Falls: A Complex, Multifactorial Syndrome With Addressable Risk Factors
Authors: Surya Davuluri, MD1,2; T.S. Dharmarajan, MD, MACP, AGSF1-4
Citation: Clinical Geriatrics. 2013;21(10). Published online October 29, 2013.
Affiliations: 1Department of Medicine, Division of Geriatrics,Montefiore Medical Center, Wakefield Campus, Bronx, NY; 2University Hospital of Albert Einstein College of Medicine of Yeshiva University, Bronx, NY; 3Department of Medicine, Montefiore Medical Center, Wakefield Campus, Bronx, NY; 4Professor of Medicine and Associate Dean, New York Medical College, Valhalla, NY
Abstract: Falls in the geriatric population are the consequence of reversible and irreversible risk factors. While falls may be inconsequential for some healthy older adults, in many they adversely affect quality of life or result in significant morbidity and mortality. A decline in future falls can occur if reversible risk factors are addressed. In this article, the authors present three case scenarios of patients who sustained falls and required hospitalization; all had reversible risk factors. Each case includes an explanation of the risk factors involved and the complications invoked by the fall. The authors also present a review of the evidence-based recommendations regarding risk screening and falls prevention.
Key words: Falls in elderly, risk factors for falls, reversible causes of falls, an approach to falls, adverse outcomes of falls, prevention of falls.
A fall is traditionally defined as “an event whereby an individual unexpectedly comes to rest on the ground or at another lower level without known loss of consciousness.”1 Falls differ from syncope, sudden onset of paralysis, or an epileptic seizure.1Syncope refers to a temporary loss of consciousness, characterized by unresponsiveness and loss of tone or posture, with spontaneous recovery, and not requiring a specific resuscitation intervention.2 Taking an accurate history helps healthcare providers distinguish between the two entities; however, in geriatric patients, obtaining a reliable history is often hampered by poor recall.
In older adults, falls are among the leading causes of injury-related death, nonfatal injuries, and hospitalizations.3 Approximately 20% to 30% of individuals experience complications of falls, including head trauma and hip fracture; soft tissue injuries are also common.4 In addition to increased morbidity and mortality posed by falls, many people who experience a fall develop a fear that they will lose their ability to live independently or that they will die prematurely.4,5 Most fractures in older adults result from falls6 and most commonly involve the forearms, hips, spine, legs, pelvis, ankles, and hands.7 Adults aged 75 years and older have high rates of traumatic brain injury associated with hospitalization and death.8 Individuals who think they are at risk of falls or have a fear of falling may initiate a vicious cycle by restricting their physical activities, resulting in loss of strength that increases their risk of falling.8 The importance of falls prevention has now been endorsed by a joint panel comprised of the American Geriatrics Society (AGS) and the British Geriatrics Society (BGS),1 as well as by the United States Preventive Services Task Force (USPSTF).9 In this article, we present three case reports of falls in older adults, each one illustrating a different etiology and outcome after the fall. These reports are followed by a discussion of reversible risk factors and a suggested approach for minimizing the risk of falls in older adults.
Case 1: Normal Pressure Hydrocephalus
An 86-year-old community-dwelling man with a history of hypertension, recurrent falls, and communicating hydrocephalus was hospitalized after experiencing a fall. The patient was alert, awake, and oriented. A physical examination showed abrasions in the supraorbital and temporooccipital regions. We were able to rule out cardiovascular and orthostatic etiologies for the fall. The chest radiograph confirmed the patient had fractures of his right posterior tenth and eleventh ribs. A computed tomography (CT) scan of the brain confirmed cerebral atrophy with dilated ventricles and moderate microvascular disease. Hydrocephalus could not be excluded. The patient had a broad-based stride, ataxia, and difficulty turning around. He also reported urinary incontinence. The patient scored a 21 out of 30 on the Folstein Mini-Mental State Examination, indicating mild dementia. A neurology evaluation confirmed normal pressure hydrocephalus (NPH; Figure 1). A lumbar puncture was recommended, along with a plan for ventriculoperitoneal shunt placement if his gait improved after the lumbar puncture.
