The relationship between auditory exostoses and cold water: a latitudinal analysis.

Area of Science:

• Paleopathology
• Human Biology
• Anthropology

Background:

• Auditory exostoses are bony growths in the external auditory canal.
• Previous observations suggested a link between exostoses and water exposure, but the specific environmental factors and geographical distribution were unclear.

Purpose of the Study:

• To investigate the geographical distribution of auditory exostoses.
• To test the hypothesis that cold water resource exploitation, particularly diving, causes auditory exostoses.
• To determine if auditory exostoses should be used in genetic population studies.

Main Methods:

• Examined the frequency of auditory exostoses across different global latitudes.
• Correlated exostosis prevalence with population-based resource exploitation, focusing on marine and freshwater activities.
• Reviewed clinical and experimental data to support or refute the proposed etiology.

Main Results:

• Auditory exostoses were rare in low (0-30° N/S) and high (>45° N) latitudes.
• Highest frequencies of exostoses were observed in mid-latitudes (30-45° N/S) among populations exploiting marine or freshwater resources.
• Data strongly support a causative relationship between auditory exostoses and cold water resource exploitation, especially diving.

Conclusions:

• Auditory exostoses are a behavioral adaptation to cold water activities, not a genetic trait.
• The prevalence of auditory exostoses is influenced by environmental and behavioral factors related to water resource exploitation.
• Auditory exostoses should be excluded from genetic analyses of population distance due to their behavioral etiology.