Abstract P401: Circadian Dietary Patterns and Weight Trajectories in Adults Using the Daily24 Mobile Application

Introduction: It is unclear whether the timing of meals relative to sleep impacts cardiometabolic risk factors (e.g., weight gain). This cohort study aimed to detect and describe the association of the timing of caloric intake and dietary patterns (e.g., skipping breakfast) with weight trajectory over 2 years among participants who used the Daily24 mobile application to record their timing of eating and sleeping.

Hypothesis: We hypothesized that skipping breakfast or consuming 50% or more of daily calories in the latter half of the day is associated with greater weight gain over 2 years.

Methods: We conducted a secondary data analysis from a multi-site, electronic health record-based cohort study of adults from 3 healthcare systems in PCORnet’s PaTH Clinical Research Network. Of the 1017 participants enrolled in the study, N=407 patients downloaded and used the Daily24 mobile application for at least 2 weekdays and 1 weekend day over 6 months. We calculated the median of each participant’s daily eating and sleeping intervals. Participants’ weights were extracted from electronic health records available for up to 10 years prior to until 10 months after baseline. Weight trajectories were calculated over 2 years of this data. Participants completed online surveys about demographics and behavioral characteristics at baseline and after 4 months. We constructed multivariate linear regression models with weight trajectory as the dependent variable and breakfast skipping (i.e., not eating anything within 3 hours of waking), having a medium or large meal within 3 hours of sleep, ≥50% caloric consumption in the latter half of the day (after 12 pm), and ≥90% caloric consumption after 7 pm as independent variables. Additional independent variables included age, sex, race, days of application use, and body mass index (BMI) category.

Results: Mean (SD) baseline age was 50.8 (15.0) years, 75.7% had a BMI≥25 kg/m 2 , 78.1% were women, and 84.0% were white. The average number of recorded Daily24 application days was 55.9 (53.5), significantly greater than the 3-day minimum inclusion criterion. The mean of participants’ median intervals from first to last meal was 11.2 (2.0) hours. Although not statistically significant, consuming 50% of daily calories in the latter half of the day and skipping breakfast were associated with an increasing weight trajectory (0.03 and 0.25 kg/year; 95% CI -0.39 to 0.45 and -0.32 to 0.82, respectively).

Conclusions: Timing of eating (e.g., skipping breakfast or eating most calories later in the day) may be associated with very small weight increases over time. Our app-based approach may not have had enough observations to establish this association. Further research is needed to understand the clinical importance of circadian dietary patterns related to cardiometabolic health.

Abstract 017: Meal Intervals And Weight Trajectories In Adults Using The Daily24 Mobile Application: A Prospective Cohort Study

Background: Small pilot and randomized controlled studies suggest that time-restricted feeding may decrease body weight. However, the role of meal timing and intervals, measured using mobile applications, has not been examined in larger population-based studies. The objective of this study is to evaluate the association between meal intervals and weight trajectories among adults from a population-based clinical cohort.

Methods: Multi-site prospective cohort study of adults recruited from three health systems. Over the 6-month study period, 547 participants downloaded and used the Daily24 mobile application to record the timing of meals and sleep for at least one day. Intervals were calculated as the average of all available daily entries for each participant. We obtained information on weight and comorbidities at each outpatient visit from electronic health records available for up to 10 years prior to until 10 months after baseline. We used mixed linear regression to model weight trajectories.

Results: The mean (SD) baseline (at consent) age was 51.1 (15.0) years and body mass index (BMI) 30.8 (7.8) kg/m 2 ; 77.9% were women and 77.5% were White. Average time in the cohort was 5.9 years prior to and 0.3 years after baseline. The mean interval from first to last meal was 11.5 (2.3) hours. The associations between meal intervals and weight trajectories are shown in the Table . The number of meals per day was positively associated with weight change before baseline, and number of snacks and drinks per day was inversely associated with weight change after baseline. Each additional occasion of snacks and drinks was associated with a 3.20 kg weight decrease (95% CI 1.41 to 4.99). None of the other associations were statistically significant.

Conclusions: Number of daily meals was positively associated with weight change in previous periods, while the number of daily snacks and drinks was inversely associated with weight trajectory. The intervals from first to last meal was not associated with weight change.

