Alcohol weakens bones and interferes with fracture healing

Zosia Chustecka

January 04, 2006

Jan 4, 2006

Omaha, NE - The holiday period is traditionally lubricated by alcohol and, as the holidays draw to an end and the empty bottles stack up in the recycling bin, thoughts turn to the toll that drinking has taken on the body. Although many people know about alcohol's effects on the liver, far fewer are aware of the adverse effects it has on bone.

Chronic and heavy alcohol consumption is known to contribute to low bone mass, decreased bone formation, an increased incidence of fractures, and delayed fracture healing, a review article in the December 2005 issue of Alcoholism, Clinical and Experimental Research points out [ 1 ]. Heavy drinking disrupts the balance in bone remodeling by suppressing new bone formation by osteoblasts, says author Dr Dennis Chakkalakal (Orthopaedic Research Laboratory and Alcohol Research Center, Omaha Veterans Affairs [VA] Medical Center, Creighton University, NE). But experimental evidence suggests that stopping drinking leads to a prompt recovery of osteoblast function, and this has important clinical implications.

Chakkalakal tells rheuma wire that alcohol's effect on bone should be considered in all patients who are known to drink heavily or who are suspected of doing so. The onset of bone loss resulting from alcohol abuse precedes increased fracture risk by one or two decades and is asymptomatic during this period. Investigating bone-mineral density is a good idea, Chakkalakal says, because if osteopenia is detected early, clinicians may be able to advise patients about the benefits of changes in alcohol consumption. "This is especially true since there is some indication of at least partial recovery of bone loss after a couple of years of abstinence."

This is especially true since there is some indication of at least partial recovery of bone loss after a couple of years of abstinence.

Also important is advice on abstaining from alcohol when broken bones are healing, because drinking has a detrimental effect on the healing process. "To heal properly, bone cells must first form a 'matrix,' which later hardens or ossifies," explains fellow researcher at the Omaha VA Medical Center, Dr Terrence Donohue (also professor of internal medicine at University of Nebraska Medical Center, Omaha). "Alcohol consumption changes the composition of this matrix by suppressing the formation of osteoblasts and/or decreasing their ability to respond to signals that normally trigger bone formation after a fracture."

Patients with a history of alcohol abuse have a significantly higher frequency of fracture-healing complications than nonalcoholic patients, the review points out. The prolonged disability associated with delayed unions and nonunions leads to "fracture disease," with joint stiffness, muscle weakness, and poor soft-tissue flexibility. Recent animal studies have suggested that alcohol may inhibit new bone formation at the fracture site, resulting in deficient bone repair, which is characterized by repair tissue of lower stiffness, strength, and mineral content. Chakkalakal notes that his group has published several animal studies showing that a switch to an alcohol-free diet after a bone fracture prevents the deficiency in fracture healing. "The review underscores the importance of abstinence from alcohol by patients with fractures," Donohue adds.


Effects manifested in a few years

Chronic and heavy drinking disrupts the normal balance between bone formation by osteoblasts and the removal of old bone by osteoclasts. Alcohol has an adverse effect on osteoblast activity, thus suppressing new bone formation. "The empty space created by normal bone-removing activity is inadequately filled by newly formed bone," Chakkalakal explains in a press release issued by the university. "The cumulative effect of this process during several remodeling cycles is manifested as measurable bone loss over a period of just a few years."

Alcohol-induced osteopenia has characteristics that are different from other disease states involving bone loss. Studies of alcoholic patients, using both bone histomorphometry and biochemical markers, show that various indices of new bone formation are considerably suppressed, whereas the indices of bone resorption remain relatively unchanged, the review notes. Alcohol decreases the rate of bone remodeling. In contrast, in postmenopausal osteoporosis, when estradiol levels fall, the rate of bone remodeling is increased. The distinction between the two is illustrated further by the finding that moderate alcohol consumption by postmenopausal women increases their bone mass in comparison with their nondrinking peers, the review notes.

The adverse effect on osteoblast activity is dose-related. In human studies, bone loss due to chronic consumption of excessive alcohol?greater than 100¿g/day?was generally greater at the higher levels of alcohol consumption and/or with longer duration of heavy drinking, Chakkalakal comments. Experimental models provide support for these findings, he adds: "In cell-culture studies, where bone-forming cells are grown in a liquid, production of various biomolecules that contribute to the formation of bone matrix in the living organism is suppressed when alcohol is added. This suppression is greater at higher doses, and at very high doses, cell death occurs."

There is also evidence that osteopenia may result from considerably less daily alcohol intake than the threshold adopted in many studies (80-100¿g/day), the review points out. In one recent study [ 2 ], half of the subjects drinking >40¿g/day had osteopenia compared with 11% of age-matched controls (drinking <20¿g/day); 22% and 17%, respectively, had osteoporosis.

Sources

  1. Chakkalakal DA. Alcohol-induced bone loss and deficient bone repair. Alcohol Clin Exp Res 2005; 29:2077-2090.

  2. Kim MJ, Shim MS, Kim MK, et al. Effect of chronic alcohol ingestion on bone mineral density in males without liver cirrhosis. Korean J Intern Med 2003; 18:174-180.

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