|Nutrition Evidence Library|
Tucker KL, Hallfrisch J, Qiao N, Muller D, Andres R, Fleg JL; Baltimore Longitudinal Study of Aging. The combination of high fruit and vegetable and low saturated fat intakes is more protective against mortality in aging men than is either alone: the Baltimore Longitudinal Study of Aging. J Nutr. 2005 Mar;135(3):556-61.
PubMed ID: 15735093
Prospective Cohort Study
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Research Design and Implementation Rating:
POSITIVE: See Research Design and Implementation Criteria Checklist below.
To examine associations between habitual fruit and vegetable intake and saturated fat intake, separately and in combination, and subsequent coronary heart disease and total mortality among men in the Baltimore Longitudinal Study of Aging (BLSA).
Men in the Baltimore Longitudinal Study of Aging (BLSA).
Description of Study Protocol:
The BLSA began in 1958 and was designed to study normal human aging and precursors to disease and death. The current analysis includes a subset of 501 BLSA participants that met the inclusion criteria.
Design: Prospective Cohort Study
Men recruited for this prospective cohort completed a biennial visit which included a 7 day diet record. BLSA participants were trained to record their food intake by dietitians during their examination visit and ambiguous or incomplete records were clarified by telephone interview. Vital status was followed for all participants and cause of death was determined by death certificate, hospital and physician records and autopsy data as available.
Blinding used (if applicable): No blinding was used.
Intervention (if applicable): No intervention was initiated.
Data Collection Summary:
Timing of Measurements
Dietary data were collected by 7-day diet record during 4 time periods: 1961-1965; 1968-1975; 1984-1991 and 1993-present time. Participants completed diet records at biennial visits. In this specific analysis, BLSA participants completed records for 4-49 days (mean = 19 days) at 1-7 visits over a mean follow-up of 18 years. Dietary records collected <2 years before death or subsequent development of clinical CHD were excluded due to the possibility diet may be affected by major illness.
Description of Actual Data Sample:
Initial N: 501 men
Attrition (final N): All subjects included in the final analysis
Age: Born before 1929 and <80 years of age at the time of first diet record
Ethnicity: Not reported
Other relevant demographics: Demographics not reported in this paper but the authors did note that participants in the BLSA were not a random sample and are predominantly white men of relatively high socioeconomic status
Anthropometrics Significant differences were observed at baseline between survivors and CHD deaths in age at baseline (participants who died of CHD were slightly older at baseline) and smoking status.
Location: Baltimore, Maryland, United States
Summary of Results:
In conclusion, the results of this study support earlier observations that dietary intakes low in saturated fat or high in fruits and vegetables each offer protection against CHD mortality. In addition, however, our data suggest that the combination of both high fruits and vegetables with relatively low saturated fat intake offers greater protection against both total and CHD mortality than either practice alone.
Limitations noted by the authors:
While the authors noted this limitation in their discussion of findings, it is important to note that this cohort was made up of only men and little demographic information was provided in this particular paper (although it may have been published elsewhere). Therefore, it is difficult to extrapolate the findings of this cohort study to the population as a whole.
It is unclear in reading the paper whether or not the investigators were blinded to outcome when conducting biennial visits with the participants, including collecting a diet history.
Copyright American Dietetic Association (ADA).