Impact of remission from type 2 diabetes on long-term health outcomes: findings from the Look AHEAD study

AIMS/HYPOTHESIS

We examined the association of attainment of diabetes remission in the context of a 12 year intensive lifestyle intervention with subsequent incidence of chronic kidney disease (CKD) and CVD.

METHODS

The Look AHEAD study was a multi-centre RCT comparing the effect of a 12 year intensive lifestyle intervention with that of diabetes support and education on CVD and other long-term health conditions. We compared the incidence of CVD and CKD among 4402 and 4132 participants, respectively, based on achievement and duration of diabetes remission. Participants were 58% female, and had a mean age of 59 years, a duration of diabetes of 6 year and BMI of 35.8 kg/m2. We applied an epidemiological definition of remission: taking no diabetes medications and having HbA1c <48 mmol/mol (6.5%) at a single point in time. We defined high-risk or very high-risk CKD based on the Kidney Disease Improving Global Outcomes (KDIGO) criteria, and CVD incidence as any occurrence of non-fatal acute myocardial infarction, stroke, admission for angina or CVD death.

RESULTS

Participants with evidence of any remission during follow-up had a 33% lower rate of CKD (HR 0.67; 95% CI 0.52, 0.87) and a 40% lower rate of the composite CVD measure (HR 0.60; 95% CI 0.47, 0.79) in multivariate analyses adjusting for HbA1c, BP, lipid levels, CVD history, diabetes duration and intervention arm, compared with participants without remission. The magnitude of risk reduction was greatest for participants with evidence of longer-term remission.

CONCLUSIONS/INTERPRETATION

Participants with type 2 diabetes with evidence of remission had a substantially lower incidence of CKD and CVD, respectively, compared with participants who did not achieve remission. This association may be affected by post-baseline improvements in weight, fitness, HbA1c and LDL-cholesterol.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00017953 DATA AVAILABILITY: https://repository.niddk.nih.gov/studies/look-ahead/.

Resilience among older adults with Type 2 Diabetes from the Look AHEAD trial

There is growing interest in identifying factors protecting against aging-related decline. This cross-sectional study evaluated associations of self-reported resilience (ability to bounce back) with factors linked to aging-related decline among older adults with Type 2 diabetes (T2DM). Participants were 3,199 adults (72.2±6.2 years, 61% female, 61% white, BMI 34.2±8.2 kg/m2) enrolled in Look AHEAD (a multi-site RCT comparing weight loss to diabetes education among individuals with T2DM), who were followed observationally after the 10-year intervention was discontinued. The following items were assessed approximately 14.4yrs post-randomization: Brief Resilience Scale; overnight hospitalizations in past year; physical functioning measured objectively (gait speed, grip strength) and via self-report (Pepper Assessment Tool for Disability; Physical quality of life (QOL; SF-36)); a composite measure of phenotypic frailty based on having ≥3 of unintentional weight loss, low energy, slow gait, reduced grip strength, physical activity. Depressive symptoms (PHQ-9) and mental QOL (SF-36) were also measured. Logistic/linear regression was used to evaluate the association of these variables with resilience adjusted for age, race, and gender. Greater resilience was associated with lower BMI (p=.01), fewer hospitalizations (p=.02), better physical functioning (i.e., lower self-reported disability, better self-reported physical QOL, faster gait speed, greater grip strength and lower likelihood of meeting criteria for frailty; all p<.001), fewer depressive symptoms and greater mental QOL. Resilience is associated with better performance on indicators of overall functioning and risk for decline among older adults. Findings correspond with efforts to shift narrative on aging beyond ‘loss and decline’ to highlight opportunities to facilitate healthy aging.

Does sexual functioning improve with migraine improvements and/or weight loss?-A post hoc analysis in the Women's Health and Migraine (WHAM) trial

BACKGROUND

Despite plausibility of migraine headaches contributing to impaired sexual function among women, data are inconsistent and point to obesity as a potential confounder. Prospective studies that assess the relative importance of migraine improvements and weight loss in relation to sexual function could help elucidate associations among migraine, obesity and female sexual dysfunction (FSD).

OBJECTIVE

To evaluate sexual function changes and predictors of improvement after behavioural weight loss (BWL) intervention for migraine or migraine education (ME).

METHODS

Women with migraine and overweight/obesity were randomized to 16 weeks of BWL (n = 54) or ME (n = 56). Participants completed a 4-week smartphone headache diary and the Female Sexual Function Index (FSFI) at pre- and post-treatment. A validated FSFI total cut-off score defined FSD. We compared changes in FSFI scores and FSD rates between conditions and evaluated migraine improvements and weight loss as predictors of sexual functioning in the full sample.

RESULTS

Among treatment completers (n = 85), 56 (65.9%) participants who reported sexual activity at pre- and post-treatment were analysed. Migraine improvements were similar between conditions, whereas BWL had greater weight losses compared with ME. FSD rates did not change overall (48.2% to 44.6%, p = .66) or by condition (BWL: 56.0% to 40.0% vs. ME: 41.9% to 48.4%, p = .17). Similar patterns were observed for changes in FSFI total and subscale scores. Across conditions, larger weight losses predicted greater improvements in FSFI total and arousal subscale scores, whereas larger migraine headache frequency reductions predicted greater improvements in FSFI satisfaction subscale scores.

CONCLUSION

Sexual functioning did not improve with either BWL or ME despite migraine headache improvements in both conditions and weight loss after BWL. However, weight loss related to improvements in physiological components of the sexual response (i.e., arousal) and overall sexual functioning, whereas reduced headache frequency related to improved sexual satisfaction. Additional research with larger samples is needed.

Conscientiousness in weight loss maintainers and regainers

OBJECTIVE

The role of personality in weight loss maintenance (WLM) is poorly understood. Although the personality trait of conscientiousness has been associated with health-promoting behaviors in general, no study has specifically evaluated the importance of conscientiousness for WLM. This study compared conscientiousness (both in aggregate and on the facet level) and control over healthy lifestyle behaviors (e.g., food quantity and temptations, consistent meal and sleep timing, exercise adherence, and psychosocial health and stress coping) in successful weight loss maintainers and regainers.

METHOD

The sample included 869 National Weight Control Registry participants who reported maintaining ≥ 30-lb weight loss for ≥ 1 year (maintainers) and 484 participants from Amazon's MTurk crowdsourcing marketplace who reported trying but failing to maintain weight loss for 1 year (regainers). Both groups self-reported the Cherynshenko Conscientiousness Scale, the Healthy Lifestyle & Personal Control Questionnaire, body mass index, and demographics in an online survey.

RESULTS

Maintainers reported higher levels of total conscientiousness (p = .005), order, virtue, responsibility, and industriousness (ps ≤ .05), but not self-control, compared with regainers after controlling for basic demographic differences. Unexpectedly, regainers scored significantly higher on the facet of traditionalism (p < .001). Maintainers also reported greater degree of control over food quantity and temptations, consistent meal and sleep timing, and exercise adherence (ps < .001), but not psychosocial health and stress coping, compared to with regainers.

