Osteoporosis and periodontal disease

Low bone mass (osteopenia) and osteoporosis are systemic skeletal diseases characterized by low bone mass and micro-architectural deterioration with a consequent increase in bone fragility and susceptibility to fracture. According to the World Health Organization, osteoporosis is considered to be present when bone mineral density is 2.5 standard deviation (SD) or more below the mean for normal young Caucasian women, i.e. a T score of )2.5. Osteopenia is defined as bone density levels between 1 and 2.5 SD below normal bone mineral density (63, 64). Both osteopenia and osteoporosis are grave publichealth concerns and are widely prevalent in developed countries, particularly among postmenopausal women. The World Health Organization considers osteoporosis to be second only to cardiovascular disease as a public-health concern. Osteoporosis affects an estimated 75 million people in Europe, the USA, and Japan. Worldwide, approximately one-third of women aged 60–70 years and two-thirds of women aged 80 years and older have osteoporosis (56). The National Osteoporosis Foundation estimates that 21.8 million women in the USA have low bone mass (osteopenia) and 7.8 million have osteoporosis; over 14 million men were estimated to have either low bone mass (11.8 million) or osteoporosis (2.3 million) (110). In the third National Health and Nutrition Examination Survey (NHANES III) the prevalence of osteoporosis when assessed at the femoral neck was 20% of postmenopausal Caucasian women (92). An alternative approach is to use morphological deformities in the vertebrae to define osteoporosis. The prevalence of the defined vertebral deformities was found to be 12% in both men and women. The increase in frequency with age was greater in women – from 5% for women aged 50–54 to 24% at age 75–79 years. For men aged 50–54 years this was 10%, rising to 18% for men 75–79 years old (101). The prevalence of this relatively silent disease is very high and on the rise. Future projections indicate a three-fold increase in osteoporosis-related hip fractures (69). In the USA, 1.3 million fractures annually are the result of osteoporosis (101). One-third of women over 50 years old will experience osteoporotic fractures, as will one in five men (65, 101, 102). Between 30% and 50% of women and between 15% and 30% of men will suffer a fracture related to osteoporosis in their lifetime (118). Nearly 75% of hip, spine, and distal forearm fractures occur among patients aged 65 years or older (103).