Anemia and activities of daily living in the Korean urban elderly population: Results from the Korean Longitudinal Study on Health and Aging (KLoSHA)

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1 DOI /s ORIGINAL ARTICLE Anemia and activities of daily living in the Korean urban elderly population: Results from the Korean Longitudinal Study on Health and Aging (KLoSHA) Soo-Mee Bang & Jeong-Ok Lee & Yu Jung Kim & Keun-Wook Lee & Soo Lim & Jee Hyun Kim & Young Joo Park & Ho Jun Chin & Ki Woong Kim & Hak-Chul Jang & Jong Seok Lee Received: 15 September 2011 / Accepted: 21 August 2012 # Springer-Verlag 2012 Abstract This study was planned to investigate the prevalence and risk factors of anemia and its impact on healthrelated quality of life and activities of daily living (ADL) in elderly Koreans. Of the 1,118 randomly sampled elderly Koreans aged 65 years or older living in Seongnam, Korea, on Aug. 1, 2005, we estimated the prevalence of anemia from 695 responders. We investigated the risk factors of anemia using a merged sample of this random sample and 270 volunteers enrolled from Seongnam residents aged 85 years or older. We diagnosed anemia according to the World Health Organization criteria. The estimated age- and gender-standardized prevalence of anemia was 8.33 % for the overall random sample (95 % confidence intervals (CI) ), % in men (95 % CI ), and 6.85 % in women (95 % CI ). The identified risk factors were age 80 years, male, iron deficiency, history of stroke, renal dysfunction, and metabolic syndrome. Anemia Soo-Mee Bang and Jeong-Ok Lee contributed equally to this work. Electronic supplementary material The online version of this article (doi: /s ) contains supplementary material, which is available to authorized users. S.-M. Bang : J.-O. Lee : Y. J. Kim : K.-W. Lee : S. Lim : J. H. Kim : Y. J. Park : H. J. Chin : H.-C. Jang : J. S. Lee Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, South Korea K. W. Kim (*) Department of Neuropsychiatry, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 166 Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi-do , South Korea kwkimmd@snu.ac.kr was associated with impairment in physical functioning (p ) and instrumental ADL (p<0.001). This is the first report about anemia s prevalence in community-dwelling Korean elders, adjusted and standardized according to the city s and nation s population. Timely diagnosis of anemia and correction of its treatable cause may improve QOL and ADL in elderly individuals. Keywords Korean. Elderly. Anemia. Quality of life. Activities of daily living Introduction The Korean population is aging rapidly. Korea became an aging society in 2000 and expected to enter into an aged society fastest in the world. As the aging population and incidence of age-related health conditions increase, expectations are that the cost of health care will also rise. In 2010, the Korean population aged 65 years or over, which formed 11.3 % of the total Korean population, consumed 32.2 % of the total medical expenditures [1, 2]. Anemia occurs commonly in the elderly in association with impaired physical performance [3, 4] and a number of health conditions, such as falls, weakness, and immobility. It can also lead to more serious complications, such as cardiovascular and neurological impairments, and may increase mortality, independently of race or gender [5, 6]. Consequently, anemia can have a significant effect on health care requirements and expenditures [7]. The prevalence of anemia in Western community-dwelling elderly populations is approximately 10 %, ranging from 4.4 to 28.0 % [3 5, 8 13]. Only one epidemiological study on

