Better Bones and Balance: Evaluation of a bone and falls specific community-based exercise program

Summer LIFE Scholar Program participant: Cathy Couey Study Mentors: Adrienne McNamara , PhD Candidate & Kathy Gunter, PhD

2008 LIFE Scholars Program – Oregon State University Center for Healthy Aging Research

Introduction

For many older Americans, falls are a chronic condition requiring medical management. The health and economic burden of falls in this population is large. Among the most costly outcomes are fall-related hip fractures. Additionally, the prevalence of osteoporosis is increasing and the total number of annual fractures and costs associated with osteoporosis are predicted to rise.

The need persists to identify successful, evidence-based, comprehensive interventions to improve function and prevent falls and osteoporosis related injuries among community-dwelling older adults. Weight bearing, balance and resistance exercises have been shown to improve bone mass and reduce the risk of falls, however most exercise data come from laboratory based or short-term community-based exercise trials. The effects of long-term participation in bone specific exercise on bone mass and structure in older women is still unknown.

In order to promote exercise for the prevention of osteoporosis, exercise programs must translate out of the laboratory and into the community. In doing so they must be safe, enjoyable and sustainable in order to keep individuals participating. To date, there have been several studies examining community-based fall prevention programs, but few have focused on bone specific community-based exercise with the intent of both improved bone and reduced fall risk factors.

The Better Bones and Balance exercise program (BBB) is a fall and hip fracture risk reduction exercise program that began with 27 postmenopausal women in 1994 and has grown to include an enrollment of over 300 participants in Linn and Benton counties, with more throughout the states of Oregon, Washington and California. The program has proven to be both enjoyable and sustainable as there are participants who have been regularly attending classes for over 14 years. We now have the opportunity to examine the relationship between participation in a true community-based bone loading and fall prevention program and parameters of bone health (hip bone mass and hip structure), strength and balance. Due to consistent long term participation, we also have the opportunity to examine a dose-response relationship between duration of participation in BBB and outcomes related to bone mass and structure.

Purpose

The purpose of this study is to determine relationships between participation in BBB and bone and health risk factors. Specifically we will address the following research questions:

1) Do estrogen deplete postmenopausal women who have been participating in BBB for a least one year have enhanced bone mass (BMD) and hip structure compared to non-participating age matched controls?

2) Is there a dose-response relationship between duration of participation in BBB and bone mass and hip structure?

3) Do estrogen deplete postmenopausal women who have been participating in BBB for at least one year have reduced risk factors for falls (greater leg strength, greater balance) than age matched non-participating controls?

Subjects

Estrogen deplete, postmenopausal women (n=50) currently participating in the BBB exercise program for at least one year, will be recruited from existing classes in the Willamette Valley via flyers, informational sessions held at classes and word of mouth from the class instructors. Estrogen deplete, sedentary, postmenopausal age matched controls (n=50) will be recruited from the Corvallis community via flyers posted on the OSU campus, at the Corvallis Senior Center and in the Corvallis community as well as by word of mouth. A subset of BBB participants (n=40) will be recruited to partake in the descriptive sub-study.

Questionnaire-based Measures

Questionnaires will assess cognitive function, health history, balance self-efficacy, physical activity, and nutrition. Nutritional status will be assessed using The Block 2005 Food Frequency Questionnaire. A health history questionnaire will be used to compile demographic statistics of our population as well as potential medications or diseases that may affect bone. BBB participants will complete a questionnaire detailing their historical involvement in the BBB program. The Aerobics Center Longitudinal Study Physical Activity Questionnaire will be used to assess regular levels of generalized, non-bone specific physical activity to compare activity levels between groups. The Bone-Specific Physical Activity Questionnaire (BPAQ) will be used to assess past and current physical activity patterns that may specifically influence the skeleton. The Mini-Mental State Examination will be used to assess cognitive impairment that might hinder the participant’s ability to participate in this study.

Functional Measures

Participants height, weight, and fitness parameters including strength, balance, and cardio-respiratory fitness are also being measured. Components of the Senior Fitness Test will be used to assess underlying physical parameters associated with functional ability. This test includes the one-leg stance (fig. 2A ) to assess static balance; the bicep curl (fig. 2B) to assess upper body strength; the 30-second chair stand (fig. 2C) to assess lower body strength needed for daily tasks as well as strength to reduce the risk of falling; the 2-minute step test (fig. 2D) to assess aerobic endurance; the 8-foot up-and-go to assess agility and dynamic balance; the tandem stance (fig. 2E) and the tandem walk (fig. 2 F) to assess dynamic balance.

Progress to Date

Figure 1: Better Bones and Balance participants lunging, balancing, and jumping during a BBB class.

Bone Strength and Structural Measures

Bone parameters are measured for each participant using dual energy x-ray absorptiometry (DXA) bone scan (fig. 3) to assess bone mineral density of their hip, spine and whole body. Bone scan data are used to determine bone mass and bone structural outcomes. Statistical analysis will be used to : 1) examine the relationship between participation in the BBB program and bone health in comparison to non-participating sedentary controls; 2) examine the relationship between participation in the BBB program and fall risk factors ; and 3) determine dose-response relationship between duration of participation in BBB and bone mass and hip structure.

