The decline in vitamin D status with age.

A cross-sectional study of plasma 25-hydroxy-vitamin D (250HD) concentrations in healthy women in the age range 20-96 years is reported. Mean values decline with increasing age while abnormally low levels of plasma 250HD are more common in the elderly. The decline in vitamin D status with age is probably the result of lack of sunlight exposure associated with social factors and physical immobility.