CONCLUSIONS

Successful weight loss maintainers reported small-to-moderately higher levels of conscientiousness compared with regainers. Evaluating whether conscientiousness can be incorporated into WLM treatment is warranted. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Ripple Effect of Lifestyle Interventions During Pregnancy on Untreated Partners' Weight

OBJECTIVE

Weight-loss interventions have a positive "ripple effect" on untreated partners' weight, but ripple effects in pregnancy are unknown. The objective of this study was to determine whether prenatal lifestyle interventions that reduce gestational weight gain in pregnant women have a positive ripple effect on untreated partners' weight.

METHODS

Two clinical trials with the same outcome measures randomly assigned pregnant women to a lifestyle intervention or usual care. Untreated partners were randomly assigned according to their pregnant partner's group allocation and were assessed at study entry (~13 weeks' gestation), 35 weeks' gestation, and 6 and 12 months after delivery.

RESULTS

A total of 122 partners (100% male, 23% Hispanic, 82% married, and 48% with obesity) were randomly assigned to the intervention (n = 59) or usual care (n = 63). There was no intervention or intervention-by-time interaction effect on partner weight (P = 0.795). Partner weight changes were not statistically significant (P = 0.120) from study entry to 35 weeks' gestation (mean 0.19 kg; 95% CI: -0.73 to 1.24) or to 12 months after delivery (mean 0.82 kg; 95% CI: -0.26 to 1.91).

CONCLUSIONS

There was no evidence of a ripple effect on partner weight. In a self-selected sample, partners of pregnant women appeared not to experience sympathy weight gain.

Psychological status and weight variability over eight years: Results from Look AHEAD

OBJECTIVE

Cross-sectional studies suggest an association between weight cycling and psychological status. Although this is often interpreted as suggesting that weight cycles "cause" psychological distress, the relationship could be bidirectional. This study provides a prospective analysis of the bidirectional association between weight variability and psychological status over an 8-year period in overweight/obese adults with Type 2 diabetes.

METHOD

Data were from the first 8 years of Look AHEAD, a randomized controlled trial comparing health outcomes in individuals with Type 2 diabetes assigned to an intensive lifestyle intervention designed to produce weight loss or a diabetes education and support control group. Psychological status (mental health, depressive symptoms, binge eating) was assessed via surveys and were examined in relation to weight variability at both baseline and year 8. Weight variability was derived from 8 possible annual measurements from participants who had a minimum of 3 consecutive body weight measurements (N = 4,774) and operationalized as the number of year-to-year cycles and the coefficient of variation across all available weight measurements.

RESULTS

Controlling for study group, higher baseline scores on mental health (Short Form-36 Mental Component Summary) and lower levels of depressive symptomatology (Beck Depression Inventory) and binge eating (Questionnaire on Eating and Weight Patterns) were associated with significantly less subsequent weight variability. The prospective association between weight variability and psychological status at year 8 was less robust.

CONCLUSIONS

These results suggest that the cross-sectional relationship between weight variability and psychological status is due primarily to poorer psychological function preceding greater weight instability. (PsycINFO Database Record

Implementing an Online Weight-Management Intervention to an Employee Population: Initial Experience with Real Appeal

OBJECTIVE

Given the disease burden and economic costs of obesity in the United States, scalable approaches to weight loss and weight management are needed. This study evaluated self-reported weight-loss outcomes associated with a commercial intensive lifestyle intervention marketed to employers and delivered electronically to employees.

METHODS

Data were collected for participants who enrolled in an online intensive lifestyle intervention weight-loss program from July 2015 through June 2016. An intent-to-treat analysis of participants who attended at least one session is reported.

RESULTS

Ninety-six companies, with approximately 437,215 eligible adult beneficiaries, launched Real Appeal in July 2015. In the first 12 months of the program, 69,598 adults enrolled and 87% met at-risk criteria for prediabetes, diabetes, or cardiovascular disease. The intent-to-treat cohort (n = 52,461), all of whom attended at least one session, lost an average of 2.8% body weight, with 23% achieving 5% or more weight loss. Active participants (n = 38,836) lost an average of 3.5% body weight, with 29% achieving 5% weight loss. Program completers (n = 27,164) lost an average of 4.3% body weight, with 36% of the cohort achieving 5% weight loss.

CONCLUSIONS

This study demonstrated that an employer-offered, online, behavioral weight-loss program was an effective, scalable solution for engaging more than 50,000 participants with overweight and obesity.

Investigating potential wet bias in the Purple Crow Lidar water vapor measurements

The Purple Crow Lidar is a large aperture lidar, capable of retrieving water vapor into the strato-sphere. A comparison with the ALVICE lidar in 2012 showed water vapor measurements were consistently larger than those of ALVICE in the lower stratosphere, prompting an investigation of the system. Processing approaches and additional instrumental corrections are considered.

Weight-Loss Induced Changes in Plasma Factor VII Coagulant Activity and Relation to the Factor VII Arg/Gln353 Polymorphism in Moderately Obese Adults

Elevated plasma factor VII coagulant activity (factor VIIc) may be an independent risk factor for coronary heart disease. Several cross-sectional studies suggest that a polymorphism of the factor VII gene (ArgGln353) interacts with plasma triglyceride level in determining factor VIIc, but prospective data are lacking. Factor VII genotype, factor VIIc, and triglyceride level were measured in moderately obese adults aged 25 to 45 who underwent a six-month clinical trial to evaluate strategies for weight loss. A total of 48 men and 50 women who experienced substantial weight loss (mean: 10 kg) provided samples for genetic analysis. Overall, 78% of participants were homozygous for the Arg353 allele, while the remaining 22% were heterozygous (Arg/Gln353). At the baseline examination, heterozygotes had lower mean factor VIIc than Arg353 homozygotes (92% vs. 112%; p<0.001), and genotype explained 18% of the variance of factor VIIc. Average six-month weight loss was similar in both genotypes; mean reductions in factor VIIc following weight loss were greatest among Arg353 homozygotes with high initial values (>120%). Cross-sectional and longitudinal associations between plasma factor VIIc and triglyceride level were not dependent on genotype. These data confirm that the Gln353 allele is associated with lower factor VII coagulant activity in moderately obese adults, but they do not support the hypothesis that the Arg-Gln353 polymorphism interacts with plasma triglyceride level in determining factor VIIc.

Cost of intervention delivery in a lifestyle weight loss trial in type 2 diabetes: results from the Look AHEAD clinical trial

Objective

The Action for Health in Diabetes (Look AHEAD) trial was a randomized controlled clinical trial to compare the effects of 10 years of intensive lifestyle intervention (ILI) with a control condition of diabetes support and education (DSE) on health outcomes in over 5,000 participants with type 2 diabetes. The ILI had significantly greater weight losses than DSE throughout the trial. The goal of this analysis is to describe the cost of delivering the intervention.

Methods

The ILI was designed to promote weight loss and increase physical activity. It involved a combination of group plus individual intervention sessions, with decreasing frequency of contact over the 10 years. The intervention incorporated a variety of strategies, including meal replacement products, to improve weight loss outcomes. The costs of intervention delivery were derived from staff surveys of effort and from records of intervention materials from the 16 US academic clinical trial sites. Costs were calculated from the payer perspective and presented in 2012 dollars.

