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Association between anemia and falls in community-dwelling older people: cross-sectional results from the KORA-Age study
https://doi.org/10.1186/1471-2318-14-29
© Thaler-Kall et al.; licensee BioMed Central Ltd. 2014
Received: 23 December 2013
Accepted: 28 February 2014
Published: 7 March 2014
Abstract
Background
Falls and fractures are among the principal causes of disability, and mortality of older people. Therefore, identifying treatable risk factors for falls in this population is very important. Here we evaluate the association between anemia and falls in community-dwelling people aged 65 years and older.
Methods
In 2009 967 community-dwelling people aged 65 years and older were included as part of the KORA-Age study. History of falls was assessed via questions derived from the National Health and Nutrition Examination Survey questionnaire. A non-fasting venous blood sample was obtained from all study participants. Anemia was defined as a hemoglobin level below 12 g/dL in women and below 13 g/dL in men according to the WHO criteria. Different logistic regression models were computed including relevant confounders such as sex, age, and disability to estimate Odds Ratios (OR) for falls.
Results
In the total sample there was no significant association between anemia and falls neither in the unadjusted (OR 1.35; 95% CI 0.87-2.09) nor in the multivariable-adjusted models (OR 1.06; 95% CI 0.66-1.70). The association between continuous hemoglobin levels and falls was significant in the unadjusted model (OR per 1 SD decrease 1.36; 95% CI 1.14-1.64), but after adjustment for age and sex the association was attenuated and lost its significance (OR 1.13; 95% CI 0.92-1.38). In age- and sex-stratified analyses, no significant associations between anemia or hemoglobin levels and falls could be found. However, in joint analysis in the total sample a significantly, more than two-fold increased risk was observed after multivariable adjustment in persons with anemia and disability (OR 2.10; 95% CI 1.12-3.93) in comparison to persons without anemia and disability.
Conclusions
In the present study we have not found an independent association between hemoglobin levels or anemia and falls in older people from the general population. Because there was an additive effect of anemia and disability on the occurrence of falls, blood count should be measured in disabled older men and women to identify persons, who are at particular high risk for falls.
Keywords
Background
Falls and fall-related injuries are considered a major public health problem in older people. Thirty percent of people aged 65 plus experience a fall at least once a year, and 15% at least twice per year [1–3]. It has been well established knowledge that falls and fractures are among the principal causes of disability, admission to hospital care, and mortality in older people [4–6]. Due to the inability to get up again without help, older people sometimes do experience a “long lie” [7], thus further aggravation of injuries occurs. It has been shown that half of older people who did lie longer after having fallen, die within 6 months [7, 8]. Falls are also associated with high costs. For Germany, Heinrich et al. estimated overall attributable costs between 2.1 and 3.8 billion Euros per year [9]. Due to these serious health and economic consequences, the identification of treatable risk factors for falls of older people is important.
Anemia is common in old age, with a prevalence of approximately 11% in subjects aged 65 years and older as documented in the Third National Health and Nutrition Examination Survey (NHANES III) study. The prevalence of anemia increases rapidly after the age of 50, approaching a rate greater than 20% in those individuals aged 85 years or older [10]. This also has been confirmed by the Leiden 85 plus study, in which the prevalence of anemia has been 26.7% for people aged 85 years or older [11]. Regarding sex differences the results of the NHANES III study showed almost no difference in the group of 65 to 74 years (7.8% in men vs. 8.5% in women), yet with increasing age, the prevalence of anemia was much higher in men than in women (26.1% vs. 20.1%; aged 85+) [10]. In the Leiden 85 plus study the difference was even higher: 35.5% anemic males vs. 22.3% anemic females [11].
Recently, anemia in old age, defined as a hemoglobin level below 12 g/dL in women and below 13 g/dL in men [12], has received increasing attention among researchers. Symptoms of anemia include low energy, fatigue, dizziness, and general weakness. In addition, late life anemia is associated with subsequent physical decline, as illustrated by increased disability, impaired performance, and muscle weakness [13, 14]. With these consequences, anemia could result in an increased risk of subsequent falls, although research confirming such a potential link is limited.
So far, only a few publications exist investigating the relation of anemia and falls in older persons. Three studies found a significant increase in risk of falls with decreasing hemoglobin (Hb) levels [15–17]. One other could not find a significant relation, but points out that anemic people fall more often than non-anemic people [18]. Two of these publications included only people living in nursing homes [15] or hospitalized for acute care [17], and two others included community-dwelling people with conflicting results [16, 18].
Therefore, the aim of this study was to analyze the association between anemia and falls in 967 community-dwelling men and women aged 65 years or older. Furthermore, we examined the combined relationship of anemia and disability as well as frailty with falls in older people.
