A general IGF-I overexpression effectively rescued somatic growth and bone deficiency in mice caused by growth hormone receptor knockout

Both growth hormone and insulin-like growth factor (IGF)-I are essential for postnatal somatic growth, while exerting distinct effects on energy homeostasis. Although growth hormone controls IGF-I production, whether IGF-I was the exclusive mediator of its growth promotion is still debated. In order to further explore their in vivo interactions in somatic growth as well as in energy homeostasis, we have crossed mutant (MT-IGF) transgenic mice onto the GHR ? / ? background. As expected, GHR gene deficiency caused growth retardation, including significant decreases in lumbar, femur and total body lengths, as well as decreased bone area, mineral content and mineral density. IGF-I overexpression alone in MT-IGF mice increased the weight, with no significant change in bone mineralization or longitudinal growth. Compared to GHR ? / ? littermates, overexpressed IGF-I in bitransgenic mice (GHR ? / ? and MT-IGF positive) exhibited fully restored body weight, lumbar (but not femur) and total body lengths, and normalized overall bone area, mineral content and density. On the other hand, there were significant changes in fasting glucose level, glucose tolerance, lean/fat masses and even adipose histology as a result of the transgenic/knockout double-crossing. IGF-I overexpression normalized glucose tolerance in GHR ? / ? mice. Intriguingly, on GHR+/ ? background of partial growth hormone insensitivity, overexpression of IGF-I caused a significant weight gain. Our results thus establish that the growth defect and bone deficiency caused by lack of growth hormone signaling can be effectively restored by increasing IGF-I production in vivo.     

Predictive performance of obesity indexes for the risk of high blood pressure in an adult population

Background and objectives

Comparisons of predictive performance of various anthropometric measures in high blood pressure have not been investigated. This study aimed at evaluating and comparing the predictive power of Body Mass Index (BMI), Body Adiposity index (BAI) and A Body Shape Index (ABSI) for predicting hypertension in adults.

The Association of Taste with Change in Adiposity-Related Health Measures

The relationship between taste-intensity patterns and 5-year change in adiposity-related health measures was determined. Participants were members of the Beaver Dam Offspring Study, a study of the adult children of participants in the population-based Epidemiology of Hearing Loss Study. There were 1,918 participants (mean baseline age=48.8 years; range=22 to 84 years) with baseline taste (2005 to 2008) and follow-up (2010 to 2013) data. Outcomes included 5-year change in body mass index, waist circumference, blood pressure, non–high-density lipoprotein cholesterol, and glycosylated hemoglobin A1c, and hedonic ratings of specific foods. Cluster analysis with Ward's minimum variance method identified the following 5 patterns of the suprathreshold taste intensities of salt, sweet, sour, and bitter: salt and sweet intensities slightly above population averages, average sour and bitter intensities; salt, sour, and bitter intensities above population average, average sweet intensity; salt, sour, and bitter intensities above population average, sweet intensity substantially above average; all intensities below population averages; and all intensities close to population average. The General Linear Model procedure was used for testing cluster differences in the outcomes. With covariate adjustment, the group with all intensities close to population averages had a significantly lower average increase in body mass index compared with the group with above-average intensities for salt, sour, and bitter (+0.4 vs +0.9), and in glycosylated hemoglobin A1c compared with the group with above-average intensities for all tastes (+0.20% vs +0.34%). Clusters differed in the hedonics of foods representing sweetness and saltiness. The study's findings provide evidence that perceived taste intensity might be related to changes in adiposity-related health.     

Body composition measured by dual-energy X-ray absorptiometry half-body scans in obese children

Aim: To perform a methods comparison of a left or right half‐body scan versus whole‐body scan for measuring body composition in a sample of obese children. Methods: A group of obese children (n = 58; ≥95th BMI percentile; 8–18 years) were required to undergo a dual‐energy X‐ray absorptiometry (DXA) body composition measurement as part of an ongoing cohort study; 34 fit within the imaging field of the DXA scanner and were eligible for inclusion in the present analysis. Percent fat, total mass, fat mass, lean mass and bone mineral content (BMC) were estimated from half‐body scans and compared with the whole‐body results. Assessment was completed using GE enCORE 11.40 software. Results: In comparing left‐ and right‐side scans to whole‐body scans, there was significant correlation for all body composition variables (p ≤ 0.005, R² = 0.996–1.0). Bland Altman analyses also showed high levels of agreement between half‐body estimates and whole‐body measurements. Conclusion: This study supports using a half‐body scan methodology for percent fat, total mass, fat mass, lean mass, and BMC as a valid alternative to full‐body analysis in obese children and youth.     

