February 2, 2009

Osteoporosis Risk for Men and Adolescents
By Pamela Stuppy, MS, RD, LD
For The Record
Vol. 21 No. 3 P. 24

Several factors, including poor diet and an abhorrence to exercise, are driving up the odds that more Americans will be faced with this condition.

Usually considered a disease affecting older women, osteoporosis is greatly underdiagnosed and left untreated in other populations, particularly men and younger adults with certain conditions or lifestyle or dietary patterns.

Because many healthcare professionals don’t look for early signs and symptoms, men often end up with severely low bone density before clinicians recognize their osteoporosis. According to the National Osteoporosis Foundation, about 2 million men currently have osteoporosis, and another 12 million are at risk. Although men still lag far behind women in the incidence of osteoporosis, the rate among men is on the rise, and projections indicate that osteoporosis in men will increase by 50% over the next 15 years. The number of hip fractures—one of the most severe and common consequences of osteoporosis—in men is expected to double by the year 2040.1

Male osteoporosis appears to occur in two distinct age periods. Osteoporosis due to secondary risk factors is evidenced at roughly 50 to 60 years of age, while primary osteoporosis occurs after about the age of 70.

Age-related bone loss begins at about 50 years of age in both men and women. One out of eight men over the age of 50 will have an osteoporotic fracture.2 Due to their greater peak bone mass, fractures of the hip, vertebrae, and distal wrist bones occur about 10 years later in men than in women. But after the age of 75, the risk of osteoporosis in men may accelerate rapidly. Some of the bone loss in men is attributed to lower hormone levels with aging—testosterone, dehydroepiandrosterone, growth hormone, and, possibly more importantly, estrogen.

About 30% of all hip fractures occur in men, and the one-year mortality rate from an osteoporotic hip fracture in men is almost twice that of women.3 This may be due in part to the older age of the onset of osteoporosis in men and the presence of comorbid conditions.

As with women, there are ethnic differences in osteoporosis incidence among men. Statistically, the prevalence of osteoporosis is 7% in white males, 4% in African American males, and 3% in Hispanic males.1

A thorough investigation of potential risk factors is a first step toward intervention, as the underlying causes for low bone density must be addressed. Recommendations indicate that men, like women, should modify lifestyle habits that contribute to osteoporosis risk, such as quitting smoking, moderating alcohol intake, increasing exercise, improving diet, achieving a healthy body weight, modifying medications (if possible), and addressing other medical conditions that may hinder bone health.

Diet
Nutrition supplies the structural components of bone and supports a number of metabolic processes needed to maintain bone. Nutritionally, men need to consume a healthy diet that contains a variety of less-processed foods in amounts that maintain a healthy body weight. A number of nutrients, not only the well-publicized calcium and vitamin D, are required for maximizing bone density; however, vitamin D and calcium remain the two most vital nutrients. Similar to postmenopausal women, men older than the age of 50 need 1,200 to 1,500 milligrams of calcium per day and at least 1,000 international units of vitamin D. However, many men are not meeting these baseline needs.4

Some conditions associated with vitamin D insufficiency are peripherally related to complications of osteoporosis. Vitamin D is involved in maintaining muscle strength; when muscles are weaker, there is a greater risk of falling. Increased fall risk and lower bone density may lead to hip fractures and potential morbidity and mortality.

Protein is one of the major structural components of bone and can affect bone density. One study concluded that higher total intakes of protein reduced hip fracture risk in men aged 50 to 69.5 Adequate protein is also necessary for supporting muscle mass, which reduces the risk of falling. Unfortunately, with increasing age, men tend to reduce their protein intake.

Because older adults may consume fewer fruits and vegetables, nutrients that are important to bone metabolism, such as vitamin C, vitamin K, and magnesium, may also be low. Improving the diet should be the first line of defense, but a supplement may be warranted in some cases. Due to a possible reduction in stomach acidity with increasing age, older men may be deficient in another bone-related nutrient as well: vitamin B12. In this case, supplemental forms of B12 are more bioavailable and therefore recommended for older adults.