Methods
Study design and participants
Data were collected in 2009 during the KORA (Cooperative Health Research in the Region of Augsburg)-Age study, a follow-up study of the four MONICA/KORA Augsburg Surveys [19]. People aged 65 years and older were taken from a population based random sample (n = 5,991). In total, 4,127 people participated in a standardized telephone interview (response 67%). Out of this group a randomly drawn sample of 1,079 participants additionally underwent extensive physical examinations including the registration of drug intake, collection of blood samples, anthropometric examination, grip force measurement, gait analysis, and an additional interview amongst others. Blood samples and answers to fall questionnaires were available for 1,048 participants. After exclusion of 81 participants because of missing data the final data set for the present analysis consisted of 967 participants (477 women and 490 men) aged 65–91 years. The study was approved by the ethics committee of the “Bayerische Landesärztekammer”; all participants provided a written informed consent.
Outcome definition
History of falls was assessed with the question “Did you fall in the previous year?” with possible answers “yes, once”, “yes, more than once” and “no”. This variable was dichotomized in “at least one fall” and “no fall”. The question was derived from the National Health and Nutrition Examination Survey (NHANES)-questionnaire [20].
A non-fasting venous blood sample was obtained from all study participants while sitting. Hematological parameters were determined from fresh venous EDTA blood samples using impedance measurements (Coulter® LH 780, Beckman Coulter GmbH, Krefeld, Germany). Anemia was defined according to WHO criteria as a hemoglobin (Hb)-level less than 12 g/dL in women and less than 13 g/dL in men [12].
Covariables
Information on socio-demographic characteristics and lifestyle behavior was collected by an interview. Frailty was assessed according to the criteria of Fried et al. [21]: weight loss in the last 6 months (short German SCREEN II questionnaire [22]), fatigue (via interview questions), low physical activity (via interview questions [23]), low walking speed (Timed Up and Go Test) and low grip force (measured via JAMAR, Saehan Corp.). Participants were classified as frail when they met 3 or more criteria, pre-frail when they met 1 or 2 criteria and non-frail when no criterion was met. The variable was dichotomized in “frail” (including pre-frail) and “non-frail”. The disability score was assessed via the Stanford Health Assessment Questionnaire [24] and categorized as disability “yes” (score ≥0.5) or “no” (score <0.5) as suggested in literature [25]. Multimorbidity was obtained with the Charlson-Comorbidity-Index from Chaudhry [26]. Participants were classified as multimorbid, if they had ≥3 diseases. Drug intake during the last 7 days before the examination was recorded with the IDOM-Software [27].
Statistical analyses
Besides descriptive analyses, different logistic regression models were computed to assess associations of anemia/hemoglobin values with falls, respectively. Hemoglobin levels were considered as continuous variable (decrease per SD) and anemia (yes/no) was defined via WHO criteria [12].
Overview of p-values for considered confounders
Hb level | Anemic-WHO [12] | Falls | |
---|---|---|---|
Multimorbidity | 0.0049 | 0.0118 | 0.1334 |
Disability | 0.0023 | <.0001 | 0.0038 |
Diuretics | 0.0584 | 0.0318 | 0.6326 |
Frailty | <.0001 | <.0001 | 0.1866 |
Hypertension | 0.1297 | 0.8939 | 0.2585 |
Diabetes | 0.0004 | 0.0369 | 0.4392 |
Anticoagulants | 0.2342 | 0.0625 | 0.2856 |
Antihypertensives | 0.1361 | 0.0553 | 0.9232 |
Number of drugs | <.0001 | <.0001 | 0.3257 |
Nutrition score | 0.7864 | 0.1241 | 0.0044 |
Elevated alcohol intake* | 0.0004 | 0.0702 | 0.4226 |
PASE† | 0.7922 | 0.2476 | 0.7308 |
BMI | 0.0012 | 0.0689 | 0.0274 |
For the outcome “falls (yes/no)” the unadjusted model included hemoglobin level or anemia as independent variables. Model 1 additionally included age (continuous), and sex (in the unstratified analyses only) as confounders. In model 2, the number of drugs was added in addition to the confounders of model 1. In model 3 the variable “disability status (yes/no)” was added to the confounders of model 2.
We stratified all models by sex, as the normal Hb-level for men (≥13.0 g/dL) is higher than for women (≥12.0 g/dL) and due to the differences regarding the frequency of falls among men and women. We also stratified all models by age groups. The group of “young-old” included participants aged 65 to 74 years; the group of the “old-old” included all participants aged 75 years and older. Linearity was checked by including a quadratic term of the hemoglobin variable in the models (total study sample). As the p-values of the quadratic terms were not significant, linearity was assumed for the parameter hemoglobin.