Figure 1. Noncontrast cranial computed tomography scans of case patient 1. Panels A and B show the patient’s enlarged ventricles (indicated by the V) relative to his cortical sulci. Evans ratio >0.4 is the ratio of maximum width of the frontal horns of the lateral ventricle (short double arrow) divided by the maximum width of the inner table (long double arrow). Panel B shows lack of cortical sulci over the vertex. In contrast, panels C and D show the normal appearance of an age-matched patient. The short white arrow indicates normal presence of cortical sulci that match the size of the sulci in panel C. These sulci are not present in panel B.
During the lumbar puncture procedure, 35 mL of cerebrospinal fluid (CSF) was removed. The CSF pressure (ie, the “opening pressure”) could not be obtained because the procedure was performed while the patient was seated. The patient’s gait improved significantly following the lumbar puncture, and he was scheduled for neurosurgical evaluation for shunt placement and discharged to a subacute rehabilitation facility.
Case 2: Vitamin D Deficiency
An 85-year-old community-dwelling woman with hypertension, type 2 diabetes mellitus, and dementia presented to the hospital with pain in her left hip after experiencing a fall. She had been using a walker to ambulate, but had a history of frequent falls without sequela. Upon presenting to the hospital, she was alert, awake, and oriented to time, place and person. A radiograph of the hip confirmed fractures of the left femoral neck and lesser trochanter (Figure 2). A review of the laboratory tests, which were done 6 months prior to the fall, revealed a low vitamin D level at 17 ng/mL (normal >30 ng/mL). At hospital admission, her 25-hydroxyvitamin D (25[OH]D) level had dropped even lower to less than 7 ng/mL. Her alkaline phosphatase level was 160 IU/L (normal, 44-147 IU/L), and her intact parathyroid hormone level was 118 pg/mL (normal, 10-55 pg/mL).
Figure 2. Anterior-posterior radiographs of the pelvis of case patient 2. A typical comminuted overriding intertrochanteric femoral fracture is visible in the left hip. The F indicates a free fragment; the angle formed by the head and neck is reduced in contrast to the normal right side.
The patient underwent open reduction and internal fixation of her left hip. Her postoperative complications included anemia, acute renal failure, electrolyte abnormalities, and delirium. Aspiration pneumonia occurred after an episode of delirium, and treatment with antibiotics resulted in Clostridium difficile colitis. She was prescribed oral vitamin D 50,000 units per week for 3 months and discharged to an acute rehabilitation facility following a hospitalization of 32 days.
Case 3: Anemia
An 83-year-old nursing home resident with a history of Alzheimer’s dementia and multiple myeloma was hospitalized because of severe anemia (hemoglobin level, 7.3 g/dL; normal in women, 12.3-15.3 g/dL) and thrombocytopenia (platelet count, 40 x 103 /ųL; normal, 150-350 x 103 /ųL). Shortly after admission, she experienced an unwitnessed fall. The patient appeared confused, but had no neurological localizing signs. A CT scan of the brain revealed subdural hemorrhage in the left parieto-occipital area and interhemispheric fissure without shift or herniation. The patient received a platelet transfusion, reaching a platelet count of 99 x 103 /ųL. Her hemoglobin level rose to 9.6 g/dL. She was placed on vest restraints with frequent evaluations for worsening mental status. On hospital day 8, her platelet count dropped to 28 x 103 /ųL. The patient was transferred to the intensive care unit (ICU) when she was found to have status epilepticus. A subsequent CT scan confirmed significant interval increase in her left subdural hemorrhage with a 1.7-cm midline shift, subfalcine herniation, uncal herniation, and cerebral edema (Figure 3). The patient died a few days later in the ICU.
Figure 3. Noncontrast-enhanced cranial computed tomography scans of the third case patient; the scans were taken 1 week apart. Panel A demonstrates small acute left posterior temporal/parietal subdural hematoma without mass effect (black arrow). Panel B shows the same patient a week later with an increase in the hematoma (indicated at the SDH). It shows a marked mass effect has caused subfalcine herniation of the left hemisphere and ventricles (indicated by the V) to the right side relative to the falx cerebri, indicated by the white arrow.
In the three case scenarios we described, all patients experienced a fall, but the contributing risk factors differed. In case 1, the man with NPH had a benign course without debilitating fractures, and he improved after receiving a lumbar puncture. His outcomes were favorable compared with the woman in case 2, who had post-hip fracture complications and a prolonged hospitalization, impaired quality of life, and subsequently required placement in a skilled nursing facility. The patient in case 3 had a fatal outcome from the most dreaded complications of falls: brain injury and subdural hemorrhage. What follows is a more detailed description of the contributing risk factors in the case patients.