Results

During the first year, when intervention delivery was most intensive, the annual cost of intervention delivery, averaged (standard deviation) across clinical sites, was $2,864.6 ($513.3) per ILI participant compared with $202.4 ($76.6) per DSE participant. As intervention intensity declined, costs decreased, such that from years 5 to 9 of the trial, the annual cost of intervention was $1,119.8 ($227.7) per ILI participant and $102.9 ($33.0) per DSE participant. Staffing accounted for the majority of costs throughout the trial, with meal replacements and materials to promote adherence accounting for smaller shares.

Conclusions

The sustained weight losses produced by the Look AHEAD intervention were supported by intervention costs that were within the range of other weight loss programmes. Future work will include an evaluation of the cost‐effectiveness of the ILI and will contain additional follow‐up data.

Association of the magnitude of weight loss and changes in physical fitness with long-term cardiovascular disease outcomes in overweight or obese people with type 2 diabetes: a post-hoc analysis of the Look AHEAD randomised clinical trial

BACKGROUND

Findings from the Look AHEAD trial showed no significant reductions in the primary outcome of cardiovascular disease incidence in adults with type 2 diabetes randomly assigned to an intensive lifestyle intervention for weight loss compared with those randomly assigned to diabetes support and education (control). We examined whether the incidence of cardiovascular disease in Look AHEAD varied by changes in weight or fitness.

METHODS

Look AHEAD was a randomised clinical trial done at 16 clinical sites in the USA, recruiting patients from Aug 22, 2001, to April 30, 2004. In the trial, 5145 overweight or obese adults aged 45-76 years with type 2 diabetes were assigned (1:1) to an intensive lifestyle intervention or diabetes support and education. In this observational, post-hoc analysis, we examined the association of magnitude of weight loss and fitness change over the first year with incidence of cardiovascular disease. The primary outcome of the trial and of this analysis was a composite of death from cardiovascular causes, non-fatal acute myocardial infarction, non-fatal stroke, or admission to hospital for angina. The secondary outcome included the same indices plus coronary artery bypass grafting, carotid endartectomy, percutaneous coronary intervention, hospitalisation for congestive heart failure, peripheral vascular disease, or total mortality. We adjusted analyses for baseline differences in weight or fitness, demographic characteristics, and risk factors for cardiovascular disease. The Look AHEAD trial is registered with ClinicalTrials.gov, number NCT00017953.

FINDINGS

For the analyses related to weight change, we excluded 311 ineligible participants, leaving a population of 4834; for the analyses related to fitness change, we excluded 739 participants, leaving a population of 4406. In analyses of the full cohort (ie, combining both study groups), over a median 10·2 years of follow-up (IQR 9·5-10·7), individuals who lost at least 10% of their bodyweight in the first year of the study had a 21% lower risk of the primary outcome (adjusted hazard ratio [HR] 0·79, 95% CI 0·64-0·98; p=0·034) and a 24% reduced risk of the secondary outcome (adjusted HR 0·76, 95% CI 0·63-0·91; p=0·003) compared with individuals with stable weight or weight gain. Achieving an increase of at least 2 metabolic equivalents in fitness change was associated with a significant reduction in the secondary outcome (adjusted HR 0·77, 95% CI 0·61-0·96; p=0·023) but not the primary outcome (adjusted HR 0·78, 0·60-1·03; p=0·079). In analyses treating the control group as the reference group, participants in the intensive lifestyle intervention group who lost at least 10% of their bodyweight had a 20% lower risk of the primary outcome (adjusted HR 0·80, 95% CI 0·65-0·99; p=0·039), and a 21% lower risk of the secondary outcome (adjusted HR 0·79, 95% CI 0·66-0·95; p=0·011); however, change in fitness was not significantly associated with a change in the primary outcome.

INTERPRETATION

The results of this post-hoc analysis of Look AHEAD suggest an association between the magnitude of weight loss and incidence of cardiovascular disease in people with type 2 diabetes. These findings suggest a need to continue to refine approaches to identify individuals who are most likely to benefit from lifestyle interventions and to develop strategies to improve the magnitude of sustained weight loss with lifestyle interventions.

FUNDING

US National Institute of Diabetes and Digestive and Kidney Diseases.

Warm Parenting Associated with Decreasing or Stable Child BMI during Treatment

BACKGROUND

While authoritative parenting, which includes high levels of warmth and behavioral control, has been associated with lower risk of obesity, little is known about how general parenting impacts child weight loss during treatment. Our goal was to examine the relationship between several general parenting dimensions and 'decreasing /stable' child BMI during a 16-week family-based behavioral weight control program.

METHODS

Forty-four overweight parent-child dyads (child age 8 to 12 years) enrolled in the program. Families were videotaped at baseline eating dinner in their home. Using the General Parenting Observational Scale (GPOS), meals were coded for several general parenting dimensions. Primary outcome was percent of children whose BMI 'decreased or stayed the same.' Multivariable logistic regression was used to determine the relationship between general parenting and decreasing/stable child BMI.

RESULTS

Forty families (91%) completed the program. Children had a mean BMI change of -0.40 (SD 1.57), which corresponds to a -0.15 (SD 0.20) change in BMI z-score (BMI-Z); 75% of children had decreasing/stable BMI. In the unadjusted models, lower parent BMI, higher parent education, and higher levels of parental warmth were significantly associated with decreasing/stable child BMI. In the multivariable model, only higher level of warmth was associated with increased odds of decreasing/stable child BMI (OR = 1.28; 95% CI, 1.01, 1.62).

CONCLUSIONS

Baseline parental warmth may influence a child's ability to lower/maintain BMI during a standard family-based behavioral weight control program. Efforts to increase parent displays of warmth and emotional support towards their overweight child may help to increase the likelihood of treatment success.

Estimating sleep from multisensory armband measurements: validity and reliability in teens

Given the recognition that sleep may influence obesity risk, there is increasing interest in measuring sleep parameters within obesity studies. The goal of the current analyses was to determine whether the SenseWear(®) Pro3 Armband (armband), typically used to assess physical activity, is reliable at assessing sleep parameters. The armband was compared with the AMI Motionlogger(®) (actigraph), a validated activity monitor for sleep assessment, and with polysomnography, the gold standard for assessing sleep. Participants were 20 adolescents (mean age = 15.5 years) with a mean body mass index percentile of 63.7. All participants wore the armband and actigraph on their non-dominant arm while in-lab during a nocturnal polysomnographic recording (600 min). Epoch-by-epoch sleep/wake data and concordance of sleep parameters were examined. No significant sleep parameter differences were found between the armband and polysomnography; the actigraph tended to overestimate sleep and underestimate wake compared with polysomnography. Both devices showed high sleep sensitivity, but lower wake detection rates. Bland-Altman plots showed large individual differences in armband sleep parameter concordance rates. The armband did well estimating sleep overall, with group results more similar to polysomnography than the actigraph; however, the armband was less accurate at an individual level than the actigraph.

