Separating the Bruce and Trivers-Willard Effects in Theory and in Human Data

Details

• Personal Author:
  Casey J ; Catalano R ; Gemmill A ; Karasek D ; Saxton K ; Stewart H
• Description:
  Objectives: Theories of reproductive suppression predict that natural selection would conserve mechanisms that abort the gestation of offspring otherwise unlikely to thrive in prevailing environments. Research reports evidence among humans of at least two such mechanisms-the Trivers-Willard and Bruce Effects. No literature, however, compares the mechanisms nor estimates their relative contribution to observed characteristics of human birth cohorts. We describe similarities and differences between the Trivers-Willard and Bruce Effects and explore high quality historical data from Sweden to determine which mechanism better describes temporal variation in the ratio of males to females in birth cohorts. Methods: We measure Trivers-Willard exposures with the death rate among women of reproductive age. We measure Bruce exposures with the death rate among children. We use time-series regression methods to estimate the relative contribution of the Trivers-Willard and Bruce Effects to temporal variation in historical Swedish secondary sex ratio data. Results: We find that the Bruce Effect appears to be a better predictor of the secondary sex ratio than does the Trivers-Willard Effect. Conclusions: Attempts to identify mechanisms by which reproductive suppression affects fetal loss and characteristics of human birth cohorts should consider the Bruce Effect as an alternative to the Trivers-Willard Effect. [Description provided by NIOSH]
• Subjects:
  Environment Fetus Mortality Occupational Health Pregnancy Safety Urogenital System
• Keywords:
  Biological Factors Environmental Factors Humans Mortality Data Reproduction Statistical Quality Control
• ISSN:
  1042-0533
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  California ; OSHA Region 9
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  30
• Issue:
  2
• NIOSHTIC Number:
  nn:20068271
• Citation:
  Am J Hum Biol 2018 Mar/Apr; 30(2):e23074
• Contact Point Address:
  Ralph Catalano, School of Public Health, University of California, Berkeley, Berkeley, California 94704
• Email:
  rayc@berkeley.edu
• Federal Fiscal Year:
  2018
• Performing Organization:
  University of California, Berkeley
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  American Journal of Human Biology
• End Date:
  20250630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:31403e9ec4e01c8601cc5e654e3f5165a784db01be75322c79c5343ad07b4275431bf4aafa01b0def3312f89d261c8802eeb04dd412c004bb8d349ec954556d2
• Download URL:
  https://stacks.cdc.gov/view/cdc/230453/cdc_230453_DS1.pdf
• File Type:
  [PDF - 783.48 KB ]