Obesity epidemics: secular trend or globalization consequence? Beyond the interaction between genetic and environmental factors

Predicting nationwide obesity from food sales using machine learning

The obesity epidemic progresses everywhere across the globe, and implementing frequent nationwide surveys to measure the percentage of obese population is costly. Conversely, country-level food sales information can be accessed inexpensively through different suppliers on a regular basis. This study applies a methodology to predict obesity prevalence at the country-level based on national sales of a small subset of food and beverage categories. Three machine learning algorithms for nonlinear regression were implemented using purchase and obesity prevalence data from 79 countries: support vector machines, random forests and extreme gradient boosting. The proposed method was validated in terms of both the absolute prediction error and the proportion of countries for which the obesity prevalence was predicted satisfactorily. We found that the most-relevant food category to predict obesity is baked goods and flours, followed by cheese and carbonated drinks.

Using Integrative Analysis of DNA Methylation and Gene Expression Data in Multiple Tissue Types to Prioritize Candidate Genes for Drug Development in Obesity

Obesity has become a major public health issue which is caused by a combination of genetic and environmental factors. Genome-wide DNA methylation studies have identified that DNA methylation at Cytosine-phosphate-Guanine (CpG) sites are associated with obesity. However, subsequent functional validation of the results from these studies has been challenging given the high number of reported associations. In this study, we applied an integrative analysis approach, aiming to prioritize the drug development candidate genes from many associated CpGs. Association data was collected from previous genome-wide DNA methylation studies and combined using a sample-size-weighted strategy. Gene expression data in adipose tissues and enriched pathways of the affiliated genes were overlapped, to shortlist the associated CpGs. The CpGs with the most overlapping evidence were indicated as the most appropriate CpGs for future studies. Our results revealed that 119 CpGs were associated with obesity (p ≤ 1.03 × 10⁻⁷). Of the affiliated genes, SOCS3 was the only gene involved in all enriched pathways and was differentially expressed in both visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT). In conclusion, our integrative analysis is an effective approach in highlighting the DNA methylation with the highest drug development relevance. SOCS3 may serve as a target for drug development of obesity and its complications.

Proximity effects in obesity rates in the US: A Spatial Markov Chains approach

In this paper, we investigate, by means of a Spatial Markov Chains approach, the existence of proximity effects at State level for US data on obesity rates in the period 1990-2011. We find that proximity effects do play an important role in the spatial diffusion of obesity (the obesity 'epidemics'), and that the actual health geography of nearby States in terms of high vs. low obesity rates makes an important difference as to the future evolution of the State's own obesity rate over time. This means, in particular, that clusters of States characterized by uniformly high levels of obesity rates, as it happens for instance in the US Southern macro-region, may suffer from a perverse 'geographical lock-in' effect that calls for coordinated action across States to implement effective countervailing policies.

Home visitation programs: an untapped opportunity for the delivery of early childhood obesity prevention

BACKGROUND

Extant obesity efforts have had limited impact among low-income underserved children, in part because of limitations inherent to existing programs: (i) short duration and low intensity; (ii) late timing of implementation, when children are already overweight or obese; (iii) intervention delivery limiting their accessibility and sustainability; and (iv) failure to address barriers such as a lack of culturally competent services, poverty and housing instability, which interfere with healthy lifestyle changes.

OBJECTIVE

This concept paper proposes an innovative model of obesity prevention implemented in infancy and sustained throughout early childhood to address the limitations of current obesity prevention efforts. Specifically, we propose to integrate sustained, weekly, in-home obesity prevention as part of the services already delivered by ongoing Home Visitation Programs, which currently do not target obesity prevention.

CONCLUSION

The home visiting structure represents an ideal model for impactful obesity prevention as home visitation programs: (i) already provide comprehensive services to diverse low-income infants and families who are most at risk for obesity and poor health because of socio-economic and structural conditions; (ii) services are initiated in infancy and sustained throughout critical developmental periods for the formation of healthy/unhealthy behaviors; and (iii) have been in place for more than 40 years, with a widespread presence across the United States and nationwide, which is critical for the scalability and sustainability of obesity prevention.

A Community-Based Participatory Research Approach for Preventing Childhood Obesity: The Communities and Schools Together Project

BACKGROUND

Childhood obesity is a systemic and complex, multilevel public health problem. Research approaches are needed that effectively engage communities in reversing environmental determinants of child obesity.