Medications
Medications that are detrimental to bone are one of the major causes of osteoporosis in men. A number of inflammatory conditions require taking prednisone or another glucocorticoid medication for various lengths of time. Even at relatively low doses, these medications can dramatically lower bone density, especially when taken over extended periods. It is recommended that men taking at least 5 milligrams of a glucocorticoid medication for five months or more take a bisphosphonate medication (which inhibits bone resorption) concurrently and maintain adequate nutrient intake to help counter some of the detrimental effects. The same is true for the use of an anticonvulsant medication, with the possible addition of calcium and vitamin D supplements.6 Bisphosphonates slow the negative impact of bone-depleting medications as long as there are sufficient nutrients on hand for bone maintenance.

A bisphosphonate medication is also usually prescribed if osteopenia or osteoporosis is diagnosed, in which case outcomes are better if the individual is consuming a healthy diet as noted previously and is getting adequate vitamin D through sun exposure, diet, and/or supplements.7

Other medications should also be reviewed to determine whether they increase the risk of falling, as in the use of some antihypertensive medications. Some medications can counter the absorption of nutrients that bones need. In some cases, correcting the timing of medication and nutrient intake can reduce the effect. For some, increasing the intake of the nutrients will suffice. The healthcare provider may also be able to find an alternative medication that does not cause the same side effect or reduce the dosage.

Medications that change stomach pH can also impair the absorption of nutrients that need gastric acidity, and the use of some diuretics can cause excessive excretion of certain minerals needed by bone that the kidneys do not reabsorb.

Exercise
Besides diet, exercise can reduce the risk of fracture in older men by as much as 25%. This includes activities for increasing or maintaining muscle strength, coordination, balance, and flexibility. Regular weight-bearing cardiovascular exercise is helpful as well. With existing osteoporosis, activities should not involve high-impact, twisting, or excessive weights.

Referral to a physical therapist is recommended for specific guidance about exercise safety for people with established osteoporosis.

Screening
To assist with diagnosing men with bone density concerns, healthcare providers should regularly monitor older men’s height for indications of vertebral bone loss. One study showed that from the age of 30 to 70, men lost an average of 3 centimeters in height; by the age of 80, they lost 5 centimeters.8

The National Osteoporosis Foundation recommends that males aged 70 and older have a dual-energy x-ray absorptiometry (DXA) scan. The American College of Physicians recently issued guidelines on screening men for osteoporosis that suggest an evaluation of risk factors and a DXA scan for men at high risk and who are candidates for drug therapy.9 The guidelines noted that other screening tools besides the DXA scan are insufficient for diagnosing men at this age.

Obviously, there are a number of factors that predispose men to a greater risk of osteoporosis. Earlier screening and interventions will be important as the number of men moving into older age increases. Besides men, however, there are other populations that should raise red flags with regard to intervention.

Malabsorptive Conditions
Celiac disease has been highly underdiagnosed and can dramatically affect nutrient absorption. Since persons sensitive to gluten may not be symptomatic, evidence of the resulting malabsorption, such as osteoporosis, often occurs before celiac disease is identified. Some clinicians, as well as the American Gastroenterological Association, recommend bone density testing for persons with celiac disease, especially if there is evidence of anemia. The anemia suggests a longer duration of malnutrition that has probably also affected bone density. The reverse is also true: Persons with early-onset osteoporosis presenting with anemia should be tested for celiac disease.

Depending on the extent of intestinal damage, a gluten-free diet can reduce or stop the malabsorption and its otherwise ongoing negative effects on bone. Unfortunately, the diet will not reverse bone density that has already been lost in adults, so early intervention is important. Clinicians may want to repeat the celiac blood tests periodically to determine whether the person is indeed free of gluten. Since malabsorption may not completely resolve in persons with long-standing celiac disease, repeat bone density tests may also be beneficial.

