Influence of Food Security Status and Diet Quality on Maternal Gestational Weight Gain

BACKGROUND

Recommended gestational weight gain (GWG) is crucial for health of women and their offspring. Food security status is hypothesized to influence diet quality and GWG. Therefore, we examined the relationship between diet quality and GWG by food security status.

METHODS

Participants (n = 679) were enrolled in the Initial Vanguard Study of the National Children's Study. GWG was calculated as third trimester weight minus prepregnancy weight. Food security status and diet quality (Healthy Eating Index [HEI]-2015) were assessed using the Household Food Security Survey and a Diet History Questionnaire, respectively. General linear models evaluated the relationship between GWG and HEI-2015 by food security status.

RESULTS

A greater proportion of women experienced food security (81.3%) compared with food insecurity (18.7%). In women with food security, GWG was negatively associated with HEI-2015 in women having overweight (r = -0.421, P = .003) and positively associated with HEI-2015 in women with inadequate GWG (r = 0.224, P = .019). Conversely, no significant relationships were found between GWG and HEI-2015 in women with food insecurity.

DISCUSSION

Improved diet quality potentially lowers GWG in women with food security. However, in vulnerable populations, including women with food insecurity, improvements in diet quality may not effectively enhance GWG.

Effects of Episodic Food Insecurity on Psychological and Physiological Responses in African American Women With Obesity (RESPONSES): Protocol for a Longitudinal Observational Cohort Study

BACKGROUND

Food insecurity is a risk factor for multiple chronic diseases, including obesity. Importantly, both food insecurity and obesity are more prevalent in African American women than in other groups. Furthermore, food insecurity is considered a cyclic phenomenon, with episodes of food adequacy (ie, enough food to eat) and food shortage (ie, not enough food to eat). More research is needed to better understand why food insecurity is linked to obesity, including acknowledging the episodic nature of food insecurity as a stressor and identifying underlying mechanisms.

OBJECTIVE

The objective of this study is to investigate the episodic nature of food insecurity as a stressor via responses in body weight and psychological and physiological parameters longitudinally and do so in a health-disparate population-African American women.

METHODS

We enrolled 60 African American women (food-insecure cohort: n=30, 50%; food-secure cohort: n=30, 50%) aged 18-65 years with obesity (BMI 30-50 kg/m2) to measure (1) daily body weight remotely over 22 weeks and (2) psychological and physiological parameters via clinic assessments at the beginning and end of the 22-week study. Furthermore, we are assessing episodes of food insecurity, stress, hedonic eating, and appetite on a weekly basis. We hypothesize that food-insecure African American women with obesity will demonstrate increased body weight and changes in psychological and physiological end points, whereas food-secure African American women with obesity will not. We are also examining associations between changes in psychological and physiological parameters and changes in body weight and performing a mediation analysis on the psychological parameters assessed at the study midpoint. Psychological questionnaires are used to assess stress; executive function, decision-making, and motivation; and affect and nonhomeostatic eating. Physiological measurements are used to evaluate the levels of cortisol, dehydroepiandrosterone-sulfate (DHEA-S), C-reactive protein, thyroid hormones, blood glucose, glycated hemoglobin, and insulin, as well as allostatic load.

RESULTS

This study has completed participant recruitment (n=60). At the time of study enrollment, the mean age of the participants was almost 47 (SD 10.8) years, and they had a mean BMI of 39.6 (SD 5.31) kg/m2. All data are anticipated to be collected by the end of 2023.

CONCLUSIONS

We believe that this is the first study to examine changes in body weight and psychological and physiological factors in food-insecure African American women with obesity. This study has significant public health implications because it addresses the cyclic nature of food insecurity to identify underlying mechanisms that can be targeted to mitigate the adverse relationship between food insecurity and obesity and reduce health disparities in minority populations.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05076487; https://clinicaltrials.gov/study/NCT05076487.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/52193.

Impact of the Neighborhood Food Environment on Dietary Intake and Obesity: a Review of the Recent Literature

PURPOSE OF REVIEW

The built environment impacts obesogenic behaviors and in turn body weight outcomes. This review summarizes recent research demonstrating environmental impacts on dietary intake and obesity with a specific focus on the neighborhood food environment.

RECENT FINDINGS

In the previous five years, an abundance of reviews and research studies have been undertaken to elucidate how the neighborhood food environment impacts diet and obesity. This includes studies using primary data collection and secondary data analyses in various populations across the globe. Taken together, current research presents mixed evidence on the impact of the neighborhood food environment on both dietary intake and obesity. While there is some evidence that certain features of the neighborhood food environment influence health behaviors and outcomes in particular populations, it is imperative to acknowledge the complexity of how neighborhood features interact and constantly evolve when considering place-based influences on health behaviors and outcomes.

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.

Exploring barriers to SARS-CoV-2 testing uptake in underserved black communities in Louisiana

OBJECTIVE

To collect qualitative data on approaches that can potentially reduce barriers to, and create strategies for, increasing SARS-CoV-2 testing uptake in underserved Black communities in Louisiana.

METHODS

A series of eight focus groups, including 41 participants, were conducted in primarily Black communities. The Nominal Group Technique (NGT) was used to determine perceptions of COVID-19 as a disease, access to testing, and barriers limiting testing uptake.

RESULTS

Common barriers to SARS-CoV-2 testing were identified as lack of transportation, misinformation/lack of information, lack of time/long wait times, fear of the test being uncomfortable and/or testing positive, the cost of testing, and lack of computer/smartphone/internet. The most impactful approaches identified to increase testing uptake included providing testing within the local communities; testing specifically in heavily traveled areas such as supermarkets, churches, schools, and so forth; providing incentives; engaging local celebrities; and providing information to the community through health fairs, or through churches and schools. The strategies that were deemed to be the easiest to implement revolved around communication about testing, with suggested strategies involving churches, local celebrities or expert leaders, social media, text messages, public service announcements, post cards, or putting up signs in neighborhoods. Providing transportation to testing sites, providing incentives, and bringing the testing to neighborhoods and schools were also identified as easy to implement strategies.

CONCLUSIONS

Several strategies to increase testing uptake were identified in this population. These strategies need to be tested for effectiveness in real-world settings using experimental and observational study designs.

The moderating role of the built environment in prenatal lifestyle interventions

This study examined whether the neighborhood built environment moderated gestational weight gain (GWG) in LIFE-Moms clinical trials. Participants were 790 pregnant women (13.9 weeks' gestation) with overweight or obesity randomized within four clinical centers to standard care or lifestyle intervention to reduce GWG. Geographic information system (GIS) was used to map the neighborhood built environment. The intervention relative to standard care significantly reduced GWG (coefficient = 0.05; p = 0.005) and this effect remained significant (p < 0.03) after adjusting for built environment variables. An interaction was observed for presence of fast food restaurants (coefficient = -0.007; p = 0.003). Post hoc tests based on a median split showed that the intervention relative to standard care reduced GWG in participants living in neighborhoods with lower fast food density 0.08 [95% CI, 0.03,0.12] kg/week (p = 0.001) but not in those living in areas with higher fast food density (0.02 [-0.04, 0.08] kg/week; p = 0.55). Interaction effects suggested less intervention efficacy among women living in neighborhoods with more grocery/convenience stores (coefficient = -0.005; p = 0.0001), more walkability (coefficient -0.012; p = 0.007) and less crime (coefficient = 0.001; p = 0.007), but post-hoc tests were not significant. No intervention x environment interaction effects were observed for total number of eating establishments or tree canopy. Lifestyle interventions during pregnancy were effective across diverse physical environments. Living in environments with easy access to fast food restaurants may limit efficacy of prenatal lifestyle interventions, but future research is needed to replicate these findings.

