FNOA: Assessment of Overweight/Obesity (2012)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

To examine the relationship between body composition (fat mass index, fat-free mass index) and adiposity (body mass index, waist circumference) to ill health and physical disability.

Inclusion Criteria:

Participants in the British Regional Heart Study who were still surviving at a 20-year follow-up.

 

Exclusion Criteria:

None specified.

Description of Study Protocol:

Recruitment

Participants were recruited for the British Regional Heart Study. Methods of recruitment were not discussed.

Design

  • Cross-sectional study 
  • All men completed a mailed questionnaire providing information on their lifestyle and medical history, had a physical exam and provided a fasting blood sample
  • Physical exam included anthropometric and physiologic measurements, including height, weight, body mass index, waist circumference, blood pressure and forced expiratory volume. Fat mass and fat-free mass were calculated using a bioelectrical impedance device. 
  • Men were asked to describe their health status as excellent, good or fair/poor. Subjects were asked to report physician diagnosis of  history of several different cardiovascular diseases, diabetes, cancer, and history of taking medications for respiratory or musculoskeletal disease.
  • Information on physical disability was collected using a questionnaire. Limitations included mobility (difficulty going up and down stairs or walking for 1/4 mile on a level surface), problems with carrying out usual activities or problems with self-care such as washing or dressing
  • Subjects were asked detailed information on their smoking and drinking habits as well as physical activity habits and were placed into different categories based on those results
  • Social class was derived from the longest-held occupation recorded at the time of baseline questionnaire
  • Metabolic risk factors were identified based on serum samples (tested for total cholesterol, HDL-cholesterol and insulin resistance).

Blinding Used

Implied with measurements.

Statistical Analysis

  • Multiple logistic regression was used to assess the relationship between body mass index, waist circumference, fat mass index, fat free mass index and descriptive statistics (age, inactivity, smoking, alcohol intake and social class) and metabolic risk factors (HTN, high cholesterol, low HDL-cholesterol, high homeostasis model assessment), ill health and physical disability. Odds ratios with 95% confidence intervals for these outcome measures were obtained for the adiposity and body composition measures by use of the lowest fifth as the reference category.
  • Models for CVD risk factors were adjusted for age, social class, smoking, alcohol intake and physical activity. The odds ratios for physical disability were adjusted for age, social class, smoking, alcohol intake, physical activity and morbidity. Tests for trends were carried out fitting body mass index, waist circumference, fat mass index and fat-free mass index as continuous variables. The odds ratios for body mass index were adjusted for fat mass index to explore the effect of fat mass index on the relation of body mass index to physical disability.

 

Data Collection Summary:

Timing of Measurements

The original data for the British Regional Heart Study was collected in 1978-1980. The 20-year follow-up occurred between 1998 and 2000.

 Dependent Variables

  • Ill health as described  by participants given the choice between excellent, good or fair/poor and reported diagnosis of history of CVD (heart attack, coronary thromboses or MI, angina, stroke), diabetes, cancer, history of taking medication for respiratory or musculoskeletal disease.
  • Physical disability:
    • Problems with mobility as determined by asking subjects whether they had difficulty going up and down stairs or walking 1/4 mile
    • Problems carrying out usual activities as self-reported
    • Problems with self care as self reported if they had problems washing or dressing themselves.

Independent Variables

  • BMI as measured by standard height and weight measurements not described
  • Waist circumference as measured by standard procedure not described
  • Fat mass as calculated after measurement with a bioelectrical impedance device (Bodystat model 500) and estimated using an equation by Duerenbergy et al
  • Fat free mass as measured by bioelectrical impedance device (Bodystat model 500) and calculated as 6,710 x height (m)²/resistance (Ω) +7.

Control Variables

  • Age
  • Social class
  • Smoking
  • Alcohol intake
  • Physical activity
  • Morbidity.