Crohn’s disease is another condition with a high incidence of osteoporosis due to a number of possible risk factors, including nutrient malabsorption, low body weight (which means less weight-bearing stress), and the use of bone-depleting medications such as prednisone. The degree of malnutrition depends on the extent and location of inflammation.

Colitis may also interfere with nutrient absorption if it is severe, but it often occurs lower in the intestinal tract where there is normally limited nutrient absorption. The use of glucocorticoids for colitis can have the same negative impact on bone as it does with Crohn’s disease.

Bone loss may also be more extensive in persons with some autoimmune diseases, such as multiple sclerosis or rheumatoid arthritis, due to the use of medications (glucocorticoids) detrimental to bone and to reduced physical activity. With rheumatoid arthritis, there may be an increase in osteoclast activity as well (causing bone resorption). Additionally, many persons with autoimmune diseases are deficient in vitamin D.

Organ Function Problems
Any factors that interfere with the function of organs involved in bone metabolism that remain unresolved (eg, undiagnosed or uncorrected hyperthyroidism or hypothyroidism) can increase the risk of osteoporosis. Once corrected, thyroid issues should not be a risk factor.

The liver and kidney are both involved in the conversion of vitamin D to the active form. As a result, changes in function of either organ can interfere with available vitamin D.
Problems with the parathyroid can impact calcium metabolism, which can lower bone density.

Surgeries
To date, studies investigating the relationship between bariatric surgery and bone loss are limited. It appears that there may be a loss of bone within the first year after surgery, but bone may stabilize thereafter. More research is needed in this area.

The impact of surgeries that reduce the absorptive surface of the intestinal tract (as in removal of sections of intestine due to Crohn’s disease) depends on the location and extent of the affected or removed tissue. Most malabsorption occurs when surgeries involve the upper sections of the intestinal tract.

Lifestyle Risk Factors
Smoking is a major risk factor for low bone density and is especially detrimental to men and women with smaller frames or lower body weight. It counters some of the positive effects of estrogen on bone and negatively affects calcium and vitamin D metabolism. The degree of impact appears related to smoking duration and the number of cigarettes smoked daily. Smoking is of special concern during adolescence, a time of potential bone building.

High alcohol intake causes myriad problems. In many cases, it may take the place of consuming healthy foods containing nutrients necessary for bone health. It can also directly reduce nutrient absorption. In addition, alcohol can impair liver function, which can negatively affect vitamin D conversion as noted previously. It may directly increase bone resorption and slow bone-building processes. Besides impacting bone density, using alcohol increases the risk of falling, which can lead to fracture.

The research is mixed regarding the link between veganism and osteoporosis. Generally, it appears that vegans do have a risk for lower bone density, but this may not necessarily increase fracture incidence. Vegans tend to consume less calcium than nonvegans, but their needs may be lower due to the lack of animal protein in their diet. Another reason that calcium status may not be as problematic as expected is that up to a point, the body may compensate for lower calcium intake by increasing uptake. Despite this possibility, however, it is still recommended that vegans consume the same level of both calcium and vitamin D for their gender and age as the rest of the population. Vegans may also have lower protein and vitamin B12 intake, which can also affect bone density. Additionally, vegans tend to have lower body weight, which means less weight-bearing stress.

Risk Factors for Women, Children, and Adolescents
Although this article has focused on risk factors for men, it is worth noting recent findings regarding women, children, and adolescents, since family nutrition is a key to prevention.

Women who undergo early menopause naturally or experience it due to a total hysterectomy or because of cancer treatments are at risk for early-onset osteoporosis unless they are receiving hormone therapy. The concern is that many of these women are unaware that they need to be more aggressive about protecting their bones or may need to avoid certain types of exercise. In some cases, medications may be warranted to slow bone loss. Proper diet and exercise are extremely important to maintaining bone density and reducing the risk of falling.