Influence of high-fat feeding, diet-induced obesity, and hyperamylinemia on the sensitivity to acute amylin

Obesity results in the increased secretion of various hormones controlling food intake and body weight, such as leptin, and insulin; increased circulating levels of pancreatic amylin have also been described in obese humans and rodents. Because leptin-resistance is present in diet-induced obese (DIO) rats, and because hyperleptinemia seems necessary for the full development of leptin resistance, we tested whether amylin sensitivity is inversely correlated with adiposity, such that DIO reduces the anorectic action of acute amylin. We also determined if hyperamylinemia leads to a change in amylin sensitivity. In the first experiment, rats were chronically exposed to a high fat (HF; 60% fat) diet or fed standard chow for control. The anorectic response to amylin was tested on several occasions over a 14 week observation period. HF feeding led to the expected increase in body adiposity; the response to an acute amylin injection (5 - 50 μg/kg s.c.) was unaltered for 10 weeks of HF feeding. Even after 12 weeks on a HF diet, which clearly caused obesity, acute administration of amylin (5 μg/kg, s.c.) was still able to suppress food intake, although the suppression was not statistically significant. Further experiments using additional doses of amylin will be necessary to demonstrate possible amylin resistance after HF feeding or in DIO rats. In the second experiment, we tested more specifically whether hyperamylinemia that may result from HF feeding and subsequent obesity, reduces the sensitivity of the amylin signaling system. To avoid confounding factors, we chronically infused lean chow fed rats with amylin (5 or 10 μg/kg/day s.c.) to elevate their plasma amylin concentration to levels observed in obese rats (30 - 40 pM). In the absence of obesity, hyperamylinemia did not lead to a reduced sensitivity to acute amylin (5 - 20 μg/kg s.c.) injections; acute amylin reduced eating similarly in all groups of rats. Overall, we concluded that direct diet effects by short term exposure to HF appear to be of little importance for amylin sensitivity; further, long-term maintenance on a HF diet and the resulting obesity only slightly attenuated the anorectic response to acute amylin. Because we observed no marked changes in amylin sensitivity in lean, chow fed rats with induced hyperamylinemia, amylin receptor downregulation in chronic hyperamylinemia does not seem to occur.     

Book review of Human Growth: Assessment and Interpretation. By Alex F. Roche and Shumei S. Sun. (Cambridge University Press,Cambridge, 2003). [pp. 311]. ISBN: 0 521 78245 7. US$95, £53.50.

Background: In many parts of the developing world, modernization has resulted in an increase in the prevalence of overweight and obesity and a subsequent rise in nutrition-related, non-communicable diseases such as cardiovascular disease and Type 2 diabetes.

Aim: The study examined the impact of socio-economic and lifestyle changes associated with modernization on the body size and shape of Balinese women.

Subjects and methods: Anthropometric data including weight, height, body mass index (BMI) and seven skinfolds were collected from 564 Balinese women, aged between 15 and 45 years. The relationship between the degree of ‘modernization’ (using such parameters as household wealth and education level) and body size and shape was analysed using multiple regression analysis, as was the effect of age, family size and breast-feeding.

Results: Using the WHO (WHO ) categories of BMI, 14% of Balinese women displayed Chronic Energy Deficiency (BMI<18.5?kg?m^?2), 7% were overweight (BMI?=?25.0–29.9?kg?m^?2) and less than 1% were obese (BMI?≥?30.0?kg?m^?2). Household wealth (p<0.0001) and education level (p<0.05) were significantly associated with fatness, while breast-feeding (p<0.05) was significantly associated with leanness. Fat distribution was largely independent of biological and socio-economic variables.

Conclusions: The trend toward increasing fatness associated with greater household wealth and higher education has important health implications for Balinese women as they continue their rapid transition from subsistence agriculture towards a more ‘western’ lifestyle.

Résumé. Arrière plan: Dans de nombreuses régions du globe, à la faveur du développement et de la modernisation, est apparue une prévalence du surpoids et de l’obésité ainsi qu’un accroissement corollaire de maladies non infectieuses telles que les maladies cardiovasculaires et le diabète de type 2.

But: L’étude examine l’impact des changements socioéconomiques et de style de vie associés à la modernisation, sur le format et la forme du corps des femmes balinaises.

Sujets et méthodes: Des données anthropométriques comprenant le poids, la stature, l’indice de masse corporelle (IMC) et sept plis cutanés, ont été collectées sur 564 femmes balinaises âgées de 15 à 45 ans. La relation entre le degré de ‘modernisation’ (au moyen de paramètres tels que l’aisance du foyer et le niveau éducatif) et la forme et le format corporel a été analysée, ainsi que les effets de l’âge, de la dimension de la famille et de l’allaitement maternel, au moyen de régressions multiples.

Résultats: Par rapport aux catégories d’IMC de l’OMS (1995), 14% des femmes balinaises présentent une déficience chronique d’énergie (IMC<18,5?kg?m^?2), 7% ont du surpoids (IMC?=?25,0–29,9?kg?m^?2) et moins de 1% sont obèses (IMC≥30,0?kg?m^?2). L’aisance du foyer (p<0,0001) et le niveau éducatif (p<0,05) sont associés significativement à l’adiposité tandis que l’allaitement maternel l’est avec la minceur. La distribution de l’adiposité est largement indépendante des variables biologiques et socioéconomiques.

Conclusion: La tendance en direction d’un accroissement de l’adiposité en association avec meilleure aisance domestique et meilleure éducation présente des implications importantes pour la santé des femmes balinaises, dans la mesure où elles poursuivent une rapide transition d’une agriculture de subsistance à un mode de vie plus ‘occidental’.

