Tolga Atay, from Suleyman Demirel University (Turkey), and colleagues studied the effects of electromagnetic waves emitted from cellular phones operating at a frequency of 900 to 1800 MHz on the bone mineral density of the pelvic bone area, a common location at which men carry their cell phones.  The researchers conducted dual X-ray absorptiometry to measure bone density at the upper rims of the pelvis (iliac wings) in 150 men, average age 32, who carried their cell phones on their belts for an average of 15 hours a day, and were cell phone users for an average of six years.  They found that bone density was slightly reduced on the side of the pelvis where the men carried their cell phones.  While the difference between the two sides was not statistically significant and did not approach bone level density reductions seen in people with osteoporosis, the researchers caution that further bone weakening could occur with continued carrying at this location.