The prevalence of NPH may be as high as 14% in extended-care facility patients.10 In a prospective study involving 151 patients with suspected idiopathic NPH, patients who improved clinically after lumbar CSF drainage were offered shunt surgery, 90% of whom had positive outcomes.11 Some studies suggest that patients with gait abnormalities, mild dementia, or mild or no incontinence fare best following shunt surgery.12,13
Ventriculomegaly is quantified by the Evans ratio, which is the farthest width of the anterior ventricular horns divided by the maximum width of the calvarium at the extent of the foramen of Monro. Hydrocephalus is defined as an Evans ratio of 0.3.14 The treatment of choice is to surgically place a ventriculoperitoneal shunt to drain the surplus CSF out of the brain ventricles. Not all patients improve following this surgery, but improved gait is the most common functional improvement.
According to 2001-2006 data from the National Health and Nutrition Examination Survey, approximately 25% of the US population are at risk of vitamin D insufficiency (12-19.6 ng/L) and 8% are at risk for vitamin D deficiency (<12 ng/mL); 66% of the population was found to have an adequate vitamin D level (20-50 ng/mL).15 Many studies have shown that vitamin D supplementation can improve muscle strength, walking distance, and functional capacity, with a reduction in falls and nonvertebral fractures.16 Dietary content seldom meets the recommended daily intake.17
Sunlight, especially ultraviolet B light, is a good source of vitamin D, but factors that limit one’s ability to benefit from sunlight include aging skin, pigmentation, time of day, cloudiness, season, latitude, clothing, and use of sunscreens. Many elderly long-term care patients are limited in their exposure to sunlight. When diet and sunlight together are inadequate to meet requirements, many individuals are advised to take vitamin D supplements or enhance their diet with vitamin D-fortified foods. The AGS/BGS and USPSTF falls prevention guidelines have emphasized the value of vitamin D in preventing falls, with a grade B recommendation by the USPSTF.1,9
Falls are the leading cause of head injuries in older adults, followed by automobile accidents,18,19 and incur huge direct and indirect costs in the United States. Data from the Centers for Disease Control and Prevention showed that in US adults older than 65 years, there have been 7946 deaths caused by fall-related traumatic brain injuries and 56,423 hospitalizations for non-fatal fall-related brain injuries.20
The prevalence of anemia increases with age21 and is linked to the occurrence of falls in the community setting, hospitalized patients, and nursing home residents.22-25 The severity of anemia appears to correlate with an increase in the prevalence of falls and with impairment to muscle strength, a factor involved in falls causation.23-26 Epidemiological information confirms that anemia predisposes to fatigue-related difficulty with mobility,23-25 decreases ability to engage in activities of daily living (ADLs) and instrumental ADLs,26 and increases the likelihood for falls, hospitalization, and mortality.27-30
Were the Falls Preventable in These Cases?
Prevention of falls is possible in many instances. The gait and balance disorders that occur in NPH can be addressed, so falls are preventable and treatable in these cases. Vitamin D status and deficiency can be determined by screening. In 2012, the USPSTF recommended vitamin D supplementation in addition to exercise and/or physical therapy for falls prevention in community-dwelling adults aged 65 years and older.9 However, earlier this year the USPSTF also issued a recommendation on the prevention of fractures, concluding that there is not enough evidence to determine the benefits and harms with daily supplementation of vitamin D and calcium to prevent fractures in men and premenopausal women; further, there are health risks associated with excessive intake of vitamin D.31 Therefore, as a general approach, providers should be judicious when using vitamin D in patients at risk of falls or fractures.
Besides NPH, gait and balance disorders may be a feature of advanced Alzheimer’s disease or a non-Alzheimer’s dementia. In a cross-sectional study, gait and balance disorders were more common in patients with Parkinson’s disease and concomitant dementia (93%), vascular dementia (79%), and dementia with Lewy bodies (75%), compared with age-matched controls (7%).32 NPH can sometimes mimic other neurodegenerative disorders, but early gait disturbance may be an important sign of possible NPH with dementia.13
Focal deficits identified during the physical examination or medical history-taking may indicate vascular dementia. If a patient responds well to the administration of a “levodopa challenge,” idiopathic Parkinson’s disease may be considered a possible diagnosis. In summary, reversible causes for impaired gait and balance should be looked for and addressed.
