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PubMed1990

Heritability of blood pressure in 7- to 12-year-old Chinese twins, with special reference to body size effects.

Systolic and diastolic blood pressures and body-size indices such as body height, body weight, sitting height, chest circumference, skinfold thickness, and body mass index (BMI) were assessed in 110 pairs of like-sex Chinese twins (75 monozygotic and 35 dizygotic) aged 7-12 years. Significant correlations of blood pressure with body-size indices were found. Prior to adjusting for body-size effects, three twin methods yielded low heritability estimates for both systolic (0.32-0.41) and diastolic (0.32-0.51) pressures. Adjusting systolic pressure for body height and BMI via multiple regression nearly halved heritability estimates, but adjusting diastolic pressure for body height and skinfold thickness only changed the estimates slightly.

Blood Pressure↗
PubMed1992

Systematics and body size: implications for feeding adaptations in New World monkeys.

The relationship between body size and feeding ecology is well established for primates. It is argued that the evolutionary history of modern New World monkeys and, in particular, the path to attainment of current body size is significant in understanding the similarities and differences between dietary strategies and other ecological parameters of similar-sized monkeys. Current interpretations of New World monkey evolutionary relationships are reviewed. Based on a synthesis of available body weights and the assumption that the earliest New World monkeys weighed close to 1 kg, similar to modern Aotus and Callicebus, predicted patterns of body size change in each lineage are given. Restrictions on directions of body size change in primates are discussed, and it is shown that "Stanley's Rule" offers a good explanation for differing body size ranges in New and Old World anthropoids. Predicted ecological correlates to body size drawn from the mammalian literature are offered and tested using data on New World monkeys, which show some concurrence and several interesting departures from predicted patterns. Sexual dimorphism in body weight of New World monkey species is reviewed, based on the new summary of body weight data given.

Adaptation, Physiological↗
PubMed2004

Movement performance and body size: the relationship for different groups of tests.

It has been shown that inconsistently applied normalization for body size could be an important methodological problem in testing physical performance in areas such as sports, physical education, ergonomy, or physical medicine and rehabilitation. The aim of this study was to evaluate a part of the recently proposed classification of physical performance tests (Jaric 2003) based on the role of body size in the tested performance. Presuming a normalization method P(n)= P/ S(b) based on an allometric relationship between the tested performance P and a selected index of body size S (P(n) performance normalized for body size; b allometric parameter), we specifically hypothesized that: (1) the tests of exertion of external force (e.g., lifting weight, pushing, pulling), (2) tests of rapid movements (jumping, sprinting, kicking) and (3) tests of supporting body weight (chin-ups, squats) would reveal the values of the allometric parameters b=0.67, b=0 and b=-0.33 when body size is expressed as body mass, or b=2, b=0 and b=-1 when body size is expressed as body height, respectively. Male physical education students (n=77) were tested on 18 standard physical performance tests belonging to the aforementioned three groups. The obtained values of the allometric parameters proved to be closely in line with the hypothesized ones. While the finding regarding the tests of exertion of external force (i.e., the tested force should be divided by m(0.67) in order to normalize the force for body size) have been already demonstrated by some authors, the findings related to the tests of rapid movements and, particularly, tests of supporting body weight are novel. Although the normalization methods discussed need further evaluation, a more accurate and consistently applied assessment of the body size-independent indices of the evaluated groups of standard tests could improve the methodology of physical performance testing in general.

Adolescent↗
PubMed2026

Genome-wide association study of body weight and body size traits in Langya hens.