Development of the General Parenting Observational Scale to assess parenting during family meals

Background

There is growing interest in the relationship between general parenting and childhood obesity. However, assessing general parenting via surveys can be difficult due to issues with self-report and differences in the underlying constructs being measured. As a result, different aspects of parenting have been associated with obesity risk. We developed a more objective tool to assess general parenting by using observational methods during a mealtime interaction.

Methods

The General Parenting Observational Scale (GPOS) was based on prior work of Baumrind, Maccoby and Martin, Barber, and Slater and Power. Ten dimensions of parenting were included; 4 were classified in the emotional dimension of parenting (warmth and affection, support and sensitivity, negative affect, detachment), and 6 were classified in the behavioral dimension of parenting (firm discipline and structure, demands for maturity, psychological control, physical control, permissiveness, neglect). Overweight children age 8–12 years old and their parent (n = 44 dyads) entering a weight control program were videotaped eating a family meal. Parents were coded for their general parenting behaviors. The Mealtime Family Interaction Coding System (MICS) and several self-report measures of general parenting were also used to assess the parent–child interaction. Spearman’s correlations were used to assess correlation between measures.

Results

The emotional dimensions of warmth/affection and support/sensitivity, and the behavioral dimension of firm discipline/structure were robustly captured during the family meals. Warmth/affection and support/sensitivity were significantly correlated with affect management, interpersonal involvement, and communication from the MICS. Firm discipline/structure was inversely correlated with affect management, behavior control, and task accomplishment. Parents who were older, with higher educational status, and lower BMIs were more likely to display warmth/affection and support/sensitivity.

Conclusion

Several general parenting dimensions from the GPOS were highly correlated with similar family functioning constructs from the MICS. This new observational tool appears to be a valid means of assessing general parenting behaviors during mealtimes and adds to our ability to measure parent-level factors affecting child weight-related outcomes. Future evaluation of this tool in a broader range of the population and other family settings should be conducted.

Long-term prevalence and predictors of urinary incontinence among women in the Diabetes Prevention Program Outcomes Study

OBJECTIVES

To examine the long-term prevalence and predictors of weekly urinary incontinence in the Diabetes Prevention Program Outcomes Study, a follow-up study of the Diabetes Prevention Program randomized clinical trial of overweight adults with impaired glucose tolerance.

METHODS

This analysis included 1778 female participants of the Diabetes Prevention Program Outcomes Study who had been randomly assigned during the Diabetes Prevention Program to intensive lifestyle intervention (n = 582), metformin (n = 589) or placebo (n = 607). The study participants completed semi-annual assessments after the final Diabetes Prevention Program visit and for 6 years until October 2008.

RESULTS

At the study entry, the prevalence of weekly urinary incontinence was lower in the intensive lifestyle intervention group compared with the metformin and placebo groups (44.2% vs 51.8%, 48.0% urinary incontinence/week, P = 0.04); during the 6-year follow-up period, these lower rates in intensive lifestyle intervention were maintained (46.7%, 53.1%, 49.9% urinary incontinence/week; P = 0.03). Statistically adjusting for urinary incontinence prevalence at the end of the Diabetes Prevention Program, the treatment arm no longer had a significant impact on urinary incontinence during the Diabetes Prevention Program Outcomes Study. Independent predictors of lower urinary incontinence during the Diabetes Prevention Program Outcomes Study included lower body mass index (odds ratio 0.988, 95% confidence interval 0.982-0.994) and greater physical activity (odds ratio 0.999, 95% confidence interval 0.998-1.000) at the Diabetes Prevention Program Outcomes Study entry, and greater reductions in body mass index (odds ratio 0.75, 95% confidence interval 0.60-0.94) and waist circumference (odds ratio 0.998, 95% confidence interval 0.996-1.0) during the Diabetes Prevention Program Outcomes Study. Diabetes was not significantly related to urinary incontinence.

CONCLUSIONS

Intensive lifestyle intervention has a modest positive and enduring impact on urinary incontinence, and should be considered for the long-term prevention and treatment of urinary incontinence in overweight/obese women with glucose intolerance.

Benefits of adding small financial incentives or optional group meetings to a web-based statewide obesity initiative

OBJECTIVE

To examine whether adding either small, variable financial incentives or optional group sessions improves weight losses in a community-based, Internet behavioral program.

METHODS

Participants (N = 268) from Shape Up Rhode Island 2012, a 3-month Web-based community wellness initiative, were randomized to: Shape Up+Internet behavioral program (SI), Shape Up+Internet program+incentives (SII), or Shape Up+Internet program+group sessions (SIG).

RESULTS

At the end of the 3-month program, SII achieved significantly greater weight losses than SI (SII: 6.4% [5.1-7.7]; SI: 4.2% [3.0-5.6]; P = 0.03); weight losses in SIG were not significantly different from the other two conditions (SIG: 5.8% [4.5-7.1], P's ≥ 0.10). However, at the 12-month no-treatment follow-up visit, both SII and SIG had greater weight losses than SI (SII: 3.1% [1.8-4.4]; SIG: 4.5% [3.2-5.8]; SI: 1.2% [-0.1-2.6]; P's ≤ 0.05). SII was the most cost-effective approach at both 3 (SII: $34/kg; SI: $34/kg; SIG: $87/kg) and 12 months (SII: $64/kg; SI: $140/kg; SIG: $113/kg).

CONCLUSIONS

Modest financial incentives enhance weight losses during a community campaign, and both incentives and optional group meetings improved overall weight loss outcomes during the follow-up period. However, the use of the financial incentives is the most cost-effective approach.

The EARLY trials: a consortium of studies targeting weight control in young adults

Young adulthood has been identified as a high-risk period for the development of obesity but few interventions have been tested in this population. One way to escalate our learning about effective interventions is to test a number of interventions simultaneously as a consortium of research trials. This paper describes the Early Adult Reduction of weight through LifestYle intervention (EARLY) trials. Seven research sites were funded to conduct intervention trials, agreeing to test similar primary outcomes and cooperating to use a set of common measurement tools. The EARLY consortium was able to work cooperatively using an executive committee, a steering committee, workgroups and subcommittees to help direct the common work and implement a set of common protocol and measurement tools for seven independent but coordinated weight-related intervention trials. Using a consortium of studies to help young adults reach or maintain a healthy weight will result in increased efficiency and speed in understanding the most effective intervention strategies.

Bariatric surgery patients exhibit improved memory function 12 months postoperatively

BACKGROUND

Previous work from our group demonstrated improved memory function in bariatric surgery patients at 12 weeks postoperatively relative to controls. However, no study has examined longer-term changes in cognitive functioning following bariatric surgery.

METHODS

A total of 137 individuals (95 bariatric surgery patients and 42 obese controls) were followed prospectively to determine whether postsurgery cognitive improvements persist. Potential mechanisms of change were also examined. Bariatric surgery participants completed self-report measurements and a computerized cognitive test battery prior to surgery and at 12-week and 12-month follow-up; obese controls completed measures at equivalent time points.

