The use of biocultural data in interpreting sex differences in body proportions among rural Amazonians

Am J Phys Anthropol. 2012 Jan;147(1):113-27. doi: 10.1002/ajpa.21636. Epub 2011 Nov 25.

Abstract

Variation in height and body proportions is relatively well-understood at the inter-population level, but less is known about intra-population variation. This study explores intra-population variation in body proportions among 172 (88 female; 84 male) adult rural Amazonians. We test the hypotheses that: (1) stunting is associated with changes in proportions and fatness; (2) the sexes express different proportions in response to similar environmental stress; and (3) female growth is negatively affected by the costs of reproduction. We examined height, sitting height, and total leg length in subsamples based on sex and nutritional status (stunted/nonstunted) in relation to biocultural factors including access to food and healthcare and female reproductive history parameters. Differences in proportions were examined using the Quick-Test (Tsutakawa and Hewett: Biometrics 33 (1977) 215-219); correlation analyses were used to detect associations between anthropometric data and body fatness, and female reproductive history parameters. We found significantly higher rates of stunting among females (X(2) = 5.31; P = 0.02; RR = 1.4). Stunted individuals exhibited relatively shorter legs than nonstunted individuals (P = 0.02), although this was not found in within-sex analyses. A significant negative correlation was found between leg length index and fatness (P < 0.01). Lastly, females exhibited relatively shorter legs than males (P = 0.0003) and, among females, height and leg length were significantly positively correlated with age-at-first-birth (P < 0.02) suggesting that adolescent pregnancy may negatively affect growth in this population. Our findings provide insights for the study of intra-population variation in body proportions and highlight the importance of biocultural data in interpreting the pattern of variation observed in living and past populations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue
  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anthropometry / methods*
  • Body Composition*
  • Body Height
  • Brazil
  • Chi-Square Distribution
  • Child
  • Female
  • Growth Disorders
  • Humans
  • Leg
  • Male
  • Menarche
  • Middle Aged
  • Nutritional Status
  • Pregnancy
  • Pregnancy in Adolescence / statistics & numerical data
  • Rural Population / statistics & numerical data*
  • Sex Characteristics*
  • Statistics, Nonparametric