages of energy intake from macronutrients, 4) perform principal component analysis or k-means clustering to group participants by similar data-driven dietary patterns, 5) generate foodtrees based on the hierarchical food group information for food items consumed, 6) perform principal coordinate analysis taking food grouping information into account, and 7) calculate diversity metrics for overall diet and specific food groups. DietDiveR includes a self-paced tutorial on a website (https://computational-nutrition-lab.github.io/DietDiveR/). As a demonstration, we applied DietDiveR to a demonstration data set and data from NHANES 2015-2016 to derive a dietary diversity measure of nuts, seeds, and legumes consumption. RESULTS: Adult participants in the NHANES 2015-2016 cycle were grouped depending on the diversity in their mean consumption of nuts, seeds, and legumes. The group with the highest diversity in nuts, seeds, and legumes consumption had 3.8 cm lower waist circumference (95% confidence interval: 1.0, 6.5) than those who did not consume nuts, seeds, and legumes. CONCLUSIONS: DietDiveR enables users to visualize dietary data and conduct data-driven dietary pattern analyses using R to answer research questions regarding diet. As a demonstration of this toolkit, we explored the diversity of nuts, seeds, and legumes consumption to highlight some of the ways DietDiveR can be used for analyses of dietary diversity.

Non-alcoholic fatty liver modifies associations of body mass index and waist circumference with cardiometabolic risk: The CARDIA study.

Background: Non-alcoholic fatty liver disease (NAFLD) is recognized as a prevalent determinant of cardiometabolic diseases. The association between NAFLD and obesity warrants further research on how NAFLD modifies associations between body mass index (BMI) and Waist circumference (WC) with cardiometabolic risk (CMR). Objective: This study assessed whether NAFLD modifies associations between BMI and WC with 5-year changes in CMR in 2366 CARDIA study participants. Methods: Non-contrast CT was used to quantify liver attenuation, with ≤51 Hounsfield Units (HU) used to define NAFLD in the absence of secondary causes of excess liver fat. The dependent variable was the average Z score of fasting glucose, insulin, triglycerides [log], (-) high-density lipoprotein cholesterol (HDL-C), and systolic blood pressure(SBP). Multivariable linear regression was used to estimate the associations between BMI and WC with CMR. Effect modification by NAFLD was assessed by an interaction term between NAFLD and BMI or WC. Results: The final sample had 539 (23%) NAFLD cases. NAFLD modified the association of BMI and WC with CMR (interaction p < 0.0001 for both). BMI and WC were associated with CMR in participants without NAFLD (p < 0.001), but not among those with NAFLD. Participants with NAFLD and normal BMI and WC had CMR estimates that were higher than those without NAFLD in the obese categories. Among those without NAFLD the 5 years CMR change estimate was 0.09 (95% CI: 0.062, 0.125) for BMI ≥30 kg/m2 compared to -0.06 (-0.092, -0.018) for BMI < 25 kg/m2, and among those with NAFLD, these estimates were 0.15 (0.108, 0.193) and 0.16 (-0.035, 0.363). Conclusions: NAFLD modifies associations of BMI and WC with CMR. Compared with BMI and WC, NAFLD was more strongly associated with CMR. In the presence of NAFLD, BMI and WC were not associated with CMR. These findings have implications for clinical screening guidelines.

Increased low-density lipoprotein cholesterol on a low-carbohydrate diet in adults with normal but not high body weight: A meta-analysis.