Langya chicken is a Chinese indigenous chicken breed with high genetic diversity. To systematically analyse the genetic basis of body size traits, eight traits (including BW, comb shape, and body size) of 2 952 Langya hens were measured at 130 days of age and at first egg of age. A total of 9 708 856 high-quality single-nucleotide polymorphisms (SNPs) were obtained through whole-genome resequencing and used for subsequent genetic parameter estimation and genome-wide association study (GWAS). The results of genetic parameter analysis revealed significant differences in the SNP heritability of different body size traits, with an overall range of 0.13-0.64. In particular, BW, comb length, comb height, and tibia length exhibited moderate-to-high heritability (0.34-0.64) during both developmental stages. GWAS revealed significantly associated SNP loci distributed across multiple chromosomal regions, indicating that body size traits have a complex multilocus genetic regulatory structure and that some chromosomal regions recur for different body size traits and during different developmental stages, showing potential pleiotropic effects or shared genomic regions. Notably, multiple stable body size trait-associated regions were identified on Gallus gallus autosome (GGA) 1, 4, and 27, including genomic regions on GGA1 (167.56-178.18 Mb), GGA4 (68.24-81.17 Mb), and GGA27 (5.22-6.73 Mb), in which significantly associated signals were repeatedly detected for multiple body size traits, such as BW and tibia length. The significant SNPs in the above regions were characterised by strong linkage disequilibrium and were associated with multiple body size traits, indicating that these SNPs may serve as important genetic hotspots for the regulation of chicken body shape and structure. Candidate genes annotated in these core regions include NCAPG, KPNA3, LDB2, PPARGC1A, FNDC3A, SOST, RB1, STON2, and TARP; the functions of these genes are involved mainly in the regulation of cell proliferation, energy metabolism, bone development, and tissue growth. NCAPG was consistently associated with multiple traits at both developmental stages. Functional enrichment analysis further revealed that these candidate genes were significantly enriched in the phosphatidylinositol, GnRH, energy metabolism, skeletal development and protein biosynthesis signalling pathways. The genetic characteristics of Langya chicken body size traits during the growth stage at the genome-wide level and the underlying molecular mechanisms were systematically revealed in this study. The findings provide important candidate gene resources and a theoretical basis for the screening of molecular markers for body size traits and the genomic breeding of regional chicken breeds.

Candidate genes↗
PubMed2005

The relationship between life span and adult body size is highly strain-specific in Drosophila melanogaster.

Among mammals, body size and life span tend to vary inversely within species, but the pattern is less clear in invertebrates. Here, we report on survival and weight of male flies from 29 laboratory strains of Drosophila melanogaster. Natural variation in body mass was enhanced by rearing larvae under normal and limited food conditions. Strain, weight, and larval treatment have significant effects on survival, but higher order interactions are also significant, indicating strain specificity. For pooled data the overall relationship between mass and life span is slight, positive, and statistically significant, but mass explains < or =1% of the variation in survival. This result is opposite to the common prediction of an inverse relationship between longevity and body size. Effects of artificially reduced body size vary substantially in both sign and magnitude from strain to strain, though long-lived strains generally retain their enhanced survival characteristics. Within-line regressions of life span on mass also vary dramatically from strain to strain; in Canton-S, the most extreme case, mass explains >40% of the variation in survival. For long-lived 'O' lines reared under normal larval conditions, smaller flies live 16% longer than larger flies; the latter are significantly underrepresented in the most advanced age class. We conclude that the body size-life span relationship is highly strain-specific; that inconsistencies in the literature probably reflect real biological variation; and that variation in body size can be a significant source of experimental noise in survival studies.

Aging↗
PubMed2004

Race differences in accuracy of self-reported childhood body size among white and black women.

OBJECTIVE: To assess the relation of self-reported current and recalled preadolescent body size to measured BMI (kilograms per meter squared) and interviewer's assessment of body size. RESEARCH METHODS AND PROCEDURES: This was a prospective cohort study of 1890 white and black women who were 9 to 10 years old at time of enrollment and were followed up 10 to 13 years later. At baseline, subjects had their weight and height measured and were asked to indicate their current body size from a series of nine pictograms. A sample of the subjects also had their body size evaluated by interviewers. At the young-adult follow-up visit, subjects were asked to recall their body size at 9 and 10 years old and to indicate their current weight, height, body size, and level of concern with weight. RESULTS: Among the women with interviewer assessments, 84% of the white women and 67% of black women recalled a body size that was within one body size of the interviewer's assessment. Independent of weight status in childhood or at follow-up, black women were 3 times more likely than white women to recall a body figure that was more than one figure leaner than the shape they reported at baseline (odds ratio = 3.5, 95% confidence interval 2.8 to 4.5) or than the interviewer's rating at baseline (odds ratio = 3.4, 95% confidence interval 2.4 to 4.9). DISCUSSION: The results suggest that the use of body figures to recall childhood size are best suited for ranking subjects in terms of BMI. The higher rate of underestimation of size by black women suggests that body figure ratings work best for white women.

Black People↗
PubMed2004

cGMP and a germ-line signal control body size in C. elegans through cGMP-dependent protein kinase EGL-4.

