Adipose tissue infiltration in skeletal muscle: age patterns and association with diabetes among men of African ancestry

BACKGROUND: Although obesity is strongly associated with diabetes, the greater prevalence of diabetes in persons of African ancestry than in those of other ancestries cannot be explained simply by differences in total or central adiposity. OBJECTIVE: We examined whether skeletal muscle composition is associated with diabetes in 1249 men of African ancestry aged >or=40 y. DESIGN: Anthropometry and fasting serum glucose were measured, and lower-leg skeletal muscle composition was assessed with peripheral quantitative computerized tomography (pQCT). RESULTS: The prevalence of diabetes in this population was high (21%). We observed an age-associated adipose tissue remodeling in skeletal muscle and greater intermuscular (IMAT) and lesser subcutaneous (SAT) adipose tissue area with advancing age (P < 0.0001). Multivariate stepwise logistic regression identified more IMAT and less SAT to be significantly associated with a greater prevalence of diabetes. Even among normal-weight men [body mass index (BMI; in kg/m(2)) < 25], diabetic men had significantly (P = 0.01) more IMAT than did those without diabetes. Greater IMAT was also associated with a greater prevalence of hyperglycemia in men with a family history of diabetes than in those without such history (P for interaction = 0.02). CONCLUSIONS: These findings underscore the independent associations of subcutaneous and intermuscular fat among men of African ancestry, an effect that may be modified by a family history of diabetes. Further studies are needed to identify the genetic and physiologic mechanisms that influence the distribution and remodeling of adipose tissue in skeletal muscle with aging.'

Blood pressure in Jamaican children: relationship to body size and composition

Blood pressure levels in adults and children are related to body size and composition, but some of these relationships are unclear and they have been incompletely described in the Jamaican population. In a cross-sectional survey of 2,332 school children (6-16 years old; 1,046 boys, 1,286 girls), we measured systolic and diastolic blood pressure and pulse rate, and explored their relationship to weight, height, and waist, hip and mid-upper arm circumferences. The effect of these and other derived measures of body composition on blood pressure was explored in univariate and multivariate analysis. Blood pressure increased with age in both boys and girls, although the increase was greater for systolic than for diastolic blood pressure. The increase of systolic blood pressure among boys continued after age 11 years, but that for girls levelled off. Height and weight were the major predictors of blood pressure, but were highly correlated with each other and with all measures of body composition. Age, height and height-sex interaction explained 11.4 percent of systolic blood pressure variation, and the largest incremental contribution to this model was provided by the addition of body mass index or hip circumference, each explaining an additional 2.6 percent of the variance. Lean body mass made a larger contribution to blood pressure than percent fatness. Blood pressure in Jamaican children rises with age and this rise may be steeper in boys than girls. Blood pressure variation is significantly related to several measures of body composition including measures of fatness and fat free masses.(AU)

Right ventricular cardiomyopathy: a rare and underdiagnosed cause of sudden death in young adults

We present an example of right ventricular cardiomyopathy, a very uncommon condition which caused sudden death in an adolescent boy. This case report is used to highlight the pathological features of this rare and poorly understood condition, which is often undiagnosed (AU)

Leptin and body composition of Nigerians, Jamaicans, and US blacks

The role of leptin in humans remains controversial. Leptin concentrations are highly correlated with body fat stores. We tested whether or not this relation was consistent across the range of body composition encompassing the lean as well as the obese. Individuals participating in community-based comparative research in Nigeria (n = 363), Jamaica (n = 372), and the United States (Maywood, IL; n = 699) had their plasma leptin concentrations and body compositions (with bioelectrical impedance analysis) measured. All participants identified themselves as being black. Body mass index (in KG/m2) ranged from across populations for both men and women in Nigeria, Jamaica, and the United States, respectively (men: 2.8, 3.9, and 6.8 microg/L; women: 10.3, 18.6, and 27.7 microg/L). An exponential function fit the relation between percentage body fat or total fat mass and leptin for men and women at each site. For women and men the exponential function with either percentage body fat or total fat mass was of the same shape, but increased by a constant in women, yielding higher leptin concentrations than in men at every level of body fat. On the basis of this broad distribution of body composition, the data suggest an exponential response of leptin to increase in body fat stores, consistent with the development of leptin resistance in individuals developing obesity. These findings likewise confirm that men and women exhibit different set points in terms of leptin production(AU)

Leptin concentration in women is influenced by regional distribution of adipose tissue