Women should be aware that high levels of the retinol form of vitamin A may increase the risk of hip fractures. Cod liver oil may indeed have vitamin D, which is beneficial for bone, but it may also contain levels of retinol that are of concern. To be on the safe side, keep retinol levels from all dietary and supplemental sources below about 3,000 international units per day. Supplements should preferably contain vitamin A in the form of beta-carotene.10,11

Childhood and adolescence are life stages when osteoporosis prevention is crucial. Because of many factors, both sexes are now at greater risk for osteoporosis at a younger age than their parents and grandparents. Of concern is the fact that fracture rates in today’s children and teens are higher than they were for their parents at the same age. Some female teens with unresolved anorexia nervosa that extends one year or more with the loss of menstrual cycling can have bone density similar to a 70-year-old woman while still in their teenage years.12

The concern in the childhood and teenage years is inadequate bone density accrual resulting in low peak bone mass (accumulation of the most bone secured for a lifetime). Maximal bone density occurs by the late teen years for girls and early 20s for boys. Once past this golden window of opportunity to build bone density, adolescents do not get another chance.

Studies indicate a relationship between the consumption of dairy products and improved intake of calcium, vitamin D, and other nutrients.13 Unfortunately, with the many beverage options now available, fewer children and teens are choosing milk.14,15 Research has noted that children and teens who avoid dairy products are more likely to sustain a fracture.

Research and clinical practice indicate suboptimal levels of vitamin D in a number of people in all age categories (eg, infants, toddlers, children, teens), which can affect long-term bone status. Low sun exposure due to living in a northern latitude, use of sunscreen, or less time spent outdoors means relying on the diet to supply vitamin D. Milk has been one of the few dietary sources of vitamin D for children and teens but, as noted, intake is on the decline.

Even breast-fed babies need sensible sun exposure or vitamin D supplementation to support bone growth and development. The American Academy of Pediatrics recently doubled its vitamin D recommendation, now suggesting 400 international units per day beginning at 2 weeks of age. For infants, this can come from either a supplement or formula.16

Researchers involved in vitamin D studies tend to agree that the current dietary reference intake for this nutrient is well below what is needed to achieve adequate blood levels. Many believe that intake should be at least 1,000 international units daily for persons of all ages who are not exposed to sufficient intensity of ultraviolet light on a regular basis. Blood level goals of 30 to 80 nanograms per milliliter of 25-hydroxyvitamin D may be more optimal for bone health and a number of other health issues.

Besides calcium and vitamin D status, there are a number of other variables that can counter the attainment of peak bone mass by the time adolescents reach the threshold of adulthood.

Loss of menstrual cycling not only means less circulating estrogen to promote bone accrual, but it also implies the possibility of poor diet and/or excessive exercise, which also counter the attainment of maximal peak bone mass.

In contrast to hormone replacement therapy protecting bone for postmenopausal women, oral contraceptives given to amenorrheic adolescent females do not appear to be protective of bone, especially if they are younger than 16 or less than three years postmenarche. The concern is not necessarily bone loss at these young ages but reduced bone accrual. Although results vary, oral contraceptives used by adolescent girls beyond these ages show limited benefit. The return of a natural menstrual cycle in conjunction with a healthy diet and appropriate body weight are the best ways to counter bone changes due to amenorrhea. The shorter the duration of the amenorrhea, the less impact it will have on bone.

Amenorrhea may also be due to excessive exercise, which is often accompanied by low body weight, poor eating habits, and/or inadequate intake in general. Reducing the intensity and length of exercise by 15% or more may be enough to prompt a return of menses.

In contrast, a sedentary lifestyle is another risk factor for lower peak bone mass in teens. Bones need gentle challenges to become denser. TV and computer time are two factors that tend to interfere with adequate weight-bearing exercise in children and adolescents.

As noted previously, smoking is a major negative factor for bone, especial in the teenage years. Girls may also smoke for weight-control purposes, which can imply low body weight-another risk factor for lower bone mass.