To examine the joint effect of anemia and disability as well as frailty on the occurrence of falls, in a second step combined anemia and disability and anemia and frailty variables were created. The subjects were classified into four categories: 1. anemia “yes” and disability (frailty) “yes”, 2. anemia “yes” and disability (frailty) “no”, and 3. anemia “no” and disability (frailty) “yes”. Those with no anemia and no disability (frailty) were category 4 and thus the reference group. These analyses were performed in the total sample but not conducted separately for men and women or for the two age-groups due to low numbers in the different subgroups.
Results of the models were presented as Odds Ratios (ORs) and corresponding 95% confidence intervals (CIs). Significance tests were two tailed and p-values ≤0.05 were considered as statistically significant. All analyses were performed with SAS (version 9.2, SAS Institute Inc, Cary, NC, USA).
Results
Study sample characteristics by sex
Study sample characteristics by sex (n (percentages) or means (±SD)
Variable | Males (n = 490) | Females (n = 477) | All (n = 967) | P value |
---|---|---|---|---|
Mean age, y | 75.9 (6.4) | 76.0 (6.6) | 76.0 (6.5) | 0.7831* |
Falls, n (%) | 52 (10.6%) | 91 (19.1%) | 143 (14.0%) | 0.0002† |
Anemia-WHO [12] n (%) | 96 (19.6%) | 75 (15.7%) | 171 (17.7%) | 0.1149† |
Mean hemoglobin, g/dL | 14.0 (1.3) | 13.0 (1.0) | - | <.0001* |
Mean hematocrit, % | 41.0 (3.8) | 38.3 (3.0) | - | <.0001* |
Multimorbidity, n (%) | 44 (9.0%) | 38 (8.0%) | 82 (8.5%) | 0.5718† |
Disability, n (%) | 91 (18.6%) | 147 (30.8%) | 238 (24.6%) | <.0001† |
Frailty, n (%) | 205 (41.8%) | 196 (41.1%) | 401 (41.5%) | 0.8137† |
Hypertension, n (%) | 367 (74.9%) | 359 (75.3%) | 726 (75.1%) | 0.8959† |
Diabetes, n (%) | 87 (17.8%) | 80 (16.8%) | 167 (17.3%) | 0.6858† |
Use of diuretics, n (%) | 226 (46.1%) | 204 (42.8%) | 430 (44.5%) | 0.2939† |
Use of anticoagulants, n (%) | 40 (8.2%) | 38 (8.0%) | 78 (8.1%) | 0.9105† |
Use of antihypertensives, n (%) | 336 (68.6%) | 328 (68.8%) | 664 (68.7%) | 0.9488† |
Use of ≥5 prescribed drugs, n (%) | 156 (31.8%) | 149 (31.2%) | 305 (31.5%) | 0.8409† |
Mean nutrition score | 39.0 (5.1) | 37.5 (5.4) | 38.3 (5.3) | <.0001* |
Elevated alcohol intake, n (%)** | 148 (30.2%) | 117 (24.5%) | 265 (27.4%) | 0.0479† |
Mean PASE†† | 124.7 (60.4) | 113.9 (48.9) | 119.4 (55.2) | 0.0025* |
Mean BMI kg/m2 | 28.4 (3.9) | 28.4 (4.6) | 28.4 (4.2) | 0.9249* |
Fall and non-fall-participant characteristics
Fall and non-fall-participant characteristics (percentages or means (±SD))
Variable | Fall participants (n = 143) | Non fall participants (n = 824) | p-value (t-test/Chi-square test) | ||||||
---|---|---|---|---|---|---|---|---|---|
All | Male (n = 52) | Female (n = 91) | All | Male (n = 438) | Female (n = 386) | All | Male | Female | |
Mean Age, y | 78.3 (7.3) | 78.0 (7.5) | 78.4 (7.2) | 75.6 (6.3) | 75.7 (6.2) | 75.5 (6.3) | <.0001 | 0.0368 | 0.0004 |
Mean hemoglobin, g/dL | 13.2 (1.2) | 13.7 (1.4) | 12.9 (0.9) | 13.6 (1.3) | 14.0 (1.3) | 13.1 (1.1) | 0.0005 | 0.1592 | 0.0880 |
Anemia,% [12] | 21.7 | 28.9 | 17.6 | 17.0 | 18.5 | 15.3 | 0.1750 | 0.0753 | 0.5881 |
Mean hematocrit, % | 38.8 (3.4) | 40.4 (3.9) | 37.9 (2.7) | 39.8 (3.7) | 41.1 (3.7) | 38.4 (3.1) | 0.0014 | 0.2190 | 0.1529 |
Multimorbidity, % | 12.6 | 11.5 | 13.2 | 7.8 | 8.7 | 6.7 | 0.0561 | 0.4948 | 0.0409 |
Disability, % | 41.3 | 34.6 | 45.1 | 21.7 | 16.7 | 27.5 | <.0001 | 0.0017 | 0.0011 |
Frailty, % | 52.5 | 46.2 | 56.0 | 39.6 | 41.3 | 37.6 | 0.0039 | 0.5045 | 0.0013 |
Hypertension % | 72.7 | 82.7 | 67.0 | 75.5 | 74.0 | 77.2 | 0.4815 | 0.1704 | 0.0431 |
History of diabetes % | 16.1 | 19.3 | 14.3 | 17.5 | 17.6 | 17.4 | 0.6844 | 0.7684 | 0.4805 |
Use of diuretics % | 49.7 | 53.9 | 47.3 | 43.6 | 45.2 | 41.7 | 0.1767 | 0.2373 | 0.3363 |
