Obesity and health risks

The composite alliance of FTO locus with obesity-related genetic variants

Obesity has become a genuine global pandemic due to lifestyle and environmental modifications, and is associated with chronic lethal comorbidities. Various environmental factors such as lack of physical activity due to modernization and higher intake of energy-rich diets are primary obesogenic factors in pathogenesis of obesity. Genome-wide association study has identified the crucial role of FTO (fat mass and obesity) in human obesity. A bunch of SNPs in the first intron of FTO has been identified and subsequently correlated to body mass index and body composition. Findings of in silico, in vitro, and in vivo studies have manifested the robust role of FTO in regulation of energy expenditure and food consumption. Numerous studies have highlighted the mechanistic pathways behind the concomitant functions of FTO in adipogenesis and body size. Current investigation has also revealed the link of FTO neighbouring genes i.e., RPGRIP1L, IRX3 and IRX5 and epigenetic factors with obesity phenotypes. The motive behind this review is to cite the consequences of FTO on obesity vulnerability.

Differences in Nutritional and Health Status in School Children from the Highlands and Lowlands of Bolivia

Children in the Bolivian Andes are exposed to endemic infections and meager nourishment, and live under poor hygienic conditions. The prevention of children malnutrition is a priority in many countries including Bolivia. In this study, the health status of schoolchildren in Taraco, a Puna district, at 4,000 meters above sea level (masl) and in Caranavi, at 650 masl in the wealthier subtropical valleys, was compared. The weight, height, and hematological and biochemical parameters in blood, parasites in stool, and clinical information in 120 children from rural Taraco and in 96 from semi-urban Caranavi, both predominantly of Aymara ethnicity, were registered. Eleven percent of Taraco children were undernourished compared with 3% in Caranavi. Instead, 41% of the children in Caranavi were obese or overweight, compared with 8% in Taraco. Anemia was found in 74% of the children in Taraco compared with 7% in Caranavi. Albumin levels were normal in all samples, albeit lower in Taraco. Similar and normal serum zinc levels were measured in both groups. Approximately 60% of the children in both locations showed insufficient vitamin D levels, with lower levels in Taraco children. Hymenolepis nana and Entamoeba coli, parasites determinant of poor hygienic conditions, were respectively detected in 78% and 21% of fecal samples from Taraco, and in 29% and 8% of samples from Caranavi. We show increased anemia, nutritional deficiencies, and indications of poor hygienic conditions in highlands compared with lowlands. The prevalence of obesity in the lowlands demands addressing diverse nutritional deficiencies in the regions of Bolivia.

Health insurance selection in Chile: a cross-sectional and panel analysis

In Chile, workers are mandated to choose either public or private health insurance coverage. Although private insurance premiums depend on health risk, public insurance premiums are solely linked to income. This structure implies that individuals with higher health risks may tend to avoid private insurance, leaving the public insurance system responsible for their care. This article attempts to explore the determinants of health insurance selection (private vs public) by individuals in Chile and to test empirically whether adverse selection indeed exists. We use panel data from Chile's 'Encuesta de Proteccion Social' survey, which allows us to control for a rich set of individual observed and unobserved characteristics using both a cross-sectional analysis and fixed-effect methods. Results suggest that age, sex, job type, income quintile and self-reported health are the most important factors in explaining the type of insurance selected by individuals. Asymmetry in insurance mobility caused by restrictions on pre-existing conditions may explain why specific illnesses have an unambiguous relationship with insurance selection. Empirical evidence tends to indicate that some sorting by health risk and income levels takes place in Chile. In addition, by covering a less healthy population with higher utilization of general health consultations, the public insurance system may be incurring disproportionate expenses. Results suggest that if decreasing segmentation and unequal access to health services are important policy objectives, special emphasis should be placed on asymmetries in the premium structure and inter-system mobility within the health care system. Preliminary analysis of the impact of the 'Garantias Explicitas de Salud' plan (explicit guarantees on health care plan) on insurance selection is also considered.

Predictors of obesity in childhood, adolescence, and adulthood in a birth cohort

To determine how characteristics of pregnancy, birth, and early infancy are related to offspring obesity at three critical developmental periods. Mothers were followed through pregnancy and 10-15 years after. Offspring data were obtained through medical record review. Maternal and offspring characteristics were examined to predict obesity in childhood (ages 4-5 years), adolescence (ages 9-14 years), and early adulthood (ages 19-20 years). The original cohort included 802 children born to 795 women. Children who were twins, who had died, or whose mothers had died were excluded (n=25). Medical records of 68.5% of the remaining 777 children documented a height and weight at childhood, adolescence, or early adulthood. Relative risks (RRs) to predict obesity at early adulthood were 12.3 for childhood and 45.1 at adolescence. RRs were also significant to predict obesity at early adulthood between the mother's obesity at prepregnancy (RR=6.4), 4-5 years postpregnancy (RR=6.3), and 10-15 years postpregnancy (RR=6.2). Excluding these variables from the multivariate models and adjusting by gender, birth insurance, and mother's marital status at delivery, the best model to predict obesity at childhood included birth weight, weight gain in infancy, and delivery type. At adolescence, it included maternal pregnancy smoking status, gestational weight gain, and weight gain in infancy, and in early adulthood, included maternal pregnancy smoking status, gestational weight gain, and birth weight. Maternal pregnancy smoking status, gestational weight gain, and weight gain in infancy have long-term effects on offspring. Maternal obesity is the strongest predictor of obesity at all times studied.

