Nature Precedings - Tag feed for Obesity

Are endocannabinoid type 1 receptor gene (CNR1) polymorphisms associated with obesity and metabolic syndrome in postmenopausal Polish women?

Katarzyna Dunajska — Fri, 06 Nov 2009 10:47:40 UTC

Objective: The aim of this study was to determine whether genetic variation at the cannabinoid receptor-1 (CNR1) locus could have an effect on adiposity, fat distribution and obesity-related metabolic disorders in Polish postmenopausal women.Design and Subjects: The A3813G, G1422A and A4895G single nucleotide polymorphisms of CNR1 were genotyped in 348 randomly selected postmenopausal women aged 50-60 years recruited from the Wroclaw city population. Measurements: CNR1 genotypes, anthropometric measures (BMI, WC, body fat distribution by DEXA) and metabolic parameters (glucose, lipid profile, insulin FIRI) were determined.Results: The 3813G allele was not significantly associated with higher body mass, BMI, WC, total fat, or fat percentage, but was associated with higher android fat deposit (2971.78 ± 1655.08 ± 2472.64 ± 1300.53, p = 0.007) and percentage of android fat (37.59 ± 8.45 vs. 35.66 ± 7.63, p = 0.062). The 1422A allele was associated with higher total fat (31587.72 ± 9161.28 g vs. 26078.26 ± 7552.14 g, p = 0.019), fat percentage (40.51 ± 5.66% vs. 37.51 ± 4.99%, p = 0.052), and percentage of android fat (40.86 ± 9.73% vs. 36.09 ± 7.70%, p = 0.047). No associations were observed for the A4895G variant.Conclusions: There is an association of variants of CNR1 with obesity-related phenotypes in Polish postmenopausal women. As CB1 is a drug target for obesity, pharmacogenetic receptor gene analysis of obesity treatment by endocannabinoid blockade may be of interest to identify the best responders.

Ablation of Galectin-12 Results in Enhanced Lipolysis and Reduced Adiposity in Mice

Ri-Yao Yang — Wed, 06 May 2009 16:15:41 UTC

Aside from leptin, galectin-12 is the only other gene exclusively expressed in mouse adipose tissue, suggesting an important role in energy homeostasis. The breakdown of triglycerides, or lipolysis, is a tightly controlled process to tailor fat mobilization according to the body’s energy status. Lipolysis is stimulated by hormones that signal energy demand, and suppressed the satiety hormone insulin. However, much still remains to be learned about the intracellular control of lipolytic signaling in adipocytes. Here we show that galectin-12 functions as an intrinsic negative regulator of lipolysis by modulating cyclic adenosine monophosphate (cAMP) levels. Galectin-12 deficiency reduced adiposity of mice on regular chow, alleviated obesity in old ob/ob mice, and accelerated fasting-induced fat mobilization in mice that had been fed a high-fat diet. This study identifies a critical intracellular function for galectin-12 in lipid metabolism that could have important implications for future research of galectins and human metabolic disorders.

The Relationship between Physical Activity and Body Mass Index: Issues in Model Specification

Gizachew Tiruneh — Wed, 01 Apr 2009 09:04:55 UTC

Objective: To investigate the best statistical models that describe the effect of physical activity on BMI.Design: Cross-sectional analyses of physical activity and BMI data. Subjects: 107 obese, overweight, and healthy college students (mean duration of physical activity for the normal, overweight, and obese students: 89, 59, and 24 months, respectively; mean BMI for the normal, overweight, and obese students: 21.61, 27.07, and 35.54 kg/m2, respectively).Measurements: Inverse linear, inverse logarithmic, and inverse logistics models were used to analyze survey data for physical activity (measured by both frequency and duration of exercise) and BMI. Gender, age, and physical intensity variables were also statistically controlled. Results: Coefficients of determination, r-squared, showed the inverse logarithmic model is more accurate in describing the effect of physical activity on BMI than is the inverse linear model. The inverse logistic method also showed physical activity affects BMI. Conclusions: Although the inverse logarithmic method can be used in some cases, the inverse logistic model seems to be theoretically and empirically best suited in describing the relationship between physical activity and body weight.