RESULTS

Bariatric surgery patients exhibited cognitive deficits relative to well-established standardized normative data prior to surgery, and obese controls demonstrated similar deficits. Analyses of longitudinal change indicated an interactive effect on memory indices, with bariatric surgery patients demonstrating better performance postoperatively than obese controls.

CONCLUSIONS

While memory performance was improved 12 months postbariatric surgery, the mechanisms underlying these improvements were unclear and did not appear attributable to obvious postsurgical changes, such as reductions in body mass index or comorbid medical conditions. Future studies employing neuroimaging, metabolic biomarkers, and more precise physiological measurements are needed to determine the mechanisms underlying memory improvements following bariatric surgery.

Changes in children's sleep duration on food intake, weight, and leptin

OBJECTIVE

To examine the effect of experimental changes in children's sleep duration on self-reported food intake, food reinforcement, appetite-regulating hormones, and measured weight.

METHODS

Using a within-subjects, counterbalanced, crossover design, 37 children, 8 to 11 years of age (27% overweight/obese) completed a 3-week study. Children slept their typical amount at home for 1 week and were then randomized to either increase or decrease their time in bed by 1.5 hours per night for 1 week, completing the alternate schedule on the third week. Primary outcomes were dietary intake as assessed by 24-hour dietary recalls, food reinforcement (ie, points earned for a food reward), and fasting leptin and ghrelin. The secondary outcome was child weight.

RESULTS

Participants achieved a 2 hour, 21 minute difference in the actigraph defined sleep period time between the increase and decrease sleep conditions (P < .001). Compared with the decrease sleep condition, during the increase condition, children reported consuming an average of 134 kcal/day less (P < .05), and exhibited lower fasting morning leptin values (P < .05). Measured weights were 0.22 kg lower during the increase sleep than the decrease sleep condition (P < .001). There were no differences in food reinforcement or in fasting ghrelin.

CONCLUSIONS

Compared with decreased sleep, increased sleep duration in school-age children resulted in lower reported food intake, lower fasting leptin levels, and lower weight. The potential role of sleep duration in pediatric obesity prevention and treatment warrants further study.

Time in Bed is Associated with Decreased Physical Activity and Higher BMI in Women Seeking Weight Loss Treatment

Short sleep duration is associated with obesity risk. Despite calls to incorporate strategies to enhance sleep within the context of behavioral weight loss (BWL) treatment, little is known regarding the association between sleep and body mass index (BMI) among individuals presenting for BWL. Moreover, most research has focused on eating pathways linking sleep and BMI, and have not explored how sleep may impact engagement in physical activity. The purpose of the present study was to determine whether, in a sample of women seeking treatment for weight loss, there was an association between reported time in bed (TIB), higher BMI, lower physical activity, and less favorable dietary composition. Prior to randomization, 318 women completed measures of TIB, eating, and activity; weight and height were measured. Findings demonstrated that report of '6 hours or less' TIB/night was associated with higher BMI and lower reported physical activity compared to the referent (>7 to ≤ 8 hours/night). It was not associated with the number of reported calories consumed each day or with the percent of calories consumed from fat, carbohydrates or protein. Better understanding the role of sleep within the context of BWL treatment in women seems warranted.

Patterns of weight change associated with long-term weight change and cardiovascular disease risk factors in the Look AHEAD Study

This article provides an assessment of the associations that weight-loss patterns during the first year of an intensive lifestyle intervention have with 4-year maintenance and health outcomes. Two components described patterns of weight change during the first year of intervention: one reflected the typical pattern of weight loss over the 12 months, but distinguished those who lost larger amounts across the monthly intervals from those who lost less. The second component reflected the weight change trajectory, and distinguished a pattern of initial weight loss followed by regain vs. a more sustained pattern of weight loss. Two thousand four hundred and thirty eight individuals aged 45-76 years with type 2 diabetes mellitus, who enrolled in the weight-loss intervention of a randomized clinical trial, were assigned scores according to how their weight losses reflected these patterns. Relationships these scores had with weight losses and health outcomes (glycosolated hemoglobin--hemoglobin A1c (HbA1c); systolic blood pressure, high-density lipoprotein (HDL)-cholesterol, and triglycerides) over 4 years were described. When compared to those with lower scores on the two components, both individuals who had larger month-to-month weight losses in year 1 and whose weight loss was more sustained during the first year had better maintenance of weight loss over 4 years, independent of characteristics traditionally linked to weight loss success (P < 0.001). While relationships with year 4 weight loss were stronger, the pattern of larger monthly weight loss during year 1 was also independently predictive of year 4 levels of HbA1c, HDL-cholesterol, and systolic blood pressure.

Cognitive function predicts weight loss after bariatric surgery

BACKGROUND

Clinically significant cognitive impairment is found in a subset of patients undergoing bariatric surgery. These difficulties could contribute to a reduced adherence to postoperative lifestyle changes and decreased weight loss. The present study is the first to prospectively examine the independent contribution of cognitive function to weight loss after bariatric surgery. Executive function/attention and verbal memory at baseline were expected to negatively predict the percentage of excess weight loss (%EWL) and body mass index (BMI) at follow-up. Three sites of the Longitudinal Assessment of Bariatric Surgery parent project were used: Columbia (New York, NY), Cornell (Princeton, NJ), and the Neuropsychiatric Research Institute (Fargo, ND).

METHODS

A total of 84 individuals enrolled in the Longitudinal Assessment of Bariatric Surgery project undergoing bariatric surgery completed a cognitive evaluation at baseline. The BMI and %EWL were calculated at the 12-week and 12-month postoperative follow-up visits.

RESULTS

Clinical impairment in task performance was most prominent in tasks associated with verbal recall and recognition (14.3-15.5% of the sample) and perseverative errors (15.5%). After accounting for demographic and medical variables, the baseline test results of attention/executive function and memory predicted the BMI and %EWL at 12 months but not at 12 weeks.

CONCLUSIONS

These results have demonstrated that baseline cognition predicts for greater %EWL and lower BMI 12 months after bariatric surgery. Additional work is needed to clarify the degree to which cognition contributes to adherence and the potential mediation of cognition on the relationship between adherence and weight loss in this group.

Improved memory function 12 weeks after bariatric surgery

BACKGROUND

Growing evidence has shown that obesity is associated with poor neurocognitive outcomes. Bariatric surgery has been shown to be an effective intervention for morbid obesity and can result in improvement of many co-morbid medical conditions that are associated with cognitive dysfunction. The effects of bariatric surgery on cognition are unknown.

METHODS

We performed a prospective study total of 150 subjects (109 bariatric surgery patients enrolled in the Longitudinal Assessment of Bariatric Surgery project and 41 obese control subjects who had not undergone bariatric surgery). These 150 subjects completed a cognitive evaluation at baseline and at 12 weeks of follow-up. The demographic, medical, and psychosocial information was also collected to elucidate the possible mechanisms of change.

