Seasonal and lifelong changes in skin colour and pigmentation of Austrian farming families: an exploratory study

Farmers are exposed chronically to solar ultraviolet radiation. Their chronically exposed skin undergoes alterations in pigmentation, but quantitative measurements have not be done yet. Therefore, we followed skin color and pigmentation in Austrian farming families (male and female farmers, their spouses, and children) for one year by objective tri-stimulus measurements on different body sites. The difference between constitutive and facultative pigmentation was quantified by the "degree-of-tan" (TAN°), which we defined as the difference in individual typology angle between constitutive and facultative pigmentation. Personal sun exposure was measured in parallel. Measurements of skin colour showed that independent of occupation, adult males had a darker red component in skin color of the forehead than adult females and children, with the highest values observed in males only. This difference develops during puberty and adolescence. Even in late winter, an obvious TAN° was found in all groups at continuously and intermittently exposed body sites. TAN° was higher in adults than in children and highest in farmers. The seasonal changes in TAN° were pronounced in all groups on intermittently exposed body sites but less so on the forehead. In conclusion, TAN° increases in farmers on average during their lifetime but not in their spouses, even though many spouses have higher TAN° than farmers of the same age. Such high TAN° is reversible if sun exposure is low in the following seasons. The highest TAN° values were found in farmers older than 50 years.