DLM: Energy Balance, Obesity and Anthropometric Measurement (2005)

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

To investigate the associations of abdominal obesity and overall obesity with the risk of acute coronary events in Finnish men.

Inclusion Criteria:
  • Participants in the Kuopio Ischaemic Heart Disease Risk Factor Study   
  • Male
  • Middle-aged.
Exclusion Criteria:
  • Prevalent cardiovascular disease, including coronary heart disease, cardiac insufficiency, claudication, stroke, cardiomyopathy, arrhythmias or other cardiovascular diseases.
  • Cancer.

 

 

Description of Study Protocol:

Recruitment: not described

Randomization: No

Blinding: No

Intervention:

  • The Kuopio Ischaemic Heart Disease Risk Factor Study is an ongoing population based study designed to investigate risk factors for atherosclerotic cardiovascular diseases and other outcomes in middle-aged men from eastern Finland, a population with a high incidence of coronary heart disease.
  • Subjects were selected randomly and were stratified and balanced for age, who were 42, 48, 54 or 60 years old at baseline examination.
  • The baseline exams were conducted between March 1984 and December 1989.

Statistical Analysis

  • Associations between continuous variables were examined by computing Pearson's correlation coefficients.
  • Associations between waist to hip ratio (WHR), waist circumference and BMI with the risk of acute coronary events were analyzed using Cox proportional hazards models.
    • Cox regression analysis adjusted for confounding factors of age, years of examination, family history of coronary heart disease, adulthood socioeconomic status, cigarette smoking, and maximal oxygen uptake.
    • Hazard ratios for the risk of acute coronary events: age, years of examination, family history of coronary heart disease, adulthood socioeconomic status, cigarette smoking, and maximal oxygen uptake, and obesity as measured by BMI, waist circumference and WHR.
  • All tests of significanced were two-sided.
  • 95% Confidence Interval.
Data Collection Summary:

 Timing of Measurements

  • Baseline measurements:
    • Anthropometric measurements
      • Height
      • Weight
      • Waist circumference
      • Hip circumference
    • Medical exam, medical history, medications
    • Blood pressure
    • Cigarette smoking
    • Maximal oxygen uptake
    • Adult socioeconomic status
    • Blood sample
      • glucose
      • serum lipids
      • insulin
      • plasma fibrinogen
      • uric acid
  • Coronary event determination.

 

Dependent Variables:

  • Non-fatal and fatal acute coronary events (first event=outcome in case of multiple events):
    • MI
    • Prolonged chest pain episodes.
  • Data collection and diagnostic classification through 1992 by WHO Monitoring of Trends and Determinants in Cardiovascular Disease Project. From 1993, data obtained from a national hospital discharge and death certificate register using ICD-9 or ICD-10 codes by a single internist.

Independent Variables:

  • Overall obesity: measured by BMI
  • Abdominal obesity (increased WHR or increased waist circumference):
    • WHR
      • Waist circumference was calculated as an average of one measurement taken after inspiration and one taken after expiration at the level of mid-distance between the bottom of the rib cage and the top of the iliac crest.
      • Hip circumference was measured at the level of the trochanter major.
    • Waist circumference.

Control Variables:

  • Age
  • Years of examination
  • Family history of coronary heart disease
  • Adulthood socioeconomic status
  • Cigarette smoking
  • Maximal oxygen uptake
  • Systolic and diastolic blood pressure
  • Diabetes
  • Fasting serum insulin
  • Serum HDL 2 cholesterol
  • Apolipoprotein B
  • Triglycerides
  • Plasma fibrinogen
  • Serum uric acid.
Description of Actual Data Sample:

Initial N: 1405 eligible (estimated from numbers in article)

Attrition (final N): 1346 (complete data for measures of obesity)

Age [mean (SD, range)]: 51.6 years (5.9, 42.0-61.3)

Ethnicity: not described

Other relevant demographics: not described

Anthropometrics [mean (SD, range)]:

  • BMI 26.7 (3.5, 19.0-48.6)
  • WHR 0.94 (0.06, 0.71-1.51)
  • Waist circumference  90.4 cm (9.8, 62.0-145.0).

Location: Kuopia and neighboring rural communities in eastern Finland

Summary of Results:

Coronary Events:

  • Mean (range) follow up time: 10.6 years (0.1 to 13.8)
  • 123 events
    • 71 definite MI
    • 37 probable MI
    • 15 acute chest pain episodes.

Obesity

  • WHR, waist circumference and BMI as continuous variables were directly associated with risk of coronary heart events adjusted for confounding factors. Additional adjustment for other covariates (blood pressure, diabetes, etc.) weakened these associations, but the risk associated with WHR remained statistically significant after these adjustments.
  • BMI had a less consistent association with the risk of acute coronary events than WHR or waist circumference.
  • Men with a high WHR alone had a higher risk of coronary events than men with a high BMI alone.
  • Combination of high WHR and reduced maximal oxygen uptake was associated with a higher risk than either of these conditions alone.
  • High WHR and cigarette smoking combined were related to a higher risk than either of these conditions alone.

 Waist to hip ratio

%

RR

P value

<0.91

1.0

 

0.91-0.94

2.69

0.004

0.95-0.98

2.73

0.003

0.98

2.91

0.002

Waist circumference

Cm

RR

P value

<83.5

1.0

 

84.0-89.5

1.38

0.283

90-95.5

1.89

0.023

>95.5

2.02

0.012

BMI

Kg/m2

RR

P value

<24.4

1.0

 

24.4-26.3

1.25

0.436

26.4-28.7

2.09

0.006

>28.7

1.52

0.137

Author Conclusion:

Abdominal obesity is an independent risk factor for coronary heart disease in middle-aged men and even more important than overall obesity. Abdominal obesity appears to provide additional information beyond overall obesity in predicting coronary heart disease. Since the effect of abdominal obesity was strongest in smoking and unfit men, the strategy for lifestyle modifications to prevent coronary heart disease should address these issues jointly.

Funding Source:
Government: Academy of Finland, Ministry of Education of Finland, NHLBI
Not-for-profit
0
Foundation associated with industry:
Reviewer Comments:

Strengths:

  • There were adjustments for variables.
  • Credible use of statistics.

Generalizability/Weaknesses: 

  • No data on ethnic composition of sample
  • Assumption that WHR, waist circumference and BMI at baseline did not change over time.
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) Yes
  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) Yes
 
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? ???
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.) No
  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.) 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? Yes
  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.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? Yes
  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? 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)? Yes
  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? No
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