Persons aged 30 years and above are susceptible to osteoporosis.

Question:

1) everyone seems to believe the myth that taking calcium-rich drinks (Anlene, Anmum and a few others) would prevent osteoporosis. Is my assumption correct that it is a misconception? Does taking calcium help at all?

2) what effect would osteoporosis have on a diver who occassionally dives deep? Would the bone already suffering from osteoporosis suffer from fatigue as metal on aircraft would?

3) would osteoporosis encourage osteonecrosis/dysbaric osteonecrosis in divers?

Doctors to answer please.

From The New York Times


Prevention: Older Bones See Benefit of Calcium and Vitamin D
 
By NICHOLAS BAKALAR
Published: September 4, 2007
Calcium supplements, or calcium and vitamin D taken in combination, may reduce the risk for bone fracture and bone density loss in older people, provided the supplements are taken regularly and in large enough doses.

 
 


A review of 29 randomized trials including more than 63,000 men and women older than 50 found that the risk for fracture could be reduced 12 percent with calcium and vitamin D supplements. The rate of bone loss was reduced by about 0.5 of 1 percent at the hip and 1.9 percent at the spine. Fracture risk was reduced by nearly one-quarter in studies in which people took their supplements conscientiously.

The review, published in the Aug. 25 issue of The Lancet, found that the effect was best with doses of 1,200 milligrams of calcium and 800 international units of vitamin D. The recommended dietary allowance for calcium in people over 50 is 1,200 milligrams, but the recommendation for vitamin D is 400 international units for people 50 to 70 and 600 for those 71 and older.

Adding vitamin D to calcium did not appear to offer increased protection. But the studies lacked enough figures on high doses of the vitamin. Still, the authors recommend that if vitamin D is to be used as an adjunct, it should be in doses that exceed 800 international units.

“For anyone over 50, especially postmenopausal women, you should see your family doctor and address with him the issue of taking calcium supplementation,” said Dr. Benjamin M. P. Tang, the lead author and a researcher at the University of Western Sydney in Australia. “It’s always better to have overall health assessed before undertaking supplements.”

First of all, osteoporosis is a process where the bone becomes softer and more fragile. It may be physiological or pathological (for example in patients with renal failure or people on steroids). In a normal person, the body and bone would grow till about the 20s. At the same time the bone mass would increase and would reach their peak at about 25-30 years. After this, regardless of what you eat you would gradually lose your bone mass (see diagram) For females, the process is hastened at menopause and thus the reason of more fracture in older women.


So to prevent severe osteoporosis, one would need to have a high Peak Bone Mass to start with. This means one have been taking high calcium containing foods while they are growing up. And to stimulate the bone to become stronger (i.e. higher Calcium content) a person needs to exercise regularly.

With regards to the 1st question, taking calcium supplements, and vitamin D helps to prevent excessive resorption of bone as the bone regulates the amount of calcium in the circulation. Thus is there is insufficient calcium in the diet, there will be low calcium in the circulation and thus that would signal to the body to release more calcium into the circulation from the bone. Thus the bone becomes weaker faster.

However, it doesn't help to increase your peak bone mass and it doesn't prevent totally bone resorption

2) No studies have shown any correlation with deep dives and osteoporosis (not that I am aware of).  The bone structure is complex of which it tends to buckle under torsional or direct force however, the pressure at depth gives a surround pressure but no nett force on the bone. Thus there is no issue of fatigue or stress fractures

3) There is no correlation between osteoporosis and dysbaric osteonecrosis in divers. They have totally 2 different aetiologies as dysbaric osteonecrosis is due to occlusion of blood supply to a portion of bone from minute gas formation and thus causes the bone to die. Over time the area (if large) will be weakened and thus collapse

As for Zimm's question, glucosamine is  currently used in treating early osteoarthritis (i.e. degenerative changes of the joints). It help the joint to prolong it's lifespan and maintain it's integrity. There is no correlation between osteoarthritis and diving. unless one gets osteoarthritis secondary to dysbaric osteonecrosis e.g in the hip joint. In such cases, no amount of glucosamine is going to help.

Long term effects in glucosamine is not known. However, glucosamine comes in either potassium or sodium based. The sodium based is best avoided in hypertensives.

As for the mentioned supplements, the studies on their effectiveness have been contradicting. If you are not a fan of milk or is lactose intolerance supplements are recommended. however, taking excessive calcium and vitamin D is a waste of time, money and is dangerous. Excessive calcium intake can lead to renal stones and other calcinosis. So see your doctor if you want to take calcium and vitamin D and check you serum calcium 6 monthly.

The best treatment for osteoporosis is PREVENTION. So encourage your kids to have a good diet of calcium daily. The myth is that calcium is only in milk. There are many foods with sufficient amounts of calcium

Thanks Dr Bones..Nice info to share.....

Coffee, tea and smoking have a negative effect on calcium absorption....

Much is said about Osteoporosis because it is such a household name especially among the women folk.

Care to elaborate more about Osteopenia, Doc?

questione time :

How do we basicaly prevent osteopornosisosteoporosis?
drink fresh milk alot?be a veggie?

dr bone..just something to ask. why when my body temp increase (fever) got back ache?