| dataset_desc |
This scientific paper provides a comprehensive, gl This scientific paper provides a comprehensive, global-scale analysis showing that human longevity and reproductive success are biologically linked through a life-history trade-off: populations where women have more children tend to have shorter average lifespans, even after adjusting for economic, geographic, ethnic, religious, and disease-related factors.
Authored by Thomas, Teriokhin, Renaud, De Meeûs, and Guégan, the study combines evolutionary theory with large-scale demographic data from 153 countries to examine whether humans—like other organisms—experience the classic evolutionary trade-off:
More reproduction → less somatic maintenance → shorter lifespan
🔶 1. Purpose of the Study
The authors aim to determine whether humans display the fundamental evolutionary principle that reproduction is costly—and that allocating energy to childbirth reduces resources for body repair, thereby shortening lifespan.
This principle is widely documented in animals but rarely tested in humans at the global level.
🔶 2. Background Theory
The paper draws on life-history theory, explaining that aging evolves due to:
Accumulation of late-acting mutations (Medawar)
Antagonistic pleiotropy: genes improving early reproduction may harm late survival (Williams)
Allocation of limited energy between reproduction and somatic maintenance (Kirkwood’s Disposable Soma theory)
Evidence from insects, worms, and other species shows that higher reproductive effort often leads to:
Reduced survival
Faster aging
Increased physiological damage
🔶 3. What Makes This Study Unique
Unlike most previous work on humans (e.g., genealogical studies of British aristocracy), this study uses broad international datasets:
153 countries
Measures of:
Female life expectancy
Fecundity (average lifetime births per woman)
Infant mortality
Economic indicators (GNP)
Disease burden (16 infectious diseases)
Geography and population structure
Religion
Ethnic/phylogenetic groupings
This allows the authors to control for confounding factors and test whether the relationship remains after adjustment.
🔶 4. Methods Overview
⭐ Longevity calculation
Life expectancy was reconstructed using:
Infant mortality rates
Gompertz mortality function (for age-related mortality)
Environmental mortality (country-specific)
Only female life expectancy at age 1 (L1) was used in final models.
⭐ Fecundity measurement
Log-transformed average number of children per woman
Only includes women who survived to reproductive age
Not affected by childhood mortality
⭐ Control variables included
Ethnic group (8 categories)
Religion (5 categories)
16 infectious disease categories
GDP per capita (log)
Population density, size, growth
Hemisphere, island vs. continent, latitude, longitude
Country surface area
⭐ Statistical approach
General linear models (GLMs)
Backward stepwise elimination
Inclusion threshold: p < 0.05
Multicollinearity checks
Residual correlations to test trade-off
🔶 5. Key Findings
⭐ 1. A strong negative raw correlation
Across 153 countries:
More children = shorter female lifespan
r = –0.70, p < 0.001
Human longevity at the cost of …
This shows that high-fecundity populations (e.g., developing nations) tend to have lower longevity.
⭐ 2. The trade-off remains after controlling for all confounders
After removing effects of:
Economy
Disease load
Ethnicity
Religion
Geography
The relationship still exists:
Women who have more children live shorter lives on average.
(r = –0.27, p = 0.0012)
Human longevity at the cost of …
⭐ 3. Economic and disease factors matter
Higher GDP → higher longevity & lower fertility
Higher infectious disease burden → lower longevity & higher fertility
⭐ 4. Ethnic and religious groupings have significant predictive power
Human phylogeny and culture influence both fertility patterns and lifespan variability.
🔶 6. Interpretation
The results strongly support the evolutionary trade-off theory:
Investing biological resources in reproduction reduces the energy available for body repair, leading to earlier aging and death.
This parallels findings in:
Fruit flies
Nematodes
Birds
Mammals
The study suggests these trade-offs operate even at the societal and population level, not only within individuals.
🔶 7. Limitations Acknowledged
The authors caution that:
Human reproduction is strongly influenced by socio-cultural factors (e.g., education, contraception), not purely biology
Some cultural factors may confound the relationship
Genetic vs. environmental contributions are not disentangled
Country-level averages do not reflect individual variation
However, despite these limitations, the consistency of the global pattern is compelling.
🔶 8. Conclusion (Perfect Summary)
This study provides robust global evidence that human longevity and reproductive success are linked by a fundamental biological trade-off: populations with higher fertility have shorter female lifespans, even after controlling for economic, geographic, disease-related, ethnic, and cultural factors. The findings extend life-history theory to humans on a worldwide scale and support the idea that allocating energy to childbearing reduces resources for somatic maintenance, accelerating aging.... |