Leptin concentration in humans are increase with obesity, and women have higher leptin concentration than men. This sex difference reflects the greater fat mass of women. However, there is evidence that factors other than the size of the adipose tissue mass contribute to serum leptin concentrations. This study was undertaken to determine whether anthropometric factors influenced leptin concentrations in our population. Leptin concentrations were measured in 375 persons from a population study of hypertension and diabetes for whom body-composition data (bioelectrical impedance analysis and anthropometry) were available. Serum leptin concentrations were more than four times higher in women than in men (18.5 ñ 13.9 compared with 3.8 ñ 3.5 ng/L, P < 0.0001). In individuals with comparable body mass indexes, these differences persisted after adjustment for either percentage fat (P < 0.05) or fat mas (P < 0.0001) by multivariate-regression analysis. After fat mass was adjusted for, the serum leptin concentration in both men and women was independent of waist circumference but in women was associated with hip circumference. Hip circumference is a proxy measure of peripheral fat and these results suggest that the larger hips of women may contribute to the sex difference in serum leptin concentration.(AU)

Field evaluation of baits and baiting strategies for delivering oral vaccine to mongooses in Antigua, West Indies

A field of study was conducted on Antigua, West Indies to determine the feasibility of delivering an oral rabies vaccine or population control agent to free-ranging mongooses (Herpestes javanicua). Two biomarkers (tetracycline hydrochloride [THCL] and Dupoint Oil Blue A dye) and two bait types (Dupont polymer fish meal and polyurethane foam) were used to bait three study sites. Four hundred polymer baits containing both biomarkers were distributed at 36 central point bait stations (11 baits/station) on an 80 ha study site (5 baits/ha); 69 percent of the mongoose population consumed one or more baits. Two thousand baits containing THCL and 400 baits containing DuPont dye were distributed on two additional 100 ha study sites (24 baits/ha). Polymer fish meal baits were used on the first site and polyurethane baits on the second site. Based on the presence of biomarkers in bone or soft tissue, 96 to 97 percent of the mongooses at both sites consumed at least one bait. We conclude that oral baiting of mongooses is a feasible method for delivery of vaccines for the control of rabies in this species (AU)

Bioelectrical-impedence analysis as a measure of body composition in a West Indian population

Percent body fat (percent BF) was estimated in 50 males and 50 females aged 8-21 y by using hydrodensitometry (percent BF) and a bioelectrical-impedance analyzer (percent BF-BIA). The sample population was racially heterogenous, though predominantly of African origin. Percent body fat was computed from density by using an equation derived specifically for blacks. The BIA predicted percent BF with r2 = 0.77 (SEE = 3.7 percent BF), underestimating by a mean of 1.7 percent BF. Residuals ( percent BFd - percent BF-BIA) were normally distributed but were significantly correlated with age (P less than 0.01), although this effect was small. The theoretical bases for impedance analysis and for hydrodensitometry would appear for different reasons to impair applicability of these techniques to the present population and age group. However, for our population sample the BIA estimated percent BF as precisely as other simple techniques applied to other populations. (AU)

Adipose tissue in foetuses, infants, children and adolescents in Curacao (Netherlands Antilles), its fatty acid content and composition: the fatty acid disappearance rate in childhood - abstract

There are uncertainties about the fatty acid (FA) disappearance rate in adipose tissue of infants. We therefore studied the adipose tissue FA content and composition in the foetal period in relation to samples obtained in infancy, childhood and adolescence. Adipose tissue samples were obtained in Curacao from Black foetuses and newborns (n = 42, gestation ages 22-43 weeks), and from infants, children and adolescents (n = 62, ages 0-19 years). FA was analysed by capillary gas chromatography. It was assumed that feeds of human milk or formula in the first ñ6 months accomplished 'pulse labelling' of newborn adipose tissue FA with medium chain saturated fatty acid (MC-SAFA), and that feeding of a "mixed" diet after 6 months of age constituted a 'wash-out' or 'chase' of the marker FAs. FA half-life was calculated from the disappearance rate of MC-SAFAs (AU)

Foetal adipose tissue fatty acid accretion - abstract

There are still uncertainties about the origin of the fatty acids (FA) deposited in the foetus, notably the percentage derived from the maternal circulation. This study describes a method to determine the amount of FA synthesized de novo in the foetus and the amount derived from the maternal circulation. Autopsy samples of subcutaeneous adipose tissue were obtained from 42 black foetuses and newborn infants. Samples of similar tissue were obtained from 50 pregnant women and 13 non-pregnant black women during surgery. FA analysis was done by gas chromatography. The accretion rate of FA in foetal adipose tissue was calculated by linear regression analysis of the FA data obtained from foetal/infant samples from the 22nd to 43rd week of gestation. The rate of foetal FA synthesized de novo in adipose tissue was calculated as the difference between the total foetal FA accretion rate and an estimate of the maternally derived FA. The latter was estimated from the values for accretion rates of saturated FA (SAFA), mono-unsaturated FA (MUFA), and polyunsaturated FA (PUFA) and total FA in foetal tissue, and the SAFA, MUFA and PUFA composition of adipose tissue in women (Table). Results show that of the total FA increment in foetal adipose tissue (22.7mg/g wet wt./week), 86.6 per cent was synthesized de novo by the foetus and the rest (13.2 per cent) was maternally derived (AU)

