EAL

FNOA: Assessment of Overweight/Obesity (2012)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To evaluate the prevalence of frailty and interrelationships among body composition, physical function and quality of life in community-dwelling obese elderly persons.

Inclusion Criteria:

Age older than 65 years
Resident of St. Louis metropolitan area
Community-dwelling
Sedentary
Stable body weight for one year prior to recruitment
Provided informed consent.

Exclusion Criteria:

Age 65 years or older
Residing in an institutional facility
Participated in regular physical activity more than two times per week
Gained or lost more than 2kg over the course of one year prior to recruitment
Had impaired glucose tolerance
Diagnosis of diabetes
Diagnosis of cancer within the last five years
Used corticosteroids, androgens, estrogens or bone-acting drugs (bisphosphonates)
Smoked cigarettes within the past year
Presence of sensory impairment
Physical disability
Presence of significant cognitive dysfunction.

Description of Study Protocol:

Recruitment

Elderly residents of the St. Louis metropolitan area were recruited by advertisements, mass mailing and regional presentations.

Design

Cross-sectional study.

Statistical Analysis

Comparisons of means among the three groups were made by using two-way ANOVA (group x gender) for quantitative variables and Tukey's post-hoc analysis was used. Categorical variables were tested using Chi-square to compare the groups. Covariance analyses were used to adjust for frailty and physical performance measures for chronic health conditions.

Data Collection Summary:

Timing of Measurements

All measurements were taken after recruitment at a research center by trained personnel.

Dependent Variables

Body composition (total body fat mass, fat-free mass and bone mineral content measured by using whole body DXA)
Systolic and diastolic blood pressure (average of two reading at rest)
Physical performance (measured using a modified physical performance test measuring seven standards)
Peak aerobic power (VO₂ peak assessed during a graded treadmill walking test)
Activities of daily living (measured using the Older American Resources and Services instrument)
Physical function (strength measured by knee extensor and flexor strength using a Cybex isokinetic dynamometer; balance assessed with a one leg stand; ambulatory activity measured by walking speed over 25 meters; muscle quality measured as the relationship between muscle strength and muscle mass).

Independent Variables

BMI
Frailty.

Control Variables

Presence of chronic health conditions not excluded in the study protocol.

Description of Actual Data Sample:

Initial N: 156 (75 women, 81 men)
Attrition (final N): 156
Age: Older than 65 years
Anthropometrics: Mean BMI 25.9±0.4 in the non-obese, non-frail group; 25.0±0.4 in the non-obese, frail group; 36.6±0.6 in the obese elderly group
Location: St. Louis, MO, US.

Summary of Results:

Key Findings

Among obese elderly subjects, 96% met the criteria for mild to moderate frailty
Compared with the non-obese non-frail group, the obese elderly and non-obese frail groups had lower and similar scores in physical performance test, peak aerobic power and functional status questionnaire and exhibited similar impairments in strength, walking speed, balance and health-related quality of life
Although absolute fat-free mass was greater, the percentage body weight at FFM and muscle quality was lower in the obese elderly group than in the other two groups.

Significant Differences in Frailty, Strength, Gait, Balance and Quality of Life

	NO-NF (N=52)	NO-F (N=52)	OE (N=52)
Measures of frailty
PPT	34.4±0.5	29.3±0.7*	27.8±0.8*
VO_2peak (ml per kg per minute)	20.0±0.6	14.9±0.4*	14.6±0.5*
Functional status questionnaire	33.9±0.4	30.1±0.5*	29.2±0.5*
Strength, gait, balance
Knee extension (Nm)	109.5±5.0	87.1±3.8*	93.1±5.5*
Knee flexion (Nm)	75.6±3.3	59.6±3.0*	60.4±3.6*
Walking speed (m per minute)	99.2±5.3	83.1±2.7*	74.0±2.9*
One leg limb stand (sec)	12.3±2.2	5.8±0.9*	4.5±0.9*
Obstacle course (sec)	9.7±0.4	13.2±0.6*	14.6±0.8*
SF-36 quality of life (percent)
Role limitations (physical)	93.2±2.9	77.0±4.8*	78.1±5.1*
Vitality	58.2±1.9	51.0±1.9*	52.5±2.6*
Change in health	45.4±1.9	40.4±2.7*	33.7±2.6*
Physical function	85.9±1.9	71.5±3.9*	62.7±3.1*

NO-NF (non-obese, non-frail), NO-F (non-obese, frail), OE (obese elderly)

PPT (physical performance test)

*Differs from NO-NF group, P<0.05

No significant differences were noted between groups in SF-36 quality of life indicators for role limitations (emotional, social functioning, bodily pain, mental health and health perceptions).