Vitamin D deficiency must be considered a possibility in any person with gait and balance disorders, those who fall, or those at-risk for falls. Serum 25(OH)D concentrations correlated absolutely with quadriceps muscle strength in one study.33 The reliable laboratory test to ascertain status is a serum 25(OH)D. Additionally serum calcium and phosphorus may be normal or low, and alkaline phosphatase may be normal or elevated.
New guidelines have been released on the acceptable ranges of adequacy and deficiency for vitamin D; however, US and Canadian guidelines differ, with lower normal levels cited as the norms for the US versus Canadian recommendations. The Canadian recommendations state the norm as a 25(OH)D level of 30 ng/mL, whereas the US recommendations state that a level above 20 ng/mL is acceptable.34-36 Intestinal calcium absorption is optimized at levels higher than 32 ng/mL.37,38 Parathyroid hormone levels begin to rise in responses to 25(OH)D levels below 31 ng/mL.39 Only 17% of older people attain a target concentration of 25(OH)D at 30 ng/mL.40 For the rest, without supplements, the severity of hypovitaminosis D may reflect to be a biomarker of disease or frailty,41 both of which can cause falls. The recommended intake of vitamin D for the elderly ranges from 800 IU to 2000 IU daily based on the source; the US Institute of Medicine recommendation is 600 IU daily for adults aged 50 to 70 years and 800 IU for those aged 70 years and older. Vitamin D levels may be reassessed following 3 months of adequate supplementation.42
Due to the high prevalence of vitamin D deficiency, vitamin D status deserves consideration as a screening measure in vulnerable people; these include the elderly, the homebound, the institutionalized, the frail, those with gait instability and prone to falling, those on medications that predispose to vitamin D deficiency, and people with malnutrition and malabsorption (eg, celiac disease, history of bariatric surgery). It must be emphasized that in addition to vitamin D, calcium intake must be adequate and consumed preferably from dietary sources rather than supplements.43
Following a fall or trauma with brain injury, serial brain CT scans may be hard to justify unless there is evidence for neurologic deterioration.44 Neuroimaging may be indicated in the setting of low platelet counts, coagulopathy, or when an anticoagulant is being used. Adverse outcomes, such as those observed in the third case patient, who had intracranial bleeding, may justify liberal use of CT scans or other neuroimaging, such as magnetic resonance imaging.45 Further, in case 3, the patient with thrombocytopenia was also subject to placement on restraints, which may increase restraint-related trauma and bleeding risk. Data do not support a lower risk of falls or injuries in those on restraints, making the use of restraints very hard to justify as a means to prevent falls.46 Clinicians should focus on promoting mobility as opposed to immobility.47
A Suggested Approach to Falls
Falls in the elderly are usually not incidental. A fall usually heralds the presence of risk factors that are likely to predispose an elderly person to falls in the future. Therefore, screening for falls is a crucial first step.1,9 A simplified approach to screening and assessment for falls, adapted from the AGS/BGS guidelines, is presented in Figure 4.1 To address the numerous predisposing risk factors for falls, a multidisciplinary approach that includes patient education may be best48; this approach may involve participation from nurses, physical and occupational therapists, pharmacists, and physicians (both primary care and specialists).49,50 A significant reduction in serious fall-related injuries has been noticed after using evidence-based fall-prevention strategies.51 These may include patient education disseminated by healthcare providers using multimedia approaches, use of fall prevention toolkits in hospitals and other facilities, and periodic medication reviews.48,52-54
Figure 4. An approach to the screening and assessment for falls in community-dwelling adults and in long-term care patients without cognitive impairment. This figure was adapted from reference 1 in the citation list.
