The Genetics of Obesity

Obesity is a result of excess body fat accumulation. This excess is associated with adverse health effects such as CVD, type 2 diabetes, and cancer. The development of obesity has an evident environmental contribution, but as shown by heritability estimates of 40% to 70%, a genetic susceptibility component is also needed. Progress in understanding the etiology has been slow, with findings largely restricted to monogenic, severe forms of obesity. However, technological and analytical advances have enabled detection of more than 20 obesity susceptibility loci. These contain genes suggested to be involved in the regulation of food intake through action in the central nervous system as well as in adipocyte function. These results provide plausible biological pathways that may, in the future, be targeted as part of treatment or prevention strategies. Although the proportion of heritability explained by these genes is small, their detection heralds a new phase in understanding the etiology of common obesity

Associations between severity of obesity in childhood and adolescence, obesity onset and parental BMI: a longitudinal cohort study

Objective: To explore the relationship between severity of obesity at age 7 and age 15, age at onset of obesity, and parental body mass index (BMI) in obese children and adolescents. Design: Longitudinal cohort study.Subjects:Obese children (n231) and their parents (n462) from the Swedish National Childhood Obesity Centre. Methods: Multivariate regression analyses were applied with severity of obesity (BMI standard deviation score (BMI SDS)) and onset of obesity as dependent variables. The effect of parental BMI was evaluated and in the final models adjusted for gender, parental education, age at onset of obesity, severity of obesity at age 7 and obesity treatment. Results: For severity of obesity at age 7, a positive correlation with maternal BMI was indicated (P<0.05). Severity of obesity at this age also showed a strong negative correlation with the age at onset of obesity. Severity of obesity at age 15 was significantly correlated with both maternal and paternal BMI (P≥0.01). In addition, BMI SDS at age 15 differed by gender (higher for boys) and was positively correlated with severity of obesity at age 7 and negatively correlated with treatment. Also, a negative correlation was indicated at this age for parental education. No correlation with age at onset was found at age 15. For age at onset of obesity there was no relevant correlation with parental BMI. Children within the highest tertile of the BMI SDS range were more likely to have two obese parents. Conclusion: The impact of parental BMI on the severity of obesity in children is strengthened as the child grows into adolescence, whereas the age at onset is probably of less importance than previously thought. The influence of parental relative weight primarily affects the severity of childhood obesity and not the timing. © 2011 Macmillan Publishers Limited All rights reserved.link_to_subscribed_fulltex

Prevalence and psychopathological characteristics of depression in consecutive otorhinolaryngologic inpatients

<p>Abstract</p> <p>Background</p> <p>High prevalence of depression has been reported in otorhinolaryngologic patients (ORL). However, studies using a semi-structured interview to determine the prevalence of depression in ORL are lacking. Therefore the present study sought to determine the depression prevalence in ORL applying a semi-structured diagnostic interview and to further characterize the pathopsychological and demographic characteristics of depression in these patients.</p> <p>Methods</p> <p>One-hundred inpatients of the otorhinolaryngologic department of a German university hospital participated voluntarily (age M = 38.8 years, SD = 13.9; 38.0% female). Depression was assessed using a clinical interview in which the International Diagnostic Checklist for depression (IDCL) was applied. Patients completed the Brief Symptom Inventory (BSI) which constitutes three composite scores and nine symptom scales and the Beck Depression Inventory (BDI). Multivariate analyses of variance, correlations and effect sizes were conducted.</p> <p>Results</p> <p>A prevalence of depression of 21.0% was determined, 38.0% of the depressed patients were female. Depressed patients showed higher scores on the BSI-scales "interpersonal sensitivity", "depression", "anxiety", "phobic anxiety" and "psychoticism" with medium effect sizes.</p> <p>Conclusions</p> <p>High prevalence of depression was found which is in accordance with results of prior studies. Depressed patients showed higher psychological distress as compared to non-depressed patients. The results call for carrying on in engaging in depression research and routine depression screening in ORL.</p

Impact of physical activity level and dietary fat content on passive overconsumption of energy in non-obese adults

Background: Passive overconsumption is the increase in energy intake driven by the high-fat energy-dense food environment. This can be explained in part because dietary fat has a weaker effect on satiation (i.e. process that terminates feeding). Habitually active individuals show improved satiety (i.e. process involved in post-meal suppression of hunger) but any improvement in satiation is unknown. Here we examined whether habitual physical activity mitigates passive overconsumption through enhanced satiation in response to a high-fat meal. Methods: Twenty-one non-obese individuals with high levels of physical activity (HiPA) and 19 individuals with low levels of physical activity (LoPA) matched for body mass index (mean = 22.8 kg/m2) were recruited. Passive overconsumption was assessed by comparing ad libitum energy intake from covertly manipulated high-fat (HFAT; 50% fat) or high-carbohydrate (HCHO; 70% carbohydrate) meals in a randomized crossover design. Habitual physical activity was assessed using SenseWear accelerometers (SWA). Body composition, resting metabolic rate, eating behaviour traits, fasting appetite-related peptides and hedonic food reward were also measured. Results: In the whole sample, passive overconsumption was observed with greater energy intake at HFAT compared to HCHO (p  0.05). SWA confirmed that HiPA were more active than LoPA (p  0.05 for all). Conclusions: Non-obese individuals with high or low physical activity levels but matched for BMI showed similar susceptibility to passive overconsumption when consuming an ad libitum high-fat compared to a high-carbohydrate meal. This occurred despite increased total daily energy expenditure and improved body composition in HiPA. Greater differences in body composition and/or physical activity levels may be required to impact on satiation

Studies of Metabolic Phenotypic Correlates of 15 Obesity Associated Gene Variants