Linking psychosocial stressors and childhood obesity

Research has established a wide array of genetic and environmental factors that are associated with childhood obesity. The focus of this review is on recent work that has established the relationship between one set of environmental factors, stressors and childhood obesity. These stressors are particularly prevalent for low-income children, a demographic group that has high rates of obesity in the USA and other developed countries. In this review, we begin by summarizing the psychosocial stressors faced by children followed by health outcomes associated with exposure to these stressors documented in the literature. We then summarize 11 articles which examined the connection between psychosocial stressors in the household and obesity and eight articles which examined the connection between individual psychosocial stressors and obesity. Policy recommendations emerging from this research include recognizing reductions in childhood obesity as a potential added benefit of social safety net programmes that reduce financial stress among families. In addition, policies and programmes geared towards childhood obesity prevention should focus on helping children build resources and capacities to teach them how to cope effectively with stressor exposure. We conclude with suggestions for future research.

FTO Biology and Obesity: Why Do a Billion of Us Weigh 3 kg More?

Few would dispute that the current obesity epidemic has been driven by lifestyle and environmental changes. However, it is clear that individuals respond differently to these "obesigenic" changes and this variation in response has a strong genetic element. Genome-wide association studies have revealed that single nucleotide polymorphisms in Fat mass and obesity-associated transcript (FTO) are robustly associated with body mass index and obesity. Although the effect of these risk alleles are modest, with heterozygous and homozygous carriers weighing approximately 1.5 and 3 kg more respectively, there are an estimated one billion homozygous carriers in the world, spanning multiple different ethnicities and populations. Yet despite its broad impact, the biological function of FTO, particularly its role in controlling energy balance, remains unknown. Although the study of severe Mendelian obesity has been invaluable in illuminating critical pathways controlling food intake, the major burden of disease is carried by those of us with "common obesity," which to date has resisted yielding meaningful biological insights. FTO has at last given us a handle on a huge, worldwide, common problem. In this review, we focus on the available genetic and in vivo evidence to date that implicates FTO in the control of energy balance.

Regulation of Fto/Ftm gene expression in mice and humans

Two recent, large whole-genome association studies (GWAS) in European populations have associated a approximately 47-kb region that contains part of the FTO gene with high body mass index (BMI). The functions of FTO and adjacent FTM in human biology are not clear. We examined expression of these genes in organs of mice segregating for monogenic obesity mutations, exposed to underfeeding/overfeeding, and to 4 degrees C. Fto/Ftm expression was reduced in mesenteric adipose tissue of mice segregating for the Ay, Lep ob, Lepr db, Cpe fat, or tub mutations, and there was a similar trend in other tissues. These effects were not due to adiposity per se. Hypothalamic Fto and Ftm expression were decreased by fasting in lean and obese animals and by cold exposure in lean mice. The fact that responses of Fto and Ftm expression to these manipulations were almost indistinguishable suggested that the genes might be coregulated. The putative overlapping regulatory region contains at least two canonical CUTL1 binding sites. One of these nominal CUTL1 sites includes rs8050136, a SNP associated with high body mass. The A allele of rs8050136 preferentially bound CUTL1[corrected] in human fibroblast DNA. 70% knockdown of CUTL1 expression in human fibroblasts decreased FTO and FTM expression by 90 and 65%, respectively. Animals and humans with various genetic interruptions of FTO or FTM have phenotypes reminiscent of aspects of the Bardet-Biedl obesity syndrome, a confirmed "ciliopathy." FTM has recently been shown to be a ciliary basal body protein.

Using focus group results to inform preschool childhood obesity prevention programming

OBJECTIVE

This study about maternal feeding practices and beliefs was conducted as background for the development of a childhood obesity prevention program for multi-ethnic parents in the USA receiving services from a federal government supplemental nutrition program for low-income mothers.

DESIGN

Using a grounded theory approach, focus groups were conducted with low-income African American, white non-Hispanic (i.e. the majority Caucasian American population), Hispanic and Vietnamese parents to collect cross-cultural perspectives on: (a) infant and child feeding practices, (b) childhood overweight, (c) healthy dietary intake, (d) physical activity and inactivity, and (e) infant feeding information sources.

