Ask the Doctors July 2005 Issue

Ask Dr. Marks: 07/05

I’ve read that elderly patients undergoing major non-cardiac surgery, such as a hip replacement, are susceptible to mental decline following surgery. Is this true?

There are concerns among anesthesiologists that anesthesia may cause a sustained decline in cognitive function in some patients undergoing surgery. These concerns are based on a study that was conducted at Duke University Medical Center involving 354 patients age 60 or older who underwent such surgeries as total knee and hip replacements. These patients were given a battery of cognitive tests before and after surgery. Of this group, 59 percent suffered from cognitive decline at the time of discharge, with 34 percent of that group experiencing cognitive decline at three months and 42 percent experiencing cognitive decline at two years. A control group of elderly patients had no measurable change in their mental function. It is not clear whether the decline was related to the surgery or the anesthesia. If it was related to the anesthesia, are all types of anesthesia as likely to cause a cognitive problem? That and many more questions need to be answered before an effective strategy for the prevention of this problem can be formulated.

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Although vitamin C is reportedly good for the joints, I’ve heard that too much of it—particularly overindulging on orange juice, which I enjoy—can be harmful to the joints. Is this true? Can you recommend other sources of vitamin C?

There are conflicting studies on the effect of vitamin C on joint health. Vitamin C helps in the formation and maintenance of collagen and other connective tissues. It is also a powerful antioxidant and helps in the healing of wounds. The recommended daily allowance is 90mg a day for men and 75mg a day for women—roughly the equivalent of three glasses of orange juice. In rheumatoid arthritis, the consumption of foods high in vitamin C seems to protect against the polyarthritis (affecting more than one joint) form of the disease. In osteoarthritis, one study reported that people taking 152mg of vitamin C daily lowered their chance of developing osteoarthritis by 50 percent. This, however, has not been borne out by animal experiments. In one such study, guinea pigs were fed diets with low, medium, and high doses of vitamin C—and those fed the highest dose of vitamin C developed osteoarthritis. Clearly, more research needs to be done. My recommendation at this time is to ingest moderate amounts of vitamin C. The best source of vitamin C is a diet that includes citrus fruits, pineapples, strawberries, peppers, and even brussels sprouts.

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I’m told that women are particularly susceptible to osteopenia, which can lead to osteoporosis. What is it, and is there anything I can do to prevent it?

More than 18 million Americans have been diagnosed with osteopenia, an abnormally low bone density that may eventually become osteoporosis. Osteopenia is painless and is usually discovered through X-ray or a DEXA (Dual-Energy X-ray Absorptiometry) scan. It is important that osteopenia be diagnosed because its treatment can reduce your chance of suffering a fracture due to osteoporosis later in life. The treatment is designed to slow down or stop bone loss. A number of drugs are used to treat this common disorder—bisphosphonates, hormone replacement therapy, calcitonin, and raloxifene are a few of the most common ones. You can help prevent this condition by exercising regularly, eating a diet that includes adequate amounts of calcium, vitamin D and protein, stopping smoking, and decreasing alcohol intake. For exercises you can do to decrease the rate of bone loss, see “Exercise To Reduce Fracture Risk” in our May 2005 issue.