Mid-upper Arm Fat Research Articles

Muscularity and fatness of infants and young children born small- or large-for-gestational-age.

There is growing interest in the extent to which body composition, both short- and long-term, differs in infants and children born at the extremes of birth weight. This is because a growing number of studies have linked low birth weight and fetal growth restriction to the chronic diseases in adulthood that often are obesity-related, and there is also evidence to suggest that heavy infants may be at increased risk for obesity in later life, again with the attendant obesity-related chronic diseases. Our objective was to compare anthropometric indices of body composition of infants and young children born small-for-gestational-age (SGA, <10th percentile) or large-for-gestational age (LGA, >/=90th percentile) with those of normal birth weight status (appropriate-for-gestational-age, AGA) in a US sample. National sample of US-born non-Hispanic white, non-Hispanic black, and Mexican-American infants and young children, 2 to 47 months of age, examined in the third National Health and Nutrition Examination Survey (NHANES III, 1988-1994), for whom birth certificates were obtained. The primary outcomes were normalized anthropometric indices (z scores or standard deviation units [SDU]) of nutritional status and body composition (mid-upper arm circumference, triceps and subscapular skinfolds, mid-upper arm muscle and mid-upper arm fat areas (UFA), and the arm fat index). The outcomes thus were scaled to permit comparison across chronologic ages. The prevalence of SGA was 8.6%, appropriate-for-gestational-age 80.9%, and LGA 10.5%. From ages 2 to 47 months, for infants and young children born SGA, there was a persistent overall deficit in muscularity (mid-upper arm circumference and mid-upper arm muscle area) of approximately -0.50 SDU, but less of a deficit in fatness, particularly at the youngest ages. For infants and young children born LGA, there was a surfeit in muscularity of approximately 0.45 SDU, with less of a surfeit in fatness, particularly at the youngest ages. Across all ages, the mean UFA showed a statistically significant deficit for SGA children (-0.27 +/- 0.10 SDU) and surfeit for LGA children (0.24 +/- 0.08 SDU). At individual ages for UFA and at individual and all ages combined for skinfold thicknesses, there were no significant differences in level of subcutaneous fatness in the three birth-weight-for-gestational-age groups. There was a tendency in the first year for the arm fat index (% arm fat) to be significantly higher for SGA infants, but the effect did not persist after the first year. SGA infants remain smaller and LGA infants larger in size through early childhood, but the discrepancies in weight are primarily attributable to differences in lean body mass (muscularity). Fatness is less affected. Thus, based on the fatness indicators used, at any given weight for infants and children 2 to 47 months of age, percent body fat appears to be relatively higher for children who were SGA at birth and lower in those who were LGA at birth. These differences in body composition for SGA infants support the evidence documenting a link between disturbances in intrauterine growth and chronic disease associated with subsequent adiposity in adulthood.

Growth of fat and lean tissue components at the mid-upper arm in well-off North West Indian children.

Attained means and standard deviations of the mid-upper arm fat cross-sectional area (CSA) and M + B (lean) CSA estimated from the arm circumference and the triceps and biceps skinfolds are presented for 327 girls and 341 boys 6-16 years of age. Tempo unconditional 1-year velocities of the two components were also calculated based on repeated measurements of 244 girls and 253 boys after a period of about 1 year. Although the attained mean total CSA displays a similar pattern in both sexes, the fat and lean components show opposite patterns. Fat CSA is distinctly larger in girls and increases continuously, while fat CSA in boys stabilizes from 10 to 13 years and then decreases. Lean CSA in girls stabilizes at about 13 years, while that of boys continues to increase. Left hand grip strength of boys is greater and increases from 6 to 16 years. The 1-year velocity curves of the girls are shifted by about 1-2 years to the left of the curves for boys, but the pattern is similar. The important features displayed are as follows: occurrence of two spurts of increased velocities, preadolescent and adolescent spurts, an adolescent decline in fat CSA velocities in boys which reaches a nadir at about 14 years, occurrence of an adolescent peak of lean CSA in boys at 14 years, high postpeak velocities of lean CSA in both sexes, which indicates continued growth of lean tissue, and a peak in strength that occurs after that in lean tissue. © 1994 Wiley-Liss, Inc.

Reference values for arm muscle area, arm fat area, subscapular skinfold thickness, and sum of skinfold thicknesses for American adults.

Reference values for the mid-upper arm muscle area, mid-upper arm fat area, subscapular skinfold thickness, and sum of triceps and subscapular skinfold thicknesses of American adults were developed from data collected by the National Center for Health Statistics during the first National Health and Nutrition Examination Survey, 1971 to 1974. The reference values were compared to other reference values derived from a similarly conducted cross-sectional survey of the American population, the Health Examination Survey of 1960 to 1962. These comparisons revealed that arm muscle area and subscapular skinfold thickness of men and arm muscle area of women continuously increase with aging from 18 to 74 yr; arm fat area and sum of skinfold thicknesses of men increase with aging from 18 to 34 yr but stabilize or decrease with further aging; and arm fat area, subscapular skinfold thickness, and sum of skinfold thicknesses of women increase with aging from 18 to 64 yr but decrease thereafter. As these parameters frequently change more than 20% over the period of a single decade, it is important that age be considered in nutritional evaluations based on anthropometric measurements. Changes in these four parameters with successive generations are also frequently large. Consequently, it is imperative that the reference values used in nutritional assessment protocols be updated at regular intervals.

Reference values and age-related trends for arm muscle area, arm fat area, and sum of skinfolds for United States adults.

Age- and sex-specific percentile distributions for mid-upper arm muscle area (AMA), mid-upper arm fat area (AFA), subscapular skinfold thickness, and sum of triceps and subscapular skinfold thickness for United States adults (18-74 yr) were developed from cross-sectional data collected by the National Center for Health Statistics (NCHS) during the Health and Nutrition Examination Survey, 1971-1974 (NHANES I). Sample weighting factors were applied to the data to assure the production of the identical data set used to calculate weight-for-height percentiles by NCHS. Smoothed curves developed from the percentile distributions for AMA and AFA are also presented. Arm muscle area and AFA were calculated from the Health Examination Survey of 1960-1962 (HES) which made possible an age-cohort analysis for age-related changes and secular trends. Secular differences were found for arm muscle area for both men and women, while men differed little in fat-related anthropometric parameters. The secular change in arm fat area for women could be explained by the greater amount of fat that surrounded a larger arm, since the ratio of AFA to AMA did not change between the two surveys. Age-cohort analysis revealed increases in AMA with age rather than the apparent decrease observed for the older age groups in the cross-sectional data. Reference values developed from the most recent cross-sectional data are the most appropriate for the nutritional assessment of United States adults, because each age cohort can be seen to display different anthropometric characteristics as well as age-related changes in these parameters.