Bone health and oral health
Elizabeth Krall Kaye, PhD, MPH
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ABSTRACT
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Background. Low bone mass in the skeleton, which increases the risk of osteoporotic fracture, also may be associated with periodontal bone loss and tooth loss. Osteoporosis and periodontal disease share several common risk factors, including older age, smoking and perhaps insufficient dietary intakes of calcium and vitamin D.
Conclusion. Research supports the idea that osteoporosis independently influences alveolar bone height loss. Strategies for reducing osteoporosis risk also may help retard alveolar bone loss. Meeting dietary intake recommendations for calcium and vitamin D is one strategy that is appropriate for a broad segment of the population.
Clinical Implications. A healthy lifestyle has multiple benefits for the mouth and throughout the body. Dental professionals can play a role in preventing osteoporosis by reinforcing this message.
Key Words: Periodontal diseases; tooth loss; bone mineral density; osteoporosis; dietary calcium; vitamin DAbbreviations: WHI: Women’s Health Initiative
Osteoporosis and osteopenia are defined by low bone mass, deteriorating bone architecture and bone fragility. These diseases are among the most prevalent chronic conditions in the United States. One and one-half million osteoporosis-related bone fractures occur in the United States each year—more than the number of new cancer cases and twice the number of strokes. Ten million Americans have the more severe form, osteoporosis, and another 34 million have osteopenia, which puts them at increased risk of osteoporosis. As the population ages, the prevalence of osteoporosis and osteopenia is expected to increase 50 percent by the year 2020.1
Osteoporosis results from an imbalance in the rates of bone formation and resorption that cause bones to lose mineral mass. Along with the loss of minerals, they also lose strength and the ability to withstand low-level trauma. The consequences of fracture in elderly people include increased risk of death, long-term nursing home care or permanent limitations in mobility and performance of daily living activities. Many of the risk factors for osteoporosis are environmental and, therefore, are preventable. Established risk factors include older age; being female, postmenopausal, or Caucasian or Asian; a low body mass index; cigarette use; alcoholism; inadequate calcium and vitamin D intakes; physical inactivity; taking medications such as glucocorticoids and anticonvulsants; and anorexia nervosa.2,3 Although osteoporosis and osteopenia can affect people of all ages, they occur most often in middle-aged and elderly people,1 the same segment of the population that has the highest risk of chronic periodontal disease and tooth loss.
Patients with osteoporosis tend to have fewer teeth, and advanced systemic bone loss may affect the type of tooth replacement that can be supported.
Despite several decades of research, there is no consensus about whether people with osteoporosis and osteopenia have greater risks of alveolar bone loss and tooth loss. Many studies of this topic were cross-sectional studies or performed as secondary analyses of longitudinal data. As a result, these studies may have been underpowered, been restricted to special populations, lacked information on confounders, relied on self-reports of tooth loss or used indirect measures of alveolar bone loss such as clinical attachment level. The Women’s Health Initiative (WHI), a large 15-year prospective investigation of postmenopausal women that began in 1991, included an oral ancillary study specifically designed to study oral bone loss.4 After preliminary analyses, investigators classified the participants according to their periodontitis status (yes or no) and osteoporosis status at the hip (yes or no) at baseline and looked at alveolar bone height loss around posterior teeth three years later. They found that women with osteoporosis had more than three times the amount of alveolar bone height loss than did women who did not have osteoporosis, regardless of whether they also had periodontitis. These findings suggest that systemic bone status may influence the progression of alveolar bone loss independently. Final analyses in the entire WHI cohort and prospective studies in other populations are needed before we fully understand if and how osteoporosis affects periodontal disease.
Patients with osteoporosis tend to have fewer teeth, and advanced systemic bone loss may affect the type of tooth replacement that can be supported. While osteoporosis is not seen as a contraindication for implant placement, more research into its relationship with long-term implant survival is needed. If osteoporosis predisposes patients to alveolar bone loss, then clinicians should identify common therapies and modifiable risk factors that may provide opportunities for oral disease prevention. Hormone replacement and bisphosphonates prescribed for osteoporosis management or prevention may reduce alveolar bone loss and tooth loss,5,6 but these therapies are not appropriate for everyone. The risk of osteonecrosis of the jaw associated with long-term bisphosphonate use7 limits widespread use of this drug.