RESULTS

Many bariatric surgery patients exhibited impaired performance on cognitive testing at baseline (range 4.6-23.9%). However, the surgery patients were no more likely to exhibit a decline on ≥2 cognitive tests at 12 weeks of follow-up than were the obese controls [12.84% versus 23.26%; chi-square (1) = 2.51, P = .11]. Group comparisons using repeated measures multivariate analysis of variance showed that the surgery patients had improved memory performance at 12 weeks of follow-up [λ = .86, F(4, 147) = 5.88, P <.001]; however, the memory performance of the obese controls had actually declined. Regression analyses showed that the surgery patients without hypertension had better short delay recall at 12 weeks than those with hypertension [β = .31, P = .005], although the other demographic and medical variables were largely unrelated to the test performance.

CONCLUSION

The present results suggest that cognitive impairment is common in bariatric surgery patients, although these deficits might be at least partly reversible. Future studies are needed to clarify the underlying mechanisms, in particular, longitudinal studies using neuroimaging and blood markers.

An intensive behavioral weight loss intervention and hot flushes in women

BACKGROUND

Higher body mass index is associated with worse hot flushes during menopause but the effect of weight loss on flushing is unclear.

METHODS

Self-administered questionnaires were used to assess bothersome hot flushes in a 6-month randomized controlled trial of an intensive behavioral weight loss program (intervention) vs a structured health education program (control) in 338 women who were overweight or obese and had urinary incontinence. Weight, body mass index, abdominal circumference, physical activity, calorie intake, blood pressure, and physical and mental functioning were assessed at baseline and at 6 months. Repeated-measures proportional odds models examined intervention effects on bothersome hot flushes and potential mediating factors.

RESULTS

Approximately half of participants (n = 154) were at least slightly bothered by hot flushes at baseline. Among these women, the intervention was associated with greater improvement in bothersome flushes vs control (odds ratio [OR] for improvement by 1 Likert category, 2.25; 95% confidence interval [CI], 1.20-4.21). Reductions in weight (OR, 1.32; 95% CI, 1.08-1.61; per 5-kg decrease), body mass index (1.17; 1.05-1.30; per 1-point decrease), and abdominal circumference (1.32; 1.07-1.64; per 5-cm decrease) were each associated with improvement in flushing, but changes in physical activity, calorie intake, blood pressure, and physical and mental functioning were not related. The effect of the intervention on flushing was modestly diminished after adjustment for multiple potential mediators (OR, 1.92; 95% CI, 0.95-3.89).

CONCLUSION

Among women who were overweight or obese and had bothersome hot flushes, an intensive behavioral weight loss intervention resulted in improvement in flushing relative to control. Trial Registration clinicaltrials.gov Identifier: NCT00091988.

Describing patterns of weight changes using principal components analysis: results from the Action for Health in Diabetes (Look AHEAD) research group

PURPOSE

To demonstrate how principal components analysis can be used to describe patterns of weight changes in response to an intensive lifestyle intervention.

METHODS

Principal components analysis was applied to monthly percent weight changes measured on 2,485 individuals enrolled in the lifestyle arm of the Action for Health in Diabetes (Look AHEAD) clinical trial. These individuals were 45 to 75 years of age, with type 2 diabetes and body mass indices greater than 25 kg/m(2). Associations between baseline characteristics and weight loss patterns were described using analyses of variance.

RESULTS

Three components collectively accounted for 97.0% of total intrasubject variance: a gradually decelerating weight loss (88.8%), early versus late weight loss (6.6%), and a mid-year trough (1.6%). In agreement with previous reports, each of the baseline characteristics we examined had statistically significant relationships with weight loss patterns. As examples, males tended to have a steeper trajectory of percent weight loss and to lose weight more quickly than women. Individuals with higher hemoglobin A(1c) (glycosylated hemoglobin; HbA(1c)) tended to have a flatter trajectory of percent weight loss and to have mid-year troughs in weight loss compared to those with lower HbA(1c).

CONCLUSIONS

Principal components analysis provided a coherent description of characteristic patterns of weight changes and is a useful vehicle for identifying their correlates and potentially for predicting weight control outcomes.

Physical activity, weight control, and breast cancer risk and survival: clinical trial rationale and design considerations

Substantial observational epidemiological evidence exists that physical activity and weight control are associated with decreased risk of postmenopausal breast cancer. Uncertainty remains regarding several aspects of these associations, including the effect of possible confounding factors on these associations. We present the rationale and design for two randomized controlled trials that can help resolve this uncertainty. In a 5-year prevention trial conducted among women at high risk of breast cancer, the primary endpoint would be breast cancer incidence. For a comparable survivorship trial, the primary endpoint would be the disease-free interval and secondary endpoints would be breast cancer recurrence-free interval, second primary breast cancer, and total invasive plus in situ breast cancer. A set of inclusion and exclusion criteria is proposed for both trials. Intervention goals are the same for both trials. Goals for the weight control intervention would be, for women whose body mass index (BMI) is greater than 25 kg/m(2), to lose 10% of body weight and, for women whose BMI is less than or equal to 25 kg/m(2), to avoid weight gain. The goal for the physical activity intervention would be to achieve and maintain regular participation in a moderate-intensity physical activity program for a total of 150-225 minutes over at least 5 days per week. Sample size calculations are based on alternative assumptions about hazard ratio, adherence, follow-up duration, and power and are presented for the primary prevention and survivorship trials. Although both studies could enhance our understanding of breast cancer etiology and benefit public health, practical considerations, including smaller sample size, ease of recruitment, and reduced likelihood of early termination, favor the survivorship trial at this time.

A prospective study of weight gain during the college freshman and sophomore years

OBJECTIVE

To assess the prevalence of weight gain among male and female college freshmen.

METHODS

Study 1 examined weight change over freshman and sophomore years among 904 students attending a state university in Indiana, from 2002-2004. Study 2 examined weight and BMI change over the freshman year among 382 students attending a private university in Rhode Island, from 2004-2006.

RESULTS

77% of Study 1 participants and 70% of Study 2 participants gained weight during their freshman year, largely during the first semester. In Study 1, weight gain averaged 3.5 kg in females and males; in Study 2, weight gain averaged 1.6 kg for females and 2.5 kg for males. Students continued to gain weight their sophomore year, with females 4.2 kg and males 4.3 kg heavier than at start of college. Overweight/obesity rates increased from baseline to end of freshman year for Study 1 (21.6% to 36%) and Study 2 participants (14.7% to 17.8%).

CONCLUSION

The first years of college may be a critical developmental window for establishing weight gain prevention efforts.

Weight loss to treat urinary incontinence in overweight and obese women

BACKGROUND

Obesity is an established and modifiable risk factor for urinary incontinence, but conclusive evidence for a beneficial effect of weight loss on urinary incontinence is lacking.

METHODS

We randomly assigned 338 overweight and obese women with at least 10 urinary-incontinence episodes per week to an intensive 6-month weight-loss program that included diet, exercise, and behavior modification (226 patients) or to a structured education program (112 patients).