There are several options for screening patients for risk of falls. The Timed Get Up and Go test is an initial simple maneuver that can be performed in any setting. The patient is timed after rising from a chair and observed while walking 3 meters and then turning around and walking back to sit in the chair again. The results of this test correlate with gait speed, the Barthel ADL Index, and the prediction of functional ability to go outdoors alone safely. In addition, the test is reliable and effective in quantifying practical mobility over time,55 is simple to perform, does not require much time or equipment, and can be performed as part of a routine medical examination. The normal time required to complete the test is 7 to 10 seconds; those unable to complete the task in this timeframe likely have impaired mobility, especially if the time exceeds 20 seconds.55 This data must be charted as a baseline measure and repeated if any alteration occurs in health or at least annually in older patients. Another example is the Mini Falls Assessment, which uses a 30-point questionnaire. Therapeutic interventions must be considered for any answer of “No” in the assessment, although the exact points scored are not significant.56
A comprehensive geriatric assessment must also include evaluation for orthostatic hypotension.57 Orthostatic hypotension, which may cause dizziness and increase the risk of falls, can result from numerous causes, including decline in volume, autonomic neuropathy, and as an adverse drug effect. Additionally, postprandial hypotension, defined as a decrease in postprandial systolic blood pressure of 20 mm Hg or more and/or diastolic pressure of 10 mm Hg or more, typically with an increase in pulse rate, is a common cause of falls and should be recognized as a risk factor in older patients. With postprandial hypotension, the drop in blood pressure occurs 1 to 3 hours after food intake, especially following carbohydrate-heavy meals. Cerebral ischemia and syncope may result58 largely from a diverted increase in splanchnic blood flow, at the cost of a decline in cerebral blood flow.59
If a patient is deemed at risk of falls following screening, we would advise a three-pronged approach to managing risk: (1) Addressing reversible risk factors; (2) reducing the burden of deficits; and (3) using adaptive devices for permanent deficits. Approximately half of falls in the elderly are attributed to accidents and extrinsic causes, such as slippery floors; the rest are linked to intrinsic causes, such as lower extremity weakness, gait imbalance, adverse drug effects, and the presence of various diseases (eg, Parkinson’s disease, dementia of any etiology, NPH).60 A targeted approach will establish correctible factors and prompt therapeutic interventions that reduce the potential for subsequent falls.61
Addressing reversible deficits may include assessing for and correcting the underlying causes of gait and balance disorders, such as orthostatic and postprandial hypotension and vitamin D deficiency, as explained above. Additionally, a visit to the home by the occupational therapist, nurse, or physician may help identify several correctible environmental factors. Examples of environmental hazards include scatter rugs, carpeting, slippery bathtubs or floors, icy paths, poor lighting, clutter from toys or cords, and poor support, such as poorly designed or missing handrails and steep steps for staircases. Almost all of these factors can be eliminated or corrected (Table1,9,46,52,54,60).
When deficits cannot be eliminated or reversed, there are several options to reduce their burden on older persons at risk of falls. Based on current evidence, exercise programs to improve balance are suggested solely for community-dwelling older persons, as persons residing in long-term care facilities may have more physical and cognitive impairments to contend with that limit participation in exercise programs.1,9 Multifactorial interventions that encourage exercise programs, such as Tai chi, physical therapy, or alternative exercises for balance, gait, and muscle strengthening, can be offered in a group or individual setting. Patients with musculoskeletal disorders must be thoroughly evaluated for safety before starting any exercise program; they may also require the use of assistive devices, such as a cane, walker, or orthotic. In general, older adults are reluctant to use a cane or walker. While walkers are more cumbersome to use than canes, the support provided by a walker is greater. Patients must be fitted with adaptive equipment, which is ideally done by a rehabilitation specialist.
Polypharmacy, an indicator of mortality in the elderly, is another aspect of patient care that must be managed carefully.62 Older adults on more than three or four medications are at greater risk of recurrent falls.63 Therefore, regular medication reviews are paramount in the setting of orthostatic hypotension, and during such reviews volume status must be addressed, taking care to avoid fluid overload. The medication review must also include over-the-counter medications, which increase the risk of falls from anticholinergic effects. High on the list of overprescribed drugs that may cause falls are antipsychotics and sedative hypnotics, which are often prescribed for behavioral disorders or insomnia.1,48 The Beers Criteria provides a large list of medications that are potentially inappropriate for older adults because they are associated with a high risk of falls.64 A sample of the many medications that predispose older adults to falls are listed in the Table.
Older adults should be screened and evaluated for falls on a periodic basis. In those with a history of falls, an assessment for risk factors and an evaluation for predisposing causes including gait and balance should follow. Most falls have a multifactorial etiology, with an overlap of intrinsic causes, environmental factors, and medications. In most cases, more than one risk factor may be responsible. A periodic medication review of prescription and over-the-counter drugs is paramount in every person who falls. Based on the results of screening, risk factors must be addressed. Although many risk factors cannot be modified, addressing some modifiable causes may lower the likelihood of recurrence. Falls and fall-related injuries in the elderly can be significantly reduced by educating patients and caregivers on preventive measures, and by making use of evidence-based falls prevention measures and interventions in clinical practice.