Mechanisms involved in the control of body size are largely unknown. In the nematode C. elegans, several small body size mutants were isolated, and the responsible genes were reported to encode putative components of a TGFbeta signalling pathway. Recently, mutants in the egl-4 gene encoding cGMP-dependent protein kinases were found to have a larger body size, and it was suggested that EGL-4 down-regulates the TGFbeta/DBL-1 pathway. We show that a permeable cGMP analogue 8-Br-cGMP significantly reduces body size of the wild-type but not that of an egl-4 mutant, indicating that cGMP controls body size through EGL-4. Laser ablation of germ-line cells revealed that a germ-line signal and EGL-4 function in the same pathway. Targeted expression of EGL-4 indicates that EGL-4 can function in hypodermis, neurones and intestine both cell-autonomously and cell-nonautonomously to control organ and body size. We propose a signal cascade for the control of body size that involves a germ-line signal, cGMP, G-kinase EGL-4 and DBL-1/TGFbeta pathway. It is interesting that two important pathways involving cGMP and TGFbeta, respectively, are related. Also, the results suggest a novel mechanism for the control of organ and body size in which hypodermis plays a key role

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed2001

Should body size preference be a target of health promotion efforts to address the epidemic of obesity in Afro-Caribbean women?

OBJECTIVE: To determine if 1) Afro-Caribbean women prefer large body sizes, 2) the body size preference of Afro-Caribbean men and women are associated, 3) women's preferences are associated with increased risk of obesity or with weight management behaviors. DESIGN: Population samples of 314 and 487 women, ages 20-55 years, were recruited on Barbados and Dominica with response rates of 74% and 77%, respectively. Body size preferences, stress related variables, and demographic data were ascertained by questionnaire. Height and weight were also measured. On Barbados, body preference data were collected from male partners of participants, and data on intentions to perform weight management behaviors were collected from 175 women. RESULTS: Most women preferred body sizes within normal limits, although women on Dominica had a slightly larger ideal body size (IBS) than did Barbadian women (P<.05). On both islands, the size that women thought men preferred was related to their IBS (P<.0001). Likewise, IBS was associated with increased odds of being overweight (P<.001), however most overweight women (>75%) wanted to be smaller. IBS was not related to the intention to exercise or to eat high fat foods. CONCLUSIONS: It is unlikely that body size preference poses a barrier to intervention efforts to reduce the prevalence of overweight in Afro-Caribbean women.

Adult↗
PubMed1990

Adaptive probit estimation and body size: the evaluation of a new psychophysical technique.

Studies of body size estimation are frequently used to identify body-image disturbances in clinical populations. No clear pattern of results has, however, so far emerged. One reason for this may be that studies confound non-sensory influences on performance deriving from motivational components with the observer's discriminative sensitivity. This study introduces an adaptive version of the method of constant stimuli and probit analysis (APE) to determine independently bias and threshold in the estimation of four body parts for two samples of undergraduate students. In the first study, test-retest reliability coefficients were obtained for body-size estimates, using the traditional technique and the new method. Estimates of subjective body size obtained by the new method were shown to have higher test-retest reliabilities than those obtained using traditional techniques. The stability of sensitivity estimates was in the .8-.9 range. In a second study we attempted to validate the new technique by comparing the body-size estimates of male and female observers. Independent bias and sensitivity estimates were found to be significantly different. Female observers were more likely to overestimate the size of their chest and waist whilst underestimating face size. There was no difference overall between the accuracy of male and female observers. Perceptual sensitivity did not differ significantly overall, but whilst female subjects showed a particularly low threshold for waist size, male observers showed the same specific sensitivity for thigh width. The extension of this method of measuring body-image distortions to relevant clinical populations is recommended.

Adolescent↗
PubMed1993

Self-esteem, parental appraisal and body size in children.

This study investigates the influence of body size, parental appraisal of body size, and children's beliefs about parental appraisal, on self-esteem in children from 9 to 11 years old. Parents' and children's responses to a matched question about body size suggest that children are accurate predictors of parental evaluation and that their self-esteem scores are influenced both by actual parental dissatisfaction and beliefs about parental dissatisfaction. For boys, lower self-esteem is associated both with thinness and being perceived as too thin. For girls, lower self-esteem is more associated with fatness.

Attitude↗
PubMed2001

Positive genetic correlation between parasite resistance and body size in a free-living ungulate population.

