Possible influence of age on the expression of the heterozygous cerumen phenotype

The relationship of cerumen (earwax) phenotype and age was examined in 2,618 women. An increasing proportion of white women with dry or unclassifiable cerumen was found with advancing age, ranging from 2.0% in women under 30 years to 13.3% in women 70 years and older. No statistically significant change with age was found in other racial groups. It is suggested that the increase of dry or unclassifiable cerumen in white women represents a change in the expressivity of alleles that determine cerumen type occurring with advancing age in women who are heterozygous for the trait.