Use of anticoagulants % | 11.9 | 11.5 | 12.1 | 7.4 | 7.8 | 7.0 | 0.0690 | 0.3471 | 0.1065 |
Use of anti-hypertensives % | 72.0 | 76.9 | 69.2 | 68.1 | 67.6 | 68.7 | 0.3478 | 0.1700 | 0.9148 |
Use of ≥5 prescribed drugs % | 37.8 | 36.5 | 38.5 | 30.5 | 31.3 | 29.5 | 0.0828 | 0.4414 | 0.0983 |
Nutrition score | 36.6 (6.0) | 38.3 (6.2) | 35.7 (5.7) | 38.6 (5.1) | 39.1 (4.9) | 38.0 (5.3) | <.0001 | 0.2502 | 0.0006 |
Increased alcohol intake % * | 22.4 | 25.0 | 20.9 | 28.3 | 30.8 | 25.4 | 0.1443 | 0.3873 | 0.3684 |
PASE † | 112.8 (53.5) | 114.5 (57.4) | 111.8 (51.5) | 120.5 (55.5) | 125.9 (60.7) | 114.4 (48.3) | 0.1150 | 0.1846 | 0.6584 |
BMI kg/m 2 | 27.7 (3.9) | 27.6 (4.1) | 27.7 (3.9) | 28.6 (4.3) | 28.6 (3.8) | 28.6 (4.7) | 0.0129 | 0.1021 | 0.1027 |
Logistic regression analysis
Results of logistic regression models
Unadjusted model | Model 1 | Model 2 | Model 3 | |
---|---|---|---|---|
Hemoglobin-level (continuous, per SD decrease) | ||||
Total sample | 1.36 (1.14-1.64) | 1.13 (0.92-1.38) | 1.11 (0.90-1.37) | 1.09 (0.89-1.34) |
Age 65-74 | 1.25 (0.91-1.73) | 1.12 (0.78-1.61) | 1.09 (0.75-1.57) | 1.10 (0.76-1.59) |
Age >74 | 1.35 (1.09-1.69) | 1.23 (0.97-1.57) | 1.21 (0.94-1.55) | 1.15 (0.89-1.48) |
Men | 1.25 (0.94-1.65) | 1.15 (0.87-1.54) | 1.14 (0.85-1.55) | 1.11 (0.83-1.49) |
Age 65-74 | 0.98 (0.60-1.62) | 1.00 (0.60-1.66) | 1.00 (0.60-1.66) | |
Age >74 | 1.33 (0.94-1.87) | 1.29 (0.89-1.85) | 1.19 (0.83-1.73) | |
Women | 1.25 (0.95-1.64) | 1.11 (0.83-1.47) | 1.09 (0.81-1.45) | 1.07 (0.80-1.43) |
Age 65-74 | 1.28 (0.77-2.13) | 1.21 (0.72-2.03) | 1.22 (0.72-2.06) | |
Age >74 | 1.15 (0.83-1.61) | 1.14 (0.81-1.60) | 1.09 (0.76-1.54) | |
Anemia definition according WHO[12] | ||||
Total sample | 1.35 (0.87-2.09) | 1.18 (0.75-1.86) | 1.13 (0.71-1.80) | 1.06 (0.66-1.70) |
Age 65-74 | 1.24 (0.50-3.12) | 1.23 (0.49-3.09) | 1.17 (0.46-2.97) | 1.21 (0.47-3.09) |
Age >74 | 1.24 (0.74-2.05) | 1.35 (0.81-2.26) | 1.29 (0.76-2.19) | 1.12 (0.65-1.92) |
Men | 1.79 (0.94-3.41) | 1.51 (0.78-2.95) | 1.49 (0.75-2.97) | 1.35 (0.67-2.71) |
Age 65-74 | 1.13 (0.24-5.30) | 1.18 (0.25-5.61) | 1.18 (0.24-5.90) | |
Age >74 | 1.85 (0.88-3.91) | 1.73 (0.79-3.78) | 1.50 (0.68-3.32) | |
Women | 1.18 (0.65-2.17) | 0.96 (0.52-1.80) | 0.92 (0.49-1.74) | 0.87 (0.46-1.66) |
Age 65-74 | 1.29 (0.41-4.09) | 1.20 (0.37-3.85) | 1.22 (0.38-3.94) | |
Age >74 | 1.03 (0.50-2.11) | 1.00 (0.48-2.08) | 0.86 (0.40-1.81) | |
Joint analyses (total sample) | ||||
Anemic & frail | 1.82 (1.05-3.15) | 1.32 (0.74-2.38) | 1.27 (0.70-2.30) | |
Anemic & not frail | 1.51 (0.73-3.14) | 1.54 (0.73-3.25) | 1.49 (0.70-3.16) | |
Not anemic & frail | 1.76 (1.17-2.63) | 1.40 (0.91-2.15) | 1.38 (0.90-2.13) | |
Not anemic & not frail | 1.00 | 1.00 | 1.00 | |
Anemic & disabled | 2.99 (1.69-5.29) | 2.17 (1.18-3.99) | 2.10 (1.12-3.93) | |
Anemic & not disabled | 0.94 (0.48-1.84) | 0.87 (0.44-1.72) | 0.85 (0.43-1.70) | |
Not anemic & disabled | 2.32 (1.50-3.58) | 1.64 (1.03-2.61) | 1.61 (1.00-2.58) | |
Not anemic & not disabled | 1.00 | 1.00 | 1.00 |
When examining the association between anemia and falls no significant relationship was found, either in the unadjusted or in the confounder-adjusted models (Table 4). This could be shown for the whole group as well for women and men and both age-groups (young-old and old-old) in the stratified analyses.
Combined analyses
