Subcutaneous fat remodelling in Southeast Asian infants and children

The path less traveled: Using structural equation modeling to investigate factors influencing bone functional morphology

OBJECTIVES

The relationship between an organism's mechanical environment and its bone strength has been long established by experimental research. Multiple intrinsic and extrinsic factors, including body mass, muscle strength, genetic background, and nutritional and/or hormonal status, are likely to influence bone deposition and resorption throughout the lifespan, complicating this relationship. Structural equation modeling (SEM) is uniquely positioned to parse this complex set of influences.

MATERIALS AND METHODS

Data from the Third National Health and Nutrition Examination Survey, including sex, total body mass, lean body mass, exercise frequency, peak body mass, and age, were analyzed using SEM to determine how they affect bone strength both individually and combined.

RESULTS

Body mass is typically the driver of cross-sectional area, but body mass and lean mass have similar effects on the polar moment of area (J). Peak body mass had a strong direct effect on J, despite decreasing strongly with increases in lean mass. Exercise also did not confer a large direct effect on cross-sectional area or J but did modify body mass and lean mass. In females, intentional weight loss was associated with decreased exercise levels.

DISCUSSION

SEM is a useful tool for parsing complex systems in bone functional morphology and has the potential to uncover causal links in the study of skeletal remodeling, including factors like weight loss or exercise that may have secondary effects.

The distribution of body fat from childhood to adulthood in a longitudinal study population

Body fat distribution, its continuity from childhood (4-6 years) to 30 years of age, and its link to that of parents is described in a longitudinal study population. A computer-assisted image analysis technique was used to measure body fat distribution (as measured by waist and hip diameters) from somatotype photographs. Pearson correlation coefficients were used to assess the association between the waist/hip diameter ratio (WHDR) and the body mass index (BMI) at all ages and between the WHDR of parents and offspring. Both Pearson correlation coefficients and the Foulkes-Davis tracking index were used to assess tracking of the WHDR from childhood to age 30 years. Stepwise regression analyses were performed to determine the predictability of the WHDR at age 30 years from WHDRs in childhood and adolescence. Among both sexes the WHDR decreased and BMIs increased with age from childhood to 18 years, then both increased from age 18 to 30 years. The correlation between the WHDR and BMI was significant only at 30 years for males (r = 0.37; p < 0.05) and during all stages of adolescence in females (p < 0.05). Age-to-age correlations were high for both sexes (p < 0.0001), and remained significant over a span of up to 25 years. Using the Foulkes-Davis tracking index, tracking from the year of peak height velocity to 30 years (a span of approximately 20 years) was strong for both sexes. Parent and child WHDRs were correlated and differed by sex. Father-son correlations were not significant in childhood, but reached significance in early adolescence (2 years before the year of peak velocity) and remained significant to 30 years (p < 0.05). Mother-daughter correlations were significant at all ages (p < 0.05). The level of the WHDR at the peak of the pubertal growth spurt (year of peak height velocity) predicted up to 58% of the variance in males and 51% of the variance in females of the WHDR at 30 years. We conclude that the adult WHDR (a proxy for the waist/hip ratio) becomes evident by the year of the pubertal growth spurt in height.

The measurement of body fat distribution using somatotype photographs and computer-assisted imaging techniques

A computer-assisted image analysis technique has been devised which allows the measurement of body fat distribution from archived somatotype photographs. This report describes the technique, which enables useful measurements to be extracted from somatotype photographs which were taken over 50 years ago. This paper describes the process of digitization of photographs, the measurement of body diameters using computer-assisted edge detection, the quantitative analysis of measurement error in this procedure, and validation techniques employed.

Nutritional resilience in a hostile environment: positive deviance in child nutrition

The term "positive deviance" applies to the study of children who demonstrate above-average growth in impoverished environments. Favorable values on known malnutrition correlates and attentive child care characterize positive deviants. Best-growing children do not necessarily mirror the malnourished; for example, best- and worst-nourished infants may both get more breast-milk substitutes than middle growers. Positive deviants receive more high-quality foods, physical interaction, affection and praise, and verbal and environmental stimulation. Factors that influence child growth through care quality also predict cognitive development, health, and social adjustment. They include: the type of society; parental education, mental health, initiative, and work burden; family and community structure; and the value of children to parents. Feeding practices related to growth include: permitting the child to control the length of feeding, encouraging eating while avoiding a power struggle, actively spoon- or hand-feeding, not displacing appetite by giving frequent sweets, and timely introduction of appropriate foods.

Fat distribution in children with cerebral palsy

Triceps and subscapular skinfolds were measured on 95 North American children with cerebral palsy. Triceps fat was far more depleted than subscapular fat in comparison with population standards for sex, age and race. This truncal distribution of fat may be related to the high prevalence of under nutrition found in the sample.