Osteoporosis or decreased bone density is a significant health problem in women and some men.  Bone density, which decreases with age, is affected by bone loading, nutrition, and hormone status.  Weight training is widely used as a method of preserving or increasing bone density.  A study from Loyola Marymount University in Los Angeles found that bone density in the hip and spine increased by 2.7 – 7.7 percent in men but did not change in women, following a 24 week weight training program that included squats and deadlifts.  Weight training increases bone density more in men than women.  (Journal Strength Conditioning Research 25:  1098-1103, 2011)