25(OH)D levels in healthy older Swiss citizens. A: The regression line illustrates reduction of these levels in 1,291 men and women (P < 0.01). B: The same data as in A were sorted into three age groups and are here represented in box plots. They further illustrate the decrease of 25(OH)D levels by decrements of median and interquartile ranges in relation to aging.
Sakem et al. BMC Medicine 2013 11:176 doi:10.1186/1741-7015-11-176