- Panel on Prevention of Falls in Older Persons, American Geriatrics Society and British Geriatrics Society. Summary of the Updated American Geriatrics Society/British Geriatrics Society clinical practice guideline for prevention of falls in older persons. J Am Geriatr Soc. 2011;59(1):148-157.
- Brignole M, Hamdan MH. New concepts in the assessment of syncope. J Am Coll Cardiol. 2012;59(18):1583-1591.
- Centers for Disease Control and Prevention. National Center for Injury Prevention and Control. Web-based Injury Statistics Query and Reporting System (WISQARS). http://www.cdc.gov/injury/wisqars/index.html. Accessed October 22, 2013.
- Stevens JA, Ryan G, Kresnow M. Fatalities and injuries from falls among older adults– United States, 1993–2003 and 2001–2005. MMWR. 2006;55(45):1221-1224.
- Stevens JA, Corso PS, Finkelstein EA, Miller TR. The costs of fatal and non-fatal falls among older adults. Inj Prev. 2006;12(5):290–295.
- Faul M, Xu L, Wald MM, Coronado VG. Traumatic brain injury in the United States: emergency department visits, hospitalizations, and deaths. Atlanta, GA: Centers for Disease Control and Prevention, National Center for Injury Prevention and Control; 2010. http://www.cdc.gov/traumaticbraininjury/pdf/blue_book.pdf. Accessed May 30, 2013.
- Jager TE, Weiss HB, Coben JH, Pepe PE. Traumatic brain injuries evaluated in U.S. emergency departments, 1992–1994. Acad Emerg Med. 2000;7(2):134-140.
- Bell AJ, Talbot-Stern JK, Hennessy A. Characteristics and outcomes of older patients presenting to the emergency department after a fall: a retrospective analysis. Med J Aust. 2000;173(4):179-182.
- Moyer VA; US Preventive Services Task Force. Prevention of falls in community-dwelling older adults: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2012;157(3):197-204.
- Marmarou A, Young HF, Aygok GA. Estimated incidence of normal pressure hydrocephalus and shunt outcome in patients residing in assisted-living and extended-care facilities. Neurosurg Focus. 2007;22(4):E1.
- Marmarou A, Young HF, Aygok GA, et al. Diagnosis and management of idiopathic normal pressure hydrocephalus: a prospective study in 151 patients. J Neurosurg. 2005;102(6):987-997.
- Burnett MG, Sonnad SS, Stein SC. Screening tests for normal-pressure hydrocephalus: sensitivity, specificity, and cost. J Neurosurg. 2006;105(6):823-829.
- Hebb AO, Cusimano MD. Idiopathic normal pressure hydrocephalus: a systematic review of diagnosis and outcome. Neurosurgery. 2001;49(5):1166-1184.
- Factora R. When do common symptoms indicate normal pressure hydrocephalus? Cleve Clin J Med. 2006;73(5):447-450, 452, 455-456.
- Looker AC, Johnson CL, Lacher DA, Pfeiffer CM, Schleicher RL, Sempos CT. Vitamin D status: United States, 2001-2006. NCHS Data Brief. 2011;(59):1-8.
- Janssen HC, Samson MM, Verhaar HJ. Vitamin D deficiency, muscle function, and falls in elderly people. Am J Clin Nutr. 2002;75(4):611-615.
- Rosen CJ. Clinical practice. Vitamin D insufficiency. N Engl J Med. 2011;364(3):248-254.
- Langlois JA, Rutland-Brown W, Thomas KE. Traumatic brain injury in the United States: emergency department visits, hospitalizations, and deaths. Atlanta, GA: Centers for Disease Control and Prevention, National Center for Injury Prevention and Control; 2004. http://www.cdc.gov/ncipc/pub-res/TBI_in_US_04/00_preliminary.htm.
- Jennett B, Frankovyski RF. The epidemiology of head injury. In: Braakman R, ed. Handbook of Clinical Neurology; vol 13. New York, NY: Elsevier; 1990:1.
- Thomas KE, Stevens JA, Sarmiento K, Wald MM. Fall-related traumatic brain injury deaths and hospitalizations among older adults—United States, 2005. J Safety Res. 2008;39(3):269-272.