2 anemia in elderly Koreans exists, conducted in Seoul, Korea. In that study, the estimated prevalence of anemia in Koreans aged 60 years or over was 13.6 %, and the study also identified female gender, old age, hypoalbuminemia, azotemia, and lower body mass index (BMI) as anemia risk factors [14]. However, the study had several limitations in its ability to capture anemia s epidemiology in elderly Koreans: its response rate was only 43.9 %; it provided the crude prevalence only; and it failed to evaluate other potential anemia risk factors, such as common geriatric disorders and nutritional and socioeconomic factors. The present study was conducted in an urban elderly Korean population for the following purposes. First, we estimated the age- and sex-standardized prevalences of anemia and of iron, cobalamin, and folate deficiencies in elderly Koreans. Second, we investigated demographic, socioeconomic, nutritional, medical, and psychiatric risk factors for anemia. Third, we evaluated anemia s impacts on health-related quality of life (HRQOL) and activities of daily living (ADL). Patients and methods Study population Current study was part of the Korean Longitudinal Study on Health and Aging (KLoSHA), a population-based, prospective cohort study on health, aging, and common geriatric diseases in elderly Koreans [15]. The baseline study was conducted from September 2005 to August 2006, and follow-up studies will be continued at 5-year intervals. The KLoSHA s baseline cohort comprised two samples of persons living in Seongnam City on Aug. 1, 2005: a simple random sample (N01,118) from a pool of 61,730 persons aged 65 years or older and a volunteer sample (N0 3,166) including all residents aged 85 years or older. They were invited to participate in the study by both letter and telephone. Of the 1,118 randomly sampled individuals, 695 agreed to participate in the baseline KLoSHA study. Of the 3,166 residents aged 85 or older, 270 volunteered to participate in the study. We estimated anemia s prevalence from the random sample (N0695) and identified its risk factors from the whole sample (N0965). At each participant s first visit, we evaluated their demographics and general health status via standardized self-questionnaires and interviews by three nurses specializing in dementia. Within 2 weeks of their first visit, participants had a second visit at which four neuropsychiatric specialists conducted comprehensive neuropsychological tests. Additionally, we conducted laboratory tests to evaluate participants general physical health and determine whether common geriatric disorders (see detailed lists in Electronic supplementary materials ) were present [15]. Each participant or their legal guardian provided informed consent before their participation in the study. The institutional review board of Seoul National University Bundang Hospital approved the study protocol, and the study followed the recommendations of the Declaration of Helsinki for biomedical research involving human subjects. Definition of anemia and nutritional deficiencies Anemia was defined as a hemoglobin level lower than 13.0 g/dl in men and lower than 12.0 g/dl in women. Anemia was graded according to severity (hemoglobin level >10 g/dl for mild, 7 10 g/dl for moderate, and <7 g/dl for severe), as defined by World Health Organization criteria [16]. Our laboratory set the normal range of fl for mean corpuscular volume (MCV) and pg for mean corpuscular hemoglobin (MCH). Normocytic anemia was defined as an anemia with an MCV of fl. The definitions of nutritional deficiencies were as follows. Iron deficiency (ID) was defined as a transferrin saturation lower than 10 % or serum ferritin levels lower than 15 μg/l. Cobalamin deficiency (CD) was defined as serum vitamin B 12 levels lower than 200 pg/ml, and folate deficiency (FD) was defined as a serum folate level lower than 4 ng/ml. Assessment of HRQOL and ADL To assess HRQOL, we used the Korean version of the 36- item Short-Form health survey (SF-36). The SF-36 comprises eight health subscales: general health (GH), physical functioning (PF), role-physical (RP), role-emotional (RE), social functioning (SF), bodily pain (BP), vitality (VT), and mental health (MH) [17]. We measured ADL using the Korean ADL (K-ADL) scale for basic activities and the Korean Instrumental ADL (K-IADL) scale for instrumental activities. The K-ADL and K-IADL were created and validated from 408 basic activities and 242 instrumental activities for Korean elders. The activities are categorized into seven basic domains (dressing, washing face and hands, bathing, eating, performing transfers, toileting, and continence) and ten IADL domains (grooming, doing housework, preparing meals, doing laundry, taking a short trip, using transportation, shopping, managing money, using a telephone, and taking medicine) [18, 19]. The participants answered both questionnaires with the aid of three nurses familiar with each parameter of the SF-36, K-ADL, and K- IADL. Statistical analysis For the randomly sampled respondents, we calculated the prevalences of anemia, ID, CD, FD, and any nutritional

3 deficiencies and stratified these by gender (men and women) and ages (65 69, 70 74, 75 79, and 80 years old or over). We derived 95 % confidence intervals (CIs) for each prevalence estimate using exact methods for a binomial parameter. In addition, we adjusted estimated prevalences by age and gender with regard to the population aged 65 and over in Seongnam City and in Korea, to more accurately estimate the overall prevalence rates in the city and country. Furthermore, we employed demographic data about age (65 79 vs. 80 or over), gender, and years of education (0 6 vs. 7 or more) in a risk analysis model for anemia. We also analyzed the following variables in the risk analysis: past medical history of cerebral or coronary artery disease (as determined by self-reported questionnaire), living status (living without vs. living with spouse), income (the minimum cost of living (1,081 US dollars for a family of four per month) or less vs. more than the minimum cost of living), the three nutritional deficiencies (defined as the previous laboratory criteria and any nutritional deficiency among iron, cobalamin, or folate), common geriatric disorders such as major depression, any neuropsychiatric disorders (including major or minor depression, alcohol or substance dependence, schizophrenia, panic disorder, and insomnia), renal dysfunction (estimated GFR <60 ml/ min/1.73 m 2 vs. 60 ml/min/1.73 m 2 ), diabetes mellitus (use of antidiabetic medication or a serum fasting glucose of >110 mg/dl), hypertension (systolic blood pressure >135 mmhg, diastolic blood pressure >85 mmhg, or the use of antihypertensive medications), dyslipidemia (total cholesterol level 240 mg/dl, triglyceride level 150 mg/dl, HDL cholesterol level <40 mg/dl in males and <50 mg/dl in females, or the use of a lipid-lowering agent), metabolic syndrome defined as having three or more among the following five criteria: BMI (mass (kilogram)/((height (meter)) 2 ) >25 kg/ m 2 or waist circumference >90 cm in males and 80 cm in females, hypertriglyceridemia, low HDL cholesterol, hypertension, and diabetes mellitus), and thyroid illness (defined as hypothyroidism or hyperthyroidism on a current thyroid function test). To analyze anemia prevalence differences by these 19 variables, we used Chi-square tests and performed multivariate analyses, using significant variables with a P value less than 0.1, using binary logistic regression analysis. We compared differences in HRQOL and ADL in participants with and without anemia via t test. Two-sided P values less than 0.05 were considered statistically significant. All analyses were performed using SPSS, version 17.0 (Chicago, IL, USA). Results Characteristics of the study population Of the 695 randomly sampled participants, 298 (42.8 %) were men. Their median age was 71 years (range, years). The mean age was 70.9±4.8 and 72.5± 5.9 years in men and women, respectively, while 67 (9.6 %) were aged 80 years or over. Their mean hemoglobin was 13.9±1.4 g/dl, and mean MCV and MCH were 93.6±4.6 fl and 30.7±1.7 pg, respectively. The mean hemoglobin levels by gender and age groups were as follows: 14.9±1.64 g/dl for males and 13.3±0.98 for females (65 69 years), 14.4±1.51 for males and 13.4± 0.95 for females (70 74), 14.6±1.48 for males and 13.2± 0.89 for females (75 79), and 13.9±1.09 for males and 13.0±1.31 for females (80 or over) Prevalence rate of anemia and nutritional deficiency Table 1 summarizes the prevalence rates of anemia, ID, CD, and FD. The age- and gender-adjusted prevalence of anemia in Seongnam was 8.19 % (95 % CI %). The estimated age- and gender-standardized prevalence rate of anemia in Koreans aged 65 