Thickening of the femoral shaft cortical bone has been mentioned in reports of atypical subtrochanteric and diaphyseal (S/D) femur fractures.  These authors examine the relationship of cortical thickness to S/D fracture risk in a large cohort of older women.  However they found no evidence that thick femoral cortices placed women at higher risk for low-energy S/D femur fractures; in fact, the opposite was true. Women with thin cortices were at a higher risk for femoral neck and intertrochanteric fractures.

http://www.ncbi.nlm.nih.gov/pubmed/22547423