Final answer:
History of prolonged corticosteroid use is a risk factor for osteoporosis, unlike weight-bearing exercise, adequate calcium intake, and increased estrogen levels, which actually decrease the risk.
Step-by-step explanation:
The appropriate answer to the question which of the following variables as a risk factor for osteoporosis should be included in a nurse's client education program is d) History of prolonged corticosteroid use. Corticosteroids are known to interfere with the bone-rebuilding process, which can lead to osteoporosis when these medications are used for prolonged periods. On the contrary, regular weight-bearing exercise, adequate calcium intake, and increased estrogen levels are generally associated with a decreased risk of developing osteoporosis. Weight-bearing exercises stimulate bone formation, adequate calcium is essential for bone health, and estrogen helps to maintain bone mass. As such, they should also be included in the education program, but as preventive measures rather than risk factors.