OBJECTIVES

This article discusses the Communities and Schools Together (CAST) Project and lessons learned about the project's community-based participatory research (CBPR) model.

METHODS

A partnership of schools, community organizations, and researchers used multiple methods to examine environmental health risks for childhood obesity and conduct school-community health programs. Action work groups structured partner involvement for designing and implementing study phases.

LESSONS LEARNED

CBPR in child obesity prevention involves engaging multiple communities with overlapping yet divergent goals. Schools are naturally situated to participate in child obesity projects, but engagement of key personnel is essential for functional partnerships. Complex societal problems require CBPR approaches that can align diverse communities and necessitate significant coordination by researchers. CBPR can provide simultaneous health promotion across multiple communities in childhood obesity prevention initiatives. Support for emergent partner activities is an essential practice for maintaining community interest and involvement in multiyear CBPR projects.

CONCLUSION

Investigator-initiated CBPR partnerships can effectively organize and facilitate large, health-promoting partnerships involving multiple, diverse stakeholder communities. Lessons learned from CAST illustrate the synergy that can propel projects that are holistically linked to the agents of a community.

Anthropometric, penile and testis measures in post-pubertal Italian males

BACKGROUND

Relationships between anthropometric measures, body proportions, weight and penile dimensions in young adult males have not been previously analyzed. Furthermore, although male fertility has declined in last decades, no data on testicular volume (the best surrogate measure for spermatogenic potential) are available for the general population of young men in Italy.

AIM

To analyze anthropometric measures and proportions, testicular volumes, and penile dimensions in a large cohort from the general population of young Italian men aged 18-19 yr. MATERIALS/SUBJECTS: We analyzed 2019 students aged 18-19 years for height, weight, body mass index (BMI), waist circumference, arm span, pubis-to-floor and crown-to-pubis length, and penile dimensions. Testicular volumes were measured by ultrasound in 776 subjects.

RESULTS

Thirty-six percent of the subjects had a pathological arm span-height difference (>3 cm) and 44.7% had a pathological pubis-to-floor/ crown-to-pubis ratio (≤ 0.92). The mean penis length was 8.9 ± 1.4 cm and the penis circumference was 9.5 ± 1.0 cm. BMI was positively associated with arm span-height difference and negatively with penis length; 23.2% of the subjects had low mean testicular volume (<12 ml).

CONCLUSIONS

The findings highlight a strong influence of BMI on skeletal proportions and penis length, identify a large proportion of subjects with testicular hypotrophy at risk for future fertility, and suggest to consider worldwide studies to redefine normal values for arm span-height difference and upper/ lower body segment ratio.

Repercussões sociais no hábito alimentar dos obesos

O trabalho tem como objetivo analisar os fatores sociais do cotidiano que mais influenciam no hábito alimentar do obeso. A pesquisa, de enfoque qualitativo, teve como participantes 11 indivíduos obesos que frequentavam o ambulatório de nutrição de um hospital público na cidade de João Pessoa, Paraíba, Brasil. Foram realizadas entrevistas semiestruturadas, gravadas para a análise de conteúdo. Observou-se que as categorias que se destacaram nos discursos foram: autoimagem negativa, discriminação, ansiedade e sentimento de culpa. Ao se tornarem obesos, os indivíduos do presente estudo parecem desenvolver uma autoimagem negativa, relacionada à ansiedade e à depressão, entre outros fatores, o que pode levar a um sentimento de culpa, reforçado pela discriminação da sociedade que, ao invés de ajudá-lo a perder peso, parece estimulá-lo a comer mais.

Frameworks of population obesity and the use of cultural consensus modeling in the study of environments contributing to obesity

Obesity in Eastern Europe has been linked to privilege and status prior to the collapse of communism, and to exposure to free-market economics after it. Neither formulation is a complete explanation, and it is useful to examine the potential value of other models of population obesity for the understanding of this phenomenon. These include those of: thrifty genotypes; obesogenic behaviour; obesogenic environments; nutrition transition; obesogenic culture; and biocultural interactions of genetics, environment, behaviour and culture. At the broadest level, obesity emerges from the interaction of thrifty genotype with obesogenic environment. However, defining obesogenic environments remains problematic, especially in relation to sociocultural factors. Furthermore, since different identity groups may share different values concerning the obesogenicity of the environment, a priori assumptions about group homogeneity may lead to flawed interpretations of the importance of sociocultural factors in obesogenic environments. A new way to identify cultural coherence of groups and populations in relation to environments contributing to obesity is put forward here, that of cultural consensus modeling.

