Preventing vitamin D deficiency — the new breakthrough in women’s health?

(Not as sure what I think of this source - it's a little commercial for me.)

Preventing vitamin D deficiency — the new breakthrough in women’s health?:

What’s more, evidence from studies tracking the prevalence of disease by geography and nationality shows clear links between vitamin D deficiency and obesity, insulin resistance, heart disease, certain cancers, and depression. Since most of these problems take many years to manifest, vitamin D deficiency has been overlooked by many providers for a very long time. I test all of my patients, and have been surprised to find that more than 85% come up with a vitamin D deficiency.