BACKGROUND: Low-density lipoprotein (LDL) cholesterol change with consumption of a low-carbohydrate diet (LCD) is highly variable. Identifying the source of this heterogeneity could guide clinical decision-making. OBJECTIVES: To evaluate LDL cholesterol change in randomized controlled trials involving LCDs, with a focus on body mass index (BMI) in kg/m2. METHODS: Three electronic indexes (Pubmed, EBSCO, and Scielo) were searched for studies between 1 January, 2003 and 20 December, 2022. Two independent reviewers identified randomized controlled trials involving adults consuming <130 g/d carbohydrate and reporting BMI and LDL cholesterol change or equivalent data. Two investigators extracted relevant data, which were validated by other investigators. Data were analyzed using a random-effects model and contrasted with results of pooled individual participant data. RESULTS: Forty-one trials with 1379 participants and a mean intervention duration of 19.4 wk were included. In a meta-regression accounting for 51.4% of the observed variability on LCDs, mean baseline BMI had a strong inverse association with LDL cholesterol change [ß = -2.5 mg/dL/BMI unit, 95% confidence interval (CI): -3.7, -1.4], whereas saturated fat amount was not significantly associated with LDL cholesterol change. For trials with mean baseline BMI <25, LDL cholesterol increased by 41 mg/dL (95% CI: 19.6, 63.3) on the LCD. By contrast, for trials with a mean of BMI 25-<35, LDL cholesterol did not change, and for trials with a mean BMI ≥35, LDL cholesterol decreased by 7 mg/dL (95% CI: -12.1, -1.3). Using individual participant data, the relationship between BMI and LDL cholesterol change was not observed on higher-carbohydrate diets. CONCLUSIONS: A substantial increase in LDL cholesterol is likely for individuals with low but not high BMI with consumption of an LCD, findings that may help guide individualized nutritional management of cardiovascular disease risk. As carbohydrate restriction tends to improve other lipid and nonlipid risk factors, the clinical significance of isolated LDL cholesterol elevation in this context warrants investigation. This trial was registered at PROSPERO as CRD42022299278.

Plasma Neuronal Growth Regulator 1 May Link Physical Activity to Reduced Risk of Type 2 Diabetes: A Proteome-Wide Study of ARIC Participants.

Habitual physical activity (PA) impacts the plasma proteome and reduces the risk of developing type 2 diabetes (T2D). Using a large-scale proteome-wide approach in Atherosclerosis Risk in Communities study participants, we aimed to identify plasma proteins associated with PA and determine which of these may be causally related to lower T2D risk. PA was associated with 92 plasma proteins in discovery (P < 1.01 × 10-5), and 40 remained significant in replication (P < 5.43 × 10-4). Eighteen of these proteins were independently associated with incident T2D (P < 1.25 × 10-3), including neuronal growth regulator 1 (NeGR1; hazard ratio per SD 0.85; P = 7.5 × 10-11). Two-sample Mendelian randomization (MR) inverse variance weighted analysis indicated that higher NeGR1 reduces T2D risk (odds ratio [OR] per SD 0.92; P = 0.03) and was consistent with MR-Egger, weighted median, and weighted mode sensitivity analyses. A stronger association was observed for the single cis-acting NeGR1 genetic variant (OR per SD 0.80; P = 6.3 × 10-5). Coupled with previous evidence that low circulating NeGR1 levels promote adiposity, its association with PA and potential causal role in T2D shown here suggest that NeGR1 may link PA exposure with metabolic outcomes. Further research is warranted to confirm our findings and examine the interplay of PA, NeGR1, adiposity, and metabolic health.

Physiologic Adaptation to Macronutrient Change Distorts Findings from Short Dietary Trials: Reanalysis of a Metabolic Ward Study.

An influential 2-wk cross-over feeding trial without a washout period purported to show advantages of a low-fat diet (LFD) compared with a low-carbohydrate diet (LCD) for weight control. In contrast to several other macronutrient trials, the diet order effect was originally reported as not significant. In light of a new analysis by the original investigative group identifying an order effect, we aimed to examine, in a reanalysis of publicly available data (16 of 20 original participants; 7 female; mean BMI, 27.8 kg/m2), the validity of the original results and the claims that trial data oppose the carbohydrate-insulin model of obesity (CIM). We found that energy intake on the LCD was much lower when this diet was consumed first compared with second (a difference of -1164 kcal/d, P = 3.6 × 10-13); the opposite pattern was observed for the LFD (924 kcal/d, P = 2.0 × 10-16). This carry-over effect was significant (P interaction = 0.0004) whereas the net dietary effect was not (P = 0.4). Likewise, the between-arm difference (LCD - LFD) was -320 kcal/d in the first period and +1771 kcal/d in the second. Body fat decreased with consumption of the LCD first and increased with consumption of this diet second (-0.69 ± 0.33 compared with 0.57 ± 0.32 kg, P = 0.007). LCD-first participants had higher ß-hydroxybutyrate levels while consuming the LCD and lower respiratory quotients while consuming LFD when compared with LFD-first participants on their respective diets. Change in insulin secretion as assessed by C-peptide in the first diet period predicted higher energy intake and less fat loss in the second period. These findings, which tend to support rather than oppose the CIM, suggest that differential (unequal) carry-over effects and short duration, with no washout period, preclude causal inferences regarding chronic macronutrient effects from this trial.