years or older was 8.33 % (95 % CI ), and the estimated age-standardized prevalence rates of anemia in Koreans aged 65 or older were % for men (95 % CI ) and 6.85 % for women (95 % CI ). Among the 56 participants with anemia, 49 (87.5 %) had mild, 6 (10.7 %) had moderate, and 1 (1.8 %) had severe anemia. Of 31 males with anemia, 26 (83.9 %) had mild, 4 (12.9 %) had moderate, and 1 (3.2 %) had severe anemia. Of 25 females with anemia, 23 (92 %) had mild and 2 (2 %) had moderate anemia. Of these participants, 47 (83.9 %) had normocytic anemia (MCV of RBCs from 80 to 100 fl), 3 (5.4 %) had microcytic anemia, and 6 (10.7 %) had macrocytic anemia. Among the nutritional deficiencies, folate deficiency (9.31 %, 95 % CI ) had a higher prevalence than did iron (2.24 %, 95 % CI ) or cobalamin deficiency (2.11 %, 95 % CI ). Anemia risk factors In the univariate analyses, 12 variables associated with anemia with a P value less than 0.1: age, sex, living status, iron or cobalamin deficiency, any nutritional deficiency, history of stroke, presence of neuropsychiatric disorder, renal dysfunction, diabetes mellitus, metabolic syndrome, and thyroid illness. In subsequent multivariate analyses, only age 80, male gender, iron deficiency, history of stroke, renal dysfunction, and metabolic syndrome remained significant (Table 2). Impacts on HRQOL, ADL, and IADL Table 3 summarizes anemia s impacts on HRQOL, ADL, and IADL. Among the HRQOL s eight domains, the

4 Table 1 Prevalence of anemia and nutritional deficiencies in Korean elders Anemia Iron deficiency Cobalamin deficiency Folate deficiency % (95 % CI) % (95 % CI) % (95 % CI) % (95 % CI) Age a years (n0299) 6.69 ( ) 2.68 (0.85 to 4.50) 1.34 (0.04 to 2.64) 5.69 ( ) years (n0211) 8.53 ( ) 2.84 (0.60 to 5.09) 1.42 ( 0.18 to 3.02) 7.58 ( ) years (n0118) 6.78 ( ) 0.85 ( 0.81 to 2.50) 1.69 ( 0.63 to 4.02) ( ) 80 years (n067) ( ) 1.49 ( 1.41 to 4.40) 5.97 (0.30 to 11.64) ( ) Gender a Male (n0298) ( ) 1.34 (0.04 to 2.65) 2.01 (0.42 to 3.61) ( ) Female (n0397) 6.30 ( ) 3.02 (1.34 to 4.71) 1.76 (0.47 to 3.06) 6.80 ( ) All, crude a 8.06 ( ) 2.30 (1.19 to 3.42) 1.87 (0.86 to 2.88) 8.78 ( ) Age-adjusted b 8.41 ( ) 2.24 (1.14 to 3.34) 2.12 (1.05 to 3.19) 9.24 ( ) Male ( ) 1.11 ( 0.08 to 2.30) 2.13 (0.49 to 3.77) ( ) Female 6.92 ( ) 2.96 (1.29 to 4.62) 2.10 (0.69 to 3.51) 7.40 ( ) Age gender, adjusted b 8.19 ( ) 2.23 (1.13 to 3.32) 2.11 (1.04 to 3.18) 9.14 ( ) Age-standardized c 8.49 ( ) 2.22 (1.13 to 3.32) 2.13 (1.06 to 3.20) 9.40 ( ) Male ( ) 1.29 (0.01 to 2.57) 2.09 (0.47 to 3.72) ( ) Female 6.85 ( ) 2.87 (1.23 to 4.52) 2.13 (0.71 to 3.55) 7.55 ( ) Age- and gender standardized c 8.33 ( ) 2.24 (1.14 to 3.34) 2.11 (1.04 to 3.18) 9.31 ( ) a Cases per 100 people in a given stratum (95 % CI) b Adjusted with regard to the population of Seongnam City c Standardized with regard to the 2005 Korean population physical functioning score was lower in the participants with anemia compared to those without (54.7±28.9 versus 48.8± 28.0, P00.031). More IADL activities (other than grooming and managing money ) were impaired in the participants with anemia compared to those without. Grooming indicates activities such as brushing hair, shaving, applying makeup, and clipping one s nails. However, all ADL activities were comparable between the participants with anemia and those without. Discussion The estimated age- and gender-standardized anemia prevalence for Korean elders is 8.33 % in our study. This is lower than the 10.6 % prevalence the National Health and Nutrition Examination Survey (NHANES) III reported [13] and lower than the 13.6 % prevalence in a previous Korean report [14]. These inconsistencies could be due to differences in the participants races, as well as heterogeneity in the estimating methods these studies used. Our cohort was limited to an urban population whose health and nutrition statuses were relatively conserved. Age differences are likely a key source of variability among studies, as anemia s prevalence increases with age. In the current study, 9.6 % of the study population is 80 years of age or older; the prevalence of anemia is % in this age group. In contrast, up