EAL

FNOA: Assessment of Overweight/Obesity (2012)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To determine whether obesity is associated with the frailty phenotype and, if so, whether comorbid conditions or inflammatory markers explain this association.

Inclusion Criteria:

Age 70-79 years
Female
Participated in either Women's Health and Aging Study I (1992) or Women's Health and Aging Study II (1994)
Consented to have blood drawn
Blood drawn within 90 days of baseline examination
BMI≥18.5kg/m².

Exclusion Criteria:

Age <70 years or >79 years
Did not participate in Women's Health and Aging Studies I or II
Did not have blood drawn within 90 days of baseline examination
Had a BMI <18.5kg/m².

Description of Study Protocol:

Recruitment

Women selected for this analysis participated in one of two population-based studies; Women's Health and Aging Studies I (1992) and II (1994)

Design

Cross-sectional analysis

Blinding used

None

Intervention

None

Statistical Analysis

Crude frequencies and means ± standard deviations were calculated for demographic characteristics, diseases and conditions, biochemical characteristics, individual frailty indicators and frailty status according to BMI categories.
Age-adjusted logistic regression models were used to determine whether there was a statistically significant trend in the increasing proportions of women with a given characteristic who were non-frail, pre-frail and frail.
Multinominal logistic regression was used to study the cross-sectional association between obesity and the frailty syndrome, allowing modeling of the pre-frail and frail states with non-frail as the reference group.

Data Collection Summary:

Timing of Measurements

Upon study entry, standardized questionnaires, physical performance measures and a directed physical examination were administered either in the participants' homes (Women's Health and Aging Study I) or in the Johns Hopkins Functional Status Laboratory (Women's Health and Aging Study II). Phlebotomy was performed on participants who consented.

Dependent Variables

Frailty syndrome (frail—defined as the presence of three or more indicators, including weakness, slowness, weight loss, low physical activity and exhaustion; and pre-frail—defined as the presence of one or two indicators).

Independent Variables

BMI
Chronic diseases
C-reactive protein
Serum carotenoids.

Control Variables

Age

Description of Actual Data Sample:

Initial N: 599 women
Attrition (final N): All included in final analysis
Age: 70-79 years (mean age 74.0±2.7)
Ethnicity: 20.3% African American
Other relevant demographics: 22.6% had completed less than a high school education
Anthropometrics: Differences in BMI and disease states was used in analysis of frailty indicators
Location: Baltimore, Maryland, United States.

Summary of Results:

Key Findings

The overall presence of frailty in the sample was 8%; with 43% of the women having pre-frail status and 49% being non-frail
The proportion of women who were non-frail decreased with increasing BMI
The proportion of women who were pre-frail increased with increasing BMI
The proportion of women who were frail was lowest for women with a BMI 25 to <30kg/m² and was highest for women with a BMI≥30kg/m²
A significant and consistent trend for all covariates, except race, was that the proportion of women with a condition increased going from non-frail to pre-frail to frail
Multinomial logistic regression models showed that obesity was significantly associated with pre-frail (OR=2.23; 95% CI=1.29-3.84) and frail status (OR=3.52; 95% CI=1.34-9.13) even after adjustment for all covariates considered
BMI of 18.5 to less than 25kg/m² was not significantly associated with pre-frail or frail status.

Other Findings from Multinomial Logistic Regression:

Age was significantly associated with frailty (OR=1.21; 95% CI=1.06-1.39)
Low education (less than high school) was significantly associated with pre-frailty (OR=2.16; 95% CI=1.26-3.70) and frailty (OR=3.23; 95% CI=1.45-7.18)
Diabetes mellitus, peripheral vascular occlusive disease and congestive heart failure were significantly associated with pre-frailty (OR=2.56; 95% CI=1.38-4.78; OR=2.05; 95% CI=1.08-3.89; OR=2.55; 95% CI=1.07-6.10, respectively) and frailty (OR=3.92; 95% CI=1.49-10.34; OR=3.27; 95% CI=1.31-8.14; OR=10.08; 95% CI=3.63-27.94)
Coronary artery disease was significantly associated with pre-frailty (OR=1.76; 95% CI=1.06-2.90) only
Chronic obstructive pulmonary disease and osteoarthritis were associated with frailty (OR=2.25; 95% CI=1.09-4.67) only
C-reactive protein was not associated with either pre-frailty or frailty
Low carotenoid level was associated with frailty (OR=2.59; 95% CI=1.24-5.42) only.

Author Conclusion:

High BMI and obesity are associated with several frailty phenotype indicators. High BMI is also associated with increasing likelihood of a pre-frail state, although overweight status was least likely associated with frailty. Obesity is associated with full-blown clinical frailty and this association is not decreased when demographic characteristics, comorbidities, increased inflammation or low antioxidant capacity are considered.
Research concerning "sarcopenic obesity" provides a key insight into the association between frailty and obesity.

Funding Source:

Government:

National Institute on Aging; National Institutes of Health

Not-for-profit

Ann Arbor Veterans Affairs Geriatric Research, Education and Clinical Center

Other non-profit:

Reviewer Comments:

One of the five criterion (defined empirically in the Cardiovascular Health Study) used to classify a participant as pre-frail or frail was weight loss. In the Cardiovascular Health Study, weight loss was defined as loss of >10 pounds unintentionally in the last year. This question was not asked in the Women's Health and Aging Studies. To compensate, the researchers in this study used weight at age 60 minus weight at exam to look for a ≥10% loss of weight. No differentiation was made as to whether the weight (lost over a decade) was intentional or unintentional. This potentially changes the validity of the instrument.
Nutritional intake, body composition and a differentiation between intentional and unintentional weight loss was not measured
Physical activity level was not measured or used as a confounder
While obesity lead to increased frailty and pre-frailty in the paper, overweight participants actually had the lowest rates of frailty and pre-frailty among the BMI categories. Normal BMI participants had the second highest percentage of frailty. Patterns of frailty indicators were the same among all three BMI categories, with the exception of weight loss, which was higher in the normal BMI group. Underweight BMI was an exclusion criteria for the study.

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?		Yes
	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?	Yes
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?	N/A
	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%.)	N/A
	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?	N/A
	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?		???
	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?	Yes
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	No
	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?	No
	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