There are various forms of vitamin D deficiency. There are genetic forms where, effectively, you get abnormal bone development because the body doesn’t respond to vitamin D properly. You can get a mother who’s vitamin D deficient, often mothers with dark skin who are not getting enough sunlight, and then that is transferred to the baby and the baby’s bones aren’t formed properly. And you can also get babies that are inadequately fed or exposed to sunlight, and they can get vitamin D deficiency with rickets.
Later on in life, vitamin D deficiency is often oversold as a problem, but it can be a problem in older Australians who are not getting out in the sun. And it also can be a problem, again, of people with dark skin who, many times they’re migrants here from Africa where they’ve been used to exposing their skin to the sun in enclosed courtyards, but here, because of cultural and religious reasons, they were completely covered and don’t have the chance to expose their skin to the sun.
And if you’ve got dark skin, dark skin doesn’t convert sunlight to vitamin D as efficiently as people with white skin, and so that’s a high-risk group for vitamin D deficiency, as are the elderly as they get older.
Vitamin D testing is not that useful in most circumstances with the elderly because vitamin D supplements are easy to take and pretty safe, as long as they’re taken in reasonable doses.
Dr Norman Swan, Physician and Journalist