Anaemia, 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 anaemia, a blood condition that affects about 13 per cent of older Americans. It also found that older people who do not yet have anaemia, 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 haemoglobin levels.
"This study suggests that even mild anaemia is a risk factor linked to reduced ability of older people to function at their fullest potential," said Dr Jack Guralnik, an epidemiologist who co-authored the study, published in the 1 August 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 anaemia averaged a 1.4 point decline on the 12-point scale during the study. In contrast, those who had borderline anaemia dipped an average of 1.8 points and those with anaemia dropped an average of 2.3 points on the 12-point scale.
Excluding people who had ailments associated with anaemia, such as cancer, kidney disease, and infections, did not change the findings, said the researchers.
Anaemia is defined by the World Health Organisation as haemoglobin levels below 12g/dL in women and below 13g/dL in men. For the study, men and women whose blood haemoglobin levels were within 1g/dL of the WHO standard (12-13g/dL for women, 13-14g/dL for men) were classified as having borderline anaemia.
"Although no study yet shows that treating anaemia in older people reduces the incidence of physical decline, our study certainly suggests that this may be the case," said lead investigator Dr Penninx.
Anaemia occurs when the body does not produce enough red blood cells or red blood cells are prematurely destroyed, leading to a low concentration of haemoglobin, which transports oxygen from the lungs to other tissues.
Anaemia 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 anaemia, 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.