Calcium and vitamin D are key nutrients for bone health, and vitamin and mineral supplementation are important components of any osteoporosis treatment or prevention plan. Calcium is a major mineral in hydroxyapatite, and vitamin D is one of several hormones that regulate calcium metabolism. Recommendations for calcium intake consider estimates of how much of it is needed to build peak bone density in children and young adults and to slow down bone loss in older adults. The Food and Nutrition Board, Institute of Medicine of the National Academies’ recommendations for calcium range from 500 to 800 milligrams per day for children and from 1,000 to 1,300 mg/day for adolescents and adults.8 Calcium is found in low concentrations in a wide variety of foods, but dairy foods and fortified juices are major sources (Table
).9 One 8-ounce glass of milk or 1.5 ounces of natural cheese provides about 300 mg of calcium. Tools that consumers can use to track daily calcium intake include the Calcium Calculator10 and MyPyramid interactive Web site.11
Vitamin D is produced in the skin from a form of cholesterol. On exposure to ultraviolet radiation, this compound is converted to a vitamin D precursor, absorbed into the bloodstream and ultimately converted to its biologically active form in the kidney. Therefore, it is not strictly necessary to obtain vitamin D from the diet. However, for people who are exposed to sunlight infrequently or inconsistently, such as elderly, home-bound or institutionalized people, dietary sources are essential to supplement endogenous production and maintain serum vitamin D levels within the normal range. Healthy, active people also may benefit from having dietary sources of vitamin D during winter months. Adequate intake of vitamin D is 5 micrograms per day for people younger than 50 years; it increases to 10 µg/day for people aged 51 to 70 years and to 15 µg/day for people 71 years and older.8 Daily intakes should not exceed 50 µg/day. In the United States, milk is fortified with vitamin D so that one 8-ounce cup provides 2.5 µg. Other good sources of vitamin D are shown in the table
. For optimal bone health, it is important to balance intakes of both calcium and vitamin D. A high calcium intake may offer little benefit if a person’s vitamin D status is poor.
The probable interrelationship of systemic and oral bone loss has led researchers to investigate whether consuming the recommended levels of calcium and vitamin D slows periodontal disease progression. Future research should include randomized vitamin and mineral supplementation trials to address this. Until that is known, it is important to stress the importance of balanced nutrition for bone health and overall health in patients of all ages. There is no evidence that excess intakes of either calcium or vitamin D will offer additional benefit, but actual consumption falls far below the recommended levels in a large proportion of the population, especially women.
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CONCLUSIONS
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Dental professionals can play a role in osteoporosis prevention by reinforcing to their patients that a healthy lifestyle has multiple benefits throughout the body. A healthy lifestyle includes physical activity, avoiding smoking, maintaining a healthy weight and making sure that dietary intakes—especially those of calcium and vitamin D—meet recommendations.
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FOOTNOTES
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Dr. Kaye is a professor, Department of Health Policy and Health Services Research, Boston University School of Dental Medicine, 715 Albany St., 560, Room 338, Boston, Mass. 02118, e-mail "kralle{at}bu.edu". Address reprint requests to Dr. Kaye.
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REFERENCES
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- National Osteoporosis Foundation. America’s bone health: The state of osteoporosis and low bone mass. Available at: "www.nof.org/advocacy/prevalence/index.htm". Accessed March 13, 2007.
- Lane NE. Epidemiology, etiology, and diagnosis of osteoporosis. Am J Obstet Gynecol 2006;194(2 supplement):S3–11.[Medline]
- Grinspoon S, Thomas E, Pitts S, et al. Prevalence and predictive factors for regional osteopenia in women with anorexia nervosa. Ann Intern Med 2000;133(10):790–4.[Abstract/Free Full Text]
- Geurs NC, Lewis CE, Jeffcoat MK. Osteoporosis and periodontal disease progression. Periodontology 2000 2003;32:105–10.[Medline]
- Krall EA. The periodontal-systemic connection: implications for the treatment of patients with osteoporosis and periodontal disease. Ann Periodontol 2001;6(1):209–13.[Medline]
- Jeffcoat MK. Safety of oral bisphosphonates: controlled studies on alveolar bone. Int J Oral Maxillofac Implants 2006;21(3):349–53.[Medline]
- Kuehn BM. Reports of adverse events from bone drugs prompt caution. JAMA 2006;295(24):2833–6.[Free Full Text]
- Food and Nutrition Board, Institute of Medicine of the National Academies. Dietary reference intakes tables: The complete set. Available at: "www.iom.edu/?id=21381". Accessed March 13, 2007.
- Agricultural Research Service, U.S. Department of Agriculture (USDA). USDA National Nutrient Database for Standard Reference, Release 18. Available at: "www.nal.usda.gov/fnic/foodcomp/Data/SR18/reports/sr18page.htm". Accessed March 13, 2007.
- International Osteoporosis Foundation. Patients and public: IOF calcium calculator. Available at: "www.iofbonehealth.org/patients-public/calcium-calculator.html". Accessed March 20, 2007.
- U.S. Department of Agriculture. Steps to a healthier you. Available at: "www.mypyramid.gov". Accessed March 13, 2007.
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