Parasite resistance and body size are subject to directional natural selection in a population of feral Soay sheep (Ovis aries) on the island of St. Kilda, Scotland. Classical evolutionary theory predicts that directional selection should erode additive genetic variation and favor the maintenance of alleles that have negative pleiotropic effects on other traits associated with fitness. Contrary to these predictions, in this study we show that there is considerable additive genetic variation for both parasite resistance, measured as fecal egg count (FEC), and body size, measured as weight and hindleg length, and that there are positive genetic correlations between parasite resistance and body size in both sexes. Body size traits had higher heritabilities than parasite resistance. This was not due to low levels of additive genetic variation for parasite resistance, but was a consequence of high levels of residual variance in FEC. Measured as coefficients of variation, levels of additive genetic variation for FEC were actually higher than for weight or hindleg length. High levels of additive genetic variation for parasite resistance may be maintained by a number of mechanisms including high mutational input, balancing selection, antagonistic pleiotropy, and host-parasite coevolution. The positive genetic correlation between parasite resistance and body size, a trait also subject to sexual selection in males, suggests that parasite resistance and growth are not traded off in Soay sheep, but rather that genetically resistant individuals also experience superior growth.

Alleles↗
PubMed2006

Evolution of body size in food webs: does the energetic equivalence rule hold?

The energetic equivalence rule (EER), which is derived from empirical observations linking population density and body size and from the allometric law linking metabolism and body size, predicts that the amount of energy used by the various species should be independent of body size. Here, we examine this hypothesis using a model that allows entire food webs to emerge from coevolution of interacting species. Body size influences both individual metabolism and interactions among species in the model. Overall, population density does decrease with body size roughly following a power law whose exponent is variable. We discuss this variability in the light of empirical data sets. The emerging relationship between the flux of resources exploited by the various species and their body size follows a decreasing power law, thus contradicting the EER. Our model emphasizes the importance of considering the influence of body size on species interactions in attempting to explain large-scale patterns related to body size.

Animals↗
PubMed2005

Trends in body size across an environmental gradient: a differential response in scavenging and non-scavenging demersal deep-sea fish.

Body size trends across environmental gradients are widely reported but poorly understood. Here, we investigate contrasting relationships between size (body mass) and depth in the scavenging and predatory demersal ichthyofauna (800-4800 m) of the North-east Atlantic. The mean size of scavenging fish, identified as those regularly attracted to baited cameras, increased significantly with depth, while in non-scavengers there was a significant decline in size. The increase in scavenger size is a consequence of both intra and inter-specific effects. The observation of opposing relationships, in different functional groups, across the same environmental gradient indicates ecological rather than physiological causes. Simple energetic models indicate that the dissimilarity can be explained by different patterns of food distribution. While food availability declines with depth for both groups, the food is likely to be in large, randomly distributed packages for scavengers and as smaller but more evenly distributed items for predators. Larger size in scavengers permits higher swimming speeds, greater endurance as a consequence of larger energy reserves and lower mass specific metabolic rate, factors that are critical to survival on sporadic food items.

Animals↗
PubMedDate not supplied

Water-balance characteristics respond to changes in body size in subantarctic weevils.

Several environmental factors leading to size-dependent mortality influence insect body size. Few investigations have been concerned with the ways in which the mechanisms underlying variation in water-balance characteristics evolve in response to changes in body size that occur independently of water-balance requirements. Using an explicitly phylogenetic analysis, we show how body size has changed over time in the Ectemnorhinus group of weevils and how water-balance characteristics have evolved in response to this change and changes in habitat use. The basal species in the group are all large bodied and from moist environments. In response to a change in resource availability, there was a marked decline in size within the group. Despite the reduction in water content and dehydration tolerance that this meant, evolution of low whole-animal water-loss rates and high tolerance of dehydration resulted in conservation of desiccation resistance. The return to moist habitats in the group resulted in a reduction in dehydration tolerance and an increase in water-loss rate. Thus, dehydration tolerance and water-loss rate respond rapidly both when there is selection for water conservation and when this requirement is relaxed. Future laboratory selection experiments might usefully explore both directions of water-balance evolution.

Animals↗
PubMed2003

Relationship between different body size indicators and hernia development in CAPD patients.