RESULTS

A content analysis of the data yielded three main themes common to all four groups: (a) lack of awareness of the relationship between increased physical activity and health, (b) the use of food to influence behavior, and (c) the loss of parental control over feeding when a child starts child care or school, and revealed perspectives on age-appropriate food, infant satiety, overweight and information sources that were specific to each group.

CONCLUSION

Interventions that enhance parent self-efficacy that build on themes that are specific to ethnic groups toward preventing childhood obesity are needed. There is also a need for culturally appropriate information for governmental nutrition programs that is in the client's own language and takes into account ethnic differences in beliefs and traditions.

An analysis of the functional health of obese children and adolescents utilizing the PODC instrument

Childhood and adolescent obesity is increasing in prevalence and is known to have long-term medical and musculoskeletal consequences. The baseline Pediatric Outcomes Data Collection Instrument (PODCI) was administered to 50 obese patients (>95th percentile BMI for age) or their parent (for those <11 years) presenting to a pediatric orthopaedic clinic to assess overall function. There were no differences between sexes (31 boys, 19 girls) or age group (>11 years, n = 36; <11 years, n = 14) in any demographic or PODCI category. Compared with normative data, there was significant impairment in sports and pain identified in both genders, African-Americans, and those older than 11 years. These findings were consistent when comparing genders, ethnicities, and ages. There was no difference in happiness between any gender, age, or ethnic group. All groups reported essentially neutral satisfaction. There appears to be a lack of self-recognition of or reluctance to admit functional impairment secondary to obesity. Being obese, African-American ethnicity, and age older than 11 years appear to be risk factors for limited, yet significant, functional impairment.

Interaction of satiety and reward response to food stimulation

Obesity is among the most pressing health issues affecting developed countries. The etiology of obesity remains unclear despite its associated health risks. We propose a framework for obesity modeled upon overeating as a substance dependence disorder arising from a combination of abnormal cognitive and neuroendocrine processes. While significant work in both of these fields has investigated the body's regulation of satiety signals, fewer studies have focused upon the mechanisms by which these two seemingly disparate systems interact. Although emotional states have been shown to mediate reward processing, the implications for hunger mediating reward have not previously been addressed. We review the interaction between central satiety signals and reward responses to food stimuli and discuss the implications of this research for understanding the causes of obesity.

Female gender and wealth are associated to overweight among adolescents in La Paz, Bolivia

OBJECTIVE

To describe the prevalence of overweight, obesity and being thin in adolescents of La Paz City, Bolivia.

DESIGN

Cross-sectional study, clustered sampling.

SETTING

La Paz, Bolivia, August-September 2003.

SUBJECTS

Height and weight of 525 adolescents (mean age 16 y; s.d.+/-1.3) attending public and private schools were measured; sociodemographic characteristics were assessed with a short questionnaire.

RESULTS

The present study reveals that 9.3% (+/-2.5) of the sample are thin adolescents; 19.8% (+/-3.4) is the overall prevalence of overweight and 2.3% (+/-1.3) the overall prevalence of obesity. The odds of being thin were higher among those working (P=0.03) and among those of higher age (P<0.001). The odds of being overweight were higher among female subjects (P<0.001). The odds of being obese were higher among younger adolescents (P=0.046) and among the more wealthy ones (P=0.044).

CONCLUSIONS

A large prevalence of 22% overweight/obesity in adolescents from La Paz City was observed. The findings support the need of enhanced nutritional surveillance and interventions particularly in female adolescents.

Measured weights in PEI adults reveal higher than expected obesity rates

BACKGROUND

The increasing prevalence of obesity and overweight in Canada is a significant health concern. Unfortunately, we know very little about the actual weight status and associated health risks in our population since most surveys use only self-reported body weights and heights and typically do not include a measure of body fat distribution. This paper summarizes the findings of the Prince Edward Island Nutrition Survey.

METHODS

A random sample of 1,995 adults aged 18-74 were interviewed in their homes and weights, heights and waist circumference measurements were obtained. Relative health risks, population proportions and their corresponding 95% confidence intervals were calculated.

RESULTS

Overall, almost one third of PEI adults are obese (BMI > or = 30). This is almost double that reported in the 1995 National Population Health Survey using self-reported heights and weights. More women were classified as being very severely obese (Class III) than men, but for both men and women there appears to be a trend of increased mild obesity with age. Based on BMI and waist circumference, over one third of the population is considered to be at high to extremely high risk for health problems.

CONCLUSION

Self-reported height and weight data appear to result in significant underestimation of the problem of obesity. Given the serious health consequences associated with this condition, it is critical that measured heights and weights be collected in future population-based surveys to ensure that public health interventions are based on accurate prevalence data.