Young Adult Physical Activity Trajectories and Midlife Nonalcoholic Fatty Liver Disease.

Importance: Physical activity (PA) is recommended for preventing and treating nonalcoholic fatty liver disease (NAFLD). Yet, how long-term patterns of intensity-based physical activity, including moderate-intensity PA (MPA) and vigorous-intensity PA (VPA), might affect the prevalence of NAFLD in middle age remains unclear. Objective: To identify distinct intensity-based PA trajectories from young to middle adulthood and examine the associations between PA trajectories and NAFLD prevalence in midlife. Design, Setting, and Participants: This population-based cohort of 2833 participants used the Coronary Artery Risk Development in Young Adults study data. The setting included field clinics in Birmingham, Alabama; Chicago, Illinois; Minneapolis, Minnesota; and Oakland, California. Data analysis was completed in March 2023. Exposures: PA was self-reported at 8 examinations over 25 years (1985-1986 to 2010-2011) and separately scored for MPA and VPA. Main Outcomes and Measures: NAFLD was defined as liver attenuation values less than 51 Hounsfield units after exclusion of other causes of liver fat, measured using computed tomography in year 25 (2010-2011). Results: Among a total of 2833 participants included in the sample, 1379 (48.7%) self-identified as Black, 1454 (51.3%) as White, 1206 (42.6%) as male, and 1627 (57.4%) as female from baseline (1985-1986) (mean [SD] age, 25.0 [3.6] years) to year 25 (2010-2011) (mean [SD] age, 50.1 [3.6] years). Three MPA trajectories were identified: very low stable (1514 participants [53.4%]), low increasing (1096 [38.7%]), and moderate increasing (223 [7.9%]); and 3 VPA trajectories: low stable (1649 [58.2%]), moderate decreasing (1015 [35.8%]), and high decreasing (169 [6.0%]). After adjustment for covariates (sex, age, race, study center, education, smoking status, and alcohol consumption), participants in the moderate decreasing (risk ratio [RR], 0.74; 95% CI, 0.54-0.85) and the high decreasing (RR, 0.59; 95% CI, 0.44-0.80) VPA trajectories had a lower risk of NAFLD in middle age, relative to participants in the low stable VPA trajectory. Adjustments for baseline body mass index and waist circumference attenuated these estimates, but the results remained statistically significant. The adjusted RRs across the MPA trajectories were close to null and not statistically significant. Conclusions and Relevance: This cohort study of Black and White participants found a reduced risk of NAFLD in middle age for individuals with higher levels of VPA throughout young to middle adulthood compared with those with lower VPA levels. These results suggest the need for promoting sustainable and equitable prevention programs focused on VPA over the life course to aid in lowering NAFLD risk.

Aerobic and Muscle-Strengthening Physical Activity, Television Viewing, and Nonalcoholic Fatty Liver Disease: The CARDIA Study.

