The amount of oxygen-carrying hemoglobin circulating in the blood of older women could have an impact on the risk for mobility problems, Johns Hopkins physicians have found.
Hemoglobin levels of 12 grams per deciliter to 16 grams per deciliter have long been considered normal by physicians, but a Hopkins study of more than 600 women in their 70s indicates that at a "low-normal" value of 12 g/dL, these women were as much as 1.5 times as likely to have difficulty performing daily tasks. The report is published in the July issue of the Journal of the American Geriatrics Society.
"The 12 g/dL criteria widely used by physicians to define anemia in older women needs serious scrutiny," says Paulo H.M. Chaves, M.D., Ph.D., lead author of the study and an assistant professor of medicine at Hopkins. "Mild anemia in elderly women has often been dismissed as 'innocent', but it might be a significant health problem."
Anemia, a condition characterized by low levels of red blood cell mass, has been recognized as a major geriatric syndrome, affecting up to 32 percent of older women, Chaves says. Among older adults, it is often a marker of chronic diseases and can cause symptoms including fatigue, chest pain, shortness of breath and dizziness. Currently, physicians recommend their patients take some combination of iron, folate and vitamin B12 supplements for anemia associated with nutritional deficiencies. However, there is no set treatment for anemia of chronic disease.
An estimated 35 percent of women ages 70 to 80 have a hard time with general mobility tasks like walking a few blocks, climbing a flight of stairs or doing heavy housework, Chaves says: "When they have difficulty, they become more sedentary. They often lose their independence and develop substantial social and health care needs. It's a major public health problem."
For the study, Chaves and colleagues evaluated data from 633 elderly Baltimore-area who lived independently and who had participated in The Women's Health and Aging Studies I and II of disability onset and progression. Twenty-two percent were African-American. After performing routine health assessments on the women between 1992 and 1996, the investigators took blood samples, then asked them how difficult it was to walk a quarter-mile or climb 10 steps. They also measured the women's ability to walk, rise quickly from a chair several times, and keep balance.
Consistently, women with hemoglobin levels between 13 g/dL and 14 g/dL performed the best in the mobility tests, while those with hemoglobin levels under 12 g/dL performed the worst and those with hemoglobin levels between 12 g/dL and 13 g/dL performed intermediately. The risk of mobility problems for those with hemoglobin levels of 12 g/dL was more than twice as high as for those with hemoglobin levels of 13 g/dL to 14 g/dL, even after researchers adjusted for all health indicators associated with physical function decline.
Questions remain whether anemia is indeed an independent risk factor for functional decline, or is merely a mark of coexistent chronic diseases, Chaves says. The study was supported by the National Institute on Aging.
Other authors of the report were Bimal Ashar, M.D.; Jack M. Guralnik, M.D., Ph.D.; and Linda P. Fried, M.D., M.P.H. Chaves also is an assistant professor with the Open University for Studies on Aging and Care of the Edlerly (UNATI) at The State University of Rio de Janeiro (UERJ), Brazil.
Chaves, P. et al, "Looking at the relationship between hemoglobin concentration and prevalent mobility difficulty in older women. Should the criteria currently used to define anemia in the elderly be reevaluated?" Journal of the American Geriatrics Society, July 2002.
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Johns Hopkins' Welch Center for Prevention, Epidemiology and Clinical Research http://www.med.jhu.edu/welchcenter/
National Institute on Aging http://www.nia.nih.gov
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Journal
Journal of the American Geriatrics Society