All testing is conducted in the OSU Bone Research Laboratory where participants complete questionnaires and are measured for height, weight and fitness parameters.

Methods

Data Analysis

Statistical analysis will be used to : 1) examine the relationship between participation in the BBB program and bone health in comparison to non-participating sedentary controls; 2) examine the relationship between participation in the BBB program and fall risk factors ; and 3) determine dose-response relationship between duration of participation in BBB and bone mass and hip structure.

Differences in BMD and hip structural parameters between BBB participants and controls will be assessed using Analysis of Covariance (ANCOVA), controlling for age, lean body mass and bone-specific physical activity. Differences between groups in strength, and balance parameters will be assessed using Multivariate Analysis of Covariance (MANCOVA), controlling for age. Stepwise regression will be used to address the relationship between duration of BBB participation (years) and BMD. Means and standard deviations of data presented in this poster were calculated using SPSS software. When available, group means were compared to national normative data (Riki and Jones, 2002).

Figure 3:

Doctoral student Adrienne McNamara conducts a bone scan on a research participant.

Senior Fitness Test Components

Test Score National Age-Matched Norms

8-ft up-and-go 6.17 + 1.47 7.1 - 4.9 seconds

30-second chair stands 18.8 + 4.2 10 rep - 15 rep

Bicep curl 23.7 + 5.2 12 rep - 17 rep

2-min step test 108.0 + 18.4 68 -101 steps

Table 3: Group means for strength and balance and age-matched national norms

Table 1: Means and SD of demographics Table 2: Mean t-scores of 4 bone values

Variable Means + SD

Age (years) 72.7 + 8.8

Time postmenopausal (years) 19.9 + 9.0

Body fat (percent) 33.2 + 6.1

Height (cm) 162.2 + 7.3

Weight (kg) 66.7 + 10.8

Time in BBB (years) 7.2 + 4.3

Bone Variable t-score (SD)

AP Lumbar Spine t-score (-)1.28 + 1.29

Femoral Neck t-score (-)1.62 + 0.95

Trochanter t-score (-)1.29 + 0.62

Total Hip t-score (-)1.3 + 0.64

Note: a t-score of 0 indicates "average" value for that of a 24 year old.

Descriptive Statistics Tables

Recruitment

We have successfully recruited thirty-eight estrogen deplete BBB participants into the study who meet all of the inclusion criteria. An additional twenty-five participants were screened and did not meet inclusion criteria. Informational sessions are underway for a second round of recruiting among the BBB participants. Recruitment of control participants is beginning this month and we expect to have all control participants tested by the end of March 2009.

To date, twenty-seven BBB participants have been tested. A descriptive statistics data analysis was performed with data collected to date from twenty-three participants, as shown in tables 1, 2 and 3. Means and standard deviations of demographic parameters are included in table 1. Mean t-score values for lumbar spine, femoral neck, trochanter and total hip are included in table 2. Group means for the strength and balance assessments are included in table 3, along with age-matched national norms.

A FEDCB

Figure 2: Components of the Senior Fitness Test. One legged stance (A); Bicep curl (B); 30-second chair stands (C); 2-minute step test (D); Tandem stance (E); Tandem walk (F)

Findings to Date

Perspectives

Study Findings

We are unable to draw any conclusions as we are still collecting data on participants. However, it is apparent from the descriptive data (when compared to normative data) that BBB participants consistently out perform the average older adult female. The t-score values are used to diagnose osteoporosis. Based on the mean t-score values, there is no indication of osteoporosis at any bone site in the twenty-three BBB participants who were tested.

Experience as a Life Scholar

The first observation made while working as a Life Scholar was that research projects do not always go as planned. There were a few setbacks initially, so I was able to assist one of Dr. Gunter’s Master’s students with her project for a time. The first set back came with a project revision that required we wait for the Institutional Review Board to review the project changes. I came to understand that even doctoral students and faculty have to revise and edit projects based on feedback from experts and mentors. The second observation made was the serious nature of working on a research project. I approached it with the same care, respect and attention to detail that I put into my own work, realizing that the Bone Research Laboratory team was trusting in and depending on me and that I was a part of the research process. The third observation made was how carefully the data is handled during data entry. It was required of anyone assisting with data entry, that the data be entered once and then double checked for errors. It was a very time consuming, redundant and not so interesting part of the research project, but vital to ensure the integrity of data outcomes later during the analysis phase. I considered it an honor to toil along side another undergraduate student as we performed behind the scenes data entry work to advance the project. I learned it is no small thing to promote the success and ultimately the credibility of a master’s student or a doctoral candidate. The part of the process to date that I enjoyed the most as a Life Scholar was working directly with the BBB participants during the participant screening and the Senior Fitness Testing.

Future Plans

Career plans after graduation are to work in the area of long -term care as a director for assisted living. What excites me about this research project is how it will positively impact the future of healthy aging. Because of what I’ve learned as a Life Scholar, instituting an exercise program like Better Bones and Balance, that promotes healthy aging through improved balance, strength and better bones, will be an important priority for me as a director for assisted living .