Apart lack of sunlight, what causes low vitamin d levels?

Insufficient intake. There are two ways to get vitamin d. Your body makes it when you are exposed to the sun, or you can take it in your diet. Vitamin d tends to be found in fish (usually cold water) and eggs. There's some in fortified milk, but not enough. Over all, it's pretty hard to get enough from your diet unless you eat huge amounts of certain fish or take a supplement, so i recommend supplements.
Hypovitaminosis D. Vitamin d deficiency can be caused by inadequate intake, inadequate sunlight, impaired absorption, and impaired conversion to the active form by the body. Within each of these categories there can be many causes.

Related Questions

What causes low vitamin d levels apart from a lack of sunlight?

Vitamin D. Usually this is genetically related. Theoretically sunshine will increase vitamin d levels but a study in hawaii showed that 50% of people with 20 hours of sunshine a week still had low vitamin d levels. You can supplement with over-the-counter vitamin d safely. Read more...

Blood work says vitamin d levels are (44nmol/L)... 17.6ng/ml. Take 2000iu vitamin d3 daily. Insight? Recommendations? Live in cold climate/lack of sun

In the darkness. B"sd Despite endless studies the "correct" recommended level of vitamin D remains quite arbitrary - usually given as 30 but as low as 15 may be fine. Some recent studies also suggest higher levels may even be harmful. In some cases I check the calcium and parathyroid hormone levels (PTH) as elevated levels usualy reflect Vit D deficiency. Reasonable to me to increase vit D3 to 3000 u/day. Read more...

What causes you to have a vitamin d deficiency (aside from lack of sun, correct foods etc usual stuff!) - methotrexate? Enbrel? Prednisone?

D. Normal levels of vitamin D vary between ethnicities with lowest in African Americans. Vitamin D in units of 1000 or 2000 per capsule and 100 tablets per bottle, and not expensive. Available over the counter in pharmacies. Read more...