Anemia, a condition caused by vitamin and mineral deficiency, doubles the risk of serious physical decline in the elderly, according to a new study. The researchers do not yet know if treating the condition, through supplements, could prevent the decline that eventually results in disability.
The study is the first to find an association between physical decline in later life and anemia, a blood condition that affects about 13 per cent of older Americans. It also found that older people who do not yet have anemia, but whose blood levels show they could be close to developing the condition, are 1.5 times more likely to develop physical declines than those who have normal blood hemoglobin levels.
"This study suggests that even mild anemia is a risk factor linked to reduced ability of older people to function at their fullest potential," said Dr Jack Guralnik, an NIA epidemiologist who co-authored the study, published in the August 1 issue of the American Journal of Medicine.
The investigators from Wake Forest University School of Medicine in Winston-Salem, North Carolina, followed a group of 1,146 people, aged 71 and older, for more than four years. They assessed their ability to perform three physical tasks and correlated the scores with blood samples.
At the end of the four-year study, two-thirds of the participants had at least modest declines in physical performance scores, with 346 people (30 per cent) having substantial decreases. Overall, those who did not have anemia averaged a 1.4 point decline on the 12-point scale during the study. In contrast, those who had borderline anemia dipped an average of 1.8 points and those with anemia dropped an average of 2.3 points on the 12-point scale.
Excluding people who had ailments associated with anemia, such as cancer, kidney disease, and infections, did not change the findings, said the researchers.
Anemia is defined by the World Health Organization as hemoglobin levels below 12g/dL in women and below 13g/dL in men. For the study, men and women whose blood hemoglobin levels were within 1g/dL of the WHO standard (12-13g/dL for women, 13-14g/dL for men) were classified as having borderline anemia.
"Although no study yet shows that treating anemia in older people reduces the incidence of physical decline, our study certainly suggests that this may be the case," said lead investigator Dr Penninx.
Anemia affects at least 3.4 million Americans and is the most common blood disorder in the United States. It occurs when the body does not produce enough red blood cells or red blood cells are prematurely destroyed, leading to a low concentration of hemoglobin, which transports oxygen from the lungs to other tissues.
Anemia can be caused by vitamin or mineral deficiencies, particularly of iron, vitamin B12, and folic acid. Underlying diseases including cancer, rheumatoid arthritis and chronic kidney disease also can trigger anemia, but in up to 25 per cent of cases, no cause can be identified. Dietary changes and nutritional supplements are thought to help treat the condition.