 

Description of Actual Data Sample:
  • Initial N: 4,252 men (those from the British Regional Heart Study who completed a follow-up questionnaire and attended a physical exam)
  • Attrition (final N): As above
  • Age: 60 to 79 years
  • Other relevant demographics: Information on social class was gathered, but not reported. The participants were described as being from a socially representative sample from all major British regions.
  • Anthropometrics: BMI varied from a low of 14kg/m² to a high of 48kg/m². Waist circumference varied from a low of 57cm to a high of 149cm. Fat mass varied from a low of 57 to a high of 149kg, and fat free mass varied from a low of 0.14 to a high of 28.9kg. Participants' anthropometric measurements were broken into five different quintiles that contained almost the exact same number of subjects.
  • Location: Participants were from a geographically representative sample representing all major British regions.
Summary of Results:

Key Findings

  • Fat mass index, body mass index and waist circumference had similar patterns of relations to ill health and physical disability. Increased body mass index, waist circumference and fat mass index were all associated with increased prevalence of cardiovascular disease, overall ill health and disability. A high fat-free mass index was associated with a decreased prevalence of respiratory problems and cancer. Body fatness was associated with CVD and disability in older men.
  • The likelihood of having HTN was similar for increasing fifths of fat mass index, body mass index and waist circumference, with a progressive increase in the odds of hypertension. Fat mass index, body mass index and waist circumference all showed strong positive associations with insulin resistance.
  • The odds of reporting fair/poor health increased with body mass index, waist circumference and fat mass index levels. The odds of cardiovascular disease increased with fat mass index and body mass index levels.
  • With increasing body mass index, waist circumference, fat mass index and fat-free mass index, subjects were more likely to be taking musculoskeletal medication and to have diabetes
  • Body mass index, waist circumference and fat mass index showed a significant positive relation with mobility limitations. Increased body mass index and waist circumference and (to a lesser degree) fat mass index, were significantly associated with problems of unusual activities.

Prevalence and Odds Ratios with 95% CI for Disability According to the Fifths of Body Mass Index, Waist Circumference, Fat Mass Index and Fat-free Mass Index in a Cross-sectional Study of British Mean-aged 60 to 79 Years from 1998 to 2000

 

Characteristics According to Fifths

(Lowest to Highest One to Five)

Mobility Limitation

N=837 (20%)

Problems with Usual Activities

N=936 (23%)

Problems with Self Care

N=238 (6%)

  % Odds Ratio 95% CI % Odds Ratio 95% CI % Odds Ratio 95% CI
Body mass index (kg/m²)
1(14-23), N=846 16  1.00    21  1.00    1.00   
2(24-25), N=847 14  0.96  0.71, 1.30   20  0.96  0.74, 1.24   1.40  0.84, 2.35 
3(26), N=846 15  1.05  0.77, 1.42  18  0.86  0.66, 1.11  1.09  0.63, 1.87 
4(27-29), N=847 20  1.44  1.08, 1.92  24  1.20  0.93, 1.55  1.43  0.87, 2.37 
5(30-48), N=846 32  1.99  1.50, 2.64  31  1.32  1.03, 1.69  1.59  0.99, 2.57 
P trend <0.001    0.005    0.07   
Waist circumference (cm         

1(57-88) N=845 

15  1.00    20  1.00    1.00   

2(89-94) N=845 

15  1.12  0.82, 1.52  20  1.07  0.89, 1.39  1.47  0.86, 2.53 

3(95-98) N=845

17  1.20  0.89, 1.63  22  1.14  0.88, 1.47  1.79  1.06, 3.01 

4(99-104) N=845

20  1.35  1.00, 1.82   22  1.04  0.80, 1.35  1.48  0.88, 2.51 
5(105-149) N=845 31  1.95  1.47, 2.59  32  1.49  1.16, 1.91  1.61  0.98, 2.66 
P trend <0.001    0.005    0.13   
Fat mass index (kg         

1(57-88) N=822

16  1.00    20  1.00    1.00   
2(89-94) N=822 14  0.73  0.54, 1.00  19  0.93   0.71, 1.21 0.99  0.57, 1.70 
3(95-98) N=823 16  0.99  0.73, 1.34   20  0.96  0.74, 1.25  5 1.17  0.69, 1.98 

4(99-104) N=822

22  1.29  0.97, 1.74  25  1.16  0.90, 1.51  1.53  0.93, 2.52 
5(105-149) N=822 30  1.59  1.20, 2.12  30  1.24  0.96, 1.59  1.28  0.78, 2.09 
P trend  <0.001    0.02    0.11   
Fat-free mass index (kg)          

1(0.14-6.9) N=832 

20  1.00    24  1.00    1.00   
2(7-7.9) N=833 18  1.03  1.77, 1.37  23  1.04  0.81, 1.34  1.45  0.89, 2.35 

3(8-9.9) N=833

17  0.99  0.74, 1.33  21  0.99  0.76, 1.27  1.27  0.78, 2.07 

4(10-11.9) N=833

21  1.22  0.92, 1.62  22  1.01  0.78, 1.29  1.54  0.96, 2.47 

5(12-28.9) N=833

21  1.26  0.95, 1.67  24  1.11  0.87, 1.43  1.36  0.84, 2.20 
P trend  0.05    0.51    0.22   

Adjusted for age, smoking, alcohol intake, physical activity, social class and morbidity (CVD, cancer, diabetes and medication for respiratory disease or musculoskeletal disease).

Prevalence of Ill Health and Odds Ratios with 95% According to the Fifths of Body Mass Index, Waist Circumference, Fat Mass Index and Fat-free Mass Index in a Cross-sectional Study of British Mean Aged 60 to 79 Years from 1998 to 2000

Characteristics According to Fifths

(Lowest to Highest One to Five)

Fair/Poor Health

N=1,093

Cardiovascular Disease

N=962

Diabetes

N=555

  % Odds Ratio 95% CI % Odds Ratio 95% CI % Odds Ratio 95% CI
Body mass index (kg/m2)

1(14-23), N=846

24  1.00    20   1.00   1.00   

2(24-25), N=847

22  1.00  0.78, 1.29  21  1.05  0.82, 1.35  14  1.49  1.09, 2.04 

3(26), N=846

20  0.77  0.59, 1.00  22  1.13  0.88, 1.45  12  1.25  0.91, 1.72 

4(27-29), N=847

25  1.09  0.85, 1.40  22  1.10  0.86, 1.41  14  1.42  1.04, 1.94 

5(30-48), N=846

37  1.49  1.17, 1.90  28  1.45  1.14, 1.86  16  1.66  1.21, 2.26 
P trend <0.001    0.004    0.008   
Waist circumference (cm)          

1(57-88) N=845 

22  1.00    20 1.00   11  1.00   

2(89-94) N=845

21  0.98  0.76, 1.27  20  1.04  0.81, 1.34  12  1.07  0.79, 1.46 
3(95-98) N=845 21  0.92  0.71, 1.19  23  1.24  0.97, 1.59  13  1.23  0.91, 1.66 

4(99-104) N=845 

27  1.29  1.00, 1.65  23  1.23  0.96, 1.58  12  1.09  0.81, 1.49 
5(105-149) N=845 37  1.64  1.28, 2.09  27  1.27  0.99, 1.62  15  1.45  1.07, 1.96  
P trend  <0.001    0.03    0.02   
Fat mass index (kg)         

1(57-88) N=822 

20  1.00    18  1.00    12  1.00   
2(89-94) N=822 22  1.11  0.86, 1.45  21  1.14  0.88, 1.47  12  0.99  0.72, 1.34 

3(95-98) N=823 

23  1.12  0.86, 1.46  21  1.15  0.89, 1.49  12  1.05  0.77, 1.42 

4(99-104) N=822

26  1.24  0.96, 1.61  24  1.33  1.03, 1.17  13  1.00  0.74, 1.36 

5(105-149) N=822 

37  1.71  1.33, 2.21  28  1.58  1.23, 2.03  16  1.24  0.92, 1.68 
P trend  <0.001    <0.001    0.18   
Fat-free mass index (kg)          

1(0.14-6.9) N=832 

28  1.00    23  1.00    11  1.00   

2(7-7.9) N=833

25  1.01  0.79, 2.28  23  1.07  0.84, 1.37  12  1.16  0.85, 1.59 

3(8-9.9) N=833 

22  0.84  0.65, 1.08  21  0.96  0.75, 1.23  13  1.16  0.85, 1.59 

4(10-11.9) N=833 

26  1.01  0.79, 1.29  23  1.13  0.88, 1.43  13  1.25  0.92, 1.71 

5(12-28.9) N=833

26  1.00  0.79, 1.28  22  0.97  0.76, 1.24  15  1.44  1.07, 1.95 
P trend  0.97    0.98    0.02   
P trend2 0.04    0.25    0.011   

Adjusted for age, social class, smoking, alcohol intake and physical activity.

²Adjusted for the above in addition to waist circumference.