Food Insecurity and Psychological Distress: a Review of the Recent Literature

PURPOSE OF REVIEW

Food insecurity is the lack of sufficient food in quantity and/or quality. Psychological distress includes mental health issues such as depression and anxiety. This review provides current information on research examining the association between food insecurity and psychological distress.

RECENT FINDINGS

Among studies published in the previous 5 years, food insecurity was significantly and positively associated with multiple indicators of psychological distress. This included cross-sectional and longitudinal studies, as well as primary data collection and secondary data analyses, from countries of varying income levels. Articles also provided evidence within various populations, such as adults of all ages, college students, those living with chronic disease, and parents. Food insecurity and psychological distress are interconnected health issues. Future research should consider a number of important gaps in the literature, with the most important being the development of interventions to improve food insecurity and psychological health concurrently.

Effects of a 2-Year Primary Care Lifestyle Intervention on Cardiometabolic Risk Factors: A Cluster-Randomized Trial

BACKGROUND

Intensive lifestyle interventions (ILIs) are the first-line approach to effectively treat obesity and manage associated cardiometabolic risk factors. Because few people have access to ILIs in academic health centers, primary care must implement similar approaches for a meaningful effect on obesity and cardiometabolic disease prevalence. To date, however, effective lifestyle-based obesity treatment in primary care is limited. We examined the effectiveness of a pragmatic ILI for weight loss delivered in primary care among a racially diverse, low-income population with obesity for improving cardiometabolic risk factors over 24 months.

METHODS

The PROPEL trial (Promoting Successful Weight Loss in Primary Care in Louisiana) randomly allocated 18 clinics equally to usual care or an ILI and subsequently enrolled 803 (351 usual care, 452 ILI) adults (67% Black, 84% female) with obesity from participating clinics. The usual care group continued to receive their normal primary care. The ILI group received a 24-month high-intensity lifestyle-based obesity treatment program, embedded in the clinic setting and delivered by health coaches in weekly sessions initially and monthly sessions in months 7 through 24.

RESULTS

As recently demonstrated, participants receiving the PROPEL ILI lost significantly more weight over 24 months than those receiving usual care (mean difference, -4.51% [95% CI, -5.93 to -3.10]; P<0.01). Fasting glucose decreased more in the ILI group compared with the usual care group at 12 months (mean difference, -7.1 mg/dL [95% CI, -12.0 to -2.1]; P<0.01) but not 24 months (mean difference, -0.8 mg/dL [95% CI, -6.2 to 4.6]; P=0.76). Increases in high-density lipoprotein cholesterol were greater in the ILI than in the usual care group at both time points (mean difference at 24 months, 4.6 mg/dL [95% CI, 2.9-6.3]; P<0.01). Total:high-density lipoprotein cholesterol ratio and metabolic syndrome severity (z score) decreased more in the ILI group than in the usual care group at both time points, with significant mean differences of the change of -0.31 (95% CI, -0.47 to -0.14; P<0.01) and -0.21 (95% CI, -0.36 to -0.06; P=0.01) at 24 months, respectively. Changes in total cholesterol, low-density lipoprotein cholesterol, triglycerides, and blood pressure did not differ significantly between groups at any time point.

CONCLUSIONS

A pragmatic ILI consistent with national guidelines and delivered by trained health coaches in primary care produced clinically relevant improvements in cardiometabolic health in an underserved population over 24 months. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02561221.

Trends in Adiposity and Food Insecurity Among US Adults

Importance

Food insecurity is a pervasive public health issue in the US that is associated with greater body weight.

Objective

To examine national trends in food insecurity among US adults from 1999 to 2016 according to surrogate measures of adiposity (body mass index [BMI] and waist circumference [WC]).

Design, Setting, and Participants

This cross-sectional study analyzed nationally representative data obtained from nine 2-year cycles (1999 to 2000 through 2015 to 2016) of the National Health and Nutrition Examination Survey in the US. The sample comprised adult survey participants aged 20 years or older. Data analyses were performed from July 1, 2019, to March 31, 2020.

Main Outcomes and Measures

The primary outcome was food insecurity. Data on BMI (calculated as weight in kilograms divided by height in meters squared) were categorized as follows: normal weight (BMI, <25), overweight (BMI, 25-29.9), and obese (BMI, ≥30). Data on WC were categorized as follows: less high risk (men: ≤102 cm; women: ≤88 cm) or high risk (men: >102 cm; women: >88 cm). Food insecurity prevalence by adiposity was further analyzed using key demographic characteristics, including sex and race/ethnicity (non-Hispanic White, non-Hispanic Black, Hispanic, and Other).

Results

Among the 46 145 adults in the final sample, the mean (SD) age was 46.9 (0.2) years. Of this sample, 23 957 were women (52.0%; 95% CI, 51.6%-52.5%) and 20 825 were non-Hispanic White adults (68.8%; 95% CI, 66.6%-71.0%). The estimated prevalence of food insecurity was 18.2% (95% CI, 15.3%-21.2%) in the 2015 to 2016 cycle, a statistically significant change from 8.7% (95% CI, 7.3%-10.2%) in the 1999 to 2000 cycle. Among all adiposity categories, food insecurity prevalence significantly increased from the 1999 to 2000 cycle to the 2015 to 2016 cycle. The prevalence of food insecurity was highest in adults with obesity (22.6%; 95% CI, 19.5%-25.8%; P for trend <.001). For both men and women, food insecurity prevalence significantly increased from the 1999 to 2000 cycle (men: 8.8% [95% CI, 6.9%-10.6%]; women: 8.7% [95% CI, 7.0%-10.5%]) to the 2015 to 2016 cycle (men: 17.2% [95% CI, 14.1%-20.2%]; women: 19.2% [95% CI, 16.2%-22.2%]; P for trends <.001). For non-Hispanic White and non-Hispanic Black adults, food insecurity prevalence increased from the 1999 to 2000 cycle (non-Hispanic White: 6.0% [95% CI, 4.0%-8.0%]; non-Hispanic Black: 12.4% [95% CI, 9.6%-15.2%]) to the 2015 to 2016 cycle (non-Hispanic White: 13.0% [95% CI, 9.8%-16.3%]; non-Hispanic Black: 29.1% [95% CI, 24.2%-34.0%]; P for trends <.001). For Hispanic adults, food insecurity prevalence significantly increased in those with obesity (1999-2000: 19.1% [95% CI, 12.0%-26.1%]; 2015-2016: 37.6% [95% CI, 33.7%-41.5%]; P for trend ≤.001) and in both less-high-risk WC (1999-2000: 19.6% [95% CI, 12.8%-26.4%]; 2015-2016: 32.5% [95% CI, 27.3%-37.7%]; P for trend = .02) and high-risk WC categories (1999-2000: 19.3% [95% CI, 12.7%-25.9%]; 2015-2016: 36.7% [95% CI, 31.7%-41.7%]; P for trend <.001).

Conclusions and Relevance

In this cross-sectional study, the estimated prevalence of food insecurity appeared to increase from 1999 to 2016 and across all levels of adiposity. These results suggest the need for multidisciplinary approaches to address the association between food insecurity and obesity in the US.