The joint relationships between anemia and disability as well as frailty for the total sample are also shown in Table 4. Men and women without anemia and without disability (frailty) were the reference group. Persons with anemia and disability showed the strongest association with falls in comparison to the reference group, even after adjustment for age, sex and number of drugs (OR 2.10; 95% CI 1.12-3.93). The corresponding OR was 1.61 (95% CI 1.00-2.58) in disabled participants without anemia; however, persons with anemia but without disability had no significantly increased OR for falls compared to the reference group. The joint associations of anemia and frailty showed also an increased odd of falls in the unadjusted analysis across the 4 categories with the highest odds in persons with anemia and frailty in comparison to the reference group. After further adjustment, these associations were attenuated and became non-significant (see Table 4).
Discussion
In the present analysis including 967 community-dwelling elderly men and women no significant association between hemoglobin levels or anemia and falls could be found. Thus, the suggestion that anemia is an independent risk factor of falls in elderly people from the general population could not be supported by these results. However, we found an additive effect of anemia and disability on the occurrence of falls.
On the contrary to our study prior studies were mostly conducted in selected groups [15–17] in women only [32] or they used self-reported data regarding anemia status or information from chart reviews [33]. Furthermore, most of the former analyses were based on smaller study samples [15, 17, 18].
The group of Duh et al. employed a retrospective open-cohort design and analyzed data of 47,350 individuals regarding anemia and risk of injurious falls in community-dwelling elderly people. Results showed that anemia increased the risk of injurious falls by 1.47 times in multivariate analysis adjusting for age, gender, health plan, history of falls, co-morbidities, and concomitant medications [16]. A 50% higher risk of fall injuries in community-dwelling adults aged 65 and older was also reported by Herndon et al. [33]. However, contrary to the present study, in that case–control study (467 cases, 691 controls), anemia based on self-report was used. Both studies mentioned above concentrated on injurious falls whereas our database includes also falls which did not cause injuries.
Pandya et al. found even more than twice the risk of falling for anemic participants when retrospectively analyzing the relationship between anemia and falls in 564 nursing home residents. However, in that study, only a selection of relevant covariables was available and collected by chart review [15]. Dharmarajan et al. investigated in a case–control study the relationship between the presence of anemia and falls during hospitalization in 362 ambulatory adults aged 59–104 years from long-term care and community settings. They found a 22% decreased risk of falls for every 1.0 g/dL increase in Hb-concentration and a 1.9 times increased risk of falls in anemic hospitalized patients [17].
In another study, Lawlor et al. analyzed data of 4,050 female participants of the population-based British Women's Heart and Health Study aged 60 to 79 and found that women reporting at least one fall per year had lower mean Hb-concentrations than women who did not report a fall; the inverse association remained even after adjustment for social class, BMI, chronic diseases, and each class of drug used (OR of any falls for a 1 SD increase of Hb was 0.90, 95% CI 0.81-0.99) [32]. In contrast to these findings we could not find significantly lower Hb-concentrations for women who reported a fall. Additionally we found no significant relationship of Hb-concentrations and falls in women. Contrary to the other publications the observational study of Penninx et al. including 394 community-dwelling older persons from The Netherlands could not prove that anemia directly affects risk of falls although longitudinal data were used and disease and functioning status were adjusted for. The authors hypothesized that anemia could still be only a manifestation of disease severity which would be the true link between anemia and falls [18].
