Effect of Periodontitis on Bone Mineral Density in Postmenopausal Women

Rapid estrogen level decline after menopause is associated with systemic bone loss in women leading to osteopenia/osteoporosis. Estrogen therapy (ET) improves bone mineral density (BMD) in postmenopausal women. Currently, ET has been associated with statistically significant increased risk of breast cancer, stroke, and thromboembolic events. Easiest lifestyle modification for the management of lower BMD is probably the adequate intake of calcium and vitamin D.

Chronic inflammatory diseases are associated with systemic bone loss. Bone has been a target in many inflammatory rheumatic diseases like rheumatoid arthritis (RA),and ankylosing spondylitis (AS). Low bone mineral density has also been documented in patients with Systemic lupus erythematosus (SLE).

Periodontitis is a chronic condition of supporting tissues of the teeth. It has been reported that 30% of individuals above the age of 50 years suffer from severe periodontitis.Hujoel et al has concluded that the mean periodontal surface area in patients with periodontitis can be as large as 8-20cm2 . The inflamed and ulcerated subgingival pocket epithelium may allow many gram negative and obligate anaerobic bacteria to enter bloodstream. Bacterial components such as endotoxins and major outer membrane proteins may also be disseminated. Studies on systemic influence of periodontitis have theorized that locally produced pro-inflammatory cytokines such as interleukin-1(IL-1), tumour necrosis factor-alpha(TNF-α), interleukin-6(IL-6) and prostaglandin-E2(PGE2) may be released into the circulation and exercise distant effects. These inflammatory cytokines have been reported to be implicated for the distinctive loss of bone density in osteoporosis through their effect on osteoclast activity.

C-reactive protein (CRP) is an extremely sensitive and non-specific acute phase reactant that is produced in response to tissue damage, inflammation, infection and hypoxia. It is a serological marker of systemic inflammation. Previous studies on elderly females and a large population based sample reported higher serum levels of CRP associated with lower BMD. A study also implicated that CRP ≥ 4.2mg/l may be used to identify the groups having rapid bone loss in older people. Various studies concluded higher levels of CRP in patients with periodontitis than in control. D Auito reported CRP reduction of 0.5mg/l at 6 months after non- surgical periodontal therapy in patients with chronic periodontitis(CP).Epidemiological studies from Buffalo, New York, reported elevated CRP in blood plasma among patients with severe periodontal attachment loss in comparison to individuals with minimal or no attachment loss. Various cross sectional studies have reported association between osteoporosis and periodontal disease in post-menopausal women. A recent study demonstrated that severe clinical attachment loss (CAL) was independently associated with low BMD of the femoral neck in postmenopausal women. These studies infer that osteoporosis is a risk factor for periodontitis. It is difficult to infer cause and effect relationship from cross sectional studies. The basis of association between osteoporosis and periodontitis may either be osteoporosis influencing periodontitis and/or vice-versa and/or both of them sharing common risk factors.

Inflammation has been reported to contribute towards post-menopausal deterioration in BMD. Levels of inflammatory cytokines responsible for the loss of bone density e.g. IL-1β, IL-6, TNF-α in osteoporosis are reported to be increased in the systemic circulation in CP. Hence, it is hypothesized that CP, an inflammatory disorder with a large wound surface area, may add to the systemic inflammatory burden and may consequently contribute towards deterioration of BMD in post-menopausal women. So, controlling systemic inflammatory burden by scaling and root planing(SRP) may have an adjunctive effect in the management of osteopenia/osteoporosis in these patients.