I recently started taking iron suppliments, as my ferritin levels are consistently low. Since I began, my right knee has been increasingly more and more arthritic. Could iron be causing such? Prior to starting iron, my RBC was a little low, and I always had a feeling of being cold. I am an adult male, 46 years of age. I don't smoke, drink, or use drugs. Glucose is excellent, as is everything else. Prognosis?