So far, no data are available showing the joint association of anemia and disability with the occurrence of falls in the elderly general population. The results of our study extend the understanding that different factors in elderly people can have an additive effect on the occurrence of falls. Although no independent association between anemia and falls was found in the present sample, it could be shown, that persons with disability and concomitant present anemia represent a high risk group for falls. The findings from the present data therefore suggest that in elderly, mainly multimorbid persons single risk factors should not be considered isolated in relation to certain outcomes, but rather in the context of other relevant disorders and restrictions.
We recognize that our study has limitations. First, participants were asked for falls which happened in the past year on the day the blood sample was taken. Therefore, the anemia status of a participant could have been different at the time when the fall occurred. However, it could be assumed that in the present sample almost all persons with anemia suffered from chronic and not from acute anemia and thus were well adapted to the low hemoglobin levels. Hence, it is most likely that the status of anemia was similar at both points of time. Second, the interview-based assessment of falls could be imprecise, as the interrogated person could have forgotten these events (consistency bias), or did not want to report them in order to not appear frail. We did not find an investigation on the reliability and validity of the NHANES questionnaire [20] used to assess falls, but the short and easy way to ask people about their history of falls indicates reliable results. Third, the exclusion of participants who could not come to the study center because of severe illnesses could have influenced the results as they would most likely have lower hemoglobin levels. This could possibly have led to an underestimation of the true association between anemia and falls. On the other hand it was necessary to exclude people who could not walk anymore as they would not experience falls. Fourth, the cross-sectional design of the study represents a limitation, implicating that cause and effect relationships cannot be discerned. Fifth we included the intermediary variable disability as confounder in the logistic regression model which could result in a decreased association between anemia and falls. But as the results of the logistic regression models were already not significant before including these variable, this should not have influenced our results.
Finally, another issue worth considering would be the number of falls, as it was analyzed by Penninx et al., who found a 1.91 times greater risk of recurrent falls in elderly people with anemia (n = 394) [18]. But in our study group only 92 participants fell once, and 51 fell more than once. When looking at the anemic participants only 22 people fell once and only 9 fell more than once. We considered these groups as too small for meaningful analyses. The strength of the study is the inclusion of a relative large number of individuals randomly drawn from the general population, and the availability of data on lifestyle, medication, and multiple metabolic risk factors.
Conclusion
In this analysis an independent relationship of anemia and falls in older people from the general population could not be demonstrated. The relationship shown in other studies including hospitalized or nursing home living participants or focusing on injurious falls could not be confirmed by our study population. Because there was an additive effect of anemia and disability on the occurrence of falls, blood count should be measured in disabled older men and women to identify persons, who are at particular high risk for falls. Further studies, in particular prospective studies need to be carried out to clarify the role of anemia regarding the occurrence of falls in elderly people from the general population.
Declarations
Acknowledgements
The authors would like to thank all study participants, the KORA Augsburg field staff and all members of the Institute of Epidemiology II from the Helmholtz Zentrum München who were involved in planning and/or conducting the study.
This research was supported by the Graduate School of Information Science in Health (GSISH) and the TUM Graduate School.