Prevalence of Ill Health and Odds Ratios with 95% According to the Fifths of Body Mass Index, Waist Circumference, Fat Mass Index and Fat-free Mass Index in a Cross-sectional Study of British Mean Aged 60 to 79 Years from n 1998 to 2000

Characteristics According to Fifths 

Cancer

N=252 

Respiratory Medication

N=487 

Musculoskeletal Medicine 
  Odds Ratio  95% CI  Odds Ratio  95% CI  Odds Ratio  95% CI 
Body mass index (kg/m2)          

1(14-23), N=846

1.00    14  1.00    1.00   

2(24-25), N=847 

0.77  0.51, 1.16  11  0.81  0.59, 1.09  11  1.51  1.08, 2.13 

3(26), N=845

0.78  0.52, 1.18  11  0.74  0.55, 1.01  11  1.54  1.09, 2.17 

4(27-29), N=847 

0.94  0.63, 1.39  0.61  0.45, 0.85  17  2.47  1.79, 3.41 
5(30-48), N=846 0.89  0.59, 1.34  12  0.67  0.49, 0.92  15  1.92  1.92, 2.69 
P trend  0.91    0.003    <0.001   
Waist circumference (cm)          
1(57-88) N=845 1.00    13  1.00    1.00   
2(89-94) N=845 0.84  0.55, 1.29  10  0.77  0.57, 1.06  1.06  0.57, 1.49 

3(95-98) N=845

1.12  0.74, 1.68  0.57  0.40, 0.79  13  1.57  1.14, 2.17 

4(99-104) N=845

0.00  0.65, 1.51  12  0.91  0.67, 1.23  15  1.65  1.19, 2.27 

5(105-149) N=845

1.08  0.71, 1.64  14  0.89  0.66, 1.21  16  1.83  1.33, 2.52 
P trend 0.51    0.89    <0.001   
Fat mass index (kg)          

1(57-88) N=822

1.00    12  1.00    11  1.00   

2(89-94) N=822 

0.79  0.72, 1.34  11  0.93  0.67, 1.28  10  0.89  0.64, 1.25 

3(95-98) N=823

1.05  0.69, 1.57  11  0.88  0.64, 1.22  12  1.09  0.79, 1.51 

4(99-104) N=822 

0.86  0.56, 1.32 10  0.77  0.55, 1.07  12   1.30 -0.95, 1.79 

5(105-149) N=822

1.19  0.79, 1.79  14  0.98  0.72, 1.35  17  1.56  1.15, 2.13 
P trend 0.35    0.59    <0.001   
Fat-free mass index (kg)          

1(0.14-6.9) N=832 

1.00    17  1.00    11  1.00   

2(7-7.9) N=833

0.69  0.47, 1.04  12  0.71  0.53, 0.95  12  1.04  0.76, 1.43 

3(8-9.9) N=833

0.74  0.50, 1.09  11  0.62  0.46, 0.83  11  1.06  0.77, 1.46 

4(10-11.9) N=833

0.60  0.39, 0.91  0.52  0.38, 0.71  14  1.23  0.90, 1.67 

5(12-28.9) N=833

0.62  0.42, 0.94  0.45  0.33, 0.62  16  1.44  1.07, 1.95 
P trend  0.02    <0.001    0.008   
P trend2  0.006    <0.001    0.16   

Adjusted for age, social class, smoking, alcohol intake and physical activity.

²Adjusted for the above in addition to waist circumference.

Other Findings

Body mass index, waist circumference and fat mass index had a strong positive correlation with each other. With increasing age, the fat-free mass index, fat mass index, body mass index and waist circumference decreased significantly.

Author Conclusion:

Fat mass index, body mass index and waist circumference had similar patterns of relations to ill health and physical disability. The results suggest that increasing fat mass, body mass index and waist circumference are associated with physical disability, ill health (cardiovascular disease, diabetes, taking musculoskeletal medication and reporting fair/poor health) and metabolic risk factors such as low HDL-Cholesterol and insulin resistance. Body fatness was observed to be associated with morbidity and physical disability, while fat-free mass was related to respiratory function and cancer.

Funding Source:
Government: Department of Health
Not-for-profit
British Heart Foundation
Reviewer Comments:

Some of the data collected, including ill health, was self-reported and is therefore subject to reporting error.

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) N/A
  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? N/A
  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? N/A
  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? N/A
  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? ???
  7.5. Was the measurement of effect at an appropriate level of precision? ???
  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