Association Between the Metabolic Syndrome and Its Components with Falls in Community-Dwelling Older Adults

Abstract

Background:

The metabolic syndrome and falls are both serious and common health problems in older adults. However, little is known about whether the metabolic syndrome contributes to falls. We investigated the relationship between the metabolic syndrome and its components with falls in community-dwelling older adults.

Methods:

We designed and conducted a cross-sectional study. A total of 1165 community-dwelling older adults who received a geriatric health examination, including interviewer-administered questionnaires and physical and biochemical examinations, were retrospectively enrolled from 2008 to 2010 and specifically asked about the history of falls in the preceding year.

Results:

The mean age of the participants was 74.9±6.7 years, and 54.3% were women. The overall prevalence of falls and metabolic syndrome were 17.9% and 27.3%, respectively. Compared with those who did not fall, the participants who fell had a higher prevalence of the metabolic syndrome (45.7% versus 23.3%, P<0.001) and four of its five components, namely, abdominal obesity (51.2% versus 40.2 %, P=0.004), hypertriglyceridemia (32.2% versus 21.8%, P=0.001), hypertension (60.0% versus 50.0%, P=0.009), and impaired glucose tolerance (28.4 % versus 16.0%, P<0.001). After adjusting for age, female sex, the Karnofsky Performance Scale, and the five-item Brief Symptom Rating Scale, the metabolic syndrome was a significant independent risk factor for falls in community-dwelling older adults (odds ratio=2.56, 95% confidence interval 1.86–3.51). Because falling is a multifactorial geriatric syndrome, many potential confounders, such as visual abnormalities, obesity, arthritis, and polypharmacy, were not considered in this study.

Conclusion:

The metabolic syndrome is an independent risk factor for falls in community-dwelling older adults and should be addressed with regard to prevention of falls.

Introduction

T he metabolic syndrome, a cluster of several components including hypertension, glucose intolerance, dyslipidemia, and abdominal obesity, is a worldwide health problem. Its prevalence increases with age, ranging from 11% to 55% in persons aged 65 years and over, and varies widely depending on the definition, geographic region, and ethnic population.^1
–3 The metabolic syndrome has been shown to be a major risk factor for cardiovascular morbidity and mortality in older adults.^1,4,5 Falling is a well-known geriatric syndrome and is the leading cause of injury and accidental death in older adults. The incidence of falls in community-dwelling older adults is around 22.4%–80.9% annually in Western countries, and ranges from 14.7% to 34% in Chinese older adults.^6,7 More than 100 risk factors for falls in older adults have been identified in the literature. The commonly reported intrinsic risk factors for falls include age, female sex, decline in functional status, chronic medical condition, diabetes mellitus, hypertension, depression, cognitive impairment, and multiple medication use.^8
–10 Our previous study suggested that waist circumference should be included as a risk factor for falls.¹¹ However, little is known about whether the metabolic syndrome contributes to falls. Both the metabolic syndrome and falls are serious and common public health problems in the elderly. The aim of this study was to investigate the relationship between the metabolic syndrome and its components with falls in community-dwelling older adults.

Material and Methods

Study population

The Department of Health in Taipei City has launched a health promotion program for elder health care for many years that offered an annual geriatric health examination as one of the free clinical services used by every citizen over the age of 65 years. We designed a cross-sectional study and retrospectively enrolled these aged citizens receiving the geriatric examination in 2008–2010. The voluntary informed consents were obtained from these elderly participants and/or their relatives. The study was reviewed and approved by the Institutional Review Board of Chang Gung Memorial Hospital.

Methods

In the geriatric health examination, we inquired about and recorded medical history, measured body weight, height, and blood pressure, and calculated body mass index (BMI, kg/m²). Waist circumference was measured midway from the lower rib margin to the anterior superior iliac crest using a nonmetallic tape without significant compression by trained nursing staff. Blood samples were collected in the morning after the participants had fasted for 12 h overnight and sent to our College of American Pathologists–certified central laboratory for biochemical analysis. The plasma levels of glucose, triglyceride, total cholesterol, and high-density-lipoprotein cholesterol (HDL-C) were measured on a Hitachi 7600 automatic analyzer (Hitachi High-Technologies Corporation, Tokyo, Japan). We administered the Short Portable Mental Status Questionnaire (SPMSQ) for cognitive evaluation¹² and the five-item Brief Symptom Rating Scale (BSRS-5) to identify possible depression or anxiety.¹³ The Karnofsky Performance Scale was applied to evaluate the overall functional and physical performance of our study population.¹⁴ The participants were also specifically asked about their history of falls in the preceding year.