The combination of low calcium intakes, a poor diet in general, suboptimal levels of vitamin D, less physical activity, the increasing incidence of eating disorders or at least disordered eating, and other lifestyle factors negative to bone accrual that are occurring before adulthood all lead to a concern as to the long-term repercussions these trends will have on bone status. Will we become a nation of early-onset osteoporosis?

— Pamela Stuppy, MS, RD, LD, owns a nutrition consulting practice, is a weekly columnist for several newspapers, has written a book/course on osteoporosis, and speaks nationally about women’s health topics for Academy Medical Systems. She is also on the board of the Maine Dietetic Association and was appointed by the governor of New Hampshire to serve as the nutrition representative on the state’s Osteoporosis Council.

References
1. Looker AC, Orwoll ES, Johnston CC Jr, et al. Prevalence of low femoral bone density in older U.S. adults from NHANES III. J Bone Miner Res. 1997;12(11):1761-1768.

2. Tarantino U, Cannata G, Lecce D, et al. Incidence of fragility fractures. Aging Clin Exp Res. 2007;19(4 Suppl):7-11.

3. Olszynski WP, Shawn Davison K, et al. Osteoporosis in men: Epidemiology, diagnosis, prevention, and treatment. Clin Ther. 2004;26(1):15-28.

4. U.S. Department of Agriculture. Continuing Survey of the Food Intakes by Individuals and the Diet and Health Knowledge Survey, 1994-96. Riverdale, Md.: Agriculture Research Service; 1998.

5. Wengreen HJ, Munger RG, West NA, et al. Dietary protein intake and risk of osteoporotic hip fracture in elderly residents in Utah. J Bone Miner Res. 2004;19(4):537-545.

6. Boling EP. Secondary osteoporosis: Underlying disease and the risk of glucocorticoid-induced osteoporosis. Clin Ther. 2004:26(1):1-14.

7. Bonnick S, Broy S, Kaiser F, et al. Treatment with alendronate plus calcium, alendronate alone, or calcium alone for postmenopausal low bone mineral density. Curr Med Res Opin. 2007;23(6):1341-1349.

8. Sorkin JD, Muller DC, Andres R. Longitudinal change in height of men and women: Implications for interpretation of the body mass index: The Baltimore Longitudinal Study of Aging. Am J Epidemiol. 1999;150(9):969-977.

9. Liu H, Paige NM, Goldzweig CL, et al. Screening for osteoporosis in men: A systematic review for an American College of Physicians guideline. Ann Intern Med. 2008;148(9):685-701.

10. Rothman KJ, Moore LL, Singer MR, et al. Teratogenicity of high vitamin A intake. N Engl J Med. 1995;333(21):1369-1373.

11. Crandall C. Vitamin A intake and osteoporosis: a clinical review. J Womens Health. 2004;13(8):939-953.

12. Misra M, Aggarwal A, Miller KK, et al. Effects of anorexia nervosa on clinical, hematologic, biochemical, and bone density parameters in community-dwelling adolescent girls. Pediatrics. 2004;114(6):1574-1583.

13. Marshall TA, Eichenberger Gilmore JM, Broffitt HB, Stumbo PJ, Levy SM. Diet quality in young children is influenced by beverage consumption. J Am Coll Nutr. 2005;24(1):65-75.

14. Fiorito LM, Mitchell DC, Smiciklas-Wright H, Birch LL. Dairy and dairy-related nutrient intake during middle childhood. J Am Diet Assoc. 2006;106(4):534-542.

15. Bowman SA. Beverage choices of young females: changes and impact on nutrient intakes. J Am Diet Assoc. 2002;102(9):1234-1239.

16. Wagner CL, Greer FR, American Academy of Pediatrics Section on Breastfeeding, Committee on Nutrition. Prevention of rickets and vitamin D deficiency in infants, children, and adolescents. Pediatrics. 2008;122(5):1142-1152.