Adaptations to exercise in compensators and noncompensators in the E-MECHANIC Trial

Rating of perceived exertion (RPE) and respiratory exchange ratio (RER) have previously been associated with acute exercise compensation. This study examined adaptations in the RPE and RER with long-term exercise training in individuals who did (noncompensators) and did not (compensators) lose the expected amount of weight. Participants (n = 110, 71.8% women, means ± SD; age 49 ± 12 yr) completed 24 wk of supervised exercise training at 65-85% V̇o_2peak to achieve a prescribed dose of 8 kcal·kg body wt^-1·wk^-1 (8 KKW) or 20 KKW. Participants were categorized as noncompensators (n = 55) or compensators (n = 55) based on the percent of expected weight loss (%EWL) achieved. Changes in RPE and RER during exercise over time (baseline, week 12, week 24) were compared by weight compensation category. Individual %EWL in relation to RPE, RER, and training intensity (%V̇o_2peak) was evaluated over the same time period. RPE and RER for a given workload decreased from baseline to week 12 and stabilized through week 24, regardless of weight compensation (time P < 0.0001). Noncompensators had a higher RPE relative to heart rate, which was partly explained by higher %V̇o_2peak. RPE and %V̇o_2peak both positively predicted %EWL, independent of age, sex, and exercise dose. Training intensity and RPE were positively associated with weight loss on the individual level, warranting further investigation into self-selection in exercise-based programs. Understanding individual heterogeneity in training intensity and behavioral responses may improve future weight management efforts that involve exercise.NEW & NOTEWORTHY In sedentary individuals with overweight and obesity, achievement of expected weight loss from long-term exercise training was associated with individual adaptations in perceived exertion. Contrary to our hypothesis, those with higher relative perceived exertion achieved a larger proportion of their expected weight loss, which was partly explained by a higher self-selected exercise training intensity.

Food Insecurity and Psychological Distress: a Review of the Recent Literature

PURPOSE OF REVIEW

Food insecurity is the lack of sufficient food in quantity and/or quality. Psychological distress includes mental health issues such as depression and anxiety. This review provides current information on research examining the association between food insecurity and psychological distress.

RECENT FINDINGS

Among studies published in the previous 5 years, food insecurity was significantly and positively associated with multiple indicators of psychological distress. This included cross-sectional and longitudinal studies, as well as primary data collection and secondary data analyses, from countries of varying income levels. Articles also provided evidence within various populations, such as adults of all ages, college students, those living with chronic disease, and parents. Food insecurity and psychological distress are interconnected health issues. Future research should consider a number of important gaps in the literature, with the most important being the development of interventions to improve food insecurity and psychological health concurrently.

Change in self-efficacy, eating behaviors and food cravings during two years of calorie restriction in humans without obesity

Calorie restriction (CR) enhances longevity in humans who are normal weight, overweight and obese. While dietary regimens can change self-efficacy, eating behaviors, and food cravings in individuals with obesity, the responses of these measures to prolonged CR in individuals who are exclusively not obese is unknown. The aim of this analysis was to test the effects of a two-year CR intervention on self-efficacy and eating attitudes and behaviors in humans without obesity by analyzing data from the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy Phase 2 (CALERIE 2) study. Participants (n = 218, BMI range = 21.3-29.0 kg/m2) were randomized to a 25% CR group or an ad libitum (AL) group. Eating attitudes and behaviors and self-efficacy were assessed using validated questionnaires at baseline, month 12, and month 24. Dietary restraint and self-efficacy increased in the CR compared to the AL group (ES ≥ 0.32). Increased self-efficacy was negatively related to weight change (ρ < -0.24). In the CR group, males showed a reduction in cravings for carbohydrates and fats at month 24, whereas females did not. The CR group showed elevations in state hunger, which were transient, and disinhibited eating (ES ≥ 0.37). In individuals without obesity, dietary restraint and self-efficacy could be important in promoting long-term CR for individuals looking to use CR as a tool to improve longevity.

Socioeconomic Position Disparities in Cardiovascular Health Before and After the Examination of Mechanisms of Exercise-Induced Weight Compensation Randomized Controlled Trial

Purpose: We examined socioeconomic position (SEP) disparities in cardiovascular health before and after an exercise intervention. Methods: Data were from the Examination of Mechanisms of Exercise-Induced Weight Compensation (E-MECHANIC) study. Cardiovascular health was measured through a composite score combining body mass index, systolic blood pressure, cholesterol, and glucose. SEP was assessed using a single measure that combined income and education. Results: At baseline, there was no significant difference in cardiovascular health between high and low SEP participants. Post-intervention, this difference reached significance. Conclusion: Although cardiovascular health improved for exercise intervention participants, SEP disparities in cardiovascular health persisted during the trial.

Effect of different doses of supervised exercise on food intake, metabolism, and non-exercise physical activity: The E-MECHANIC randomized controlled trial

BACKGROUND

Exercise is recommended for weight management, yet exercise produces less weight loss than expected, which is called weight compensation. The mechanisms for weight compensation are unclear.

OBJECTIVE

The aim of this study was to identify the mechanisms responsible for compensation.

METHODS

In a randomized controlled trial conducted at an academic research center, adults (n = 198) with overweight or obesity were randomized for 24 wk to a no-exercise control group or 1 of 2 supervised exercise groups: 8 kcal/kg of body weight/wk (KKW) or 20 KKW. Outcome assessment occurred at weeks 0 and 24. Energy intake, activity, and resting metabolic rate (RMR) were measured with doubly labeled water (DLW; with and without adjustments for change in RMR), armband accelerometers, and indirect calorimetry, respectively. Appetite and compensatory health beliefs were measured by self-report.

RESULTS

A per-protocol analysis included 171 participants (72.5% women; mean ± SD baseline body mass index: 31.5 ± 4.7 kg/m2). Significant (P < 0.01) compensation occurred in the 8 KKW (mean: 1.5 kg; 95% CI: 0.9, 2.2 kg) and 20 KKW (mean: 2.7 kg; 95% CI: 2.0, 3.5 kg) groups, and compensation differed significantly between the exercise groups (P = 0.01). Energy intake by adjusted DLW increased significantly (P < 0.05) in the 8 KKW (mean: 90.7 kcal/d; 95% CI: 35.1, 146.4 kcal/d) and 20 KKW (mean: 123.6 kcal/d; 95% CI: 64.5, 182.7 kcal/d) groups compared with control (mean: -2.3 kcal/d; 95% CI: -58.0, 53.5 kcal/d). Results were similar without DLW adjustment. RMR and physical activity (excluding structured exercise) did not differentially change among the 3 groups. Participants with higher compared with lower compensation reported increased appetite ratings and beliefs that healthy behaviors can compensate for unhealthy behaviors. Furthermore, they increased craving for sweet foods, increased sleep disturbance, and had worsening bodily pain.

CONCLUSIONS

Compensation resulted from increased energy intake and concomitant increases in appetite, which can be treated with dietary or pharmacological interventions. Compensation was not due to activity or metabolic changes. This trial was registered at clinicaltrials.gov as NCT01264406.

Racial Variations in Appetite-Related Hormones, Appetite, and Laboratory-Based Energy Intake from the E-MECHANIC Randomized Clinical Trial

African Americans (AAs) have a higher obesity risk than Whites; however, it is unclear if appetite-related hormones and food intake are implicated. We examined differences in appetite-related hormones, appetite, and food intake between AAs (n = 53) and Whites (n = 111) with overweight or obesity. Participants were randomized into a control group or into supervised, controlled exercise groups at 8 kcal/kg of body weight/week (KKW) or 20 KKW. Participants consumed lunch and dinner at baseline and follow-up, with appetite and hormones measured before and after meals (except leptin). At baseline, AAs had lower peptide YY (PYY; p < 0.01) and a blunted elevation in PYY after lunch (p = 0.01), as well as lower ghrelin (p = 0.02) and higher leptin (p < 0.01) compared to Whites. Despite desire to eat being lower and satisfaction being higher in AAs relative to Whites (p ≤ 0.03), no racial differences in food intake were observed. Compared to Whites, leptin increased in the 8 KKW group in AAs (p = 0.01), yet no other race-by-group interactions were evident. Differences in appetite-related hormones between AAs and Whites exist; however, their influence on racial disparities in appetite, food intake, and obesity within this trial was limited.