AIMS: A small body size may increase the risk for hernia development in patients on continuous ambulatory peritoneal dialysis (CAPD). The present study investigates whether there is a relationship between body size and hernia development in CAPD patients. MATERIAL AND METHODS: The records of 78 patients on CAPD were reviewed retrospectively. Body mass index (BMI), body surface area (BSA) and total body water (TBW) were calculated in all patients. Correlations between different body size indicators (BMI, BSA and TBW) and hernia development were assessed using analysis of covariance in which we adjusted for sex. RESULTS: A total of 14 patients (17.9%) with no physical evidence of hernia before catheter insertion developed hernias. Body size was significantly lower in CAPD patients with hernias than those without hernias when adjusted for sex. CONCLUSIONS: We conclude that patients with small body size tend to have an increased risk for hernia development. A simple estimation of patients' height, weight, body surface area and total body water would be helpful to predict development of hernias or other complications related to increased intraperitoneal pressure in CAPD patients.

Adult↗
PubMed1993

Temperature related fertility selection on body size and the sex-ratio gene arrangement in Drosophila pseudoobscura.

We measured temperature-dependent fertility selection on body size in Drosophila pseudoobscura in the laboratory. One hundred single females of each of the three karyotypes involving the 'sex-ratio' (SR) and the standard (ST) gene arrangement on the sex chromosome laid eggs at either 18 or 24 degrees C. The experiment addressed the following hypotheses: (a) Fertility selection on body size is weaker at the higher temperature, explaining in part why genetically smaller flies appear to evolve in populations at warmer localities. (b) Homokaryotypic SR females are less fecund than homokaryotypic ST females, possibly mediated by the effect of body size on fertility, explaining the low frequencies of SR despite its strong advantage due to meiotic drive. The data were also expected to shed light on a mechanism for the evolution of plasticity of body size through fertility selection in environments with an unpredictable temperature regime. Hypothesis (a) was clearly refuted because phenotypically larger ST females had an even larger fertility surplus at the higher temperature and, more importantly, the genetic correlation between fertility and body size disappeared at the lower temperature. As to (b), we found that temperature affects fertility directly and indirectly through body size such that ST and SR females were about equally fecund at both temperatures, although different in size and size-adjusted fertility. We observed heterosis for both size and fertility, which might stabilize the polymorphism in nature. The reaction norms of body size to the temperature difference were steeper for ST females than for SR females, implying that fertility selection could change phenotypic plasticity of body size in a population. Selection on body size depended not only on the temperature, but also on the karyotypes, suggesting that models of phenotype evolution using purely phenotypic fitness functions may often be inadequate.

Animals↗
PubMed2004

Variation in body size in the tick complex Rhipicephalus appendiculatus/Rhipicephalus zambeziensis.

We examined the relationship between body size and the phenology of the tick complex Rhipicephalus appendiculatus/Rhipicephalus zambeziensis. These ticks transmit Theileria parva in cattle. In Africa, the body size of R. appendiculatus increases with latitude while the body size of the morphologically similar Rhipicephalus zambeziensis is constant at two different latitudes. A larger body size is necessary once survival becomes a constraint. The most plausible explanation for the smaller R. appendiculatus in equatorial Africa is the cost to produce a larger egg. The consequences of these findings for the introduction of R. appendiculatus in new environments are discussed. New field observations from southern Zambia indicate that R. appendiculatus body size does not vary seasonally as compared to eastern Zambia. This is an additional indication of the presence of a single diapausing population of larger ticks.

Animals↗
PubMed2003

Ecological community description using the food web, species abundance, and body size.

Measuring the numerical abundance and average body size of individuals of each species in an ecological community's food web reveals new patterns and illuminates old ones. This approach is illustrated using data from the pelagic community of a small lake: Tuesday Lake, Michigan, United States. Body mass varies almost 12 orders of magnitude. Numerical abundance varies almost 10 orders of magnitude. Biomass abundance (average body mass times numerical abundance) varies only 5 orders of magnitude. A new food web graph, which plots species and trophic links in the plane spanned by body mass and numerical abundance, illustrates the nearly inverse relationship between body mass and numerical abundance, as well as the pattern of energy flow in the community. Species with small average body mass occur low in the food web of Tuesday Lake and are numerically abundant. Larger-bodied species occur higher in the food web and are numerically rarer. Average body size explains more of the variation in numerical abundance than does trophic height. The trivariate description of an ecological community by using the food web, average body sizes, and numerical abundance includes many well studied bivariate and univariate relationships based on subsets of these three variables. We are not aware of any single community for which all of these relationships have been analyzed simultaneously. Our approach demonstrates the connectedness of ecological patterns traditionally treated as independent. Moreover, knowing the food web gives new insight into the disputed form of the allometric relationship between body mass and abundance.

Body Constitution↗