Age- and sex-related differences in urinary cortisol level.

A comparative study between normal groups showed that the 24-h urinary cortisol level is age-dependent both in men and women. The comparison between men and women with age-matched groups revealed a significant difference in the lower age groups up to 20-24 years. When urinary cortisol values were corrected for creatinine excretion, the age-related variation was eliminated to some extent, but not completely. The correction could correct the sex-related difference in the lower age groups, but it brought about another sex-related difference in the advanced age groups. There was no remarkable age- or sex-related difference in the circadian rhythm.