Cardiovascular Health, Adiposity, and Food Insecurity in an Underserved Population

This study investigated associations between cardiovascular health (CVH), adiposity, and food insecurity by race, sex, and health literacy in a sample of 800 underserved patients with obesity (body mass index [BMI] ≥ 30 kg/m²). CVH was assessed using American Heart Association Life’s Simple 7 (LS7) and adiposity was estimated using BMI and waist circumference (WC). Mixed models including interaction terms between food insecurity and sex, race, and health literacy were analyzed for LS7, BMI, and WC. Stratified models were analyzed as indicated by significant interactions. Mean BMI and WC were 37.3 kg/m² (4.6 SD) and 113.5 cm (12.4 SD), respectively. Among patients, 31% were food insecure and 31% had low health literacy. There were significant positive associations between food insecurity and BMI (p = 0.03) and WC (p = 0.03) in the overall sample. In sex-stratified models, women who were food insecure had higher BMI (p = 0.02) and WC (p = 0.007) than their food secure counterparts. Further, food insecure patients with better health literacy had greater BMI (p = 0.004) and WC (p = 0.007) than their food secure counterparts. Results suggest that adiposity is a greater burden in food insecure patients, which may be an important consideration for obesity treatment in underserved populations.

Food cravings and body weight: a conditioning response

PURPOSE OF REVIEW

To provide current information on interventions that alter food cravings. Specifically, dietary, physical activity, pharmacologic, and bariatric surgery interventions are examined. Lastly, the effects of social determinants and current controversies on food cravings are outlined.

RECENT FINDINGS

Dietary, pharmacologic, and bariatric surgery weight loss interventions decrease food cravings. Physical activity interventions also decrease cravings. There is potential to see differential responses in food cravings in different demographic and socioeconomic groups, but more research is needed.

SUMMARY

Food cravings influence body weight. Food craving reductions are because of reductions in the frequency of consuming craved foods, independent of energy content, but further research is warranted. Most findings continue to support the conditioning model of food cravings.

Subjective social status is associated with compensation for large meals - A prospective pilot study

OBJECTIVES

Subjective social status (SSS) is known to be inversely associated with obesity. Our objective was to determine if SSS is associated with eating behaviors that would predispose to weight gain, specifically, with inadequate compensation for excess energy consumed during a single large meal. Therefore, we conducted a pilot study to determine the association of SSS with 24-h energy balance, 24-h and post-lunch energy intake, changes in body composition and changes in adjusted resting energy expenditure on days when a high-energy lunch was consumed in free-living human subjects.

METHOD

Female participants (7 normal weight and 10 overweight) consumed 60% of' estimated 24-h energy requirements as a lunchtime meal in the laboratory for 14 days. Subjective social status was measured at baseline using the MacArthur Scale. Remote Food Photography Method was used to record food intake outside of the lab on days 1-2, 7-8, and 12-13. Associations of 24-h energy balance, 24-h and post-lunch energy intake, changes in adjusted resting energy expenditure and changes in percent body fat (measured by dual x-ray absorptiometry) with SSS were studied.

RESULTS

Mean (standard deviation) age and BMI were 36.29 (8.25) years and 26.43 (2.32) kg/m², respectively. Lower SSS was significantly associated with positive energy balance (p for trend 0.002), and higher post-lunch energy intake (p = 0.02) when controlled for age and initial body mass index.

CONCLUSIONS

Our pilot data show that lower SSS is associated with higher post-lunch energy intake, which is indicative of poor energy compensation following a large meal. Over a longer time period, this could result in fat mass gain. Studies that are of longer duration and well-powered are warranted to confirm our findings.

Validity of a Digital Diet Estimation Method for Use with Preschool Children

BACKGROUND

The validity of using the Remote Food Photography Method (RFPM) for measuring food intake of minority preschool children's intake is not well documented.

OBJECTIVE

Our aim was to determine the validity of intake estimations made by human raters using the RFPM compared with those obtained by weighing all foods and beverages consumed by 3- to 5-year-old children (weighed method).

DESIGN

We conducted a cross-sectional observational study.

PARTICIPANTS/SETTINGS

A convenience sample of 54 3- to 5-year-old Hispanic and African-American children were observed during a 12-hour period at Baylor Metabolic Research Unit between June 2013 and January 2014.

MAIN OUTCOME MEASURES

All foods/beverages consumed by the children were provided by Baylor research coordinators who took and wirelessly transmitted before-and-after pictures of the trays to trained human raters at the Pennington Biomedical Research Center who estimated grams consumed. Energy and macronutrients were calculated using the Food and Nutrient Database for Dietary Studies or food facts data provided by manufacturers.

STATISTICAL ANALYSES

Paired t test, mean differences, and Bland-Altman limits of agreement were performed.

RESULTS

Compared to the weighed method, the rater method significantly overestimated total intake by 34±71 g (P<0.0001), with a mean percent error of 2.9% (root mean square error=7.1%), and total energy intake by 75±102 kcal (P<0.0001), with a mean percent error of 7.5% (root mean square error=12.3%). The standard error for the macronutrient intakes ranged from 11.0% to 20.2%. The Bland-Altman approach demonstrated a positive slope for the rater method relative to the weighed method for total intake in grams (P=0.006), carbohydrate (P=0.01), and protein (P=0.01) (ie, magnitude of the bias increased with increasing intakes).

CONCLUSIONS

The rater method overestimated total intake in grams and energy in kilocalories in minority preschool children in a well-controlled condition and needs to be further tested in a free-living environment.

Reliability and Validity of a Novel Internet-Based Battery to Assess Mood and Cognitive Function in the Elderly

Dementia is a chronic condition in the elderly and depression is often a concurrent symptom. As populations continue to age, accessible and useful tools to screen for cognitive function and its associated symptoms in elderly populations are needed. The aim of this study was to test the reliability and validity of a new internet-based assessment battery for screening mood and cognitive function in an elderly population. Specifically, the Helping Hand Technology (HHT) assessments for depression (HHT-D) and global cognitive function (HHT-G) were evaluated in a sample of 57 elderly participants (22 male, 35 female) aged 59-85 years. The study sample was categorized into three groups: 1) dementia (n = 8; Mini-Mental State Exam (MMSE) score 10-24), 2) mild cognitive impairment (n = 24; MMSE score 25-28), and 3) control (n = 25; MMSE score 29-30). Test-retest reliability (Pearson correlation coefficient, r) and internal consistency reliability (Cronbach's alpha, α) of the HHT-D and HHT-G were assessed. Validity of the HHT-D and HHT-G was tested via comparison (Pearson r) to commonly used pencil-and-paper based assessments: HHT-D versus the Geriatric Depression Scale (GDS) and HHT-G versus the MMSE. Good test-retest (r = 0.80; p < 0.0001) and acceptable internal consistency reliability (α= 0.73) of the HHT-D were established. Moderate support for the validity of the HHT-D was obtained (r = 0.60 between the HHT-D and GDS; p < 0.0001). Results indicated good test-retest (r = 0.87; p < 0.0001) and acceptable internal consistency reliability (α= 0.70) of the HHT-G. Validity of the HHT-G was supported (r = 0.71 between the HHT-G and MMSE; p < 0.0001). In summary, the HHT-D and HHT-G were found to be reliable and valid computerized assessments to screen for depression and cognitive status, respectively, in an elderly sample.

Validity of the Remote Food Photography Method Against Doubly Labeled Water Among Minority Preschoolers

OBJECTIVE

The aim of this study was to determine the validity of energy intake (EI) estimations made using the remote food photography method (RFPM) compared to the doubly labeled water (DLW) method in minority preschool children in a free-living environment.

METHODS

Seven days of food intake and spot urine samples excluding first void collections for DLW analysis were obtained on thirty-nine 3- to 5-year-old Hispanic and African American children. Using an iPhone, caregivers captured before and after pictures of each child's intake, pictures were wirelessly transmitted to trained raters who estimated portion size using existing visual estimation procedures, and energy and macronutrients were calculated. Paired t tests, mean differences, and Bland-Altman limits of agreement were performed.

