Susan A. New, BA, MSc, PhD

Disclosures

September 02, 2003

Question

I have a postmenopausal patient who consumes a moderate level of alcohol. What is the effect of moderate alcohol consumption on bone health?

Response from Susan A. New, BA, MSc, PhD

Alcohol is, in part, a nutritional source, providing 29 kJ/mL (ie, 7 kcal) of energy, as well as moderate amounts of protein, carbohydrates, and fat. Beers contain small amounts of a variety of the B vitamins, and both red and white wines contain several trace elements, including iron, potassium, copper, and sodium -- although this varies (predominantly for iron) depending on year of harvest, wine preparation method, grape type, etc. Other important components are also found in alcoholic beverages, including flavonols, flavones, flavan-3-ols, flavanones, and anthocyanins.

American and European guidelines on alcohol consumption are given as daily and weekly upper limits. There are no significant health risks at levels of consumption of between 3 and 4 units a day or less for men and between 2 and 3 units a day or less for women. (A "unit" of alcohol is the amount contained in a half pint [284 mL] of beer, a single glass [125 mL] of table wine, a single glass [50 mL] of fortified wine, eg, sherry, or a single measure [25 mL] of spirits; it approximates to 10 mL or 8 g of absolute alcohol.) However, in the United Kingdom, for example, trends in alcohol consumption are a cause for concern.[1] The Health Survey for England found that 38% (two fifths) of men had consumed more than 4 units of alcohol on at least 1 day in the previous week, and approximately 20% of women (one fifth) had consumed more than 3 units of alcohol on at least 1 day in the previous week. Mean alcohol consumption per week was 16.4 units for men and 6.4 units for women. Similar findings have also been noted in the United States and a number of European countries.

There can be no doubt that chronic alcohol abuse is an important risk factor for risk of osteoporosis and fracture.[2,3,4] The mechanisms remain to be clearly defined, but there is evidence to suggest that in the human model, alcohol in large amounts is directly toxic to osteoblasts, thus reducing bone formation, and may also directly affect bone mineral density (BMD) by impairing liver function and altering both vitamin D and calcium metabolism. Furthermore, the trauma associated with alcohol-related falls is clearly important to fracture risk.

Recent work by Clark and Sowers[5] suggests that women treated for alcohol abuse had a lower femoral neck and lumbar spine BMD when compared with women who did not abuse alcohol. Women in treatment and recovery reported more fractures during childhood and early adolescence than did non-alcohol-dependent women, suggesting that factors other than acute toxification contributed to the greater fracture prevalence.

However, there is evidence for a positive effect of moderate alcohol consumption on bone. Data predominantly for postmenopausal women do indicate a positive correlation between BMD and alcohol consumption. In a study of elderly women by Felson and colleagues,[6] an alcohol intake of more than 210 mL (7 oz) per week was found to be associated with a higher BMD compared with those women consuming less than this amount. In a prospective study by Holbrook and Barrett-Connor,[7] social drinking was associated with higher bone mass, a finding that was consistent across both sexes. In a recent study of 489 elderly women aged 65-77 years by Rapuri and associates,[8] moderate alcohol intake was found to be associated with higher bone mass.

It is important to note, however, that a number of published studies have found no association between moderate alcohol intake and bone mass, including data on American,[4] British,[9] Finnish,[10] Australian,[11] and Danish[12] women.

Few studies have undertaken thorough investigations into the mechanisms of action of the proposed beneficial effect of moderate alcohol intake on bone health. In the study by Rapuri and associates, a reduction in bone remodeling was observed, as evidenced by the decrease in bone resorption markers as well as a decrease in serum parathyroid concentrations. Other possible reasons for the increase seen in bone mass with moderate alcohol consumption include: (1) the stimulation of calcitonin production, which has been shown to increase spine BMD with little effect on femoral sites and (2) the effect of alcohol on endogenous hormone levels -- for example, the influence of alcohol upon inducing adrenal production of androstenedione and its adrenal conversion to estrone. Higher estrogen concentrations have been found in postmenopausal women who consume alcohol.

Although more research is certainly required, there is some good evidence to suggest that moderate alcohol consumption in postmenopausal women is of some benefit to bone health.

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