to 26 % of those over age 85 had anemia in the NHANES III study [13]. Our study shows that male gender, iron deficiency, history of stroke, renal dysfunction, and metabolic syndrome are significant independent risk factors for anemia. Increased prevalence of anemia with age is more pronounced in men than in women. Several studies [13, 20, 21] report that anemia is more common in men than in women for persons aged 75 years and older, which could be due to aging-related decreases in testosterone levels [22 24]. However, the hemoglobin criteria for defining anemia in older adults are debatable. Use of a lower hemoglobin threshold for women than men might be at least partially responsible for the lower anemia prevalence in women [10]. In the current study population, if we had categorized women with g/dl of hemoglobin as anemic, the crude prevalences of anemia in women and men would have been 34.0 % (135 of 397) and 10.4 % (31 of 298), respectively. Therefore, more epidemiologic studies are needed to verify that gender can be an independent anemia risk factor in older adults. Iron deficiency and azotemia are common causes of anemia in older adults [13, 14]. Decreased physical and cognitive function is not only an outcome but can be also a cause of anemia. A previous study shows that ADL and Mini-Mental State Examination scores associate significantly and positively with hemoglobin and albumin levels [25].

5 Table 2 Multivariate analysis for the risk factors on anemia Factor No. of patients (%) P value Exp(B) 95 % CI for Exp(B) Lower Upper Age of 80 or more 335 (34.7 %) < Male (vs. female) 432 (44.8 %) Living without spouse 153 (15.9 %) Iron deficiency a 23 (2.4 %) Cobalamin deficiency b 28 (2.9 %) Any nutritional deficiency c 139 (14.4 %) History of stroke 97 (10.1 %) Any neuropsychiatric disorder d 224 (23.2 %) Renal dysfunction e 461 (47.8 %) Diabetes mellitus f 303 (31.4 %) Metabolic syndrome g 498 (51.6 %) < Thyroid illnesses h 197 (20.4 %) a Iron deficiency was defined as transferrin saturation <10 % or serum ferritin <15 μg/l b Cobalamin deficiency was defined as serum vitamin B 12 <200 pg/ml c Any nutritional deficiency means one or more deficiency among iron, cobalamin, and folate. Folate deficiency was defined as serum folate levels <4 ng/ml d Any neuropsychiatric disorder means one or more disorder including major or minor depression, alcohol or substance dependence, schizophrenia, panic disorder, or insomnia e Renal dysfunction means that the estimated GFR of less than 60 ml/min/1.73 m 2 f Diabetes mellitus was defined as use of antidiabetic medicine or a serum fasting glucose of >110 mg/dl g Metabolic syndrome was defined as having three or more criteria among the following five criteria: (1) body mass index >25 kg/m 2 or waist circumference >90 cm in male and 80 cm in female, (2) hypertriglyceridemia (a triglyceride level 150 mg/dl), (3) low HDL cholesterol (a HDL cholesterol level <40 mg/dl in male and <50 mg/dl in female), (4) hypertension (a systolic blood pressure >135 mmhg, a diastolic blood pressure >85 mmhg, or the use of antihypertensive medications), (5) diabetes mellitus h Thyroid illnesses was defined as hypothyroidism or hyperthyroidism in thyroid function test History of stroke may also associate with anemia due to nutritional deficiency. Metabolic syndrome affected over 50 % of the current study population, and it confers a significant risk of anemia. Researchers and clinicians typically consider that BMI associates negatively with hemoglobin levels [14]. However, factors associating with metabolic syndrome, especially obesity, also associate with chronic low-grade inflammation, which could be a mediator or moderator in the relationship between metabolic syndrome and anemia in the elderly [26]. In addition, in one study of 2,157 patients with acute myocardial infarction, anemia had a higher prevalence among patients with lower BMIs, but patients with BMIs of 23.5 or over had similar incidences of anemia, and the U-shaped relationship between BMI and mortality was stronger among patients with concomitant anemia [27]. Therefore, the identification and treatment of