Age and sex specific reference serum selenium levels estimated for the Italian population.

The association between the concentration of selenium in serum and the risk of degenerative processes of the cardiovascular apparatus or of neoplastic disease remains still uncertain. An inaccurate selection of the study populations, and above all the lack of age, sex and area of residence specific reference values could have contributed to create confusion on the biological relevance of selenium in human diseases. In our present work the serum selenium levels for the Italian population have been studied, adopting standardized methods. The study population (4201 adult subjects and 1217 children) was derived from samples of populations previously enrolled in epidemiological preventive programs. The mean observed values for the various adult populations examined varied between 87 and 93 micrograms/l and resulted approximately 5 micrograms/l higher than the mean observed values in ten European countries. The mean observed values for the paediatric population (less than 15 years of age) were slightly lower (78-83 micrograms/l). A decreasing trend of the values with age, above 60 years, especially in males, has been observed. No significant difference has been observed for sex and geographic area of residence. A preliminary study of the variations of the serum selenium levels during certain diseases has shown a sharp reduction in children with phenylketonuria and undergoing dietary restrictions, in subject with active systemic Lupus erythematosus, and in certain neoplasias.