Claus Holst

The Diet, Obesity and Genes (Diogenes) Dietary Study in eight European countries – a comprehensive design for long-term intervention

Diogenes is a Pan‐European, randomized, controlled dietary intervention study investigating the effects of dietary protein and glycaemic index on weight (re)gain, metabolic and cardiovascular risk factors in obese and overweight families in eight European centres. The article is methodological in character, and the presentation of ‘results’ will be limited to baseline characteristics of the study populations included. A total of 891 families with at least one overweight/obese parent underwent screening. The parents started an initial 8‐week low‐calorie diet and families with minimum one parent attaining a weight loss of ≥8%, were randomized to one of five energy ad libitum, low‐fat (25–30 E%) diets for 6 or 12 months: low protein/low glycaemic index, low protein/high glycaemic index, high protein/low glycaemic index, high protein/high glycaemic index or control (national dietary guidelines). At two centres the families were provided dietary instruction plus free foods for 6 months followed by 6‐month dietary instruction only. At the remaining six centres the families received dietary instruction only for 6 months. The median weight loss during the low‐calorie diet was 10.3u2003kg (inter‐quartile range: 8.7–12.8u2003kg, nu2003=u2003775). A total of 773 adults and 784 children were randomized to the 6‐month weight (re)gain prevention phase. Despite major cultural and dietary regional differences in Europe, interventions addressing effects of dietary factors are feasible with a reasonable attrition.

Lack of Association of Fatness-Related FTO Gene Variants with Energy Expenditure or Physical Activity

CONTEXTnA common variant in the first intron of FTO (rs9939609, T/A) is associated with fatness in Caucasians.nnnOBJECTIVEnFTO may regulate energy homeostasis through the hypothalamus, and we hypothesized that AA-genotypes of rs9939609 FTO have lower energy expenditure and/or a lower level of physical activity.nnnMETHODSnThe study population included all obese young men (body mass index > or = 31 kg/m(2)) at the mandatory draft board examinations in the Copenhagen area from 1943 to 1977 and a randomly selected control group from this population. Subgroups of 234 obese and 323 controls were examined in 1998-2000 (median age 48 yr). Fat mass (FM), lean body mass (LBM), leisure-time physical activity (LTPA), maximum oxygen uptake (VO(2)max), resting energy expenditure (REE), and glucose-induced thermogenesis (GIT) were measured. The FTO rs9939609 variant was genotyped. A recessive transmission mode fit the data best. Logistic regression was used to assess the odds ratios of the AA-genotype in relation to LTPA, VO(2)max, REE, and GIT.nnnRESULTSnThe AA-genotype of FTO rs9939609 had higher REE in the age-adjusted model, but the association was eliminated when adjusting for FM and LBM. The AA-genotype was not associated with LTPA, VO(2)max, or GIT. This was not influenced by adjustment for age, FM, or LBM. The AA-genotype had increased FM, even with adjustment for age, LBM, REE, GIT, VO(2)max, and LTPA. Results were similar for FTO rs8050136 and rs7193144.nnnCONCLUSIONSnHomozygous carriers of the A-allele of rs9939609 FTO do not have lower REE, GIT, VO(2)max, or LTPA but higher FM, irrespective of LBM, REE, GIT, VO(2)max, and LTPA.

Genome-Wide Population-Based Association Study of Extremely Overweight Young Adults - The GOYA Study