Interpersonal Abuse and Long-term Outcomes Following Bariatric Surgery

BACKGROUND

History of abuse may impact weight loss (WL) following bariatric surgery. Some investigations have indicated slower WL rates among patients reporting abuse; however, among studies with multiple assessments, significant differences in WL are not evidenced at later measurement. Few investigations have extended follow-up beyond 18 months, limiting understanding of the impact of abuse on weight trajectory over time. Furthermore, existing research has insufficiently accounted for forms of interpersonal trauma beyond sexual abuse (i.e., emotional, physical) that may impact WL and other health outcomes.

OBJECTIVES

To determine whether post-surgical percent total WL (%TWL) and specific clinical outcomes are differentially impacted by history of interpersonal abuse.

SETTING

Large, comprehensive medical center.

METHODS

Retrospective data was collected from patients who underwent bariatric surgery at a single center (N = 433). Based on pre-surgical interview, patients were grouped according to reported history of interpersonal abuse (Y/N). Nonlinear repeated measures regression examined impact of abuse history on %TWL, and clinical selequae.

RESULTS

Differences in %TWL at 6, 12, 18, 24, and 36 months post-surgically did not differ significantly. Further, %TWL did not differ across time, according to group. A significantly greater number of those with history of interpersonal abuse had a clinical diagnosis of depression as compared with those not reporting interpersonal abuse (38% vs. 22% respectively), p < .001.

CONCLUSIONS

Interpersonal abuse history does not negatively impact %TWL post-surgically but is associated with diagnosis of depression, indicating depressive symptoms may be a viable clinical intervention target for surgery patients with interpersonal trauma history.

Optimizing the dammed: water supply losses and fish habitat gains from dam removal in California

Dams provide water supply, flood protection, and hydropower generation benefits, but also harm native species by altering the natural flow regime and degrading aquatic and riparian habitat. Restoring some rivers reaches to free-flowing conditions may restore substantial environmental benefits, but at some economic cost. This study uses a systems analysis approach to preliminarily evaluate removing rim dams in California's Central Valley to highlight promising habitat and unpromising economic use tradeoffs for water supply and hydropower. CALVIN, an economic-engineering optimization model, is used to evaluate water storage and scarcity from removing dams. A warm and dry climate model for a 30-year period centered at 2085, and a population growth scenario for year 2050 water demands represent future conditions. Tradeoffs between hydropower generation and water scarcity to urban, agricultural, and instream flow requirements were compared with additional river kilometers of habitat accessible to anadromous fish species following dam removal. Results show that existing infrastructure is most beneficial if operated as a system (ignoring many current institutional constraints). Removing all rim dams is not beneficial for California, but a subset of existing dams are potentially promising candidates for removal from an optimized water supply and free-flowing river perspective. Removing individual dams decreases statewide delivered water by 0-2282 million cubic meters and provides access to 0 to 3200 km of salmonid habitat upstream of dams. The method described here can help prioritize dam removal, although more detailed, project-specific studies also are needed. Similarly, improving environmental protection can come at substantially lower economic cost, when evaluated and operated as a system.

The medical and legal risks of the electronic fetal monitor

Electronic fetal heart monitoring (EFM) is the most widely used method of monitoring the fetal heartbeat for possible signs of distress during delivery. Soon after its development in the 1960s, EFM replaced intermittent auscultation as the standard of care in the obstetrical community. However, Margaret Lent argues that the widespread use of EFM is both medically and legally unsound. Lent points to a series of clinical trials that demonstrate that EFM does not reduce fetal mortality, morbidity, or cerebral palsy rates. These studies suggest that EFM has a very high false positive rate, and that EFM usage correlates strongly with a rise in cesarean section rates. Similarly, EFM provides no protection in the courtroom. Though obstetricians believe that they should use EFM because its status as the standard of care will protect them from liability, Lent argues that it may in fact expose them to liability given its failings. Instead, she argues that auscultation is equally, if not more, safe and effective, and is more likely to protect physicians from liability. Lent concludes that obstetricians have an obligation to their patients and to themselves to adopt auscultation as the new standard of care.