RESULTS

The mean EI was 1,191 ± 256 kcal/d using the RFPM and 1,412 ± 220 kcal/d using the DLW method, resulting in a mean underestimate of 222 kcal/d (-15.6%; P < 0.0001) that was consistent regardless of intake. The RFPM underestimated EI by -28.5% in 34 children and overestimated EI by 15.6% in 5 children.

CONCLUSIONS

The RFPM underestimated total EI when compared to the DLW method among preschoolers. Further refinement of the RFPM is needed for assessing the EI of young children.

Frequency of Consuming Foods Predicts Changes in Cravings for Those Foods During Weight Loss: The POUNDS Lost Study

OBJECTIVE

Food cravings are thought to be the result of conditioning or pairing hunger with consumption of certain foods.

METHODS

In a 2-year weight loss trial, subjects were randomized to one of four diets that varied in macronutrient content. The Food Craving Inventory (FCI) was used to measure cravings at baseline and at 6 and 24 months. Food intake was also measured at those time points. To measure free-living consumption of food items measured in the FCI, items on the FCI were matched to the foods consumed from the food intake assessments. Secondarily, the amount of food consumed on food intake assessments from foods on the FCI was analyzed.

RESULTS

Three hundred and sixty-seven subjects with overweight and obesity were included. There was an association between change from baseline FCI item consumption and change in cravings at months 6 (P < 0.001) and 24 (P < 0.05). There was no association between change from baseline amount of energy consumed per FCI item and change in cravings.

CONCLUSIONS

Altering frequency of consuming craved foods is positively associated with cravings; however, changing the amount of foods consumed does not appear to alter cravings. These results support the conditioning model of food cravings and provide guidance on how to reduce food cravings.

Personalized Mobile Health Intervention for Health and Weight Loss in Postpartum Women Receiving Women, Infants, and Children Benefit: A Randomized Controlled Pilot Study

BACKGROUND

Prepregnancy maternal obesity and excessive weight gain during pregnancy lead to significant morbidities in mothers and their children. Mothers who never return to their prepregnancy weight begin subsequent pregnancies at a greater weight and have a larger propensity for excess gestational weight gain and postpartum weight retention.

METHODS

In this pilot study, 40 postpartum women credentialed to receive postpartum women, infants, and children (WIC) service were randomized to usual care ("WIC Moms") or a personalized health intervention delivered via a SmartPhone ("E-Moms"). Assessments, including body weight, vital signs, circumferences, and body composition, were completed at week 0 (6-8 weeks postpartum), week 8, and week 16.

RESULTS

Results are presented as change from week 0 at 16. As per the completers analysis, body weight change was not different between the groups (WIC Moms vs. E-Moms; 1.8 ± 0.9 vs. -0.1 ± 0.9 kg; p = 0.10), neither was the change in percent body fat (1.7 ± 0.6 vs. 0.1% ± 0.6%; p = 0.90) or waist/hip ratio (-0.01 ± 0.01 vs. -0.02 ± 0.01 cm; p = 0.60). However, due to notable variability in intervention adherence as the study progressed, participants were classified post hoc as having low (<40% adherence), medium (40%-70% adherence), or high adherence (>70% adherence). Participants with high intervention adherence (n = 5) had a significant reduction in body weight (-3.6 ± 1.6 vs. 1.8 ± 0.9 kg; p = 0.005) and percent body fat (-2.5 ± 1.0 vs. 1.7% ± 0.6%; p = 0.001) when compared to WIC Moms.

CONCLUSIONS

Overall, the E-Moms intervention was not able to decrease postpartum weight retention in women receiving WIC benefits compared to usual care received through the current WIC program. However, there is some evidence to suggest improved adherence to the intervention would improve weight management.

Diabetes prevalence is associated with different community factors in the diabetes belt versus the rest of the United States

OBJECTIVE

To investigate differences in community characteristics associated with diabetes prevalence between the Diabetes Belt and the rest of the contiguous United States (U.S.) METHODS: County-level adult diabetes prevalence estimates (i.e., percent of people [≥20 years] with diagnosed diabetes 2009) were used from the Centers for Disease Control and Prevention, in addition to data from the U.S. Census Bureau, U.S. Department of Agriculture, and U.S. Department of Health and Human Services, to carry out a spatial regime analysis to identify county-level factors correlated with diabetes prevalence in the Diabetes Belt versus the remainder of the U.S.

RESULTS

Counties outside of the Diabetes Belt demonstrated stronger positive associations between diabetes prevalence and persistent poverty and greater percentages of unemployed labor forces. For counties in the Diabetes Belt, diabetes prevalence showed a stronger positive association with natural amenities (e.g., temperate climate and topographic features) and a stronger negative association with fitness/recreation facility density.

CONCLUSIONS

Community-level correlates of diabetes prevalence differed between the Diabetes Belt and elsewhere in the U.S. Economic hardship was shown to be more relevant outside the Diabetes Belt, while recreational context effects were more pronounced among counties within the region. Prevention and treatment targets are geographically unique, and public health efforts should acknowledge these differences in crafting policy.

The context of context: Examining the associations between healthy and unhealthy measures of neighborhood food, physical activity, and social environments

Multilevel health research often focuses on a singular dimension of the neighborhood environment in relation to individual-level health behaviors (e.g., diet, physical activity) and outcomes (e.g., obesity). This study examined associations between healthy and unhealthy neighborhood features across food, physical activity, and social environments. We used neighborhood-level (i.e., census block group) access (0/1) measures of the 1) food (grocery store, convenience store, fast food restaurant), 2) physical activity (fitness/recreation facility, park), and 3) social (crime, renter occupancy) environments to capture both healthy and unhealthy neighborhood features for a sample of neighborhoods (n=126) in East Baton Rouge Parish, Louisiana, United States. We employed a) bivariate correlations, or spatial regression where necessary, to identify significant associations between neighborhood access measures; and b) two-step cluster analysis to identify neighborhood typologies based upon neighborhood access measures. Results demonstrated multiple significant associations between healthy and unhealthy access measures across the three neighborhood environments. Cluster analysis further confirmed that neighborhoods are not completely healthy or unhealthy, but rather can be characterized by neighborhood features that are both health-promoting and health-constraining. This study elucidates a 'context of context' whereby no singular aspect of a neighborhood completely explains health in individuals. Rather, in order to effectively model the association between neighborhood and individual-level health, it may be necessary to account for the inter-related nature of neighborhood features.

INFLUENCE OF THE CIVIC COMMUNITY RELIGIOUS ENVIRONMENT ON FAMILY POVERTY: A MULTILEVEL ANALYSIS

This study integrates research in the civic community tradition and structuralist and individualist perspectives on poverty to assess the relationship between religious-based civic community structures and family poverty in the United States. Using multilevel analyses of 2006-2008 American Community Survey, 2000 Census of Population and Housing, and 2000 Religious Congregations and Membership Survey data, results demonstrate that the presence of Mainline Protestant and Catholics adherents within communities - measured as the percentage of a community's population comprised of Mainline Protestant and Catholic adherents - is significantly and negatively associated with family poverty risks, net of other family and community factors. That is, in communities with a greater presence of Mainline Protestants and Catholics, there were also lower risks of families being in poverty. These findings suggest the importance of the ecology of religion within communities in understanding poverty outcomes for families.

