ArticleEvolution, medicine, and public health2026
Amazonian Shuar testosterone levels are related to parasite infection: immunocompetence handicap hypothesis implications.
Article in Evolution, medicine, and public health, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
10 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Background: Testosterone is hypothesized to influence energetic tradeoffs between male reproduction and immune function. Testosterone is generally thought to be immunosuppressive, with high testosterone levels signaling male health and infection resistance. The Immunocompetence Handicap Hypothesis (ICHH) posits that testosterone's role in developing male secondary sexual characteristics and suppressing immune function creates a tradeoff between testosterone-linked traits and immunocompetence. Yet, the immune effects of testosterone in humans remain poorly understood. Research is particularly limited among energetically constrained, natural fertility populations characterized by high pathogen loads and long-lasting infections (such as parasitic disease), characteristics relevant to the evolution of hypothesized testosterone-linked tradeoffs. Methods: We test whether salivary testosterone concentrations are associated with parasitic helminth infection status and parasite load among 90 Indigenous Shuar males aged 12-67 years. Results: Higher testosterone levels were associated with increased infection risk but lower parasite load. However, these findings were only evident among adolescents (ages 12-19) and only for Conclusions: These findings suggest higher testosterone may increase the risk of becoming infected with some parasite species, but that heavy pathogen loads lead to a shift in resource allocation from testosterone production to immune activity during a life stage with high testosterone-related energetic demands. While some results aligned with the ICHH, the significant effects of participant age and parasite species on testosterone-infection associations indicate that the ICHH does not completely capture the full complexity of human immune-related life history tradeoffs and variation in host-parasite interactions.
Indexed as
Identifiers
What Socratic holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.