elderly patients with metabolic syndrome who may also have anemia is important. Previous studies demonstrate that anemia, even mild anemia, in the elderly could worsen quality of life and physical performance [28, 29]. Anemia is also a risk factor for functional and cognitive impairment [6]. Penninx et al. show that the positive association between anemia and physical decline also appears in anemic patients without cancer, infectious disease, or renal failure [3]. Although most (87.5 %) anemia cases in our study are mild, these patients show decreased physical functioning and limitations in most of the IADL scale activities (other than grooming and managing money). Our study was targeted to a healthy population. Healthy population would likely neglect to perceive their asymptomatic and mild anemia, as they were generally healthy. One systematic study, including 12,928 patients with renal insufficiency or cancer, shows that treatment of anemia with erythropoiesis-stimulating protein improves HRQOL [30]. Therefore, carefully screening and providing treatment for anemia in elders is important. The present study has some limitations. First, the sample size was not large enough to estimate anemia s age- and gender-standardized prevalence. Second, although our study population comprised community-dwelling participants, common comorbidities or other subclinical diseases might possibly contribute to HRQOL and IADL. Third, this study did not examine for the presence of chronic inflammatory

6 Table 3 Differences of healthrelated quality of life, activity of daily living, and instrumental activity of daily living according to the presence of anemia SD standard deviation a Higher score means better QOL, and lower score means worse QOL b Higher score means the more limited activity of daily living and instrumental activity of daily living No anemia Anemia P value Mean SD Mean SD Health-related quality of life (QOL) a General health (GH) Physical functioning (PF) Role-physical (RP) Role-emotional (RE) Social functioning (SF) Bodily pain (BP) Vitality (VT) Mental health (MH) Physical component summary (PCS) Mental component summary (MCS) Korean activity of daily living (K-ADL) b Dressing Washing face and hands Bathing Eating Performing transfers Toileting Continence K-ADL summary Korean instrumental ADL (K-IADL) b Grooming Doing housework <0.001 Preparing meals Doing laundry Taking a short trip Using transportation <0.001 Shopping Managing money Using a telephone Taking medicine K-IADL summary <0.001 diseases, such as degenerative arthritis, nor analyze the association between acute phase proteins, including C- reactive protein and erythrocyte sedimentation rate, and anemia. Future studies should examine these additional potential contributors to anemia risk. Nevertheless, this is the first report about anemia s prevalence in community-dwelling Korean elders, adjusted and standardized according to the city s and nation s population. Therefore, this research provides fundamental information for planning medical care to treat anemia in the elder population. One of this study s key findings is the relationship between mild anemia and functional impairments, demonstrating the necessity of early diagnosis and prompt management of anemia in the elderly. Anemia is prevalent in older people and a significant factor in the deterioration of an independent quality of life. Anemia can be treatable, particularly in its mild form. Therefore, appropriate diagnosis and treatment of anemia is very important in the elderly. Acknowledgments This work was supported by an Independent Research Grant (IRG) from Pfizer Global Pharmaceuticals (Grant No ), a grant from the Korean Health Technology R&D Project, Ministry for Health, Welfare, & Family Affairs, Republic of Korea (Grant No. A092077), and a grant from Seoul National University Bundang Hospital Research Fund (Grant No ). Conflict of interest The authors report no potential conflicts of interest. None of the sponsors had any role in the study design, methods, analyses, and interpretation, or in preparation of the manuscript and the decision to submit it for publication.