Genome-wide association studies have identified novel BMI/obesity associated susceptibility loci. The purpose of this study is to determine associations with overweight, obesity, morbid obesity and/or general adiposity in a Danish population. Moreover, we want to investigate if these loci associate with type 2 diabetes and to elucidate potential underlying metabolic mechanisms.15 gene variants in 14 loci including TMEM18 (rs7561317), SH2B1 (rs7498665), KCTD15 (rs29941), NEGR1 (rs2568958), ETV5 (rs7647305), BDNF (rs4923461, rs925946), SEC16B (rs10913469), FAIM2 (rs7138803), GNPDA2 (rs10938397), MTCH2 (rs10838738), BAT2 (rs2260000), NPC1 (rs1805081), MAF (rs1424233), and PTER (rs10508503) were genotyped in 18,014 middle-aged Danes.Five of the 15 gene variants associated with overweight, obesity and/or morbid obesity. Per allele ORs ranged from 1.15-1.20 for overweight, 1.10-1.25 for obesity, and 1.41-1.46 for morbid obesity. Five of the 15 variants moreover associated with increased measures of adiposity. BDNF rs4923461 displayed a borderline BMI-dependent protective effect on type 2 diabetes (0.87 (0.78-0.96, p = 0.008)), whereas SH2B1 rs7498665 associated with nominally BMI-independent increased risk of type 2 diabetes (1.16 (1.07-1.27, p = 7.8×10(-4))).Associations with overweight and/or obesity and measures of obesity were confirmed for seven out of the 15 gene variants. The obesity risk allele of BDNF rs4923461 protected against type 2 diabetes, which could suggest neuronal and peripheral distinctive ways of actions for the protein. SH2B1 rs7498665 associated with type 2 diabetes independently of BMI

Phone and e-mail counselling are effective for weight management in an overweight working population: a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>The work setting provides an opportunity to introduce overweight (i.e., Body Mass Index ≥ 25 kg/m²) adults to a weight management programme, but new approaches are needed in this setting. The main purpose of this study was to investigate the effectiveness of lifestyle counselling by phone or e-mail on body weight, in an overweight working population. Secondary purposes were to establish effects on waist circumference and lifestyle behaviours, and to assess which communication method is the most effective.</p> <p>Methods</p> <p>A randomized controlled trial with three treatments: intervention materials with phone counselling (phone group); a web-based intervention with e-mail counselling (internet group); and usual care, i.e. lifestyle brochures (control group). The interventions used lifestyle modification and lasted a maximum of six months. Subjects were 1386 employees, recruited from seven companies (67% male; mean age 43 (SD 8.6) y; mean BMI 29.6 (SD 3.5) kg/m²). Body weight was measured by research personnel and by questionnaire. Secondary outcomes fat, fruit and vegetable intake, physical activity and waist circumference were assessed by questionnaire. Measurements were done at baseline and after six months. Missing body weight was multiply imputed.</p> <p>Results</p> <p>Body weight reduced 1.5 kg (95% CI -2.2;-0.8, p < 0.001) in the phone group and 0.6 kg (95% CI -1.3; -0.01, p = 0.045) in the internet group, compared with controls. In completers analyses, weight and waist circumference in the phone group were reduced with 1.6 kg (95% CI -2.2;-1.0, p < 0.001) and 1.9 cm (95% CI -2.7;-1.0, p < 0.001) respectively, fat intake decreased with 1 fatpoint (1 to 4 grams)/day (95% CI -1.7;-0.2, p = 0.01) and physical activity increased with 866 METminutes/week (95% CI 203;1530, p = 0.01), compared with controls. The internet intervention resulted in a weight loss of 1.1 kg (95% CI -1.7;-0.5, p < 0.001) and a reduction in waist circumference of 1.2 cm (95% CI -2.1;-0.4, p = 0.01), in comparison with usual care. The phone group appeared to have more and larger changes than the internet group, but comparisons revealed no significant differences.</p> <p>Conclusion</p> <p>Lifestyle counselling by phone and e-mail is effective for weight management in overweight employees and shows potential for use in the work setting.</p> <p>Trial registration</p> <p>ISCRTN04265725.</p

Depression and HIV in Botswana: A Population-Based Study on Gender-Specific Socioeconomic and Behavioral Correlates

Depression is a leading contributor to the burden of disease worldwide, a critical barrier to HIV prevention and a common serious HIV co-morbidity. However, depression screening and treatment are limited in sub-Saharan Africa, and there are few population-level studies examining the prevalence and gender-specific factors associated with depression.We conducted a cross-sectional population-based study of 18–49 year-old adults from five districts in Botswana with the highest prevalence of HIV-infection. We examined the prevalence of depressive symptoms, using a Hopkins Symptom Checklist for Depression (HSCL-D) score of ≥1.75 to define depression, and correlates of depression using multivariate logistic regression stratified by sex.Of 1,268 participants surveyed, 25.3% of women and 31.4% of men had depression. Among women, lower education (adjusted odds ratio [AOR] 2.07, 95% confidence interval [1.30–3.32]), higher income (1.77 [1.09–2.86]), and lack of control in sexual decision-making (2.35 [1.46–3.81]) were positively associated with depression. Among men, being single (1.95 [1.02–3.74]), living in a rural area (1.63 [1.02–2.65]), having frequent visits to a health provider (3.29 [1.88–5.74]), anticipated HIV stigma (fearing discrimination if HIV status was revealed) (2.04 [1.27–3.29]), and intergenerational sex (2.28 [1.17–4.41]) were independently associated with depression.Depression is highly prevalent in Botswana, and its correlates are gender-specific. Our findings suggest multiple targets for screening and prevention of depression and highlight the need to integrate mental health counseling and treatment into primary health care to decrease morbidity and improve HIV management efforts