BACKGROUND: The prevalence of non-alcoholic fatty liver disease (NAFLD) in U.S. adults is over 30%, yet the role of lifestyle factors in the etiology of NAFLD remains understudied. We examined the associations of physical activity, by intensity and type, and television viewing with prevalent NAFLD. METHODS: Cross-sectional analysis of a population-based sample of 2726 Black (49%) and White (51%) adults (Mean (SD) age, 50 (3.6) years; 57.3% female) from the CARDIA study. Exposures were aerobic activity by intensity (moderate, vigorous; hours/week); activity type (aerobic, muscle-strengthening; hours/week); and television viewing (hours/week), examined concurrently in all models and assessed by validated questionnaires. Our outcome was NAFLD (liver attenuation < 51 Hounsfield Units), measured by non-contrast computed tomography, after exclusions for other causes of liver fat. Covariates were sex, age, race, study center, education, diet quality, smoking status, alcohol consumption, and body mass index or waist circumference. RESULTS: 648 participants had NAFLD. In the fully adjusted modified Poisson regression model, the risk ratios per interquartile range of each exposure were moderate-intensity aerobic activity, 1.10 (95% CI, 0.97-1.26); vigorous-intensity aerobic activity, 0.72 (0.63-0.82); muscle-strengthening activity, 0.89 (0.80-1.01); and television viewing, 1.20 (1.10-1.32). Relative to less active participants with higher levels of television viewing, those who participated in ≥2 h/week of both vigorous-intensity aerobic and muscle-strengthening activity and <7 h/week of television viewing had 65% lower risk of NAFLD (risk ratio = 0.35, 95% CI = 0.23-0.51). CONCLUSION: Adults who follow public health recommendations for vigorous-aerobic and muscle-strengthening activity, as well as minimize television viewing, are considerably less likely to have NAFLD than those who do not follow the recommendations and who have relatively high levels of television viewing.

Body Mass Index Trajectories and Biomarkers of Cardiometabolic Risk in Children from Low-Income and Racially and Ethnically Diverse Households.

Background: This study examined the associations between BMI trajectories and emerging cardiometabolic risk (CMR) in children living in low-income and racially and ethnically diverse households in the United States. Methods: Data were drawn from NET-Works randomized intervention trial and NET-Works 2 prospective follow-up study (N = 338). BMI was measured across 6 follow-up visits and biomarkers of cardiometabolic risk (CMR) at the sixth visit. Group-based trajectory modeling identified child BMI trajectories. Adjusted multivariable linear regressions evaluated the associations between BMI trajectories and CMR. Results: We identified two BMI trajectories: 25% followed a trajectory of steep BMI increase, and 75% followed a moderate decreasing BMI trajectory over time. Relative to children in the moderate decreasing trajectory, children in the increasing trajectory had higher adjusted mean levels of C-reactive protein [CRP; 3.3; 95% confidence interval (CI): 1.6 to 5.0], leptin (63.1; 95% CI: 44.3 to 81.8), triglycerides (35.4; 95% CI: 22.1 to 48.6), triglyceride/high-density lipoprotein (HDL) ratio (1.2; 95% CI: 0.8 to 1.6), hemoglobin A1c (HbA1C; 0.1; 95% CI: 0.03 to 0.2), fasting glucose (1.8; 0.1 to 3.5) and insulin (8.8; 95% CI: 6.5 to 11.0), overall CMR score (0.7; 95% CI: 0.5 to 0.9), and lower adiponectin (-1.3; 95% CI: -2.5 to -0.1) and HDL (-10.8; 95% CI: -14.3 to -7.4). Conclusions: Children with high BMIs early in childhood were more likely to maintain an accelerated BMI trajectory throughout childhood, which was associated with adverse CMR in pre-adolescence. To advance health equity and support children's healthy weight and cardiovascular health trajectories, public health efforts are needed to address persistent disparities in childhood obesity and CMR.

Association between dairy products consumption and the prevalences of combined prediabetes and type 2 diabetes mellitus in Brazilian adolescents: a cross-sectional study.

The association between dairy products consumption in adults and the likelihood of type 2 diabetes mellitus (T2DM) has been described, but more information on the adolescent population is needed. This nationally representative, cross-sectional school-based study aimed to describe the consumption of dairy products and their subtypes and to evaluate their association with prediabetes and T2DM in adolescents. The Study of Cardiovascular Risks in Adolescents (ERICA) includes adolescents aged 12-17 years. Dairy products consumption was evaluated by 24-h food recall. Associations with fasting glucose, glycated hemoglobin (HbA1c) and insulin resistance, as measured by homeostatic model assessment-insulin resistance (HOMA-IR), were evaluated by multivariate linear regression. Poisson regression was also used to assess the association between dairy products consumption and the combined prevalence of prediabetes and T2DM. Models were adjusted for sociodemographic, nutritional, behavioural and anthropometrics. The final sample analysed consisted of 35 614 adolescents. Total intake of dairy products was inversely associated with fasting blood glucose levels after adjusting for all covariates (ß = -0·452, 95 % CI -0·899, -0·005). The associations were stronger for overweight and obese adolescents. Findings were similar for full-fat dairy products and yogurt. Higher consumption of low-fat dairy products and cheese were associated with a 46 % (prevalence ratio, PR 1·46, 95 % CI 1·18, 1·80) and 33 % (PR 1·33, 95 % CI 1·14, 1·57) higher combined prevalence of prediabetes and T2DM, respectively. The total consumption of dairy products and full-fat dairy products was associated with a lower combined prevalence of prediabetes and T2DM, while the consumption of cheese and low-fat dairy products was associated with higher combined prevalence of prediabetes and T2DM in Brazilian adolescents.

