LDL is precursor to vitamin D
From http://stephanie-on-health.blogspot.com/2009/07/6-very-low-ldl-and-vitamin-d.html 
Recall that LDL delivers cholesterol  to the tissues . Vitamin D is manufactured  from cholesterol  in the skin upon exposure to sunlight  (Vitamin D Synthesized from Cholesterol) . If your LDL is low, then you are not going to be able to supply adequate amounts of cholesterol to the skin, and the result will be severe vitamin D deficiency, and, ultimately, an increased susceptibility to cancer. Even if you spend gobs of time out in the sun, your vitamin D levels will still be low, because your supply chain of LDL is insufficient for production of vitamin D.