http://www.bmj.com/content/353/bmj.i1246
BMJ 2016; 353 doi: http://dx.doi.org/10.1136/bmj.i1246 (Published 12 April 2016) Cite this as: BMJ 2016;353:i1246
- Christopher E Ramsden, medical investigator1 2,
- Daisy Zamora, epidemiologist3,
- Sharon Majchrzak-Hong, research chemist1,
- Keturah R Faurot, epidemiologist2,
- Steven K Broste, retired statistician4,
- Robert P Frantz, professor of medicine5,
- John M Davis, professor of psychiatry3 6,
- Amit Ringel, guest researcher1,
- Chirayath M Suchindran, senior biostatistician7,
- Joseph R Hibbeln, senior clinical investigator1
- Correspondence to: C E Ramsden Chris.Ramsden@nih.gov
- Accepted 19 February 2016
Abstract
Objective To
examine the traditional diet-heart hypothesis through recovery and
analysis of previously unpublished data from the Minnesota Coronary
Experiment (MCE) and to put findings in the context of existing
diet-heart randomized controlled trials through a systematic review and
meta-analysis.
Design The MCE (1968-73)
is a double blind randomized controlled trial designed to test whether
replacement of saturated fat with vegetable oil rich in linoleic acid
reduces coronary heart disease and death by lowering serum cholesterol.
Recovered MCE unpublished documents and raw data were analyzed according
to hypotheses prespecified by original investigators. Further, a
systematic review and meta-analyses of randomized controlled trials that
lowered serum cholesterol by providing vegetable oil rich in linoleic
acid in place of saturated fat without confounding by concomitant
interventions was conducted.
Setting One nursing home and six state mental hospitals in Minnesota, United States.
Participants Unpublished
documents with completed analyses for the randomized cohort of 9423
women and men aged 20-97; longitudinal data on serum cholesterol for the
2355 participants exposed to the study diets for a year or more; 149
completed autopsy files.
Interventions Serum
cholesterol lowering diet that replaced saturated fat with linoleic
acid (from corn oil and corn oil polyunsaturated margarine). Control
diet was high in saturated fat from animal fats, common margarines, and
shortenings.
Main outcome measures Death
from all causes; association between changes in serum cholesterol and
death; and coronary atherosclerosis and myocardial infarcts detected at
autopsy.
Results The intervention group had significant reduction in serum cholesterol compared with controls (mean change from baseline −13.8% v
−1.0%; P<0.001). Kaplan Meier graphs showed no mortality benefit for
the intervention group in the full randomized cohort or for any
prespecified subgroup. There was a 22% higher risk of death for each 30
mg/dL (0.78 mmol/L) reduction in serum cholesterol in covariate adjusted
Cox regression models (hazard ratio 1.22, 95% confidence interval 1.14
to 1.32; P<0.001). There was no evidence of benefit in the
intervention group for coronary atherosclerosis or myocardial infarcts.
Systematic review identified five randomized controlled trials for
inclusion (n=10 808). In meta-analyses, these cholesterol lowering
interventions showed no evidence of benefit on mortality from coronary
heart disease (1.13, 0.83 to 1.54) or all cause mortality (1.07, 0.90 to
1.27).
Conclusions Available evidence
from randomized controlled trials shows that replacement of saturated
fat in the diet with linoleic acid effectively lowers serum cholesterol
but does not support the hypothesis that this translates to a lower risk
of death from coronary heart disease or all causes. Findings from the
Minnesota Coronary Experiment add to growing evidence that incomplete
publication has contributed to overestimation of the benefits of
replacing saturated fat with vegetable oils rich in linoleic acid.
Complete article at link if you want to try wading thru it.
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