Zusammenfassung. Hintergrund: In vielen Entwicklungsländern hat die Modernisierung zu einem Anstieg der Prävalenz von Übergewicht und Adipositas geführt und in der Folge zu einem Anstieg ernährungsabhängiger nicht-übertragbarer Erkrankungen wie kardiovaskulärer Krankheiten und Typ2 Diabetes.

Ziel: Die Studie untersuchte die Bedeutung der mit der Modernisierung einhergehenden, sozio-ökonomischen Veränderungen und der Veränderungen des Lebensstils auf Körpermaße und Körperproportionen Balinesischer Frauen.

Probanden und Methoden: Anthropometrische Daten einschließlich Gewicht, Höhe, Körpermasse-Index (body mass index, BMI) und sieben Hautfettfalten wurden bei 564 Balinesischen Frauen im Alter zwischen 15 und 45 Jahren erhoben. Die Beziehung zwischen dem Grad der ‘Modernisierung’ (unter Verwendung von Begriffen wie verfügbares Haushaltseinkommen und Schulbildung) und Körpermaßen und Körperproportionen wurde mittels multipler Regressionsanalysen hinsichtlich der Effekte von Alter, Familiengröße und Stillen untersucht.

Ergebnisse: Unter Verwendung der WHO-Kategorien () für BMI zeigten 14% der Balinesischen Frauen Zeichen eines chronischen kalorischen Defizits (BMI??2), 7% waren übergewichtig (BMI?=?25,0—29,9?kg?m^?2) und weniger als 1% waren adipös (BMI?≥?30,0?kg?m^?2). Verfügbares Haushaltseinkommen (p<0,0001) und Schulbildung (p<0,05) waren signifikant mit übergewicht, Stillen jedoch (p<0,05) signifikant mit Magerkeit korreliert. Die Fettverteilung war überwiegend unabhängig von den biologischen und sozio-ökonomischen Variablen.

Zusammenfassung: Der Trend zu zunehmendem Übergewicht, der mit größerem verfügbaren Haushaltseinkommen und besserer Schulbildung assoziiert ist, hat große gesundheitliche Bedeutung für Balinesischer Frauen, solange ihr rasanter Übergang von einer landwirtschaftlichen Subsistenzkultur zu einem mehr ‘westlichen’ Lebensstil anhält.

Resumen. Antecedentes: En muchos lugares del mundo en vías de desarrollo, la modernización ha producido un incremento de la prevalencia del sobrepeso y la obesidad así como del riesgo subsecuente de sufrir enfermedades no transmisibles relacionadas con la nutrición, como la enfermedad cardiovascular y la diabetes tipo 2.

Objetivo: El estudio examinó el impacto de los cambios socioeconómicos y del estilo de vida asociados con la modernización sobre el tamaño y la forma corporal de las mujeres balinesas.

Sujetos y Métodos: Se recogieron datos antropométricos que incluían el peso, la estatura y el índice de masa corporal (IMC) de 564 mujeres de Bali, con edades comprendidas entre los 15 y 45 años. La relación entre el grado de ‘modernización’ (utilizando parámetros como la salud familiar y el nivel de educación) y el tamaño y la forma del cuerpo se analizó mediante un análisis de regresión múltiple, que consideraba el efecto de la edad, el tamaño familiar y el amamantamiento.

Resultados: Según las categorías de la WHO () para el IMC, el 14% de las mujeres balinesas mostraron una Deficiencia Energética Crónica (IMC<18,5?kg?m^?2), el 7% presentaba sobrepeso (IMC?=?25,0–29,9?kg?m^?2) y menos del 1% eran obesas (IMC?≥?30,0?kg?m^?2). La salud familiar (p<0,0001) y el nivel de estudios (p<0,05) estaban significativamente asociados con la adiposidad (exceso de peso), mientras que el amamantamiento (p<0,05) estaba significativamente asociado con la delgadez. La distribución de grasa era muy independiente de las variables biológicas y socioeconómicas.

Conclusiones: La tendencia hacia un incremento de la adiposidad cuanto mejor es la salud familiar y mayor el nivel de educación tiene importantes implicaciones sanitarias para las mujeres balinesas, a medida que éstas continúan su rápida transición desde la agricultura de subsistencia hacia un estilo de vida más ‘occidentalizado’.     

Why are children living in poverty getting fatter?

In recent decades, there has been a dramatic increase in unhealthy weight for both children and adults. The Canadian standard of living has changed in favour of more easily prepared, calorie-dense foods and sedentary practices. Many family characteristics have also changed over the past 50 years. More Canadian families are living in disadvantaged situations, forecasting a host of unhealthy behaviours and attitudes in adults. The poor are not only getting poorer, they are also becoming heavier. Children from disadvantaged families seem to be leading the trend in increasing prevalence of unhealthy weight. Because they live in neighbourhoods that are perceived as unsafe, these children are likely spending more time indoors. This is associated with watching more television, which not only displaces other forms of educational and active entertainment but also places them at risk of learning inaccurate information about proper eating. Social science research helps identify factors contributing most to the rise in excess weight within this population, thus providing essential clues for effective approaches to its eradication.