Definitions

The metabolic syndrome was defined according to the modified Adult Treatment Panel III criteria for Asians as having three or more of the following components: (1) Waist circumference >90 cm for men and >80 cm for women, (2) triglycerides >150 mg/dL, (3) HDL-C <40 mg /dL for men and <50 mg/dL for women, (4) systolic blood pressure >130 mmHg or diastolic blood pressure >85 mmHg or current use of antihypertensive medication, and (5) fasting blood glucose >100 mg/dL or previous diagnosis of type 2 diabetes.^15,16

A fall was defined as an event in which a person comes to rest unintentionally on the ground or other lower level, not due to any intentional movement, a major intrinsic event (e.g., stroke), or extrinsic force (e.g., forcefully pushed down or knocked down by a car).⁷

Statistical analysis

Continuous variables were expressed as means and standard deviations and compared using Student t-tests. Categorical variables were summarized as proportions and compared using chi-squared tests. Multivariate analysis was performed using logistic regression to identify independent risk factors for falls. A P value of less than 0.05 was taken as statistically significant. Data were compiled and analyzed with SPSS for Windows version 17.0 (SPSS, Chicago, IL).

Results

A total of 1165 participants were enrolled in our study. The mean age was 74.9±6.7 years and 54.3% were women. The prevalence of falls and metabolic syndrome was 17.9% and 27.3%, respectively. Most of the participants in our study were independent community-dwelling older adults with high functional status and intact cognition, with a mean Karnofsky Performance Scale of 89.2 and SPMSQ score of 0.2. The characteristics and metabolic factors that differentiate participants who fell from those who did not fall are shown in Table 1. Compared to those who did not fall, participants who fell had a higher BSRS-5 score (3.4±3.4 versus 2.8±3.7, P=0.010) and lower Karnofsky Performance Scale (88.4±4.1 versus 89.3±2.7, P=0.001).

Table 1.

Comparison of the Participant Characteristics and the Prevalence of the Metabolic Syndrome, and Its Components Between the Participants Who Fell (Group 1) and Those Who Did Not Fall (Group 2)

Characteristic	Group 1 Fall (n=208)	Group 2 No fall (n=957)	P value
Age (years)	76.1±6.7	74.7±6.6	0.007
Female (n, %)	130 (62.5)	501 (52.6)	0.008
SPMSQ	0.3±1.2	0.2±0.9	0.200
BSRS-5	3.4±3.4	2.8±3.7	0.010
Karnofsky Scale	88.4±4.1	89.3±2.7	0.001
Waist circumference (cm)	86.4±9.8	83.5±10.2	<0.001
Triglyceride (mg/dL)	139.4±82.2	121.3±62.0	<0.001
HDL-C (mg/dL)	56.8±15.5	59.9±14.7	0.885
Systolic pressure (mmHg)	132±17.5	131.1±17.5	0.272
Diastolic pressure (mmHg)	71.3±10.9	73.1±10.9	0.036
Fasting blood sugar (mg/dL)	106.2±25.1	100.9±20.1	0.001
Total cholesterol (mg/dL)	193.3±33.0	191.4±33.6	0.474
BMI (kg/m²)	24.5±3.5	24.2±4.0	0.282
Abdominal obesity (n, %)	106 (51.0)	385 (40.2)	0.004
High triglyceride (n, %)	67 (32.2)	209 (21.8)	0.001
Low HDL (n, %)	49 (23.6)	180 (18.8)	0.118
Hypertension (n, %)	125 (60.0)	479 (50.0)	0.009
Impaired glucose tolerance (n, %)	59 (28.4)	153 (16.0)	<0.001
Metabolic syndrome (n, %)	95 (45.7)	223 (23.3)	<0.001

Except where noted, continuous variables are provided as mean±standard deviation (SD).

SPMSQ, Short Portable Mental Status Questionnaire; BSRS-5, the five-item Brief Symptom Rating Scale; HDL-C, high-density lipoprotein cholesterol; BMI, body mass index.