7 References 1. Korean National Statistical Office. Korean statistical information service: The 2010 national census. Available at: index/index.jsp Accessed 7 July The National Health Insurance Corporation. Available at: Accessed 28 February Penninx BW, Guralnik JM, Onder G et al (2003) Anemia and decline in physical performance among older persons. Am J Med 115: Penninx BW, Pahor M, Cesari M et al (2004) Anemia is associated with disability and decreased physical performance and muscle strength in the elderly. J Am Geriatr Soc 52: Izaks GJ, Westendorp RG, Knook DL (1999) The definition of anemia in older persons. JAMA 281: Denny SD, Kuchibhatla MN, Cohen HJ (2006) Impact of anemia on mortality, cognition, and function in community-dwelling elderly. Am J Med 119: Robinson B (2003) Cost of anemia in the elderly. J Am Geriatr Soc 51:S14 S17 8. Woodman R, Ferrucci L, Guralnik J (2005) Anemia in older adults. Curr Opin Hematol 12: Cesari M, Pahor M, Lauretani F et al (2005) Bone density and hemoglobin levels in older persons: results from the InCHIANTI study. Osteoporos Int 16: Patel KV (2008) Epidemiology of anemia in older adults. Semin Hematol 45: Fleming DJ, Jacques PF, Tucker KL (2001) Iron status of the freeliving, elderly Framingham Heart Study cohort: an iron-replete population with a high prevalence of elevated iron stores. Am J Clin Nutr 73: Olivares M, Hertrampf E, Capurro MT, Wegner D (2000) Prevalence of anemia in elderly subjects living at home: role of micronutrient deficiency and inflammation. Eur J Clin Nutr 54: Guralnik JM, Eisenstaedt RS, Ferrucci L et al (2004) Prevalence of anemia in persons 65 years and older in the United States: evidence for a high rate of unexplained anemia. Blood 104: Choi CW, Lee J, Park KH et al (2004) Prevalence and characteristics of anemia in the elderly: cross-sectional study of three urban Korean population samples. Am J Hematol 77: Park JH, Lim S, Lim JY et al (2007) An overview of the Korean Longitudinal Study on health and aging. Psychiatry Inverst 4: Nandigam V, Nandigam K, Badhe BA, Dutta TK (2004) Is adult definition of anemia applicable to a geriatric population? Study of erythrocyte parameters in Indian geriatric inpatients. J Am Geriatr Soc 52: Nam BH, Lee SW (2003) Testing the validity of the Korean SF-36 Health Survey. J Korean Soc Health Statistics 28: Won CW, Rho YG, Sun WD, Lee YS (2002) The validity and reliability of Korean Instrumental Activities of Daily Living (K- IADL) Scale. J Korean Geriatr Soc 6: Won CW, Rho YG, Kim SY et al (2002) The validity and reliability of Korean Activities of Daily Living (K-ADL) Scale. J Korean Geriatr Soc 6: Salive ME, Cornoni-Huntley J, Guralnik JM et al (1992) Anemia and hemoglobin levels in older persons: relationship with age, gender, and health status. J Am Geriatr Soc 40: Skjelbakken T, Langbakk B, Dahl IM, Lochen ML (2005) Haemoglobin and anaemia in a gender perspective: the Tromso Study. Eur J Haematol 74: Ferrucci L, Maggio M, Bandinelli S et al (2006) Low testosterone levels and the risk of anemia in older men and women. Arch Intern Med 166: Yeap BB, Beilin J, Shi Z et al (2009) Serum testosterone levels correlate with haemoglobin in middle-aged and older men. Intern Med J 39: Beghe C, Wilson A, Ershler WB (2004) Prevalence and outcomes of anemia in geriatrics: a systematic review of the literature. Am J Med 116(Suppl 7A):3S 10S 25. Onem Y, Terekeci H, Kucukardali Y et al (2010) Albumin, hemoglobin, body mass index, cognitive and functional performance in elderly persons living in nursing homes. Arch Gerontol Geriatr 50: Zeyda M, Stulnig TM (2009) Obesity, inflammation, and insulin resistance a mini-review. Gerontology 55: Aronson D, Nassar M, Goldberg T et al (2010) The impact of body mass index on clinical outcomes after acute myocardial infarction. Int J Cardiol 145: Cesari M, Penninx BW, Lauretani F et al (2004) Hemoglobin levels and skeletal muscle: results from the InCHIANTI study. J Gerontol A Biol Sci Med Sci 59: Chaves PH, Ashar B, Guralnik JM, Fried LP (2002) Looking at the relationship between hemoglobin concentration and prevalent mobility difficulty in older women. Should the criteria currently used to define anemia in older people be reevaluated? J Am Geriatr Soc 50: Ross SD, Fahrbach K, Frame D et al (2003) The effect of anemia treatment on selected health-related quality-of-life domains: a systematic review. Clin Ther 25: