EAL

FNOA: Assessment of Overweight/Obesity (2012)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To examine potential gender differences in the relationship between body mass index and functional decline.

Inclusion Criteria:

Patient in the Geisinger Health System (rural Pennsylvania)
Medicare participant
Completed an initial nutrition screening questionnaire
Completed a follow-up questionnaire between three and four years after the initial questionnaire was completed.

Exclusion Criteria:

Not a Medicare participant from the Geisinger Health System
Did not complete a follow-up questionnaire due to no response, death, admission into a skilled nursing facility or discontinued membership in the managed health care plan.

Description of Study Protocol:

Recruitment: Subjects were recruited from more than 100 clinic sites in rural Pennsylvania as a part of a regional nutrition screening program initiated by the Geisinger Health System
Design: Prospective cohort study
Blinding used: None.

Statistical Analysis

T-tests were used to compare differences in descriptive variables between men and women and between baseline and re-screening
Chi-square tests were used to test for statistical significance between functional decline by BMI category and gender
The likelihood of functional decline was predicted using logistic regression with BMI category or weight change as the main independent variable
Items identified in a previous investigation as confounding variables of the relationship between BMI and functional status (depression and polypharmacy) were included in the analysis as covariates.

Data Collection Summary:

Timing of Measurements

An initial screening questionnaire (including recent weight change, living and eating habits, alcohol and medication use, depression, dentition and limitations in functional status) was completed at baseline. A physical exam was also completed at baseline, including measured height and weight.
A second questionnaire was mailed to participants between three and four years after initial enrollment.

Dependent Variables

Functional decline (defined as any increase in reported limitations in activities of daily living or instrumental activities of daily living over the study period).

Independent Variables

Weight, height, BMI (measured and reported)
Gender
Weight change (reported).

Control Variables

Living and eating habits (reported by questionnaire)
Alcohol and medication use (reported by questionnaire)
Depression (assessed by questionnaire using a single question, "Do you feel depressed?')
Dentition (reported by questionnaire).

Description of Actual Data Sample:

Initial N: 2,634 (1,218 men and 1,416 women)
Attrition (final N): 2,634
Age: Mean age was 71 years at baseline and 75 years at follow-up
Ethnicity: 99% non-Hispanic white
Other relevant demographics: Rural; majority of participants reside in a community of fewer than 2,500 residents and less than 1% of subjects have access to a hospital in their community
Anthropometrics: Mean BMI at baseline was 28.3±4.5kg/m² for men and 28.7±5.6kg/m² for women
Location: Rural Pennsylvania.

Summary of Results:

Key Findings

For both men and women at a BMI of 35 or greater, a significant relationship was detected for increased risk of reporting instrumental activities of daily living decline [OR and 95% CI for men, 3.10 (1.10 to 8.57); for women, 2.31 (1.21 to 4.39)] or any functional decline [3.32 (1.29 to 8.46) for men and 2.61 (1.39 to 4.95) for women]
For both men and women, there are significant relationships between further weight gain of at least 20 pounds [3.00 (1.05 to 7.43) for men and 3.42 (1.35 to 7.82) for women] or weight loss of at least 10 pounds [1.98 (1.21 to 3.25) for men and 1.93 (1.34 to 2.78) for women] and risk of any functional decline
A general trend was seen in decline in BMI in both genders over the follow-up period with increases in polypharmacy and self-reported functional limitations.

Author Conclusion:

The relationship between obesity and functional impairment extended in longitudinal follow-up to men and women at a BMI of 35 or greater
Participants appeared to well represent the rural population being studied, but it is unclear whether these findings can be generalized beyond this setting to other populations of older persons
Body composition or fat distribution measurements were not obtained, which limits the ability of this study to address these factors in relation to functional outcomes
Weight gain and weight loss were associated with functional decline. For many older persons, the emphasis should be on weight maintenance. It would be preferable to enter older age with a BMI of less than 35 kg/m².

Funding Source:

Not-for-profit

Robert Wood Johnson Foundation; Geisinger Foundation

Other non-profit:

Reviewer Comments:

Several baseline factors differed in men and women that may have an effect of functionality. Women were more likely to feel depressed, take multiple prescription medications at baseline, skip eating on one of more days of the month, have an income of less than $6,000 per person per year, to live alone and report needing assistance with preparing food or performing any activity of daily living.
Activity level was not reported in this study. Along with the lack of data on body composition, it is difficult to know whether changes in fat and lean body tissue affects functionality.
While it was noted that change in weight (loss of greater than 10 pounds and gain of greater than 20 pounds) had an effect on functionality, inadequate subject numbers prevented analysis to be done to examine changes in only obese individuals (i.e., could an obese individual lose weight without a change in function vs. a person with a healthy or underweight BMI?).
It is unknown, in this study, whether weight was lost intentionally or unintentionally.

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?		???
	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?	???
3.	Were study groups comparable?		No
	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?	No
	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?	No
	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.)	N/A
	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?	Yes
	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?	Yes
	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?	Yes
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	Yes
	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?	Yes
	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?	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