Lipid metabolism in rats fed different fats during rehabilitation from malnutrition

Little is known of the effects of malnutrition on the composition of adipose tissue in children. Total body fat is severely depleted in most cases but it is not known how this affects the structure and subsequent regeneration and metabolic activity of the tissue. There is evidence that during normal growth in both children and animals that there are sensitive periods during which the cell number and cell size in adipose tissue may be altered by nutritional factors. This study was designed first to develop methodology for use in the analysis of small samples of tissues and then to study the composition of adipose tissue of rats which had been malnourished and then refed with high fat diets. Two different fats, peanut oil and coconut oil were used in order to investigate whether the type of fat in the diet infleunced the tissue composition. The available literature has been reviewed and the results of the measurement of DNA, protein and fat content of the tissue, of total body fat and of total body water are presented. The study has shown that: (a) adipose tissue of rats fed a protein-free diet containing peanut oil was more depleted of fat than if the diet contained coconut oil; (b) the accumulation of fat in the tissue of malnourished rats which had been refed with a diet containing peanut oil was more rapid than in those which were fed coconut oil. The increase in adipose tissue mass in both cases occurred by an increase in cell size rather than cell number; (c) total body water and total body fat were lower than normal in the malnourished rats. There was a progressive increase in total body fat as refeeding continued. Total body water increased very rapidly in the early stages of refeeding with peanut oil. Greater than normal values were attained only after 4 days refeeding. These values thereafter declined to normal. There was a slower increase to normal in the rats fed coconut oil. Total body fat was measured in children recovering from malnutrition on high energy diets containing either peanut oil or coconut oil. There was a tendency for the total body fat to increase more slowly in those fed coconut oil (Summary)

Radiological changes associated with leg ulcers in the tropics

The radiological changes associated with four distinct types of leg ulceration common in the tropics are reviewed. Only mild changes occurred in the tropical phagedenic group, but more marked radiological abnormalities occurred in the three chronic groups. The frequency and pattern of the periosteal reaction is the most useful guide to radiological differentiation of these groups. (AU)

The use and interpretation of ponderal index and other weight-height ratios in epidemiological studies

Criteria for an index of weight corrected for height are presented and used to investigate, both theoretically and practically, the properties of three weight-height ratios: weight/height, weight height 2 and ponderal index. The data on height, weight and skinfold thickness used in the analysis were collected during the fourth examination of the Framingham study. Based on the criterion that the ratio should be independent of height, the best of the three proposed ratios depends on the value of the intercept and the coefficient of the regression of weight on height for the population under consideration. The most likely best ratio in Western male populations is weight /height2 and it seems probable that in Western female populations it is weight/height: the least likely for both sexes is ponderal index. Evidence is also given to show that all three indices are poor measures of adiposity (Summary)

Calorie requirements of children recovering from protein-calorie malnutrition

Weight gains in forty-seven malnourished infants have been studied in relation to the type of diet given during the recovery phase. Twenty-three (group P) were given substantially more calories than the rest (group O). Group P gained weight at a significantly greater rate (10.6 as against 7.65 g. per kg. per day). The response was particularly striking in marasmic infants, who grew more rapidly than those admitted to hospital with kwashiorkor. The rapid weight gains were achieved with relatively modest protein intakes (about 4 g. per kg. per day). This finding will be important in countries where malnutrition is a serious problem and where it is easier to provide calories than protein. (Summary)

The long-term prognosis of severe infantile malnutrition

65 Jamaican children who had been treated for severe malnutrition in hospital were traced and examined 2-8 years after their discharge from hospital. They were found to be small by North American standards, but not when they were compared with Jamaican children, similar genetically and from the same economic background. When 56 of the previously malnourished children were matched with siblings or close relatives as controls they were slightly taller and heavier, broader in the chest, and had thicker bone and muscle in the leg than the sibling who had never been severely malnourished. There is no clear evidence that a period of severe malnutrition in infancy per se causes stunting of growth in children as it does in some animals. On the contrary, children who have been successfully treated for malnutrition tend to outgrow their siblings when they return home; this may have a genetic basis.(Summary)

The prediction of total body fat from simple field anthropometry

This paper postulates a simple method of deriving total body fat from measurements commonly taken in field anthropometry. It proposes a model and tests it with a sample of young children in Jamaica against alternative measurements of body composition derived from estimates of total body potassium obtained in a liquid scintillation counter