Intestinal Electric Stimulation Accelerates Whole Gut Transit and Promotes Fat Excrement in Conscious Rats

Ying Sun — Thu, 05 Feb 2009 10:34:43 UTC

Introduction: Intestinal electric stimulation (IES) is proposed as a potential tool for the treatment of morbid obesity. Our previous study showed that IES with one pair of electrodes accelerated intestinal transit and decreased fat absorption in a segment of the jejunum in the anesthetized rats. The aims of this study were to assess the effects of IES on the whole gut transit and fat absorption in conscious rats, to examine the effects of multi-channel IES, and to explore the cholinergic mechanism behind the effects of IES. Methods: Thirty-eight male rats implanted with serosal electrodes were randomized into five groups: control without IES, 2/3 channel IES with short pulses, atropine and atropine plus IES. The whole gut transit and fat remained and emptied from the gut were analyzed after continuous 2-hour IES. Results: Two and three channel IES significantly accelerated phenol red (marker used for transit) excretion (ANOVA, P < 0.001). No significant difference was found between two and three channel IES. Two channel IES significantly increased the excretion of fat (P < 0.05). Atropine significantly blocked the accelerated transit induced by IES (ANOVA, P < 0.001). Correlation was found between the percentage of phenol red and fat retained in the whole gut (r = 0.497, P < 0.01). Conclusions: IES accelerates whole gut transit and promotes fat excrement in conscious rats, and these effects are mediated through the cholinergic nerves. These findings are in support of the concept that IES may be a promising treatment option for obesity.

The Relationship between Physical Activity and Body Mass Index: Issues in Model Specification

Gizachew Tiruneh — Wed, 21 Jan 2009 20:21:03 UTC

Objective: To investigate the best statistical models that describe the effect of physical activity on BMI.Design: Cross-sectional analyses of physical activity and BMI data.Subjects: 107 obese, overweight, and healthy college students (mean duration of physical activity for the normal, overweight, and obese students: 89, 59, and 24 months, respectively; mean BMI for the normal, overweight, and obese students: 21.61, 27.07, and 35.54 kg/m2, respectively).Measurements: Inverse linear, inverse logarithmic, and inverse logistics models were used to analyze survey data for physical activity (measured by both frequency and duration of exercise) and BMI. Gender, age, and physical intensity variables were also statistically controlled. Results: Coefficients of determination, r-squared, showed the inverse logarithmic model is more accurate in describing the effect of physical activity on BMI than is the inverse linear model. The inverse logistic method also showed physical activity affects BMI. Conclusions: Although the inverse logarithmic method can be used in some cases, the inverse logistic model seems to be theoretically and empirically best suited in describing the relationship between physical activity and body weight.

The Relationship between Physical Activity and Body Mass Index: Issues in Model Specification

Gizachew Tiruneh — Thu, 08 Jan 2009 10:54:31 UTC

Objective: To investigate the best statistical models that describe the effect of physical activity on BMI.Design: Cross-sectional analyses of physical activity and BMI data.Subjects: 107 obese, overweight, and healthy college students (mean duration of physical activity for the normal, overweight, and obese students: 89, 59, and 24 months, respectively; mean BMI for the normal, overweight, and obese students: 21.61, 27.07, and 35.54 kg/m2, respectively).Measurements: Inverse linear, inverse logarithmic, and inverse logistics models were used to analyze survey data for physical activity (measured by both frequency and duration of exercise) and BMI. Gender, age, and physical intensity variables were also statistically controlled. Results: Coefficients of determination, r-squared, showed the inverse logarithmic model is more accurate in describing the effect of physical activity on BMI than is the inverse linear model. The inverse logistic method also showed physical activity affects BMI. Conclusions: Although the inverse logarithmic method can be used in some cases, the inverse logistic model seems to be theoretically and empirically best suited in describing the relationship between physical activity and body weight.

The Relationship between Physical Activity and Body Mass Index: Issues in Model Specification

Gizachew Tiruneh — Mon, 05 Jan 2009 20:35:56 UTC

Objective: To investigate the best statistical models that describe the effect of physical activity on BMI.Design: Cross-sectional analyses of physical activity and BMI data.Subjects: 107 obese, overweight, and healthy college students (mean duration of physical activity for the normal, overweight, and obese students: 89, 59, and 24 months, respectively; mean BMI for the normal, overweight, and obese students: 21.61, 27.07, and 35.54 kg/m2, respectively).Measurements: Inverse linear, inverse logarithmic, and inverse logistics models were used to analyze survey data for physical activity (measured by both frequency and duration of exercise) and BMI. Gender, age, and physical intensity variables were also statistically controlled. Results: Coefficients of determination, r-squared, showed the inverse logarithmic model is more accurate in describing the effect of physical activity on BMI than is the inverse linear model. The inverse logistic method also showed physical activity affects BMI. Conclusions: Although the inverse logarithmic method can be used in some cases, the inverse logistic model seems to be theoretically and empirically best suited in describing the relationship between physical activity and body weight.