Detection of free fatty acids following a conditioned taste aversion in rats

A gustatory transduction mechanism for free fatty acids (FFAs) has been described in isolated rat taste receptor cells; however, the ability of behaving rats to detect FFAs has not been characterized. Through conditioned taste aversion (CTA) methodology, this study defines the ability of rats to detect and avoid the two principal FFA components of corn oil, linoleic and oleic acid. Following taste aversion conditioning, rats avoided both linoleic and oleic acid at greater than or equal to 66 muM and failed to avoid either 44 muM linoleic or oleic acid. Rats demonstrated generalized avoidances between 88 muM linoleic and oleic acid irrespective of presenting the FFAs as either unesterified acids dissolved in 5 mM ethanol or aqueous sodium salts, sodium linoleate and sodium oleate. Following a CTA to linoleic acid, rats did not show generalized avoidance of NaCl or ethanol, two potentially concomitant tastants in the oral cavity. A CTA to linoleic or oleic acid did produce a generalized avoidance to the other FFA. These results support the ability of rats to detect linoleic and oleic acid (>44 muM) and suggest that the two FFAs share common orosensory properties. Furthermore, it is unlikely that the detection of the FFAs is due to an enhancement of other concomitant tastants such as saliva or the delivery solution.

Six novel mutations in the proopiomelanocortin and melanocortin receptor 4 genes in severely obese adults living in southern Italy

BACKGROUND

The genetic characterization of obese individuals could clarify the molecular mechanisms underlying body weight regulation and lead to targeted therapy. Here we report variants of the proopiomelanocortin (POMC) and melanocortin receptor 4 (MC4R) genes detected in severely obese adults living in southern Italy.

METHODS

A total of 196 unrelated nondiabetic severely obese individuals [111 females and 85 males; mean (SD) age, 32.2 (11.5) years; mean body mass index, 48.8 (8.1) kg/m(2)] and 100 normal-weight healthy volunteers (34 males and 66 females) entered the study. POMC and MC4R were genotyped by sequencing analysis. Leptin, insulin, glucose, and the lipid profile were measured in fasting serum samples. We used the protein truncation test to verify the stop-codon mutation. Anthropometric measurements, sitting blood pressure, and heart rate were also recorded.

RESULTS

Of the obese participants, 1.5% had mutations in POMC exon 3 (new mutations, P231L and E244X; known, R236G) and 2.5% had MC4R mutations (new mutations, W174C, Q43X, S19fsX51, and I317V; known, A175T). These mutations were not present in the controls. Gene polymorphisms were identified in similar percentages of severely obese and nonobese individuals, i.e., respectively, 52.5% and 51% (POMC) and 1% and 2% (MC4R).

CONCLUSIONS

We detected 2 new POMC mutations and 4 new MC4R mutations in a large number of severely obese adults living in southern Italy. These mutations, not present in normal-weight individuals, are further evidence that defects in the melanocortin pathway are related to severe obesity.

Obesity epidemics: simple or simplicistic answers?

Among the strategies suggested to face obesity epidemics there is also a mere reduction of only 100-200 kcal day, i.e. less mouthfuls of food and a little more walking every day. Are these proposals "simple and feasible" or, vice versa, "simplicistic and unrealistic" solutions? A possible source of such confusion comes firstly from dietary guidelines: the "food pyramid" may easily lead to misinterpretation as low-fat foods enriched in simple sugars produce similar metabolic abnormalities as saturated fat rich foods. Replacement of fruit derived fructose with other fructose-enriched beverages is not adequately considered. In total, 45-60 min of moderately intense physical activity, instead of "few steps", daily appears a more realistic evaluation of the role of physical activity in energy balance but is still an unrealistic intervention strategy in many obese individuals requiring a long preliminary rehabilitation period. Another complaint is the current poor distinction between "preventive, population oriented" and "therapeutic, clinical" intervention strategies possibly due to the long duration of the latent "preclinical" phase of the disease and the scarcity of safe and effective drugs. Obesity may be considered a "culture-bound" disease and as such it requires a proper cultural, political and educational strategies. The number of obesity clinics worldwide is too limited; educational interventions in the crucial period of the developmental age are lacky. The social science content of medical school curricula, and teaching healthy behaviours, needs to be improved. In conclusion, a deeper reflection from Medical Societies on the relationship between the negative aspects of the "transition diet" and "globalization process" may help to produce really "simple" and more successful strategies against obesity epidemics and its complications.