risk of atrial fibrillation which was found to be threefold in subjects over the age of 60 over a 10-year period, reduced exercise capacity and cardiac function, decreased bone mineral density and increased fracture risk, and again a three- to fourfold increased risk of fracture, an increased all-cause mortality in a recent study by Parle and colleagues. So, there can be significant effects even with a moderately suppressed TSH of below .1 if it is suppressed long term.
This just shows the study by Sawin and colleagues where a normal thyrotropin -- this is the risk of atrial fibrillation over time, and if someone has a low thyrotropin, which again in this study was less than .1, there is a significantly increased risk of atrial fibrillation.
So, the patient was on .125 milligrams of levothyroxine. The levothyroxine was decreased to 112 micrograms per day, a decrease of only 10 percent. Seven weeks later, she returned with no complains and her TSH now was in that target range we have talked about between .5 and 2. So, you can see that very minor adjustments in levothyroxine of even 10 percent can have