Psychosocial and behavioral outcomes in the adult workforce during the COVID-19 pandemic: a 1-Year longitudinal survey.

BACKGROUND: Efforts to limit the spread of COVID-19 have included public space closures, mask usage, and quarantining. Studies regarding the impact of these measures on the psychosocial and behavioral health outcomes of the workforce have focused frequently on healthcare employees. To expand the literature base, we deployed a one-year longitudinal survey among mostly non-healthcare employees assessing changes in select psychosocial outcomes, health behaviors, and COVID-19-related transmission prevention behaviors and perceptions. METHODS: We deployed the CAPTURE baseline survey across eight companies from November 20, 2020-February 8, 2021. The baseline survey included questions on psychosocial outcomes, health behaviors, and COVID-19 transmission prevention behaviors, with several questions containing a retrospective component to cover the time period prior to the pandemic. Additional questions on vaccination status and social support were subsequently added, and the updated survey deployed to the same baseline participants at three, six, and 12 months after baseline survey deployment. We analyzed data descriptively and performed Friedman's and subsequent Wilcoxon-signed rank tests, as appropriate, to compare data within and between time points. RESULTS: A total of 3607, 1788, 1545, and 1687 employees completed the baseline, 3-month, 6-month, and 12-month CAPTURE surveys, respectively, with 816 employees completing all four time points. Employees reported higher stress, anxiety, fatigue, and feelings of being unsafe across all time points compared to pre-pandemic. Time spent sleeping increased initially but returned to pre-pandemic levels at follow-up. Lower rates of physical activity and higher rates of non-work screen time and alcohol consumption relative to pre-pandemic were also reported. Over 90% of employees perceived wearing a mask, physical distancing, and receiving the COVID-19 vaccine as 'moderately' or 'very important' in preventing the spread of COVID-19 across all time points. CONCLUSIONS: Relative to pre-pandemic, poorer psychosocial outcomes and worsened health behaviors were observed across all time points, with values worse at the baseline and 12-month time points when COVID-19 surges were highest. While COVID-19 prevention behaviors were consistently deemed to be important by employees, the psychosocial outcome and health behavior data suggest the potential for harmful long-term effects of the pandemic on the well-being of non-healthcare employees.

Does frequency or duration of standing breaks drive changes in glycemic response? A randomized crossover trial.

Intervention strategies to break up sitting have mostly focused on the modality (i.e., comparing different intensities and/or type of activities) and less on how frequency and duration of breaks affect health outcomes. This study compared the efficacy of different strategies to break up sitting time [i.e., high frequency, low duration standing breaks (HFLD) and low frequency, high duration standing breaks (LFHD)] in reducing postprandial glucose. Eleven sedentary and prediabetic adults (mean ± SD age = 46.8 ± 10.6 years; 73% female) participated in a cross-over trial. There were six blocks that represented all potential combinations (ordering) of the study conditions and participants were randomly assigned to a block. Each participant underwent three 7.5-h laboratory visits (1 week apart) where they engaged in either continuous sitting, HFLD, or LFHD condition while performing their usual office-related tasks. Standardized breakfast and lunch meals were provided. Postprandial mean glucose, area under the curve (AUC), and incremental area under the curve (iAUC) were evaluated using mixed models. Compared with LFHD condition, the HFLD standing breaks condition significantly lowered mean glucose by -9.94 (-14.13, -5.74) mg/dL·h after lunch, and by -6.23 (-9.93, -2.52) mg/dL·h, for the total lab visit time. Overall, the results favor frequently interrupting sitting with standing breaks to improve glycemic control in individuals with prediabetes. Further studies are needed with larger sample sizes to confirm the results.