Obesity as a perceived social signal

Milind Watve — Tue, 23 Dec 2008 16:59:39 UTC

Fat accumulation has been classically considered as a means of energy storage. Obese people are theorized as metabolically ‘thrifty’, saving energy during times of food abundance. However, recent research has highlighted many neuro-behavioral and social aspects of obesity, with a suggestion that obesity, abdominal obesity in particular, may have evolved as a social signal. We tested here whether body proportions, and abdominal obesity in particular, are perceived as signals revealing personality traits. Faceless drawings of three male body forms namely lean, muscular and feminine, each with and without abdominal obesity were shown in a randomized order to a group of 222 respondents. A list of 30 different adjectives or short descriptions of personality traits was given to each respondent and they were asked to allocate the most appropriate figure to each of them independently. The traits included those directly related to physique, those related to nature, attitude and moral character and also those related to social status. For 29 out of the 30 adjectives people consistently attributed specific body forms. Based on common choices, the 30 traits could be clustered into distinct ‘personalities’ which were strongly associated with particular body forms. A centrally obese figure was perceived as “lethargic, greedy, political, money-minded, selfish and rich”. The results show that body proportions are perceived to reflect personality traits and this raises the possibility that in addition to energy storage, social selection may have played some role in shaping the biology of obesity.

Evolution of Thriftiness: An analytical viewpoint

Milind Watve — Tue, 23 Dec 2008 16:39:31 UTC

We examine here, using a simple mathematical model, the conditions under which thrifty genes or fetal programming could evolve. Obesity and related disorders are thought to have their roots in metabolic thirftiness that evolved to combat periodic starvation. The failure to detect any thrifty genes and the association of low birth weight with type 2 diabetes, caused a shift in the concept from thrifty gene to thrifty phenotype and fetal programming. This hypothesis assumes that intra-uterine undernutrition programs the body to be thrifty, predicting and preparing for starvation in later life. However, there are reproductive costs associated with thriftiness. Results of the model suggest that under no condition thrifty and non-thrifty genes would co-exist stably in a population. The conditions for evolution of fetal programming are also very restricted. For species with longer life spans, programming for thriftiness is unlikely to evolve if starvation is decided by seasonality or stochastic annual climatic variations since the correlation between intra-uterine and life-time conditions is poor. On the other hand, if starvation is governed by longer periodicity factors such as population oscillations or social hierarchies, there can be better correlation between intra-uterine and life time conditions. Therefore social and population processes are more likely to have selected for fetal programming rather than seasonal and climatic “feast and famine” conditions. Since social and population processes can have cues other than diet, these cues may also influence the incidence of obesity related disorders as some recent evidence suggest.

Money handling influences BMI: a survey of cashiers

Milind Watve — Mon, 22 Dec 2008 11:55:13 UTC

Money is a recent phenomenon in the evolutionary history of man and therefore no separate brain centre to handle money is likely to have evolved. The brain areas activated by food reward and money reward are extensively overlapping. In an experimental set-up, hunger was demonstrated to influence money related decisions and money related thoughts to influence hunger. This suggests that the brain areas evolved for handling food related emotions are exapted to handle money and therefore there could be a neuronal cross-talk between food and money. If this is true then attitude and behavior related to money and wealth could influence obesity. We conducted a survey of 211 individuals working as full time cashiers in order to test whether ownership over the cash, the amount of cash handled per day and the duration of cash handling work affected their body mass index (BMI). Cashiers who had ownership over the money had a significantly higher age corrected mean BMI than salaried cashiers. The BMI correlated positively with duration of service as cashier even after correcting for age and duration of sedentary job in males. Among salaried cashiers of both sexes, bank cashiers whose mean daily cash handling was one or two orders of magnitude greater than that of shop cashiers, had a significantly higher BMI. The effects of amount of money handled per day, years of service as cashier and ownership over the money handled could be shown to influence BMI independent of each other. The results support the exaptation hypothesis and suggest that the changing economy and attitudes towards money may be a contributing factor to the current obesity epidemic.