RESULTS

The mean (+/-SD) age of the participants was 53+/-11 years. The body-mass index (BMI) (the weight in kilograms divided by the square of the height in meters) and the weekly number of incontinence episodes as recorded in a 7-day diary of voiding were similar in the intervention group and the control group at baseline (BMI, 36+/-6 and 36+/-5, respectively; incontinence episodes, 24+/-18 and 24+/-16, respectively). The women in the intervention group had a mean weight loss of 8.0% (7.8 kg), as compared with 1.6% (1.5 kg) in the control group (P<0.001). After 6 months, the mean weekly number of incontinence episodes decreased by 47% in the intervention group, as compared with 28% in the control group (P=0.01). As compared with the control group, the intervention group had a greater decrease in the frequency of stress-incontinence episodes (P=0.02), but not of urge-incontinence episodes (P=0.14). A higher proportion of the intervention group than of the control group had a clinically relevant reduction of 70% or more in the frequency of all incontinence episodes (P<0.001), stress-incontinence episodes (P=0.009), and urge-incontinence episodes (P=0.04).

CONCLUSIONS

A 6-month behavioral intervention targeting weight loss reduced the frequency of self-reported urinary-incontinence episodes among overweight and obese women as compared with a control group. A decrease in urinary incontinence may be another benefit among the extensive health improvements associated with moderate weight reduction. (ClinicalTrials.gov number, NCT00091988.)

Baseline characteristics of the randomised cohort from the Look AHEAD (Action for Health in Diabetes) study

OBJECTIVE

The Look AHEAD (Action for Health in Diabetes) study is a 16-centre randomised clinical trial in overweight and obese individuals with type 2 diabetes, designed to evaluate the long-term effects (up to 11.5 years) of intensive weight loss intervention on the time to incidence of major cardiovascular events.

RESEARCH DESIGN AND METHODS

Eligibility requirements are diagnosis of type 2 diabetes (determined by self-report and verification) in individuals aged 4574 years and body mass index (BMI) > 25 kg/m2 (> 27 kg/m2 if currently taking insulin). The intensive lifestyle intervention is designed to achieve and maintain weight loss through decreased caloric intake and increased physical activity. The study is designed to provide 90% probability of detecting an 18% difference in major cardiovascular disease event rates in patients randomised to the intensive lifestyle intervention compared to the control group receiving standard diabetes support and education.

RESULTS

The 5,145 participants who were randomised between 2001 and 2004 were 63.3% white, 15.6% African-American, 13.2% Hispanic, 5.0% American Indian and 1.0% Asian-American, which closely paralleled the ethnic distribution of diabetes in the National Health and Nutrition Examination Survey (NHANES) 1999-2000 survey. Their average age at entry was 59+/-6.8 years (mean+/-SD), and 60% were women. There were 31.5% between 4555 years of age, 51.5% were 5665, and 17.0% were 6676 years of age. Some 15.4% of participants were taking insulin at the time of randomisation and 14.0% had a history of cardiovascular disease. More men (21.3%) than women (9.2%) had a history of cardiovascular disease. Few participants (4.4%) were current cigarette smokers, compared to 16.2% in the NHANES 1999-2000 survey. Furthermore, 65.0% of participants had a first-degree relative with diabetes. Overall, BMI averaged 36+/-5.9 kg/m2 at baseline, with 83.6% of the men and 86.1% of women having a BMI > 30 kg/m2 and 17.9% of men and 25.4% of women having a BMI > 40 kg/m2.

CONCLUSIONS

The Look AHEAD study has successfully randomised a large cohort of participants who have type 2 diabetes with a wide distribution of age, obesity, ethnicity and racial background and will examine the effects of lifestyle intervention on the incidence of major cardiovascular events.

Lifestyle intervention is associated with lower prevalence of urinary incontinence: the Diabetes Prevention Program

OBJECTIVE

Diabetes is associated with increased urinary incontinence risk. Weight loss improves incontinence, but exercise may worsen this condition. We examined whether an intensive lifestyle intervention or metformin therapy among overweight pre-diabetic women was associated with a lower prevalence of incontinence.

RESEARCH DESIGN AND METHODS

We analyzed data from the Diabetes Prevention Program, a randomized controlled trial in 27 U.S. centers. Of the 1,957 women included in this analysis, 660 (34%) were randomized to intensive lifestyle therapy, 636 (32%) to metformin, and 661 (34%) to placebo with standard lifestyle advice. The main outcome measure was incontinence symptoms by frequency and type by a validated questionnaire completed at the end-of-trial visit (mean 2.9 years).

RESULTS

The prevalence of total (stress or urge) weekly incontinence was lower among women in the intensive lifestyle group (38.3%) than those randomized to metformin (48.1%) or placebo (45.7%). This difference was most apparent among women with stress incontinence (31.3% for intensive lifestyle group vs. 39.7% for metformin vs. 36.7% for placebo, P = 0.006). Changes in weight accounted for most of the protective effect of the intensive lifestyle intervention on stress incontinence.

CONCLUSIONS

Less-frequent urinary incontinence may be a powerful motivator for women to choose lifestyle modification to prevent diabetes.

Epidemiology of erectile dysfunction: the role of medical comorbidities and lifestyle factors

Erectile dysfunction (ED) is a highly prevalent condition in aging men with significant interpersonal and psychosocial consequences. Large-scale epidemiologic studies have demonstrated a consistent age-related loss of erectile function in men from different geographic and ethnic backgrounds, with approximately half of men over 70 years of age reporting moderate to severe symptoms. ED is associated strongly with specific comor-bidities, such as cardiovascular disease and hypertension, diabetes mellitus, lower urinary tract symptoms, prostate cancer, and depression. Lifestyle factors, including obesity and exercise frequency, also have been implicated in recent studies.

The National Weight Control Registry: is it useful in helping deal with our obesity epidemic?

The National Weight Control Registry (NWCR) consists of over 4800 individuals who have been successful in long-term weight loss maintenance. The purpose of establishing the NWCR was to identify the common characteristics of those who succeed in long-term weight loss maintenance. We found very little similarity in how these individuals lost weight but some common behaviors in how they are keeping their weight off. To maintain their weight loss NWCR participants report eating a relatively low-fat diet, eating breakfast almost every day, weighing themselves regularly, and engaging in high levels (about 1 hour/day) of physical activity. Because this is not a random sample of those who attempt weight loss, the results have limited generalizability to the entire population of overweight and obese individuals. The value of this project lies in identifying potential strategies that may help others be more successful in keeping weight off.

Involving Support Partners in Obesity Treatment

In this study, the authors examined whether the number or success of weight loss partners influences participants' outcomes in behavioral weight loss treatment. Overweight participants (n=109) assigned to an exercise intensive group in a larger trial were encouraged to invite up to 3 partners to attend treatment. Weight losses at 6, 12, and 18 months were not associated with the number of partners (0-3) but were associated with the weight loss success of the partners. Participants with at least 1 successful partner (weight loss>or=10% at 6 months) lost significantly (p=.004) more weight at 6, 12, and 18 months than those with no successful partners and those without partners. Interclass correlations of weight change between participants and their partner(s) were strong at all time points (ps<.01). Support partners appear to only be beneficial in obesity treatment when partners themselves lose weight.