Evidence for the carbohydrate-insulin model in a reanalysis of the Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) trial.

BACKGROUND: The Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) trial demonstrated that meaningful weight loss can be achieved with either a "healthy low-carbohydrate diet" (LCD) or "healthy low-fat diet" (LFD). However, because both diets substantially decreased glycemic load (GL), the dietary factors mediating weight loss remain unclear. OBJECTIVES: We aimed to explore the contribution of macronutrients and GL to weight loss in DIETFITS and examine a hypothesized relationship between GL and insulin secretion. DESIGN: This study is a secondary data analysis of the DIETFITS trial, in which participants with overweight or obesity (aged 18-50 y) were randomized to a 12-mo LCD (N = 304) or LFD (N = 305). RESULTS: Measures related to carbohydrate intake (total amount, glycemic index, added sugar, and fiber) showed strong associations with weight loss at 3-, 6-, and 12-mo time points in the full cohort, whereas those related to total fat intake showed weak to no associations. A biomarker of carbohydrate (triglyceride/HDL cholesterol ratio) predicted weight loss at all time points (3-mo: ß [kg/biomarker z-score change] = 1.1, P = 3.5 × 10-9; 6-mo: ß = 1.7, P = 1.1 × 10-9; and 12-mo: ß = 2.6, P = 1.5 × 10-15), whereas that of fat (low-density lipoprotein cholesterol + HDL cholesterol) did not (all time points: P = NS). In a mediation model, GL explained most of the observed effect of total calorie intake on weight change. Dividing the cohort into quintiles of baseline insulin secretion and GL reduction revealed evidence of effect modification for weight loss, with P = 0.0009 at 3 mo, P = 0.01 at 6 mo, and P = 0.07 at 12 mo. CONCLUSIONS: As predicted by the carbohydrate-insulin model of obesity, weight loss in both diet groups of DIETFITS seems to have been driven by the reduction of GL more so than dietary fat or calories, an effect that may be most pronounced among those with high insulin secretion. These findings should be interpreted cautiously in view of the exploratory nature of this study. TRIAL REGISTRATION: ClinicalTrials.gov (NCT01826591).

Effect of Weight Goals on Sitting and Moving During a Worksite Sedentary Time Reduction Intervention.

Introduction/Purpose: Although many US adults report trying to lose weight, little research has examined weight loss goals as a motivator for reducing workplace sitting and increasing physical activity. This exploratory analysis examined weight goals and the association with changes in workplace sitting, physical activity, and weight. Methods: Employees (N = 605) were drawn from worksites participating in Stand and Move at Work. Worksites (N = 24) were randomized to a multilevel behavioral intervention with (STAND+) or without (MOVE+) sit-stand workstations for 12 months; MOVE+ worksites received sit-stand workstations from 12 to 24 months. At each assessment (baseline and 3, 12, and 24 months), participants were weighed and wore activPAL monitors. Participants self-reported baseline weight goals and were categorized into the "Lose Weight Goal" (LWG) group if they reported trying to lose weight or into the "Other Weight Goal" (OWG) group if they did not. Results: Generalized linear mixed models revealed that within STAND+, LWG and OWG had similar sitting time through 12 months. However, LWG sat significantly more than OWG at 24 months. Within MOVE+, sitting time decreased after introduction of sit-stand workstations for LWG and OWG, although LWG sat more than OWG. Change in physical activity was minimal and weight remained stable in all groups. Conclusions: Patterns of change in workplace sitting were more favorable in OWG relative to LWG, even in the absence of notable weight change. Expectations of weight loss might be detrimental for reductions in workplace sitting. Interventionists may want to emphasize non-weight health benefits of reducing workplace sitting.

Qualitative comparative analysis of the implementation fidelity of a workplace sedentary reduction intervention.

