KatCarney

MEDICALFORUM by Sheila Laredo, M.D.
Source: http://www.utoronto.ca/miru/pcos/PCOS_AugSept2001.pdf

Osteoporosis is a condition characterized by decreased bone mass. Osteoporotic bones are char-acterized by loss of both the structural and mineral tissue that makes up the bone. These bones aremore "porous" or spongy, and thus more brittle. People with osteoporosis are more prone tofractures than those without it. Osteoporosis is diagnosed with a test called a bone mineral den-sity test. This is a non-invasive, painless test that involves small amounts of radiation (considerably less than a routine chest X-ray, forexample).The risk of osteoporosis typically increases quite rapidly around the time of menopause when the ovaries cease production of femalehormones that contribute to the maintenance of bone strength. Conventional wisdom tells us that it is estrogen that is the mostimportant hormone for maintaining bone strength in women.Women with PCOS do not ovulate regularly, which means that they will generally have low levels of progesterone most of the time(progesterone is the hormone that we test for in the study when we are looking for evidence of ovulation). However, the ovariesproduce adequate amounts of estrogen. Also, in women who have extra body fat, fat cells are able to convert certain male hormonesto a form of estrogen called estrone. It is not intuitive then, in women with PCOS, that there would be any difference in bone densitycompared to women with regular menstrual cycles. In other situations in which women do not ovulate regularly (for example due tolow body mass), women are estrogen deficient, and in those situations, there is a known significantly increased risk of osteoporosis.However, a recent study (Yuksel O et al, J Bone Miner Metab 2001; 19:257-62) demonstrated that women with PCOS were morelikely to have a low bone density compared with women with regular menstrual cycles. In this study, 28 women with PCOS werecompared to 11 women with other causes for irregular periods and to 15 women with regular menstrual cycles. The study found thatwomen with other causes for irregular cycles had the lowest bone mineral densities, followed by women with PCOS. Women withregular cycles had the highest values. Interestingly, they also found a correlation between insulin resistance and bone density, suchthat women with insulin resistance were more likely to have higher bone densities. The researchers thought that perhaps high levels ofserum insulin might be protective of bone mass, although this is just a hypothesis and requires further research.Other groups had not previously found this association of low bone mass with PCOS. An older study (Dagogo-Jack et al, J ClinEndocrinol Metab 1997; 82(9): 2821-25) showed that women who had excessive male pattern hair had higher bone densities thanwomen without excess hair, and that women with male-pattern hair and irregular periods (the majority would have PCOS) had some-what lower bone densities than the regular cycling women with excess hair, but higher bone densi-ties than regular cycling women with no excess male-pattern hair.Confused?You're not alone. While it is not clear exactly what is going on with women withPCOS, it appears that more irregular cycling is associated with lowering of bone density, whichmay predispose to increased risk of fracture. Some researchers think that this may be related to lowprogesterone levels in women with PCOS, but this is controversial.What can you do to reduce your risk? It is well known that most North American women do notget adequate calcium in their diets, in part due to substitution of milk for sodas. Most adult womenrequire 1,000 mg of elemental calcium in the diet (more with pregnancy, lactation, and in elderlywomen after menopause if they are not taking hormone replacement). As a general rule, a cup ofmilk, yogurt, ice cream or cottage cheese, or an ounce of hard cheese contain 200-300 mg of el-emental calcium. Peas, beans, fish and dark leafy vegetables are also a good source of calcium. Inaddition, for your body to absorb calcium, you need to have adequate vitamin D. This can be obtained from certain foods (like fattyfish), or milk or cereal fortified in vitamin D, or from sunlight (when no sunscreen is worn, and in Canada in the summer monthsprimarily). Otherwise, supplements sometimes need to be considered. Daily intake of Vitamin D is usually suggested at 400-800 IUper day.As part of the PCOS Diet & Exercise study, you may already have been told to increase your consumption of low-fat dairy products.This is a good way to maintain a healthy overall diet, and may help minimize the risk of reduced bone density possibly related toPCOS.

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