Bacterial artificial chromosome (BAC) library resource for positional cloning of pest and disease resistance genes in cassava (Manihot esculenta Crantz)

Pest and disease problems are important constraints of cassava production and host plant resistance is the most efficient method of combating them. Breeding for host plant resistance is considerably slowed down by the crop's biological constraints of a long growth cycle, high levels of heterozygosity and a large genetic load. More efficient methods such as gene cloning and transgenesis are required to deploy resistance genes. To facilitate the cloning of resistance genes, bacterial artificial chromosome (BAC) library resources have been developed for cassava. Two libraries were constructed from the cassava clones, TMS 30001, resistant to the cassava mosaic disease (CMD) and the cassava bacterial blight (CBB), and MECU72, resistant to cassava white fly. The TMS30001 library has 55, 296 clones with an insert size range of 40-150 kb with an average of 80 kb, while the MECU72 library consists of 92 160 clones and an insert size range of 25-250 kb average of 93 kb. Based on a genome size of 772 Mb, the TMS30001 and MECU72 libraries have a 5 and 11.3 haploid genome equivalents and a 95 and 99 chance of finding any sequence, respectively. To demonstrate the potential of the libraries, the TMS30001 library was screened by southern hybridization using a cassava analog (CBB1) of the Xa21 gene from rice that maps to a region containing a QTL for resistance to CBB as probe. Five BAC clones that hybridized to CBB1 were isolated and a Hind III fingerprint revealed 2-3 copies of the gene in individual BAC clones. A larger scale analysis of resistance gene analogs (RGAs) in cassava has also been conducted in order to understand the number and organization of RGAs. To scan for gene and repeat DNA content in the libraries, end-sequencing was performed on 2,301 clones from the MECU72 library. A total of 1705 unique sequences were obtained with an average size of 715 bp. Database homology searches using BLAST revealed that 458 sequences had significant homology with known proteins and 321 with transposable elements. The use of the library in positional cloning of pest and disease resistance genes is discussed.

Construction of BAC libraries from two apomictic grasses to study the microcolinearity of their apospory-specific genomic regions

We have constructed bacterial artificial chromosome (BAC) libraries from two grass species that reproduce by apospory, a form of gametophytic apomixis. The library of an apomictic polyhaploid genotype (line MS228-20, with a 2C genome size of approximately 4,500 Mbp) derived from a cross between the obligate apomict, Pennisetum squamulatum, and pearl millet ( P. glaucum) comprises 118,272 clones with an average insert size of 82 kb. The library of buffelgrass ( Cenchrus ciliaris, apomictic line B-12-9, with a 2C genome size of approximately 3,000 Mbp) contains 68,736 clones with an average insert size of 109 kb. Based on the genome sizes of these two lines and correcting for the number for false-positive and organellar clones, library coverages were found to be 3.7 and 4.8 haploid genome equivalents for MS 228-20 and B12-9, respectively. Both libraries were screened by hybridization with six SCARs (sequence-characterized amplified regions), whose tight linkage in a single apospory-specific genomic region had been previously demonstrated in both species. Analysis of these BAC clones indicated that some of the SCAR markers are actually amplifying duplicated regions linked in coupling in both genomes and that restriction enzyme mapping will be necessary to sort out the duplications.

Complete nucleotide sequence and organization of the atrazine catabolic plasmid pADP-1 from Pseudomonas sp. strain ADP

The complete 108,845-nucleotide sequence of catabolic plasmid pADP-1 from Pseudomonas sp. strain ADP was determined. Plasmid pADP-1 was previously shown to encode AtzA, AtzB, and AtzC, which catalyze the sequential hydrolytic removal of s-triazine ring substituents from the herbicide atrazine to yield cyanuric acid. Computational analyses indicated that pADP-1 encodes 104 putative open reading frames (ORFs), which are predicted to function in catabolism, transposition, and plasmid maintenance, transfer, and replication. Regions encoding transfer and replication functions of pADP-1 had 80 to 100% amino acid sequence identity to pR751, an IncPbeta plasmid previously isolated from Enterobacter aerogenes. pADP-1 was shown to contain a functional mercury resistance operon with 99% identity to Tn5053. Complete copies of transposases with 99% amino acid sequence identity to TnpA from IS1071 and TnpA from Pseudomonas pseudoalcaligenes were identified and flank each of the atzA, atzB, and atzC genes, forming structures resembling nested catabolic transposons. Functional analyses identified three new catabolic genes, atzD, atzE, and atzF, which participate in atrazine catabolism. Crude extracts from Escherichia coli expressing AtzD hydrolyzed cyanuric acid to biuret. AtzD showed 58% amino acid sequence identity to TrzD, a cyanuric acid amidohydrolase, from Pseudomonas sp. strain NRRLB-12227. Two other genes encoding the further catabolism of cyanuric acid, atzE and atzF, reside in a contiguous cluster adjacent to a potential LysR-type transcriptional regulator. E. coli strains bearing atzE and atzF were shown to encode a biuret hydrolase and allophanate hydrolase, respectively. atzDEF are cotranscribed. AtzE and AtzF are members of a common amidase protein family. These data reveal the complete structure of a catabolic plasmid and show that the atrazine catabolic genes are dispersed on three disparate regions of the plasmid. These results begin to provide insight into how plasmids are structured, and thus evolve, to encode the catabolism of compounds recently added to the biosphere.

Physical mapping of the barley stem rust resistance gene rpg4

The barley stem rust resistance gene rpg4 was physically and genetically localized on two overlapping BAC clones covering an estimated 300-kb region of the long arm of barley chromosome 7(5H). Initially, our target was mapped within a 6.0-cM region between the previously described flanking markers MWG740 and ABG391. This region was then saturated by integrating new markers from several existing barley and rice maps and by using BAC libraries of barley cv. Morex and rice cv. Nipponbare. Physical/genetic distances in the vicinity of rpg4 were found to be 1.0 Mb/cM, which is lower than the average for barley (4 Mb/cM) and lower than that determined by translocation breakpoint mapping (1.8 Mb/cM). Synteny at high resolution levels has been established between the region of barley chromosome 7(5H) containing the rpg4 locus and the subtelomeric region of rice chromosome 3 between markers S16474 and E10757. This 1.7-cM segment of the rice genome was covered by two overlapping BAC clones, about 250 kb of total length. In barley the markers S16474 and E10757 genetically delimit rpg4, lying 0.6 cM distal and 0.4 cM proximal to the locus, respectively.

Anchoring of rice BAC clones to the rice genetic map in silico

A wealth of molecular resources have been developed for rice genomics, including dense genetic maps, expressed sequence tags (ESTs), yeast artificial chromosome maps, bacterial artificial chromosome (BAC) libraries and BAC end sequence databases. Integration of genetic and physical maps involves labor-intensive empirical experiments. To accelerate the integration of the bacterial clone resources with the genetic map for the International Rice Genome Sequencing Project, we cleaned and filtered the available EST and BAC end sequences for repetitive sequences and then searched all available rice genetic markers with our filtered databases. We identified 418 genetic markers that aligned with at least one BAC end sequence with >95% sequence identity, providing a set of large insert clones with an average separation of 1 Mb that can serve as nucleation points for the sequencing phase of the International Rice Genome Sequencing Project.