There was a statistically significant difference in the prevalence of metabolic syndrome between the participants who fell and those who did not fall (45.7% versus 23.3 %, P<0.001). When the components of the metabolic syndrome were considered, those who fell were more likely to have abdominal obesity (51.2% versus 40.2 %, P=0.004), hypertriglyceridemia (32.2% versus 21.8%, P=0.001), hypertension (60.0% versus 50.0%, P=0.009), and impaired glucose tolerance (28.4% versus 16.0%, P<0.001) than those who did not fall. The level of HDL-C alone showed no significant association with falls in older adults.

To investigate the relationship between the metabolic syndrome and the occurrence of falls, the variables that were significantly different between participants who fell and those who did not, as listed in Table 1, were entered into a multivariate regression model (Table 2). After adjusting for age, female sex, BSRS-5, Karnofsky Scale, and metabolic syndrome in the logistic regression model, the metabolic syndrome [odds ratio (OR)=2.56, 95% confidence interval (CI) 1.86–3.51], age (OR=1.03, 95% CI 1.01–1.06), Karnofsky Scale (OR=0.94, 95% CI 0.90–0.99), and female sex (OR=0.64, 95% CI 0.46–0.89) were independent risk factors for falls in the community-dwelling older adults.

Table 2.

Multivariate Logistic Regression Analysis on Risk Factors for Falls in Community-Dwelling Older Adults

Variable	OR (95 % CI)	P value
Metabolic syndrome	2.56 (1.86–3.51)	<0.001
Age	1.03 (1.01–1.06)	0.008
Karnofsky Scale	0.94 (0.90–0.99)	0.009
Female sex	0.64 (0.46–0.89)	0.007
BSRS-5	1.03 (0.99–1.08)	0.159

OR, odds ratio; CI, confidence intervals; BSRS-5, the five-item Brief Symptom Rating Scale.

Discussion

In our study, the metabolic syndrome was significantly associated with falls in community-dwelling older adults. An approximately 2.5-fold higher prevalence of the metabolic syndrome was found in the group who fell. Meanwhile, participants who fell were more likely to have abdominal obesity, hypertriglyceridemia, hypertension, and impaired glucose tolerance. Previous studies on fall interventions have scarcely addressed the importance of modifying the metabolic syndrome and its components.^7
–9 The actual mechanisms by which the metabolic syndrome and its components increase the risk of falls deserve further investigation.

Older adults with high blood pressure have a significantly higher prevalence of falls. The actual relationship between hypertension and falls is not very clear. Hypertension in older adults should be treated with the goal of lowering the incidence of stroke, myocardial infarction, and chronic kidney disease.¹⁷ However, uncontrolled hypertension in older adults and the attendant side effects of antihypertensive medications have been implicated as potential causes of falls.^18,19

Impaired blood glucose tolerance and a history of diabetes increase the prevalence of falls in older adults. Previous studies showed that the risk of falling significantly increased in older adults with diabetes.^20,21 The microangiopathic and macroangiopathic complications of diabetes lead to peripheral neuropathy and retinopathy, which may induce dizziness, visual impairment, gait instability, and balance disorder, and increase fall risks.^7
–9 Previous studies also showed that antidiabetic medications were related to increased risk of falls and fall-related morbidity in the elderly.^22,23

In our study, hypertriglyceridemia and abdominal obesity were associated with a higher prevalence of falls in older adults. To our knowledge, there is no report showing that hypertriglyceridemia is directly associated with falls. Elevated triglyceride is associated with obesity, hypertension, sedentary lifestyle, and low HDL-C^24,25 and indirectly related to falls. Obesity is associated with adverse cardiovascular outcomes, osteoarthritis, and type 2 diabetes and contributes to the high burden of diseases and functional impairment.^26,27 Any type of arthritis increases the risk of falls through muscle weakness, pain, decreased perception, and gait and balance disturbance.^7,8

Among the components of the metabolic syndrome, hypertension and diabetes have gained more attention from clinical investigators as explanatory predictors for falls in older adults. Specific training can improve gait speed, balance, and muscle strength and reduce fall risk in older adults with type 2 diabetes.^28,29 Our study showed that the metabolic syndrome and its components had a statistically significant association with falls in community-dwelling older adults. Insulin resistance, a condition that is related to older age and excess adiposity, has been hypothesized as the mechanism underlying the metabolic syndrome.^30,31 Evidence shows that insulin resistance mediates all the metabolic risk factors and is associated with lean mass loss and fat mass gain.^32,33 Metabolic syndrome may be associated with falls by way of the association of insulin resistance with muscle weakness. One study showed an association between insulin resistance and decreased quadriceps muscle strength in nondiabetic adults aged over 70 years, in addition to other well-established factors such as increased fat mass or decreased physical activity.³⁴

However, falling is a multifactorial geriatric syndrome, which has predisposing factors and precipitating factors interrelated with each other.⁸ The modifiable risk factors deserve more attention in the effort to prevent serious complications of falls. The possible complex interaction between these two syndromes is worthy of further investigation. Previous studies in the literature proposed that older adults be screened for the metabolic syndrome, its components, and falls as part of the geriatric health examination.^35,36 Our results suggest that the identification of the metabolic syndrome is a practical way to predict future occurrence of falls in older adults from the perspective of health prevention.