The Influence of Neighborhood Crime on Increases in Physical Activity during a Pilot Physical Activity Intervention in Children

The purpose of this study was to examine whether neighborhood crime moderated the response (increases in steps) to a pilot intervention to increase physical activity in children. Twenty-seven insufficiently active children aged 6-10 years (mean age = 8.7 years; 56 % female; 59 % African American) were randomly assigned to an intensive intervention group (IIG) or minimal intervention group (MIG). Change in average daily number of steps from baseline was regressed against an index of neighborhood crime in a multilevel repeated-measures model that included a propensity score to reduce confounding. Safer neighborhoods were associated with higher increases in steps during the pilot intervention (interaction p = 0.008). Children in the IIG living in low-crime neighborhoods significantly increased their physical activity (5275 ± 1040 steps/day) while those living in high-crime neighborhoods did not (1118 ± 1007) (p for difference = 0.046). In the IIG, the increase in daily steps was highly correlated with neighborhood crime (r = 0.58, p = 0.04). These findings suggest the need for physical activity interventions to account for participants' environments in their design and/or delivery. To promote healthy behaviors in less-supportive environments, future studies should seek to understand how environments modify intervention response and to identify mediators of the relationship between environment and intervention.

Smartloss: A Personalized Mobile Health Intervention for Weight Management and Health Promotion

Background

Synonymous with increased use of mobile phones has been the development of mobile health (mHealth) technology for improving health, including weight management. Behavior change theory (eg, the theory of planned behavior) can be effectively encapsulated into mobile phone-based health improvement programs, which is fostered by the ability of mobile phones and related devices to collect and transmit objective data in near real time and for health care or research professionals and clients to communicate easily.

Objective

To describe SmartLoss, a semiautomated mHealth platform for weight loss.

Methods

We developed and validated a dynamic energy balance model that determines the amount of weight an individual will lose over time if they are adherent to an energy intake prescription. This model was incorporated into computer code that enables adherence to a prescribed caloric prescription determined from the change in body weight of the individual. Data from the individual are then used to guide personalized recommendations regarding weight loss and behavior change via a semiautomated mHealth platform called SmartLoss, which consists of 2 elements: (1) a clinician dashboard and (2) a mobile phone app. SmartLoss includes and interfaces with a network-connected bathroom scale and a Bluetooth-connected accelerometer, which enables automated collection of client information (eg, body weight change and physical activity patterns), as well as the systematic delivery of preplanned health materials and automated feedback that is based on client data and is designed to foster prolonged adherence with body weight, diet, and exercise goals. The clinician dashboard allows for efficient remote monitoring of all clients simultaneously, which may further increase adherence, personalization of treatment, treatment fidelity, and efficacy.

Results

Evidence of the efficacy of the SmartLoss approach has been reported previously. The present report provides a thorough description of the SmartLoss Virtual Weight Management Suite, a professionally programmed platform that facilitates treatment fidelity and the ability to customize interventions and disseminate them widely.

Conclusions

SmartLoss functions as a virtual weight management clinic that relies upon empirical weight loss research and behavioral theory to promote behavior change and weight loss.

Change in Obesity Prevalence across the United States Is Influenced by Recreational and Healthcare Contexts, Food Environments, and Hispanic Populations

OBJECTIVE

To examine change in county-level adult obesity prevalence between 2004 and 2009 and identify associated community characteristics.

METHODS

Change in county-level adult (≥20 years) obesity prevalence was calculated for a 5-year period (2004-2009). Community measures of economic, healthcare, recreational, food environment, population structure, and education contexts were also calculated. Regression analysis was used to assess community characteristics associated (p<0.01) with change in adult obesity prevalence.

RESULTS

Mean±SD change in obesity prevalence was 5.1±2.4%. Obesity prevalence decreased in 1.4% (n = 44) and increased in 98% (n = 3,060) of counties from 2004-2009. Results showed that both baseline levels and increases in physically inactive adults were associated with greater increases in obesity prevalence, while baseline levels of and increases in physician density and grocery store/supercenter density were related to smaller increases in obesity rates. Baseline levels of the Hispanic population share were negatively linked to changing obesity levels, while places with greater Hispanic population growth saw greater increases in obesity.

CONCLUSIONS

Most counties in the U.S. experienced increases in adult obesity prevalence from 2004 to 2009. Findings suggest that community-based interventions targeting adult obesity need to incorporate a range of community factors, such as levels of physical inactivity, access to physicians, availability of food outlets, and ethnic/racial population composition.

Regional disparities in obesity prevalence in the United States: A spatial regime analysis

OBJECTIVE

Significant clusters of high- and low-obesity counties have been demonstrated across the United States (US). This study examined regional disparities in obesity prevalence and differences in the related structural characteristics across regions of the US.

METHODS

Drawing on model-based estimates from the Centers for Disease Control and Prevention, regional differences in county-level adult obesity prevalence (percent of the adult population [≥ 20 years] that was obese [BMI ≥ 30 kg/m(2) ] within a county, 2009) were assessed with a LISA (Local Indicators of Spatial Association) analysis to identify geographic concentrations of high and low obesity levels. Regional regime analysis was utilized to identify factors that were differentially associated with obesity prevalence between regions of the US.

RESULTS

High- and low-obesity county clusters and the effect of a number of county-level characteristics on obesity prevalence differed significantly by region. These included the positive effect of African American populations in the South, the negative effect of Hispanic populations in the Northeast, and the positive effect of unemployed workers in the Midwest and West.

CONCLUSIONS

Our findings suggest the need for public health policies and interventions that account for different regional characteristics underlying obesity prevalence variation across the US.

Examination of mechanisms (E-MECHANIC) of exercise-induced weight compensation: study protocol for a randomized controlled trial

BACKGROUND

Weight loss induced only by exercise is frequently less than expected, possibly because of compensatory changes in energy intake and/or energy expenditure. The purpose of the Examination of Mechanisms (E-MECHANIC) of Exercise-Induced Weight Compensation trial is to examine whether increased energy intake and/or reduced spontaneous activity or energy expenditure (outside of structured exercise) account for the less than expected, exercise-associated weight loss.

METHODS/DESIGN

E-MECHANIC is a three-arm, 6-month randomized (1:1:1) controlled trial. The two intervention arms are exercise doses that reflect current recommendations for (1) general health (8 kcal/kg body weight per week (8 KKW), about 900 kcal/wk) and (2) weight loss (20 KKW, about 2,250 kcal/wk). The third arm, a nonexercise control group, will receive health information only. The sample will include a combined total of 198sedentary, overweight or obese (body mass index: ≥25 kg/m² to ≤45 kg/m²) men and women ages 18 to 65 years. The exercise dose will be supervised and tightly controlled in an exercise training laboratory. The primary outcome variables are energy intake, which will be measured using doubly labeled water (adjusted for change in energy stores) and laboratory-based food intake tests, and the discrepancy between expected weight loss and observed weight loss. Secondary outcomes include changes in resting metabolic rate (adjusted for change in body mass), activity levels (excluding structured exercise) and body composition. In an effort to guide the development of future interventions, the participants will be behaviorally phenotyped and defined as those who do compensate (that is, fail to lose the amount of weight expected) or do not compensate (that is, lose the amount of weight expected or more).

DISCUSSION

In this study, we will attempt to identify underlying mechanisms to explain why exercise elicits less weight loss than expected. This information will guide the development of interventions to increase exercise-induced weight loss and maximize weight loss retention and related health benefits.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT01264406 (registration date: 20 December 2010).

The geographic concentration of US adult obesity prevalence and associated social, economic, and environmental factors

OBJECTIVE

This study used spatial statistical methods to test the hypotheses that county-level adult obesity prevalence in the United States is (1) regionally concentrated at significant levels, and (2) linked to local-level factors, after controlling for state-level effects.

METHODS

Data were obtained from the Centers for Disease Control and Prevention and other secondary sources. The units of analysis were counties. The dependent variable was the age-adjusted percentage of adults who were obese in 2009 (body mass index >30 kg/m2).

RESULTS

The prevalence of county-level obesity varied from 13.5% to 47.9% with a mean of 30.3%. Obesity prevalence across counties was not spatially random: 15.8% belonged to high-obesity regions and 13.5% belonged to low-obesity regions. Obesity was positively associated with unemployment, outpatient healthcare visits, physical inactivity, female-headed families, black populations, and less education. Obesity was negatively correlated with physician numbers, natural amenities, percent ≥65 years, Hispanic populations, and larger population size. A number of variables were notable for not reaching significance after controlling for other factors, including poverty and food environment measures.

