Association between Metabolic Syndrome(Mets) and Physical Function in Community-Dwelling Older Women in Korea

Decreased functional capacity in older adults will be a major public concern in most countries. It is of significant public health importance to be able to predict decline in functional status, and loss of personal independence, especially decline in mobility, because problems with mobility typically arise before decline in instrumental and basic activities of daily living. Understanding characteristics of older people caused to functional problem may facilitate intervention strategies that may slow the rate of further functional decline. Abstract

Metabolic syndromes (Mets) have been related not only to presence of multiple chronic diseases but also to the development of disability. With the increased rate and growing expense of Mets [1], and greater probability of exposing this into older population, understanding the relationship between metabolic syndrome and functional decline in older adults is critical issue. This is important because it suggests that there may be a link between the mechanical and metabolic functions of ageing muscle. The mechanism is unclear, but aged muscle and insulin-resistant states share common cellular and molecular changes [2,3,4].Previous studies reported the inverse associations between metabolic syndrome and physical function [5][6][7][8]. The impact of metabolic syndrome in functional capacity of older population is not established, however. The purpose of this study was to examine the effect of metabolic syndrome on physical function in Korean older women. We hypothesized that older women with metabolic syndrome would have lower score of physical function than one without metabolic syndrome. Data were collected on body composition, blood pressure, waist circumference and fasting glucose, triglyceride in 275 communitydwelling older women aged 60-95 years. The characteristics of the study population are presented in (Table 1). Of the study participants, 116 women were classified in metabolic syndrome. Accounting for all the participants, the mean age was 74 years, and mean BMI was 25.7kg/m2. More than 66% of women were widow and 76.1% of participants had ≤6 years of education. Additionally 61.9% of women had arthritis and 64% of women had hypertension ( Table 1).

Definition of the metabolic syndrome
The definition of the metabolic syndrome proposed by the NCEP ATP III(National Heart Lung and Blood Institute, 2001) was applied for this study. As detailed in the NCEP ATP III report, participants having three or more of the five following criteria were defined as having the metabolic syndrome: high blood pressure (≥130/≥85 mmHg), elevated fasting blood glucose (≥110 mg/ dl or ≥6.05 mmol/l), hypertriglyceridemia (≥150 mg/dl or ≥1.65 mmol/l), low high density lipoprotein (HDL)-cholesterol (men, <40 mg/dl or <1.05 mmol/l; women, <50 mg/dl or <1.30 mmol/l), and abdominal obesity, as measured by a waist circumference of >102 cm for men and >88 cm for women.

Anthropometric measurements
Participants' height was measure to the nearest 0.1cm. Weight was measure in the upright position to the nearest 0.1 kg. Body Mass Index (BMI) was calculated by dividing weight (kg) by height squared(m2). Waist circumference measurements were taken at the end of normal expiration to the nearest 0.1 cm, measuring from the narrowest point between the lower borders of the rib cage and the iliac crest.

Cardiovascular risk factors
The blood pressure of each subjects in the sitting position after 10-minute rest period using TM-2655P (Biospace 720, Korea). Two readings, each of systolic and diastolic blood pressure were recorded and the average of each measurement was used for data analysis.

Physical Function
Participants proceeded to complete the Senior Fitness Test (SFT) items. The SFT utilized in this study consisted of 5 different assessments: chair stand to assess lower body strength, arm curl to assess upper body strength, 2-minute step to assess aerobic endurance, chair sit-and-reach to assess lower body flexibility, back scratch to assess upper body flexibility, and the 8-foot up-andgo to assess the agility and dynamic balance( Table 2).

Data Analysis
Unpaired t-test, univariate analysis, and chi-square test were used to assess whether differences in the clinical characteristics existed between the older women with and without metabolic syndrome. All analyses were performed using the SPSS-PC (SPSS Inc, Chicago, IL) statistical package. Statistics significance was set at P<.05. Measurements are presented as mean ± standard deviations.

Results
General characteristics of study populationTwo hundred seventy-five older women (mean age of 74.24 (60-95)) participated in the assessments over the testing period. The overall prevalence of metabolic syndrome in participants was 42.5%. The characteristics of the study group are displayed in (Table 3). The clinical characteristics of the older women with and without metabolic syndrome are presented in (Table 2). As expected, women with metabolic syndrome had a higher prevalence (p<.05) of each characteristic of metabolic syndrome (diabetes, high BMI) than those without metabolic syndrome. However, the two groups were similar in age, height, and weight.As summarized in (Table  4), women with metabolic syndrome also had higher percent body fat(p<.01), higher waist circumference (p<.01) and higher systolic(p<.01] and diastolic blood pressure (p<.05) ( Table 4).The association between metabolic syndrome and physical function is shown in Table 5. Different from our expectation, there were no differences in chair stand, arm-curl, sit and reach between older women with and without metabolic syndrome. However, Older women without metabolic syndrome had better balance --more extended one-leg stand(p<.01), better agility & dynamic balance --shorter 244 TUG (p<.05) and better aerobic endurance --higher 2-minute steps(p<.05) than women without the Metabolic syndrome (Table 5).   had lower peak oxygen uptake and a shorter 6-minute walk distance [5,6,9]. This can be explained that the loss of muscle mass and strength combined with the gain in abdominal fat may act synergistically to exacerbate metabolic disorders and increased chance of disability [10][11][12]. Given these considerations, it would be expected that metabolic syndrome would predict a decline in mobility over time. Furthermore, it is intuitive that having high levels of fat mass together with low muscle mass may lead to more functional limitations, as well as to more metabolic disorders [13]. Previous research reported that physical inactivity, obesity, and diet composition appear to be risk factors for the development of the metabolic syndrome. Several studies have shown that the effectiveness of regular physical activities such as resistance and aerobic training in reducing cardiovascular risk in older women [14,15]. Further, structure PA prevents from mobility disability and Metabolic syndrome in older adults with functional limitation [16,17] reported elastic band training produced improvements in both metabolic parameters and functional fitness. Also, reported that moderate-to high-intensity aerobic exercise produced improvements in insulin sensitivity, triglyceride and low-density lipoprotein cholesterol in sedentary obese adults. These findings suggest that variation in exercise training might help to maximize physical adaptations.
Not only physical activity but also diet has been reported that's inverse association with Mets [18] reported that a Mediterraneanstyle intake was inversely associated with the cumulative incidence of MetS. Further, Mediterranean diet improves physical domain of health-related quality of life and lowers the odds of LDL-C [19] TGs, and low HDL-C levels [20][21][22][23]. Therefore, future research needs to further analyze controlling diet and physical activity factors to investigate the association between physical function and Mets. There are several study limitations that must be addressed. A longer intervention might have allowed for the investigation of significant differences between seniors with Mets and without Mets. In addition, intervention studies are necessary to establish dose-dependent relationships of PA and physical function in elders with Mets.

Conclusion
Metabolic syndrome may worsen physical function in older women. Older women with MetS have the lower level of several functional capacities such as static balance, agility & dynamic balance and aerobic endurance than older women without MetS.