Prevention and risk factors for osteoporosis

An individual’s peak bone mass is typically achieved by the age of 30. The amount of bone that is obtained at one’s peak, and how much is retained thereafter, is influenced by several factors, including:

1. Genetics and osteoporosis
   
   Genetics plays an important role - it is estimated that about 75% of an individual’s peak bone mass is influenced by genetics. There are genes that code for Vitamin D receptors and for estrogen receptors that both significantly affect peak bone mass. If one is genetically predisposed to osteoporosis, then exercise, diet and regular bone mass testing are even more important.
   
   
2. Exercise and osteoporosis
   
   Weight bearing exercise and muscle contraction combined have been shown to effectively increase bone density in the spine. It is recommended that an individual perform 20 to 30 minutes of aerobic exercise 3 to 4 times weekly to increase bone mass.
   
   In a study by Dalsky in 1988, jogging, walking, or stair climbing at 70-90% of maximum effort three times per week, along with 1,500 mg of calcium per day, increased bone density of the lumbar (lower) spine by 5% over 9 months. Exercises in a pool have not been shown to increase bone density.
   
   
3. Diet and osteoporosis
   
   Adequate calcium intake is critical in keeping bones strong, and it is estimated that approximately 70% of people do not regularly ingest adequate amounts of calcium.

The recommended amounts of calcium for adults are as follows:


• For people over 50 (postmenopausal women), 1,500 milligrams of calcium per day is recommended along with 400-800 i.u. of Vitamin D.
• For people 25-50 years old (premenopausal women), 1,000 milligrams of calcium per day is recommended with 400 i.u. of Vitamin D.

Calcium can be found in many everyday foods. Examples of foods that contain calcium include: dairy products (e.g. milk, yogurt, cheese), dark green vegetables (e.g. spinach), grains, beans and some fish.

Additionally, there are a number of calcium supplements that are available. Calcium supplements have varying amounts of calcium, so it is important to speak to a pharmacist before taking calcium to make sure that the appropriate amount is being used.

In addition to adequate intake of calcium and Vitamin D, it has been shown that an overall balanced and healthy diet plays an important role in preventing osteoporosis. For example, diets that are high in protein and/or sodium increase the loss of calcium through the urine and contribute to decreased calcium availability.

It is important to note that over 2000 milligrams of calcium per day can be harmful to the kidneys and cause kidney stones. However, when calcium is taken in the recommended dose there is no increase in kidney stone formation. People with pre-existing kidney disease should consult their physician.