Background Thirty-two common variants associated with body mass index (BMI) have been identified in genome-wide association studies, explaining ∼1.45% of BMI variation in general population cohorts. We performed a genome-wide association study in a sample of young adults enriched for extremely overweight individuals. We aimed to identify new loci associated with BMI and to ascertain whether using an extreme sampling design would identify the variants known to be associated with BMI in general populations. Methodology/Principal Findings From two large Danish cohorts we selected all extremely overweight young men and women (nu200a=u200a2,633), and equal numbers of population-based controls (nu200a=u200a2,740, drawn randomly from the same populations as the extremes, representing ∼212,000 individuals). We followed up novel (at the time of the study) association signals (p<0.001) from the discovery cohort in a genome-wide study of 5,846 Europeans, before attempting to replicate the most strongly associated 28 SNPs in an independent sample of Danish individuals (nu200a=u200a20,917) and a population-based cohort of 15-year-old British adolescents (nu200a=u200a2,418). Our discovery analysis identified SNPs at three loci known to be associated with BMI with genome-wide confidence (P<5×10−8; FTO, MC4R and FAIM2). We also found strong evidence of association at the known TMEM18, GNPDA2, SEC16B, TFAP2B, SH2B1 and KCTD15 loci (p<0.001), and nominal association (p<0.05) at a further 8 loci known to be associated with BMI. However, meta-analyses of our discovery and replication cohorts identified no novel associations. Significance Our results indicate that the detectable genetic variation associated with extreme overweight is very similar to that previously found for general BMI. This suggests that population-based study designs with enriched sampling of individuals with the extreme phenotype may be an efficient method for identifying common variants that influence quantitative traits and a valid alternative to genotyping all individuals in large population-based studies, which may require tens of thousands of subjects to achieve similar power.

FTO Gene Associated Fatness in Relation to Body Fat Distribution and Metabolic Traits throughout a Broad Range of Fatness

Background A common single nucleotide polymorphism (SNP) of FTO (rs9939609, T/A) is associated with total body fatness. We investigated the association of this SNP with abdominal and peripheral fatness and obesity-related metabolic traits in middle-aged men through a broad range of fatness present already in adolescence. Methodology/Principal Findings Obese young Danish men (nu200a=u200a753, BMI≥31.0 kg/m2) and a randomly selected group (nu200a=u200a879) from the same population were examined in three surveys (mean age 35, 46 and 49 years, respectively). The traits included anthropometrics, body composition, oral glucose tolerance test, blood lipids, blood pressure, fibrinogen and aspartate aminotransferase. Logistic regression analysis was used to assess the age-adjusted association between the phenotypes and the odds ratios for the FTO rs9939609 (TT and TA genotype versus the AA genotype), for anthropometrics and body composition estimated per unit z-score. BMI was strongly associated with the AA genotype in all three surveys: ORu200a=u200a1.17, pu200a=u200a1.1*10−6, ORu200a=u200a1.20, pu200a=u200a1.7*10−7, ORu200a=u200a1.17, pu200a=u200a3.4*10−3, respectively. Fat body mass index was also associated with the AA genotype (ORu200a=u200a1.21, pu200a=u200a4.6*10−7 and ORu200a=u200a1.21, pu200a=u200a1.0*10−3). Increased abdominal fatness was associated with the AA genotype when measured as waist circumference (ORu200a=u200a1.21, pu200a=u200a2.2*10−6 and ORu200a=u200a1.19, pu200a=u200a5.9*10−3), sagittal abdominal diameter (ORu200a=u200a1.17, pu200a=u200a1.3*10−4 and ORu200a=u200a1.18, pu200a=u200a0.011) and intra-abdominal adipose tissue (ORu200a=u200a1.21, pu200a=u200a0.005). Increased peripheral fatness measured as hip circumference (ORu200a=u200a1.19, pu200a=u200a1.3*10−5 and ORu200a=u200a1.18, pu200a=u200a0.004) and lower body fat mass (ORu200a=u200a1.26, pu200a=u200a0.002) was associated with the AA genotype. The AA genotype was significantly associated with decreased Stumvoll insulin sensitivity index (ORu200a=u200a0.93, pu200a=u200a0.02) and with decreased non-fasting plasma HDL-cholesterol (ORu200a=u200a0.57, pu200a=u200a0.037), but not with any other of the metabolic traits. However, all significant results for both body fat distribution and metabolic traits were explained by a mediating effect of total fat mass. Conclusion The association of the examined FTO SNP to general fatness throughout the range of fatness was confirmed, and this association explains the relation between the SNP and body fat distribution and decreased insulin sensitivity and HDL-cholesterol. The SNP was not significantly associated with other metabolic traits suggesting that they are not derived from the general accumulation of body fat.

Impact on weight dynamics and general growth of the common FTO rs9939609: a longitudinal Danish cohort study.

Objective and design:We investigated the impact of the fatness-related FTO rs9939609 A-allele on cross-sectional and longitudinal measures of body mass index (BMI), height and lean body mass (LBM) in a unique cohort representing a broad range of BMI.Subjects and measurements:A random sample of all men attending the Danish draft boards during 1943–1977 plus all men with a BMI⩾31.0u2009kg/m2 (assuring representation of the right end of the distribution) was taken. Anthropometric measures were available at up to eight points in time from birth to adulthood in 1629 genotyped men. The odds ratio (OR) for being a carrier of FTO rs9939609 according to (1) one unit alteration in z-scores for BMI, height and LBM at given ages and (2) longitudinal changes in BMI and height z-scores were assessed by logistic regression.Results:Except at birth, the AA genotype was associated with increased BMI z-scores at all point during the monitored lifespan, starting at the age of 7 years. This effect remained stable until early adulthood, where further weight gain occurred. The AA genotype was also—mainly through the effect on fatness—associated with accelerated linear growth in childhood (age 7 years; OR, 1.36; 95% confidence interval (CI), 1.06–1.74) and increased LBM in adulthood (OR, 1.24; 95% CI, 1.14–1.35).Conclusion:Fatness induced by FTO rs9939609 in early childhood is sustained until early adulthood, where further weight gain may occur. FTO rs9939609 may, however, also be associated with linear growth and LBM mainly through the effect on fat mass.

Adipose tissue transcriptome reflects variations between subjects with continued weight loss and subjects regaining weight 6 mo after caloric restriction independent of energy intake

BACKGROUNDnThe mechanisms underlying body weight evolution after diet-induced weight loss are poorly understood.nnnOBJECTIVEnWe aimed to identify and characterize differences in the subcutaneous adipose tissue (SAT) transcriptome of subjects with different weight changes after energy restriction-induced weight loss during 6 mo on 4 different diets.nnnDESIGNnAfter an 8-wk low-calorie diet (800 kcal/d), we randomly assigned weight-reduced obese subjects from 8 European countries to receive 4 diets that differed in protein and glycemic index content. In addition to anthropometric and plasma markers, SAT biopsies were taken at the beginning [clinical investigation day (CID) 2] and end (CID3) of the weight follow-up period. Microarray analysis was used to define SAT gene expression profiles at CID2 and CID3 in 22 women with continued weight loss (successful group) and in 22 women with weight regain (unsuccessful group) across the 4 dietary arms.nnnRESULTSnDifferences in SAT gene expression patterns between successful and unsuccessful groups were mainly due to weight variations rather than to differences in dietary macronutrient content. An analysis of covariance with total energy intake as a covariate identified 1338 differentially expressed genes. Cellular growth and proliferation, cell death, cellular function, and maintenance were the main biological processes represented in SAT from subjects who regained weight. Mitochondrial oxidative phosphorylation was the major pattern associated with continued weight loss.nnnCONCLUSIONSnThe ability to control body weight loss independent of energy intake or diet composition is reflected in the SAT transcriptome. Although cell proliferation may be detrimental, a greater mitochondrial energy gene expression is suggested as being beneficial for weight control. This trial was registered at clinicaltrials.gov as NCT00390637.

Fatness-Associated FTO Gene Variant Increases Mortality Independent of Fatness – in Cohorts of Danish Men

Background The A-allele of the single nucleotide polymorphism (SNP), rs9939609, in the FTO gene is associated with increased fatness. We hypothesized that the SNP is associated with morbidity and mortality through the effect on fatness. Methodology/Principal Findings In a population of 362,200 Danish young men, examined for military service between 1943 and 1977, all obese (BMI≥31.0 kg/m2) and a random 1% sample of the others were identified. In 1992–94, at an average age of 46 years, 752 of the obese and 876 of the others were re-examined, including measurements of weight, fat mass, height, and waist circumference, and DNA sampling. Hospitalization and death occurring during the following median 13.5 years were ascertained by linkage to national registers. Cox regression analyses were performed using a dominant effect model (TT vs. TA or AA). In total 205 men died. Mortality was 42% lower (pu200a=u200a0.001) with the TT genotype than in A-allele carriers. This phenomenon was observed in both the obese and the randomly sampled cohort when analysed separately. Adjustment for fatness covariates attenuated the association only slightly. Exploratory analyses of cause-specific mortality and morbidity prior to death suggested a general protective effect of the TT genotype, whereas there were only weak associations with disease incidence, except for diseases of the nervous system. Conclusion Independent of fatness, the A-allele of the FTO SNP appears to increase mortality of a magnitude similar to smoking, but without a particular underlying disease pattern barring an increase in the risk of diseases of the nervous system.