Our study has several limitations. First, this was a cross-sectional study and the history of falls was asked retrospectively. Recall bias could be a problem and may result in underestimation of the actual occurrence of falls. These cross-sectional findings cannot be used to impute a casual association between the metabolic syndrome and falls. Second, many confounding variables of particular importance for falls, such as obesity, associated mobility issues, co-morbidities, visual acuity, and polypharmacy with attendant side effects, were not considered in the data analysis. However, this study was specifically designed to investigate the association between the metabolic syndrome and its components with falls. Third, we only enrolled community-dwelling older adults, and the results cannot be appropriately applicable and generalized to other geriatric populations across various settings.

In conclusion, the metabolic syndrome is an independent risk factor for falls in community-dwelling older adults. Because the metabolic syndrome and its components are substantially modifiable, interventions targeting these risk factors in older adults can be potentially important in the prevention of falls.

Footnotes

Author Disclosure Statement

The study was carried out as part of our routine clinical services. The authors did not receive any funding for the preparation of this manuscript. No competing financial interests exist.

K.C. Liao and S.J. Pu participated in the study design and preparation of the manuscript. C.H. Lin and H.J. Chang contributed to the statistical analysis, and Y.J. Chen and M.S. Liu assisted in drafting the manuscript and provided feedback.

References

Denys

, Cankurtaran

, Janssens

et al. Metabolic syndrome in the elderly: An overview of the evidence. Acta Clin Belg, 2009; 64:23–34.

Rigo

, Vieira

, Dalacorte

et al. Prevalence of metabolic syndrome in an elderly community: Comparison between three diagnostic methods. Arquivos Brasileiros de Cardiol, 2009; 93:85–91.

Lin

, Liu

, Lai

et al. Metabolic syndrome in a Taiwanese metropolitan adult population. BMC Publ Health, 2007; 7:239.

McNeill

, Katz

, Girman

et al. Metabolic syndrome and cardiovascular disease in older people: The cardiovascular health study. J Am Geriatr Soc, 2006; 54:1317–1324.

Mozaffarian

, Kamineni

, Prineas

et al. Metabolic syndrome and mortality in older adults: The Cardiovascular Health Study. Arch Int Med May, 2008; 168:969–978.

Rubenstein

. Falls in older people: Epidemiology, risk factors and strategies for prevention. Age Ageing, 2006; 35,Suppl 2:ii37–ii41.

Kwan

, Close

, Wong

et al. Falls incidence, risk factors, and consequences in Chinese older people: A systematic review. J Am Geriatr Soc, 2011; 59:536–543.

Tinetti

, Speechley

, Ginter

. Risk factors for falls among elderly persons living in the community. N Engl J Med, 1988; 319:1701–1707.

Guideline for the prevention of falls in older persons. American Geriatrics Society, British Geriatrics Society, and American Academy of Orthopaedic Surgeons Panel on Falls Prevention. J Am Geriatr Soc, 2001; 49:664–672.

10.

Vaapio

, Salminen

, Vahlberg

et al. Effects of risk-based multifactorial fall prevention on health-related quality of life among the community-dwelling aged: A randomized controlled trial. Health Qual Life Outcomes, 2007; 5:20.

11.

Lin

, Liao

, Pu

et al. Associated factors for falls among the community-dwelling older people assessed by annual geriatric health examinations. PloS One, 2011; 6:e18976.

12.

Erkinjuntti

, Sulkava

, Wikstrom

et al. Short Portable Mental Status Questionnaire as a screening test for dementia and delirium among the elderly. J Am Geriatr Soc, 1987; 35:412–416.

13.

Chen

, Wu

, Lee

et al. Validity of the five-item Brief Symptom Rating Scale among subjects admitted for general health screening. J Formosan Med Assn=Taiwan yi zhi, 2005; 104:824–829.

