Should I be concerned about a low vitamin d 25-hydroxy level?

Optimize vit D Level. 25-hydroxyvitamin d in infants and children should be at least 50 nmol/l (20 ng/ml), based on the available evidence. Dr. Dowd, M.D., who has worked extensively with vit d in his clinical practice recommends levels between 50 and 70 nmol/l for optimal health.
Yes. Vitamin d has many functions. Low vitamin d can contribute to Insulin resistance , elevate cortisol levels and impact other hormones including thyroid hormone. Vitamin d is important for your immune system and low levels have been linked to cancer and autoimmune disease.