Good article on www.footmaxx.com or www.lowerextremityreview.com on the back and orthoses (orthotics).
"Excessive foot pronation (rolling in), relates to chronic low back pain and the use of orthoses might help alleviate the problem. Women have a 51% higher risk of low back pain than in men with a pronated foot function." Marian T. Hannan
Also, an orthoses has proven it reduces spending on prescription medicines! It also provides more support and stability of the foot that it may not necessarily have from the musculature and joint itself.