CONCLUSIONS

The findings demonstrate the importance of local-level factors in explaining geographic variation in obesity prevalence, and thus hold implications for geographically targeted interventions to combat the obesity epidemic.

Understanding the geography of food stamp program participation: Do space and place matter?

This study examines the extent to which geographic variation in Food Stamp Program (FSP) participation is explained by place-based factors, with special attention to the case of the three poorest regions of the United States: Central Appalachia, the Texas Borderland, and the Lower Mississippi Delta. We use descriptive statistics and regression models to assess the prevalence and correlates of county-level FSP participation circa 2005. Our findings show that the economic distress that has long characterized Appalachia, the Borderland, and the Delta clearly translates into greater reliance on the FSP relative to other areas of the country. State-level effects and local-level variations in poverty, labor market conditions, population structure, human capital, and residential context explain much of this reality. Yet, even after taking all of these factors into account, these regional geographies remain home to particularly high FSP participation. Our findings underscore the importance of considering these regions as key cases of study in the stratification of American society and hold a variety of implications for public policy.

Interaction of the Neurospora crassa mitochondrial tyrosyl-tRNA synthetase (CYT-18 protein) with the group I intron P4-P6 domain. Thermodynamic analysis and the role of metal ions

The Neurospora crassa mitochondrial tyrosyl-tRNA synthetase (CYT-18 protein) functions in splicing group I introns by promoting the formation of the catalytically active structure of the intron's catalytic core. Previous studies suggested a model in which the protein binds first to the intron's P4-P6 domain, and then makes additional contacts with the P3-P9 domain to stabilize the two domains in the correct relative orientation to form the intron's active site. Here, we analyzed the interaction of CYT-18 with a small RNA (P4-P6 RNA) corresponding to the isolated P4-P6 domain of the N. crassa mitochondrial large subunit ribosomal RNA intron. RNA footprinting and modification-interference experiments showed that CYT-18 binds to this small RNA around the junction of the P4-P6 stacked helices on the side opposite the active-site cleft, as it does to the P4-P6 domain in the intact intron. The binding is inhibited by chemical modifications that disrupt base-pairing in P4, P6, and P6a, indicating that a partially folded structure of the P4-P6 domain is required. The temperature-dependence of binding indicates that the interaction is driven by a favorable enthalpy change, but is accompanied by an unfavorable entropy change. The latter may reflect entropically unfavorable conformational changes or decreased conformational flexibility in the complex. CYT-18 binding is inhibited at > or =125 mM KCl, indicating a strong dependence on phosphodiester-backbone interactions. On the other hand, Mg(2+) is absolutely required for CYT-18 binding, with titration experiments showing approximately 1.5 magnesium ions bound per complex. Metal ion-cleavage experiments identified a divalent cation-binding site near the boundary of P6 and J6/6a, and chemical modification showed that Mg(2+) binding induces RNA conformational changes in this region, as well as elsewhere, particularly in J4/5. Together, these findings suggest a model in which the binding of Mg(2+) near J6/6a and possibly at one additional location in the P4-P6 RNA induces formation of a specific phosphodiester-backbone geometry that is required for CYT-18 binding. The binding of CYT-18 may then establish the correct structure at the junction of the P4/P6 stacked helices for assembly of the P3-P9 domain. The interaction of CYT-18 with the P4-P6 domain appears similar to the TyrRS interaction with the D-/anticodon arm stacked helices of tRNA(Tyr).

Characterization of BCE-1, a transcriptional enhancer regulated by prolactin and extracellular matrix and modulated by the state of histone acetylation

We have previously described a 160-bp enhancer (BCE-1) in the bovine beta-casein gene that is activated in the presence of prolactin and extracellular matrix (ECM). Here we report the characterization of the enhancer by deletion and site-directed mutagenesis, electrophoretic mobility shift analysis, and in vivo footprinting. Two essential regions were identified by analysis of mutant constructions: one binds C/EBP-beta and the other binds MGF/STAT5 and an as-yet-unidentified binding protein. However, no qualitative or quantitative differences in the binding of these proteins were observed in electrophoretic mobility shift analysis using nuclear extracts derived from cells cultured in the presence or absence of ECM with or without prolactin, indicating that prolactin- and ECM-induced transcription was not dependent on the availability of these factors in the functional cell lines employed. An in vivo footprinting analysis of the factors bound to nuclear chromatin in the presence or absence of ECM and/or prolactin found no differences in the binding of C/EBP-beta but did not provide definitive results for the other factors. Neither ECM nor prolactin activated BCE-1 in transient transfections, suggesting that the chromosomal structure of the integrated template may be required for ECM-induced transcription. Further evidence is that treatment of cells with inhibitors of histone deacetylase was sufficient to induce transcription of integrated BCE-1 in the absence of ECM. Together, these results suggest that the ECM induces a complex interaction between the enhancer-bound transcription factors, the basal transcriptional machinery, and a chromosomally integrated template responsive to the acetylation state of the histones.

A tyrosyl-tRNA synthetase suppresses structural defects in the two major helical domains of the group I intron catalytic core

The Neurospora crassa mitochondrial tyrosyl-tRNA synthetase, the CYT-18 protein, functions in splicing group I introns by promoting the formation of the catalytically active structure of the intron RNA. The group I intron catalytic core is thought to consist of two extended helical domains, one formed by coaxial stacking of P5, P4, P6, and P6a (P4-P6 domain) and the other consisting of P8, P3, P7, and P9 (P3-P9 domain). To investigate how CYT-18 stabilizes the active RNA structure, we used an Escherichia coli genetic assay based on the phage T4 td intron to systematically test the ability of CYT-18 to compensate for structural defects in three key regions of the catalytic core: J3/4 and J6/7, connecting regions that form parts of the triple-helical-scaffold structure with the P4-P6 domain, and P7, a long-range base-pairing interaction that forms the guanosine-binding site and is part of the P3-P9 domain. Our results show that CYT-18 can suppress numerous mutations that disrupt the J3/4 and J6/7 nucleotide-triple interactions, as well as mutations that disrupt base-pairing in P7. CYT-18 suppressed mutations of phylogenetically conserved nucleotide residues at all positions tested, except for the universally conserved G-residue at the guanosine-binding site. Structure mapping experiments with selected mutant introns showed that the CYT-18-suppressible J3/4 mutations primarily impaired folding of the P4-P6 domain, while the J6/7 mutations impaired folding of both the P4-P6 and P3-P9 domains to various degrees. The P7 mutations impaired the formation of both P7 and P3, thereby grossly disrupting the P3-P9 domain. The finding that the P7 mutations also impaired formation of P3 provides evidence that the formation of these two long-range pairings is interdependent in the td intron. Considered together with previous work, the nature of mutations suppressed by CYT-18 supports a model in which CYT-18 helps assemble the P4-P6 domain and then stabilizes the two major helical domains of the catalytic core in the correct relative orientation to form the intron's active site.

Patterns of communication about AIDS among Hispanic and Anglo adolescents

This study examined exposure to AIDS information from mass media and interpersonal communication among a nonprobability sample of Hispanic and Anglo lower middle-class adolescents. Subjects were drawn predominantly from community health clinics, word of mouth recruiting, public service announcements, churches, schools, and health fairs in San Diego County. Both Hispanic (n = 220) and Anglo (n = 159) youths reported substantial exposure to information about AIDS from both mass media and interpersonal communication. Hispanics watched more general television than Anglos, but had less exposure to newspapers and interpersonal communication with friends. Communication among friends was most consistently related to sociodemographic variables, with older, higher status persons and girls communicating to the greatest extent. Boys reported the greatest communication with family. Anglo youths had greater exposure to information about AIDS and condoms regardless of the medium of communication, while Hispanic adolescents had greater exposure to information on risks of IV drug use. Of the three main types of mass media, print and radio provided the most exposure to AIDS information. It is important for preventive medicine practitioners to exploit these differences in communication patterns when planning preventive intervention strategies that target specific adolescent populations.

Tenascin-C inhibits extracellular matrix-dependent gene expression in mammary epithelial cells. Localization of active regions using recombinant tenascin fragments

The physiological role of tenascin in vivo has remained obscure. Although tenascin is regulated in a stage and tissue-dependent manner, knock-out mice appear normal. When tenascin expression was examined in the normal adult mouse mammary gland, little or none was present during lactation, when epithelial cells actively synthesize and secrete milk proteins in an extracellular matrix/lactogenic hormone-dependent manner. In contrast, tenascin was prominently expressed during involution, a stage characterized by the degradation of the extracellular matrix and the subsequent loss of milk production. Studies with mammary cell lines indicated that tenascin expression was high on plastic, but was suppressed in the presence of the laminin-rich, Engelbreth-Holm-Swarm (EHS) tumour biomatrix. When exogenous tenascin was added together with EHS to mammary epithelial cells, beta-casein protein synthesis and steady-state mRNA levels were inhibited in a concentration-dependent manner. Moreover, this inhibition by tenascin could be segregated from its effects on cell morphology. Using two beta-casein promoter constructs attached to the chloramphenicol acetyltransferase reporter gene we showed that tenascin selectively suppressed extracellular matrix/prolactin-dependent transcription of the beta-casein gene in three-dimensional cultures. Finally, we mapped the active regions within the fibronectin type III repeat region of the tenascin molecule that are capable of inhibiting beta-casein protein synthesis. Our data are consistent with a model where both the loss of a laminin-rich basement membrane by extracellular matrix-degrading enzymes and the induction of tenascin contribute to the loss of tissue-specific gene expression and thus the involuting process.

A novel transcriptional enhancer is involved in the prolactin- and extracellular matrix-dependent regulation of beta-casein gene expression

Lactogenic hormones and extracellular matrix (ECM) act synergistically to regulate beta-casein expression in culture. We have developed a functional subpopulation of the mouse mammary epithelial cell strain COMMA-1D (designated CID 9), which expresses high level of beta-casein, forms alveolar-like structures when plated onto the EHS tumor-derived matrix, and secretes beta-casein unidirectionally into a lumen. We have further shown that ECM- and prolactin-dependent regulations of beta-casein occur mainly at the transcriptional level and that 5' sequences play an important role in these regulations. To address the question of the nature of the DNA sequence requirements for such regulation, we analyzed the bovine beta-casein gene promoter in these cells. We now have located a 160-bp transcriptional enhancer (BCE1) within the 5' flanking region of the beta-casein gene. Using functional assays, we show that BCE1 contains responsive elements for prolactin- and ECM-dependent regulation. BCE1 placed upstream of a truncated and inactive beta-casein promoter (the shortest extending from -89 to +42 bp with regard to the transcription start site) reconstitutes a promoter even more potent than the intact promoter, which contains BCE1 in its normal context more than 1.5 kb upstream. This small fusion promoter also reconstitutes the normal pattern of regulation, including a requirement for both prolactin and ECM and a synergistic action of prolactin and hydrocortisone. By replacing the milk promoter with a heterologous viral promoter, we show that BCE1 participates in the prolactin- and ECM-mediated regulation.

Gene transfer in primary cultures of human hepatocytes

Using liposomes as the mediator of DNA transfer, we were successful in the transfection of human hepatocytes isolated from surgical samples with an E. coli beta-galactosidase gene (beta-gal). A comparison of transfection efficiency showed that of the four promoters used, cytomegalovirus (CMV) promoter yielded higher transfection efficiencies than Rous sarcoma virus (RSV), Simian virus-40 (SV-40) and human alpha-1 antitrypsin (AAT) promoters. These studies represent the first report on the successful transfection of primary cultures of human hepatocytes.

Paradoxical effects of blood alcohol concentration charts

BACKGROUND

This study was designed to determine the association between alcohol drinking and the possession of blood alcohol concentration charts.

METHOD

A total of 30 college-age subjects participated in the study. Subjects were randomly assigned to either an experimental or a control group. All subjects answered a short entrance questionnaire to determine their height and weight. Those assigned to the experimental group were supplied a copy of a blood alcohol concentration chart and instructed in its use. The volume of alcoholic beverages consumed was surreptitiously counted for all subjects. Prior to leaving the premises the subjects completed an exit questionnaire which asked them to estimate the amount of alcohol they had consumed, whether they had driven to the pub, and whether they intended to drive away. The time spent in the pub was noted for each subject.

RESULTS

Among those in the control group there was a tendency to overestimate the volume consumed, and for those in the experimental group, a tendency to more accurately estimate their consumption. Those given blood alcohol concentration charts consumed alcohol at a significantly higher rate than did those in the control group.

CONCLUSION

A likely explanation for this outcome is that the chart served as a stimulus to prompt a drinker to more quickly achieve a blood alcohol level consistent with his/her drinking expectancies.

Extracellular matrix and hormones transcriptionally regulate bovine beta-casein 5' sequences in stably transfected mouse mammary cells

Milk protein regulation involves synergistic action of lactogenic hormones and extracellular matrix (ECM). It is well established that substratum has a dramatic effect on morphology and function of mammary cells. The molecular mechanisms that regulate the ECM- and hormone-dependent gene expression, however, have not been resolved. To address this question, a subpopulation (designated CID 9) of the mouse mammary epithelial cell strain COMMA-1D has been developed in which more than 35% of the cells express beta-casein, form alveoli-like structures when plated onto a reconstituted basement membrane, and secrete beta-casein unidirectionally into a lumen. These cells were stably transfected with a series of chloramphenicol acetyltransferase (CAT) fusion genes to study transcriptional regulation of the bovine beta-casein gene. The expression of CAT in these lines demonstrated a striking matrix and hormone dependency (greater than 150-fold induction in some cases). This regulation occurred primarily at the transcriptional level and was dependent on the length of the 5' flanking region of the beta-casein promotor. Both matrix and hormonal control of transcription occurred within at least the first 1790 base pairs upstream and/or 42 base pairs downstream of the transcriptional initiation site. The ECM effect was independent of glucocorticoid stimulation. However, prolactin was essential and hydrocortisone further increased CAT expression. Endogenous beta-casein expression in these lines was similar to that of the parent CID 9 cells. Our data indicate the existence of matrix-dependent elements that regulate transcription.

Determination of peak trabecular bone density: interplay of dietary fiber, carbohydrate, and androgens

To elucidate mechanisms linking nutrition and sex hormones to magnitude of peak trabecular bone density, we studied 11 normal women aged 19-21 y. Trabecular bone density was related inversely to dietary fiber (r = -0.69, p = 0.02) and carbohydrate (r = -0.70, p = 0.02) and directly to serum free-and-albumin-bound testosterone (fab T) (r = -0.70, p = 0.02) and total testosterone (total T) (r = 0.66, p = 0.03). Dietary fiber was correlated negatively with fab T (r = -0.74, p = 0.009), total T (r = -0.70, p = 0.02), and androstenedione (Adione) (r = -0.72, p = 0.01). Controlling for the effect of fab T or Adione weakened the relationship between dietary fiber and bone density and the relationship was no longer statistically significant. Conversely, controlling for sex hormones did not abolish the effect of carbohydrate on bone density. The contributions of fab T and carbohydrate to bone density were independent. These results suggest that dietary fiber may depress serum androgens which in turn decrease trabecular bone density. Carbohydrate may also depress bone density but independently of sex steroid hormones.