DLM: Physical Activity (2001)
Citation:
Blair SN. Influences of cardiorespiratory fitness and other precursors on cardiovascular disease and all-cause mortality in men and women. Aerobics center longitudinal study. JAMA. 1996;276:205-210
Worksheet created prior to Spring 2004 using earlier ADA research analysis template.
Study Design:
nonrandomized trial with concurrent or historical controlsPopulation-Based Descriptive Study
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
POSITIVE:Research Purpose:
Inclusion Criteria:
Complete data from exam >85% of age-predicted maximal heart on treadmill test
Exclusion Criteria:
Description of Study Protocol:
25,341 men 7,080 women ages 20-88 years who completed baseline preventive medical exam between Dec 6, 1970 and Dec 31, 1989
Data Collection Summary:
Clinical exam: Personal an family history Physical exam Questionnaire on demographics and health habits Anthropometry Resting ECG Blood pressure Blood chemistries Standardized maximal exercise test on treadmill Fitness categories: Low fit, moderately fit and high fit based on results of treadmill Outcome measures: CVD and all-cause mortality
Description of Actual Data Sample:
601 deaths during 211,996 man-years of follow-up (mean years of follow-up 8.4) 89 deaths during 52,982 woman-years of follow-up (mean years of follow-up 7.5) Well defined fitness levels using maximal heart rate during treadmill test. Subjects were well educated. Differences between survivors and descendents: descendents ~10 years older, and more were smokers, and had higher BP.
Summary of Results:
independent predictors of mortality among men with adjusted RR were: Low fitness: RR 1.52, (95% CI, 1.28-1.82) Smoking: RR 1.65, (95% CI, 1.39-1.97) Abnormal ECG RR 1.64, (95% CI, 1.34-2.01) Chronic illness RR 1.63 (5% CI, 1.37-1.95) Serum cholesterol RR 1.34 (95% CI, 1.13-1.59) systolic blood pressure RR 1.34 (95% CI, 1.13-1.59) The only statistically significant independent predictors of mortality in women were: Low fitness: RR 2.10 (95% CI, 1.36-3.21 Smoking: RR 1.99 (95% CI, 1.25-3.17) Low fitness is an important precursor of mortality. The protective effect of fitness held for smokers and nonsmokers, those with and without cholesterol or blood pressure, and unhealthy and healthy persons. Moderate fitness seems to protect against the influence of these other predictors of mortality. Physicians should encourage sedentary patients to become physically active and thereby reduce the risk of premature mortality.
Author Conclusion:
Well defined fitness levels using maximal heart rate during treadmill test. Subjects were well educated. Differences between survivors and descendents: descendents ~10 years older, and more were smokers, and had higher BP. MINIMUM REQUIREMENTS TO VIEW THIS WEBSITE Netscape 4.x or Internet Explorer 4.x 14" SVGA Monitor set to 24bit Color 486/33 Mhz or faster processor 28.8K Modem
Funding Source:
| Government: | NIA |
Reviewer Comments:
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Quality Criteria Checklist: Primary Research
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| 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? | ??? | |
| 2.2. | Were criteria applied equally to all study groups? | ??? | |
| 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.) | ??? | |
| 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? | ??? | |
| 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.) | ??? | |
| 3.6. | If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? | ??? | |
| 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? | Yes | |
| 5. | Was blinding used to prevent introduction of bias? | ??? | |
| 5.1. | In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? | ??? | |
| 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.) | ??? | |
| 5.3. | In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? | ??? | |
| 5.4. | In case control study, was case definition explicit and case ascertainment not influenced by exposure status? | ??? | |
| 5.5. | In diagnostic study, were test results blinded to patient history and other test results? | ??? | |
| 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? | Yes | |
| 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? | Yes | |
| 6.6. | Were extra or unplanned treatments described? | Yes | |
| 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? | Yes | |
| 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? | ??? | |
| 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? | ??? | |
| 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? | ??? | |
| 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 | |