No Positive Correlation Between Anemia and Disability in Older People in Japan

To the Editor: We have read with interest the article entitled “Anemia Is Associated with Disability and Decreased Physical Performance and Muscle Strength in the Elderly” by Penninx et al.1 Anemia in older people may result from diverse causes associated with economic situation and life-style as well as underlying diseases such as malignancy, subclinical infection, and malnutrition. To confirm the findings of Penninx et al. we compared quantitative scores in activities of daily living (ADLs) and depression of community-dwelling elderly with and without anemia living in three towns in Japan. The study population consisted of 411 community-dwelling older people (174 men, 237 women, mean age=71.7) living in Kyoto, 138 living in Hokkaido (54 men, 84 women, mean age=79.8), and 379 living in Kochi (147 men, 232 women, mean age=78.6) in Japan. According to the World Health Organization's criteria for anemia (hemoglobin<13 g/dL in men and<12 g/dL in women),2 the percentage of elderly subjects with anemia in Kyoto, Hokkaido, and Kochi was 11.9%, 26.0%, and 27.0%, respectively. Although reports of the prevalence of anemia varied from 2.9% to 61.0%,3 the higher prevalence of elderly subjects with anemia in Hokkaido and in Kochi than in Kyoto was presumed to be due to the higher mean age of the population in Hokkaido and Kochi. Seven basic ADL items (walking, ascending and descending stairs, feeding, dressing, going to the toilet, bathing, grooming) were assessed. Each basic ADL item was evaluated on a four-level scale (3=completely independent; 2=needing some help; 1=needing much help; 0=completely dependent). Then each item's score was summed to generate a total basic ADL score ranging from 0 to 21.4 For higher-level daily activities, using the Tokyo Metropolitan Institute of Gerontology (TMIG) index of competence, a 13-item index including three sublevels of competence, each rated on a yes/no basis, was assessed: instrumental self-maintenance (5 items: the ability to use public transport, buy daily necessities, prepare a meal, pay bills, and manage banking matters), intellectual activities (4 items: the ability to fill out forms, read newspapers, read books or magazines, and take interest in television programs or news articles on health-related matters), and social roles (4 items: the ability to visit friends, give advice to relatives and friends, visit someone at the hospital, and initiate a conversation with younger people). The Geriatric Depression Scale-15 (GDS-15) was used to screen older people for depression. Table 1 compares the mean age, sex ratio, body mass index, ADL scores, mean GDS-15 score, and the prevalence of depression (GDS cutoff=6 (mild depression) and 10 (severe depression) of the groups with and without anemia in Kyoto. The nonanemic group was significantly younger than the anemic group, there were proportionally more women in the anemic group than in the nonanemic group, and body mass index was lower in the anemic group than in the nonanemic group, but there were no significant differences in basic and advanced ADLs, depression score, and prevalence of depression between the two groups. These findings were common to the other two towns (Hokkaido and Kochi) in Japan. The findings5 concluding that anemia in elderly residents in a nursing home in Japan might decrease the survival rate but that anemia itself did not lead to lower ADL scores coincided with our findings in Japan. Our findings suggest that the relationship between anemia and disability in older people in Italy that Penninx et al. reported is not necessarily a universal phenomenon, at least in community-dwelling elderly population in Japan. Anemia in older people may be associated with long-standing dietary habits and economic status as well as underlying diseases. Although anemia is an important issue in geriatric medicine, diverse relationships between anemia and other health conditions in older people require further study.