A distinct adipose tissue gene expression response to caloric restriction predicts 6-mo weight maintenance in obese subjects

BACKGROUNDnWeight loss has been shown to reduce risk factors associated with cardiovascular disease and diabetes; however, successful maintenance of weight loss continues to pose a challenge.nnnOBJECTIVEnThe present study was designed to assess whether changes in subcutaneous adipose tissue (scAT) gene expression during a low-calorie diet (LCD) could be used to differentiate and predict subjects who experience successful short-term weight maintenance from subjects who experience weight regain.nnnDESIGNnForty white women followed a dietary protocol consisting of an 8-wk LCD phase followed by a 6-mo weight-maintenance phase. Participants were classified as weight maintainers (WMs; 0-10% weight regain) and weight regainers (WRs; 50-100% weight regain) by considering changes in body weight during the 2 phases. Anthropometric measurements, bioclinical variables, and scAT gene expression were studied in all individuals before and after the LCD. Energy intake was estimated by using 3-d dietary records.nnnRESULTSnNo differences in body weight and fasting insulin were observed between WMs and WRs at baseline or after the LCD period. The LCD resulted in significant decreases in body weight and in several plasma variables in both groups. WMs experienced a significant reduction in insulin secretion in response to an oral-glucose-tolerance test after the LCD; in contrast, no changes in insulin secretion were observed in WRs after the LCD. An ANOVA of scAT gene expression showed that genes regulating fatty acid metabolism, citric acid cycle, oxidative phosphorylation, and apoptosis were regulated differently by the LCD in WM and WR subjects.nnnCONCLUSIONnThis study suggests that LCD-induced changes in insulin secretion and scAT gene expression may have the potential to predict successful short-term weight maintenance. This trial was registered at clinicaltrials.gov as NCT00390637.

Empirical Bayes Age-Period-Cohort Analysis of Retrospective Incidence Data

We analyse the (age, time)-specific incidence of diabetes based on retrospective data obtained from a prevalent cohort only including survivors to a particular date. From underlying point processes with intensities corresponding to the (age, time)-specific incidence rates the observed point pattern is assumed to be generated by an independent thinning process with parameters (assumed known) depending on population density and survival probability to the sampling date. A Bayesian procedure is carried out for the optimal adjustment and comparison of isotropic and anisotropic smoothing priors for the intensity functions, as well as for the decomposition of the intensity on the (time, age) Lexis diagram into the three factors of age, period and cohort.

Initial weight loss on an 800-kcal diet as a predictor of weight loss success after 8 weeks: The Diogenes study

Objective:The purpose of this study was to investigate whether pre-treatment subject characteristics and weight change during the first weeks of a low-calorie diet (LCD) can predict weight loss outcomes at the end of a controlled 8-week weight loss period in overweight and obese adults.Subjects:A total of 932 overweight and obese subjects of both genders were included at eight European centers, and underwent an 8-week LCD period.Results:The weight loss at week 8 was positively correlated with initial body weight (Spearmans ρ=0.62), height (ρ=0.43), body mass index (ρ=0.43), waist (ρ=0.48) and hip circumference (ρ=0.33), sagittal diameter (ρ=0.45), fat mass (ρ=0.35) and fat-free mass (ρ=0.52), and gender (ρ=−0.36) (all P<0.01). In the multivariate regression model, adjusted for center, only initial body weight, early weight loss (week 1) and weight loss at week 3 were significant predictors of weight loss outcome at week 8: weight loss (kg) at week 8=0.09+0.046 × baseline body weight (kg)−0.311 × weight loss (kg) at week 1+1.284 × weight loss (kg) at week 3 (R 2=68%, P<0.0001). A weight loss of ⩾2.6u2009kg at week 1 during the LCD period was identified as the optimal cut-off predictor for at least 10u2009kg weight loss at week 8.Conclusions:This study suggests that initial body weight, early weight loss (week 1) and weight loss at week 3 are predictors of final weight loss during an 8-week LCD, and may be used as early biomarkers of subsequent responses to an LCD diet.