14.

Crooks

, Waller

, Smith

et al. The use of the Karnofsky Performance Scale in determining outcomes and risk in geriatric outpatients. J Gerontol, 1991; 46:M139–M144.

15.

Grundy

, Cleeman

, Daniels

et al. Diagnosis and management of the metabolic syndrome: An American Heart Association/National Heart, Lung, and Blood Institute Scientific Statement. Circulation, 2005; 112:2735–2752.

16.

Tan

, Ma

, Wai

et al.

Can we apply the National Cholesterol Education Program Adult Treatment Panel definition of the metabolic syndrome to Asians?

Diabetes Care, 2004; 27:1182–1186.

17.

Kithas

, Supiano

. Practical recommendations for treatment of hypertension in older patients. Vasc Health Risk Manag, 2010; 6:561–569.

18.

Gribbin

, Hubbard

, Gladman

et al. Risk of falls associated with antihypertensive medication: population-based case-control study. Age Ageing, 2010; 39:592–597.

19.

Gangavati

, Hajjar

, Quach

et al. Hypertension, orthostatic hypotension, and the risk of falls in a community-dwelling elderly population: The maintenance of balance, independent living, intellect, and zest in the elderly of Boston study. J Am Geriatr Soc, 2011; 59:383–389.

20.

Schwartz

, Vittinghoff

, Sellmeyer

et al. Diabetes-related complications, glycemic control, and falls in older adults. Diabetes Care, 2008; 31:391–396.

21.

Agrawal

, Carey

, Della Santina

et al. Diabetes, vestibular dysfunction, and falls: Analyses from the National Health and Nutrition Examination Survey. Otol Neurotology, 2010; 31:1445–1450.

22.

Berlie

, Garwood

. Diabetes medications related to an increased risk of falls and fall-related morbidity in the elderly. Ann Pharmacother, 2010; 44:712–717.

23.

Mayne

, Stout

, Aspray

. Diabetes, falls and fractures. Age Ageing, 2010; 39:522–525.

24.

AbouRjaili

, Shtaynberg

, Wetz

et al. Current concepts in triglyceride metabolism, pathophysiology, and treatment. Metabolism: Clin Exp, 2010; 59:1210–1220.

25.

Lavie

, Milani

, O'Keefe

. Dyslipidemia intervention in metabolic syndrome: emphasis on improving lipids and clinical event reduction. Am J Medical Sci, 2011; 341:388–393.

26.

Witham

, Avenell

. Interventions to achieve long-term weight loss in obese older people: A systematic review and meta-analysis. Age Ageing, 2010; 39:176–184.

27.

Puenpatom

, Victor

. Increased prevalence of metabolic syndrome in individuals with osteoarthritis: An analysis of NHANES III data. Postgrad Med, 2009; 121:9–20.

28.

Allet

, Armand

, de Bie

et al. The gait and balance of patients with diabetes can be improved: A randomised controlled trial. Diabetologia, 2010; 53:458–466.

29.

Morrison

, Colberg

, Mariano

et al. Balance training reduces falls risk in older individuals with type 2 diabetes. Diabetes Care, 2010; 33:748–750.

30.

Reaven

. Insulin resistance, the insulin resistance syndrome, and cardiovascular disease. Panminerva Medica, 2005; 47:201–210.

31.

Levine

, Crimmins

. Sarcopenic obesity and cognitive functioning: The mediating roles of insulin resistance and inflammation? Curr Gerontol Geriatr Res, 2012; 2012:826398.

32.

Lee

, Boyko

, Strotmeyer

et al. Association between insulin resistance and lean mass loss and fat mass gain in older men without diabetes mellitus. J Am Geriatr Soc, 2011; 59:1217–1224.

33.

Grundy

. Pre-diabetes, metabolic syndrome, and cardiovascular risk. J Am Coll Cardiol, 2012; 59:635–643.

34.

Barzilay

, Cotsonis

, Walston

et al. Insulin resistance is associated with decreased quadriceps muscle strength in nondiabetic adults aged ≥70 years. Diabetes Care, 2009; 32:736–738.

35.

Moylan

, Binder

. Falls in older adults: Risk assessment, management and prevention. Am J Med, 2007; 120L493:e491–e496.

36.

Soriano

, DeCherrie

, Thomas

. Falls in the community-dwelling older adult: A review for primary-care providers. Clin Intervent Aging, 2007; 2:545–554.