BACKGROUND: Stand and Move at Work was a 12-month, multicomponent, peer-led (intervention delivery personnel) worksite intervention to reduce sedentary time. Although successful, the magnitude of reduced sedentary time varied by intervention worksite. The purpose of this study was to use a qualitative comparative analysis approach to examine potential explanatory factors that could distinguish higher from lower performing worksites based on reduced sedentary time. METHODS: We assessed 12-month changes in employee sedentary time objectively using accelerometers at 12 worksites. We ranked worksites based on the magnitude of change in sedentary time and categorized sites as higher vs. lower performing. Guided by the integrated-Promoting Action on Research Implementation in Health Services framework, we created an indicator of intervention fidelity related to adherence to the protocol and competence of intervention delivery personnel (i.e., implementer). We then gathered information from employee interviews and surveys as well as delivery personnel surveys. These data were aggregated, entered into a truth table (i.e., a table containing implementation construct presence or absence), and used to examine differences between higher and lower performing worksites. RESULTS: There were substantive differences in the magnitude of change in sedentary time between higher (-75.2 min/8 h workday, CI95: -93.7, -56.7) and lower (-30.3 min/8 h workday, CI95: -38.3, -22.7) performing worksites. Conditions that were present in all higher performing sites included implementation of indoor/outdoor walking route accessibility, completion of delivery personnel surveys, and worksite culture supporting breaks (i.e., adherence to protocol). A similar pattern was found for implementer willingness to continue role and employees using face-to-face interaction/stair strategies (i.e., delivery personnel competence). However, each of these factors were also present in some of the lower performing sites suggesting we were unable to identify sufficient conditions to predict program success. CONCLUSIONS: Higher intervention adherence and implementer competence is necessary for greater program success. These findings illustrate the need for future research to identify what factors may influence intervention fidelity, and in turn, effectiveness. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02566317 . Registered 2 October 2015, first participant enrolled 11 January 2016.

Levels of abdominal adipose tissue and metabolic-associated fatty liver disease (MAFLD) in middle age according to average fast-food intake over the preceding 25 years: the CARDIA Study.

BACKGROUND: Higher levels of intra-abdominal adipose tissue (IAAT) comprising visceral adipose tissue (VAT), intermuscular adipose tissue (IMAT), and liver fat are posited drivers of obesity-related chronic disease risk. Fast food is hypothesized to contribute to IAAT patterns. OBJECTIVES: We quantified levels of abdominal subcutaneous adipose tissue (SAT), IAAT, and odds of metabolic-associated fatty liver disease (MAFLD) in middle age according to average fast-food intake over the preceding 25 y. METHODS: We analyzed data from the Coronary Artery Risk Development in Young Adults (CARDIA) study. Participants underwent 6 clinical exams and measurements over 25 y with computed tomography-measured VAT, SAT, and IMAT (n = 3156), plus MAFLD defined by liver attenuation (≤40 Hounsfield units) and 1 metabolic abnormality at year 25 (2010, n = 3001, n cases = 302). We estimated means of VAT, SAT, IMAT, and liver attenuation at the year 25 exam according to categories of average fast-food intake over the previous 25 y adjusted for sociodemographic and lifestyle factors and logistic regression to estimate the odds ratio of MAFLD at year 25. RESULTS: With higher average fast-food intake over 25 y (categorized as follows: never-1×/mo, >1×-3×/mo, 1-<2×/wk, 2-<3×/wk, ≥3×/wk), there were monotonic higher levels of VAT (98.5, 127.6, 134.5, 142.0, 145.5 cm3), P-trend < 0.0001, which were consistent across anthropometrically classified obesity categories. There was a similar pattern with liver fat. There were higher levels of IMAT and SAT with higher fast-food intake (P-trend = 0.003, 0.0002, respectively), with amounts leveling off at ≥2×/wk. In addition, compared with participants who ate fast food never-1×/mo, there were monotonic higher odds of having MAFLD at year 25 with higher average fast-food intake, with participants who ate fast food ≥3×/wk having an OR of MAFLD = 5.18 (95% CI: 2.87, 9.37). CONCLUSIONS: There were monotonic higher levels of VAT, liver fat, and odds of having MAFLD in middle age according to higher average fast-food intake over the preceding 25 y.