Significant Differences in Frailty, Strength, Gait and Balance of Subjects after Controlling for Chronic Health Conditions

	NO-NF (N=52)	NO-F (N=52)	OE (N=52)
Measures of frailty
PPT	33.6±1.1	29.6±0.7*	28.0±0.8*
VO_2peak (ml per kg per minute)	19.8±0.9	15.1±0.4*	14.7±0.4*
Functional status questionnaire	33.6±1.0	30.2±0.5*	29.3±0.5*
Strength, gait, balance
Knee extension (Nm)	109.5±5.0	87.1±3.8*	93.1±5.5*
Knee flexion (Nm)	75.6±3.3	59.6±3.0*	60.4±3.6*
Walking speed (m per minute)	99.2±5.3	83.1±2.7*	74.0±2.9*
One-leg limb stand (sec)	12.4±1.7	6.0±1.0*	4.7±1.1*
Obstacle course (sec)	10.0±1.1	13.0±0.6*	14.3±0.7*

NO-NF (non-obese, non-frail), NO-F (non-obese, frail), OE (obese elderly)

PPT (physical performance test)

^*Differs from NO-NF group, P<0.05

Other Findings

Differences in Body Composition of the Subjects

	NO-NF (N=52)	NO-F (N=52)	OE (N=52)
Body composition
BMI (kg/m²)	25.9±0.4	25.0±0.4	36.6±0.6*
Weight (kg)	72.7±1.3	71.1±1.3	96.5±2.3*
Total fat (kg)	23.0±1.0	25.2±1.0	40.4±1.3*
Total fat (percent)	31.0±1.1	36.0±1.2**	42.5±1.2*
Total fat free mass (kg)	49.0±1.5	45.5±1.3	54.0±1.7*
Total fat free mass (percent)	70.0±1.1	64.1±1.2**	57.1±1.2*
Bone mineral density
Total body (g per cm²)	1.09±0.16	1.06±0.14	1.14±0.16*
Lumbar spine (g per cm²)	1.01±0.03	1.00±0.04	1.12±0.03*
Total hip (g per cm²)	0.84±0.03	0.79±0.02	0.93±0.02*

NO-NF (non-obese, non-frail), NO-F (non-obese, frail), OE (obese elderly)

PPT (physical performance test)

^*Differs from NO-NF and NO-F groups, P<0.05

^**Differs from NO-NF and OE groups, P<0.05

Author Conclusion:

Obesity is an important cause of physical dysfunction in community-dwelling elderly persons
Almost all obese subjects in this study had both subjective and objective evidence of physical frailty
Physical frailty was associated with a low percentage of body weight as fat-free mass and poor muscle quality
Although obese subjects had an absolute amount of fat-free mass greater than non-obese subjects, the proportion of body weight as fat-free mass was lowest in the obese group suggesting that relative sarcopenia contributes to frailty.

Funding Source:

Government:

National Institutes of Health

Reviewer Comments:

This sample consisted of elderly individuals that were community-dwelling and willing/able to travel to a research center for testing. The sample is self-selected and may not represent community-dwelling elderly obese individuals as a whole.

Quality Criteria Checklist: Primary Research
Relevance Questions
	1.	Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies)	N/A
	2.	Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about?	Yes
	3.	Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice?	Yes
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	N/A

Validity Questions
1.	Was the research question clearly stated?		Yes
	1.1.	Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?	Yes
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	Yes
	1.3.	Were the target population and setting specified?	Yes
2.	Was the selection of study subjects/patients free from bias?		No
	2.1.	Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study?	Yes
	2.2.	Were criteria applied equally to all study groups?	Yes
	2.3.	Were health, demographics, and other characteristics of subjects described?	Yes
	2.4.	Were the subjects/patients a representative sample of the relevant population?	No
3.	Were study groups comparable?		Yes
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	Yes
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	Yes
	3.3.	Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)	Yes
	3.4.	If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis?	Yes
	3.5.	If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.)	Yes
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	N/A
4.	Was method of handling withdrawals described?		Yes
	4.1.	Were follow-up methods described and the same for all groups?	Yes
	4.2.	Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.)	Yes
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	Yes
	4.4.	Were reasons for withdrawals similar across groups?	N/A
	4.5.	If diagnostic test, was decision to perform reference test not dependent on results of test under study?	N/A
5.	Was blinding used to prevent introduction of bias?		No
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	N/A
	5.2.	Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.)	No
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	No
	5.4.	In case control study, was case definition explicit and case ascertainment not influenced by exposure status?	N/A
	5.5.	In diagnostic study, were test results blinded to patient history and other test results?	N/A
6.	Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?		Yes
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	N/A
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	Yes
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	N/A
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	N/A
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	N/A
	6.6.	Were extra or unplanned treatments described?	N/A
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	Yes
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	N/A
7.	Were outcomes clearly defined and the measurements valid and reliable?		Yes
	7.1.	Were primary and secondary endpoints described and relevant to the question?	Yes
	7.2.	Were nutrition measures appropriate to question and outcomes of concern?	Yes
	7.3.	Was the period of follow-up long enough for important outcome(s) to occur?	N/A
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	Yes
	7.5.	Was the measurement of effect at an appropriate level of precision?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	Yes
	7.7.	Were the measurements conducted consistently across groups?	Yes
8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?		Yes
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	Yes
	8.2.	Were correct statistical tests used and assumptions of test not violated?	Yes
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	Yes
	8.4.	Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)?	N/A
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	Yes
	8.6.	Was clinical significance as well as statistical significance reported?	Yes
	8.7.	If negative findings, was a power calculation reported to address type 2 error?	N/A
9.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	Yes
10.	Is bias due to study's funding or sponsorship unlikely?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes