LAUSR

The proposals and questions posed by Leopold [1] in reply to our Letter to the Editor [2] apparently are based on the erroneous assumption that evolution by natural selection shapes the body for health; it does so only to the extent that health promotes reproductive success. Leopold's proposal “that vascular calcification co-evolved as a defense mechanism concomitant with the increased prevalence of other systemic diseases now associated with increased longevity,” and the question “why there has not been a co-evolution of an ectopic calcification regression mechanism?” prompt the answer—natural selection is unable to pursue either or both since “it is not interested” in promoting health after the reproductive age. On the same grounds, vascular calcification plausibly may have an adaptive value early in life, but a “negative connotation” late in life, a usual trade-off in evolution. Adaptations do not promote health; they foster reproductive success even if this results in harm. On the other hand, natural selection has no direction toward a purpose, so