Association of proton density fat fraction in adipose tissue with imaging-based and anthropometric obesity markers in adults.

BACKGROUND/OBJECTIVES: The purpose of this study was to examine the relationship of the proton density fat fraction (PDFF), measured by magnetic resonance imaging (MRI), of supraclavicular and gluteal adipose tissue with subcutaneous and visceral adipose tissue (SAT and VAT) volumes, liver fat fraction and anthropometric obesity markers. The supraclavicular fossa was selected as a typical location where brown adipocytes may be present in humans and the gluteal region was selected as a typical location enclosing primarily white adipocytes. SUBJECTS/METHODS: In this cross-sectional study, 61 adults (44 women, median age 29.3 years, range 21-68 years) underwent an MRI examination of the neck and the abdomen/pelvis (3T, Ingenia, Philips Healthcare). PDFF maps of the supraclavicular and gluteal adipose tissue and the liver were generated. Volumes of SAT and VAT were calculated and supraclavicular and subcutaneous fat were segmented using custom-built post-processing algorithms. Body mass index (BMI), waist circumference and waist-to-height ratio were recorded. Statistical analysis was conducted using the Student's t-test and Pearson correlation analysis. RESULTS: Mean supraclavicular PDFF was 75.3±4.7% (range 65.4-83.8%) and mean gluteal PDFF was 89.7±2.9% (range 82.2-94%), resulting in a significant difference (P<0.0001). Supraclavicular PDFF was positively correlated with VAT (r=0.76, P<0.0001), SAT (r=0.73, P<0.0001), liver PDFF (r=0.42, P=0.0008) and all measured anthropometric obesity markers. Gluteal subcutaneous PDFF also correlated with VAT (r=0.59, P<0.0001), SAT (r=0.63, P<0.0001), liver PDFF (r=0.3, P=0.02) and anthropometric obesity markers. CONCLUSIONS: The positive correlations between adipose tissue PDFF and imaging, as well as anthropometric obesity markers suggest that adipose tissue PDFF may be useful as a biomarker for improving the characterization of the obese phenotype, for risk stratification and for selection of appropriate treatment strategies.

The challenge of a 2-year follow-up after intervention for weight loss in primary care.

BACKGROUND: Many weight loss programmes show short-term success, but long-term data in larger studies are scarce, especially in community settings. Attrition is common and complicates the interpretation of long-term outcomes. OBJECTIVE: To investigate 2-year outcomes and explore issues of attrition and missing data. SUBJECTS: A total of 772 overweight and obese adults recruited by primary care practices in Australia, Germany and the UK and randomised to a 12-month weight loss intervention delivered in a commercial programme (CP) or in standard care (SC). MEASUREMENT: Weight change from 0-24 and 12-24 months including measured weights only and measured and self-reported weights, using last observation carried forward (LOCF), baseline observation carried forward (BOCF), completers-only and missing-at-random (MAR) analyses. RESULTS: A total of 203 participants completed the 24-month visit. Using measured weights only, there was a trend for greater 24-month weight loss in CP than in SC, but the difference was only statistically significant in the LOCF and BOCF analyses: LOCF: -4.14 vs -1.99 kg, difference adjusted for centre -2.08 kg, P<0.001; BOCF: -1.33 vs -0.74 kg, adjusted difference -0.60 kg, P=0.032; completers: -4.76 vs -2.99 kg, adjusted difference -1.53 kg, P=0.113; missing at random: -3.00 vs -1.94 kg, adjusted difference -1.04 kg, P=0.150. Both groups gained weight from 12-24 months and weight regain was significantly (P<0.001) greater for CP than for SC in all analysis approaches. Inclusion of self-reported weights from a further 138 participants did not change the interpretation of the findings. CONCLUSION: Initial weight loss was poorly maintained during the no-intervention follow-up, but both groups did have lower weight over the 24 months. Attrition was high in both groups, and assumptions about missing data had considerable impact on the magnitude and statistical significance of treatment effects. It is vital that trials on weight loss interventions consider the plausibility of these differences in an analytical approach when interpreting research findings and comparing data between studies.

Changes in physical activity during a weight loss intervention and follow-up: a randomized controlled trial.

Physical activity is an important component in weight loss treatment and weight maintenance. We evaluated the physical activity component of two weight loss programmes, either standard care (SC) as defined by national guidelines, or a commercial programme (CP; Weight Watchers) over the period of weight loss and follow-up. 772 adults (mean body mass index: 31.4 ± 2.6 kg m(-2)) were recruited by primary care practices in Australia, the United Kingdom, and Germany, and randomly assigned to 12 months SC, or the CP. They were then followed up at 24 months. Change in physical activity levels were assessed by the International Physical Activity Questionnaire (IPAQ)-short form, and pedometer recordings. Both groups reported increases in physical activity using the IPAQ from baseline to 12 months and 24 months (within groups P < 0.0001) and in pedometer steps from baseline to 12 months only (within groups P < 0.0001). Differences between groups with both methods of assessment were not significant. There was a significant difference in weight loss between the groups at 12 months favouring the CP group; however, this statistical difference was not maintained at 24 months. In conclusion, despite similar increases in reported activity, there were significant differences in weight loss and regain between groups. Therefore, greater weight loss seen with the CP is unlikely to be due to increases in physical activity. Trends in pedometer steps mirrored changes in weight over time more closely than the IPAQ; however, both assessment tools have limitations. Better activity assessment measures are needed to more accurately gauge changes in physical activity during weight loss interventions.

[Weight reduction: evaluation of the possibilities in primary care and patient satisfaction. Results from a weight reduction trial]. / Gewichtsreduktion: Evaluation der Möglichkeiten auf hausärztlicher Versorgungsebene und der Patientenzufriedenheit. Ergebnisse einer Gewichtsreduktionsstudie.

BACKGROUND: Commercial weight loss programs offer support to overweight and obese patients to reduce excess bodyweight. Many patients seek advice for weight loss from their general practitioners. PATIENTS AND METHODS: In the framework of a randomized controlled 1-year trial the effectiveness and safety of a commercial weight loss program was compared with a primary care intervention. At the end of the trial the participating general practitioners and study participants were asked to answer specific questions about their offered weight loss management. This paper relates to the German study part (268 participants, 40 general practitioners). RESULTS: More than half of the general practitioners reported to offer a dietary concept which varied strongly across general practitioners. About one third of the general practitioners considered commercial weight loss programs as an alternative to support weight reduction. Participants reported that they considered weight loss advice by their general practitioners as helpful. But patients in the commercial weight loss program assessed the advice as more positive and achieved twice as much weight loss as patients in the primary care intervention. CONCLUSION: Evaluated commercial weight loss programs can be effective and safe alternatives for general practitioners to achieve weight loss in overweight and obese patients.

Geography of the circadian gene clock and photoperiodic response in western North American populations of the three-spined stickleback Gasterosteus aculeatus.

Controlled laboratory experiments were used to show that Oregon and Alaskan three-spined stickleback Gasterosteus aculeatus, collected from locations differing by 18° of latitude, exhibited no significant variation in length of the polyglutamine domain of the clock protein or in photoperiodic response within or between latitudes despite the fact that male and female G. aculeatus are photoperiodic at both latitudes. Hence, caution is urged when interpreting variation in the polyglutamine repeat (PolyQ) domain of the gene clock in the context of seasonal activities or in relationship to photoperiodism along geographical gradients.

A within-trial cost-effectiveness analysis of primary care referral to a commercial provider for weight loss treatment, relative to standard care--an international randomised controlled trial.

BACKGROUND: Due to the high prevalence of overweight and obesity there is a need to identify cost-effective approaches for weight loss in primary care and community settings. OBJECTIVE: We evaluated the cost effectiveness of two weight loss programmes of 1-year duration, either standard care (SC) as defined by national guidelines, or a commercial provider (Weight Watchers) (CP). DESIGN: This analysis was based on a randomised controlled trial of 772 adults (87% female; age 47.4±12.9 years; body mass index 31.4±2.6 kg m(-2)) recruited by health professionals in primary care in Australia, United Kingdom and Germany. Both a health sector and societal perspective were adopted to calculate the cost per kilogram of weight loss and the ICER, expressed as the cost per quality adjusted life year (QALY). RESULTS: The cost per kilogram of weight loss was USD122, 90 and 180 for the CP in Australia, the United Kingdom and Germany, respectively. For SC the cost was USD138, 151 and 133, respectively. From a health-sector perspective, the ICER for the CP relative to SC was USD18 266, 12 100 and 40 933 for Australia, the United Kingdom and Germany, respectively. Corresponding societal ICER figures were USD31,663, 24,996 and 51,571. CONCLUSION: The CP was a cost-effective approach from a health funder and societal perspective. Despite participants in the CP group attending two to three times more meetings than the SC group, the CP was still cost effective even including these added patient travel costs. This study indicates that it is cost effective for general practitioners (GPs) to refer overweight and obese patients to a CP, which may be better value than expending public funds on GP visits to manage this problem.

Genetic correlations and the evolution of photoperiodic time measurement within a local population of the pitcher-plant mosquito, Wyeomyia smithii.

The genetic relationship between the daily circadian clock and the seasonal photoperiodic timer remains a subject of intense controversy. In Wyeomyia smithii, the critical photoperiod (an overt expression of the photoperiodic timer) evolves independently of the rhythmic response to the Nanda-Hamner protocol (an overt expression of the daily circadian clock) over a wide geographical range in North America. Herein, we focus on these two processes within a single local population in which there is a negative genetic correlation between them. We show that antagonistic selection against this genetic correlation rapidly breaks it down and, in fact, reverses its sign, showing that the genetic correlation is due primarily to linkage and not to pleiotropy. This rapid reversal of the genetic correlation within a small, single population means that it is difficult to argue that circadian rhythmicity forms the necessary, causal basis for the adaptive divergence of photoperiodic time measurement within populations or for the evolution of photoperiodic time measurement among populations over a broad geographical gradient of seasonal selection.

[Weight maintenance after weight loss - how the body defends its weight]. / Gewichtserhaltung nach Gewichtsreduktion - wie der Körper sein Gewicht verteidigt.

Mean weight loss of most conservative therapeutic weight loss programmes is about five to six kilograms after one year. In our "obesogenic" environment it is difficult for persons to maintain the new weight. Also continuation of the programme cannot prevent a moderate weight increase in the follow-up year. The reasons for this are not clear: individual lifestyle, environmental and genetic factors may play a role, but also the complex regulatory system of the body "to defend its weight". Nevertheless, for weight maintenance a lifelong change of lifestyle is of critical importance. Concerning nutrition a fat-reduced diet with a decrease of energy density together with regular eating habits and adequate portion size promises the greatest benefit and is likely to allow sufficient satiety.

Psychometric evaluation of the German version of the impact of weight on Quality of Life-Lite (IWQOL-Lite) questionnaire.

OBJECTIVE: To evaluate the psychometric properties of a German version of the Impact of Weight on Quality of Life-Lite (IWQOL-Lite) questionnaire. METHOD: IWQOL-Lite scores were obtained from 351 overweight/obese individuals and 127 lean adult volunteers. In addition, a subgroup of 126 obese subjects completed also the German versions of the 36-item short-form health survey (SF-36), the Beck Depression Inventory (BDI), the Eating Disorder Examination-Questionnaire (EDE-Q), and the German validated version of the Three-Factor Eating Questionnaire (TFEQ). RESULTS: The German version of the IWQOL-Lite has psychometric properties comparable to those found for the original version and demonstrates high internal consistency and excellent construct validity. Furthermore, the German IWQOL-Lite clearly discriminates between groups based on BMI on all subscales and the total score. CONCLUSION: The results of the present study suggest that the German IWQOL-Lite is a psychometrically validated instrument with which to measure weight-specific health related quality of life.