Trial registration/Funding
The KORA-Age study was part of the program “Health in Old Age”, which was financed by the German Federal Ministry of Education and Research (BMBF FKZ 01ET0713). The KORA-Age project was conducted on the KORA platform (KORA, Cooperative Health Research in the Region of Augsburg), which was initiated and financed by the Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, and funded by the German Federal Ministry of Education, Science, Research and Technology as well as the State of Bavaria. The study “Functioning and Disability in Old Age” was funded by the German Research Foundation (Deutsche Forschungsgemeinschaft) (GR 3608/1-1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Authors’ Affiliations
References
- Tromp AM, Smit JH, Deeg DJ, Bouter LM, Lips P: Predictors for falls and fractures in the longitudinal aging study Amsterdam. J Bone Miner Res. 1998, 13 (12): 1932-1939. 10.1359/jbmr.1998.13.12.1932.View ArticlePubMedGoogle Scholar
- Nevitt MC, Cummings SR, Kidd S, Black D: Risk factors for recurrent nonsyncopal falls. A prospective study. JAMA. 1989, 261 (18): 2663-2668. 10.1001/jama.1989.03420180087036.View ArticlePubMedGoogle Scholar
- Tinetti ME, Speechley M, Ginter SF: Risk factors for falls among elderly persons living in the community. N Engl J Med. 1988, 319 (26): 1701-1707. 10.1056/NEJM198812293192604.View ArticlePubMedGoogle Scholar
- Cummings SR, Melton LJ: Epidemiology and outcomes of osteoporotic fractures. Lancet. 2002, 359 (9319): 1761-1767. 10.1016/S0140-6736(02)08657-9.View ArticlePubMedGoogle Scholar
- Tinetti ME, Williams CS: The effect of falls and fall injuries on functioning in community-dwelling older persons. J Gerontol A Biol Sci Med Sci. 1998, 53 (2): M112-M119.View ArticlePubMedGoogle Scholar
- Tinetti ME, Williams CS: Falls, injuries due to falls, and the risk of admission to a nursing home. N Engl J Med. 1997, 337 (18): 1279-1284. 10.1056/NEJM199710303371806.View ArticlePubMedGoogle Scholar
- Narayanan MR, Lord SR, Budge MM, Celler BG, Lovell NH: Falls management: detection and prevention, using a waist-mounted triaxial accelerometer. Conf Proc IEEE Eng Med Biol Soc. 2007, 2007: 4037-4040.PubMedGoogle Scholar
- Lord SR, Sherrington C, Menz HB, Close J: Falls in Older People. Risk Factors and Strategies for Prevention. 2001, Cambridge University PressGoogle Scholar
- Heinrich S, Weigelt I, Rapp K, Becker C, Rissmann U, Konig HH: Fall and fracture prevention based on the national expert standard. Implementation and costs in a real world setting in nursing homes. Z Gerontol Geriatr. 2012, 45 (2): 128-137. 10.1007/s00391-011-0243-9.View ArticlePubMedGoogle Scholar
- Guralnik JM, Eisenstaedt RS, Ferrucci L, Klein HG, Woodman RC: Prevalence of anemia in persons 65 years and older in the United States: evidence for a high rate of unexplained anemia. Blood. 2004, 104 (8): 2263-2268. 10.1182/blood-2004-05-1812.View ArticlePubMedGoogle Scholar
- den Elzen WP, Willems JM, Westendorp RG, de Craen AJ, Assendelft WJ, Gussekloo J: Effect of anemia and comorbidity on functional status and mortality in old age: results from the Leiden 85-plus study. CMAJ. 2009, 181 (3–4): 151-157.View ArticlePubMedPubMed CentralGoogle Scholar
- WHO: Nutritional anemia. Technical Report Series, Volume 405. 1968, Geneva Switzerland: World Health OrganizationGoogle Scholar
- Penninx BW, Guralnik JM, Onder G, Ferrucci L, Wallace RB, Pahor M: Anemia and decline in physical performance among older persons. Am J Med. 2003, 115 (2): 104-110. 10.1016/S0002-9343(03)00263-8.View ArticlePubMedGoogle Scholar
- Penninx BW, Pahor M, Cesari M, Corsi AM, Woodman RC, Bandinelli S, Guralnik JM, Ferrucci L: Anemia is associated with disability and decreased physical performance and muscle strength in the elderly. J Am Geriatr Soc. 2004, 52 (5): 719-724. 10.1111/j.1532-5415.2004.52208.x.View ArticlePubMedGoogle Scholar
- Pandya N, Bookhart B, Mody SH, Funk Orsini PA, Reardon G: Study of anemia in long-term care (SALT): prevalence of anemia and its relationship with the risk of falls in nursing home residents. Curr Med Res Opin. 2008, 24 (8): 2139-2149. 10.1185/03007990802215844.View ArticlePubMedGoogle Scholar
- Duh MS, Mody SH, Lefebvre P, Woodman RC, Buteau S, Piech CT: Anaemia and the risk of injurious falls in a community-dwelling elderly population. Drugs Aging. 2008, 25 (4): 325-334. 10.2165/00002512-200825040-00005.View ArticlePubMedGoogle Scholar
- Dharmarajan TS, Avula S, Norkus EP: Anemia increases risk for falls in hospitalized older adults: an evaluation of falls in 362 hospitalized, ambulatory, long-term care, and community patients. J Am Med Dir Assoc. 2007, 8 (3 Suppl 2): e9-e15.View ArticlePubMedGoogle Scholar
- Penninx BW, Pluijm SM, Lips P, Woodman R, Miedema K, Guralnik JM, Deeg DJ: Late-life anemia is associated with increased risk of recurrent falls. J Am Geriatr Soc. 2005, 53 (12): 2106-2111. 10.1111/j.1532-5415.2005.00491.x.View ArticlePubMedGoogle Scholar
- Peters A, Doring A, Ladwig KH, Meisinger C, Linkohr B, Autenrieth C, Baumeister SE, Behr J, Bergner A, Bickel H, Bidlingmaier M, Dias A, Emeny RT, Fischer B, Grill E, Gorzelniak L, Hänsch H, Heidbreder S, Heier M, Horsch A, Huber D, Huber RM, Jörres RA, Kääb S, Karrasch S, Kirchberger I, Klug G, Kranz B, Kuch B, Lacruz ME, et al: Multimorbidity and successful aging: the population-based KORA-Age study. Z Gerontol Geriatr. 2011, 44 (Suppl 2): 41-54.View ArticlePubMedGoogle Scholar
- Centers for Disease Control and Prevention (CDC). National Center for Health Statistics (NCHS): National Health and Nutrition Examination Survey Questionnaire. 2003–2004, Hyattsville, MD: U.S. Department of Health and Human Services, Centers for Disease Control and PreventionGoogle Scholar
- Fried LP, Tangen CM, Walston J, Newman AB, Hirsch C, Gottdiener J, Seeman T, Tracy R, Kop WJ, Burke G, McBurnie MA, Cardiovascular Health Study Collaborative Research Group: Frailty in older adults: evidence for a phenotype. J Gerontol A Biol Sci Med Sci. 2001, 56 (3): M146-M156. 10.1093/gerona/56.3.M146.View ArticlePubMedGoogle Scholar
- Keller HH, Goy R, Kane SL: Validity and reliability of SCREEN II (Seniors in the community: risk evaluation for eating and nutrition, Version II). Eur J Clin Nutr. 2005, 59 (10): 1149-1157. 10.1038/sj.ejcn.1602225.View ArticlePubMedGoogle Scholar
- Meisinger C, Lowel H, Thorand B, Doring A: Leisure time physical activity and the risk of type 2 diabetes in men and women from the general population. The MONICA/KORA Augsburg cohort study. Diabetologia. 2005, 48 (1): 27-34. 10.1007/s00125-004-1604-3.View ArticlePubMedGoogle Scholar
- Bruce B, Fries JF: The Health Assessment Questionnaire (HAQ). Clin Exp Rheumatol. 2005, 23 (5 Suppl 39): S14-S18.PubMedGoogle Scholar
- Tas U, Verhagen AP, Bierma-Zeinstra SM, Hofman A, Odding E, Pols HA, Koes BW: Incidence and risk factors of disability in the elderly: the Rotterdam study. Prev Med. 2007, 44 (3): 272-278. 10.1016/j.ypmed.2006.11.007.View ArticlePubMedGoogle Scholar
- Chaudhry S, Jin L, Meltzer D: Use of a self-report-generated Charlson Comorbidity Index for predicting mortality. Med Care. 2005, 43 (6): 607-615. 10.1097/01.mlr.0000163658.65008.ec.View ArticlePubMedGoogle Scholar
- Mühlberger N, Behernd C, Stark T, Holle R: Datenbankgestützte Online-Erfassung von Arzneimitteln im Rahmen gesundheitswissenschaftlicher Studien - Erfahrungen mit der IDOM-Software. Inform Biom Epidemiol Med Biol. 2003, 34: 601-611.Google Scholar
- Ziere G, Dieleman JP, Hofman A, Pols HA, van der Cammen TJ, Stricker BH: Polypharmacy and falls in the middle age and elderly population. Br J Clin Pharmacol. 2006, 61 (2): 218-223. 10.1111/j.1365-2125.2005.02543.x.View ArticlePubMedGoogle Scholar
- Ganz DA, Bao Y, Shekelle PG, Rubenstein LZ: Will my patient fall?. JAMA. 2007, 297 (1): 77-86. 10.1001/jama.297.1.77.View ArticlePubMedGoogle Scholar
- Hartikainen S, Lonnroos E, Louhivuori K: Medication as a risk factor for falls: critical systematic review. J Gerontol A Biol Sci Med Sci. 2007, 62 (10): 1172-1181. 10.1093/gerona/62.10.1172.View ArticlePubMedGoogle Scholar
- Washburn RA, Smith KW, Jette AM, Janney CA: The Physical Activity Scale for the Elderly (PASE): development and evaluation. J Clin Epidemiol. 1993, 46 (2): 153-162. 10.1016/0895-4356(93)90053-4.View ArticlePubMedGoogle Scholar
- Lawlor DA, Patel R, Ebrahim S: Association between falls in elderly women and chronic diseases and drug use: cross sectional study. BMJ. 2003, 327 (7417): 712-717. 10.1136/bmj.327.7417.712.View ArticlePubMedPubMed CentralGoogle Scholar
- Herndon JG, Helmick CG, Sattin RW, Stevens JA, DeVito C, Wingo PA: Chronic medical conditions and risk of fall injury events at home in older adults. J Am Geriatr Soc. 1997, 45 (6): 739-743.View ArticlePubMedGoogle Scholar
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