- 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.
- Artz AS, Fergusson D, Drinka PJ, et al. Mechanisms of unexplained anemia in the nursing home. J Am Geriatr Soc. 2004;52(3):423-427.
- 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. 2006;7(5):287-293.
- Patel KV, Harris TB, Faulhaber M, et al. Racial variation in the relationship of anemia with mortality and mobility disability among older adults. Blood. 2007;109(11):4663-4670.
- Dharmarajan TS, Norkus EP. Mild anemia and the risk of falls in older adults from nursing homes and the community. J Am Med Dir Assoc. 2004;5(6):395-400.
- Chaves PH, Xue QL, Guralnik JM, Ferrucci L, Volpato S, Fried LP. What constitutes normal hemoglobin concentration in community-dwelling disabled older women? J Am Geriatr Soc. 2004;52(11):1811-1816.
- Dharmarajan TS, Pankratov A, Morris E, et al. Anemia: its impact on hospitalizations and length of hospital stay in nursing home and community older adults. J Am Med Dir Assoc. 2008;9(5):354-359.
- Culleton BF, Manns BJ, Zhang J, Tonelli M, Klarenbach S, Hemmelgarn BR. Impact of anemia on hospitalization and mortality in older adults. Blood. 2006;107(10):3841-3846.
- Penninx BW, Pluijm SM, Lips P, et al. Late-life anemia is associated with increased risk of recurrent falls. J Am Geriatr Soc. 2005;53(12):2106-2111.
- Zakai NA, Katz R, Hirsch C, et al. A prospective study of anemia status, hemoglobin concentration, and mortality in an elderly cohort: the Cardiovascular Health Study. Arch Intern Med. 2005;165(19):2214-2220.
- US Preventive Services Task Force. Vitamin D and calcium supplementation to prevent fractures. http://www.uspreventiveservicestaskforce.org/uspstf12/vitamind/vitdfact.pdf. Published February 2013. Accessed October 3, 2013.
- Allan LM, Ballard CG, Burn DJ, Kenny RA. Prevalence and severity of gait disorders in Alzheimer's and non-Alzheimer's dementias. J Am Geriatr Soc. 2005;53(10):1681-1687.
- Dretakis OE, Tsatsanis C, Fyrgadis A, Drakopoulos CG, Steriopoulos K, Margioris AN. Correlation between serum 25-hydroxyvitamin D levels and quadriceps muscle strength in elderly cretans. J Int Med Res. 2010;38(5):1824-1834.
- Hanley DA, Cranney A, Jones G, Whiting SJ, Leslie WD; Guidelines Committee of the Scientific Advisory Council of Osteoporosis Canada. Vitamin D in adult health and disease: a review and guideline statement from Osteoporosis Canada (summary). CMAJ. 2010;182(12):1315-1319.
- Ginde AA, Liu MC, Camargo CA Jr. Demographic differences and trends of vitamin D insufficiency in the US population, 1988-2004. Arch Intern Med. 2009;169(6):626-632.
- Holick MF, Chen TC. Vitamin D deficiency: a worldwide problem with health consequences. Am J Clin Nutr. 2008;87(4):1080S-1086S.
- Hollis BW, Wagner CL. Normal serum vitamin D levels. N Engl J Med. 2005;352(5):515-516; author reply 515-516.
- Heaney RP, Dowell MS, Hale CA, Bendich A. Calcium absorption varies within the reference range for serum 25-hydroxyvitamin D. J Am Coll Nutr. 2003;22(2):142-146.
- Heaney RP. Vitamin D depletion and effective calcium absorption. J Bone Miner Res. 2003;18(7):1342.
- Annweiler C, Souberbielle JC, Schott AM, de Decker L, Berrut G, Beauchet O. Vitamin D in the elderly: 5 points to remember. Geriatr Psychol Neuropsychiatr Vieil. 2011;9(3):259-267.
- Chapuy MC, Preziosi P, Maamer M, et al. Prevalence of vitamin D insufficiency in an adult normal population. Osteoporos Int. 1997;7(5):439-443.
- Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: Institute of Medicine, 2010. http://www.iom.edu/~/media/Files/Report%20Files/2010/Dietary-Reference-Intakes-for-Calcium-and-Vitamin-D/Vitamin%20D%20and%20Calcium%202010%20Report%20Brief.pdf. Accessed October 9, 2013.
- Dharmarajan TS, Sohagia A. Vitamin D and calcium. In: Pitchumoni CS, Dharmarajan TS, eds. Geriatric Gastroenterology. New York, NY: Springer Publishing; 2012;185-195.
- Brown CV, Weng J, Oh D, et al. Does routine serial computed tomography of the head influence management of traumatic brain injury? A prospective evaluation. J Trauma. 2004;57(5):939-943.
- Stein SC, Burnett MG, Glick HA. Indications for CT scanning in mild traumatic brain injury: a cost-effectiveness study. J Trauma. 2006;61(3):558-566.
- Tinetti ME, Liu WL, Ginter SF. Mechanical restraint use and fall-related injuries among residents of skilled nursing facilities. Ann Intern Med. 1992;116(5):369-374
- Capezuti E, Evans L, Strumpf N, Maislin G. Physical restraint use and falls in nursing home residents. J Am Geriatr Soc. 1996;44(6):627-633.
- Haines TP, Hill AM, Hill KD, et al. Patient education to prevent falls among older hospital inpatients: a randomized controlled trial. Arch Intern Med. 2011;171(6):516-524.
- Tinetti ME. Clinical practice. Preventing falls in elderly persons. N Engl J Med. 2003;348(1):42-49.
- Tinetti ME, Kumar C. The patient who falls: “It's always a trade-off.” JAMA. 2010;303(3):258-266.
- Day L, Finch C, Segal L. Reducing injuries from falls. N Engl J Med. 2008;359(15):1626.
- Dykes PC, Carroll DL, Hurley A, et al. Fall prevention in acute care hospitals: a randomized trial. JAMA. 2010;304(17):1912-1918.
- Tinetti ME, Baker DI, King M, et al. Effect of dissemination of evidence in reducing injuries from falls. N Engl J Med. 2008;359(3):252-261.
- Chang CM, Chen MJ, Tsai CY, et al. Medical conditions and medications as risk factors of falls in the inpatient older people: a case-control study. Int J Geriatr Psychiatry. 2011;26(6):602-607.
- Podsiadlo D, Richardson S. The timed “Up & Go”: a test of basic functional mobility for frail elderly persons. J Am Geriatr Soc. 1991;39(2):142-148.
- Morley JE, Rolland Y, Tolson D, Vellas B. Increasing awareness of the factors producing falls: the mini falls assessment. J Am Med Dir Assoc. 2012;13(2):87-90.
- Vloet LC, Pel-Little RE, Jansen PA, Jansen RW. High prevalence of postprandial and orthostatic hypotension among geriatric patients admitted to Dutch hospitals. J Gerontol A Biol Sci Med Sci. 2005;60(10):1271-1277.
- Ruggieri G, Quadri P, Noseda G. A case of postprandial hypotension in an elderly subject. Praxis (Bern 1994). 1996;85(50):1621-1625.
- Aronow WS, Ahn C. Postprandial hypotension in 499 elderly persons in a long-term health care facility. J Am Geriatr Soc. 1994;42(9):930-932.
- Rubenstein LZ, Josephson KR. Falls and their prevention in elderly people: what does the evidence show? Med Clin North Am. 2006;90(5):807-824.
- Steinweg KK. The changing approach to falls in the elderly. Am Fam Physician. 1997;1;56(7):1815-1823.
- Jyrkkä J, Enlund H, Korhonen MJ, Sulkava R, Hartikainen S. Polypharmacy status as an indicator of mortality in an elderly population. Drugs Aging. 2009;26(12):1039-1048.
- Leipzig RM, Cumming RG, Tinetti ME. Drugs and falls in older people: a systematic review and meta-analysis: II. Cardiac and analgesic drugs. J Am Geriatr Soc. 1999;47(1):40-50.
- Fick D, Semla T, Beizer J, et al; the American Geriatrics Society 2012 Beers Criteria Update Expert Panel. American Geriatrics Society updated Beers Criteria for potentially inappropriate medication use in older adults. J Am Geriatr Soc. 2012;60(4):616-631.
Address correspondence to: T.S. Dharmarajan, MD; Montefiore Medical Center (Wakefield Campus), Department of Medicine, 600 East 233rd Street, Bronx, NY 10466; firstname.lastname@example.org.