The authors of a recent paper in the European Journal of Preventive Cardiology on nut intake and the risk of high blood pressure and diabetes have pulled their article from publication for an undisclosed conflict of interest.
Now, you wouldn’t know this unless you were willing to pony up the $32 to read the notice, which is behind a pay wall — something that drives us, well, nuts. But here it is:
At the request of the authors ‘Nut consumption with risk of hypertension and type 2 diabetes mellitus: A meta-analysis of prospective cohort studies’
European Journal of Preventive Cardiology, first published on August 8, 2013 as DOI: 10.1177/2047487313501120 has been retracted due to a conflict of interest arising at a late stage. The authors apologise to the journal and to readers.
In the original paper, the authors, from the department of cardiology at Xinhua Hospital in Shanghai, report that:
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Conflict of interest
The authors declare that there are no conflicts of interest.
Here’s the abstract:
Background: The consumption of nuts was reported to be associated with risk of hypertension and type 2 diabetes mellitus (T2DM), but the results were inconclusive. The aim of this study was to systematically examine longitudinal studies investigating nut intake in relation to risk of hypertension and T2DM.
Methods: A systematic search of the PubMed and EMBASE databases to 31 March 2013 was performed. Reference lists of retrieved articles were also screened. Summary relative risks (SRRs) and 95% confidence intervals (CIs) were calculated using a random-effects model. Q and I2 statistics were used to examine between-study heterogeneity.
Results: A total of nine prospective cohort studies (three for hypertension and six for T2DM) were identified. Using random effects models, we found that based on the highest vs lowest analysis, nut consumption were inversely associated with risk of hypertension (SRR = 0.84, 95% CI: 0.76–0.93, pheterogeneity = 0.831, I2 = 0%). Dose-response analyses indicated that nut consumption at more than two servings/wk, but not ne serving/wk, had a preventative role in the hypertension. In addition, nut consumption was not associated with risk of T2DM (SRRs = 0.98, 95% CI: 0.84–1.15; pheterogeneity = 0.008, I2 = 67.7%) on the basis of the highest vs lowest analysis. This null association was also shown in the dose-response analysis.
Conclusion: In our meta-analysis, nut consumption is found to be inversely associated with hypertension risk but is not associated with the risk of T2DM.
Not surprisingly, the paper caught the attention of the California Walnut Commission.
Diederick Grobbee, editor-in-chief of the EJPC, told us that he doesn’t know the full extent of the conflict of interest:
The conflict of interest was reported to us by one of the authors. We were unable to find out the details apart from being a case of “personal rivalry”, and immediately decided to withdraw.
(Grobbee also said keeping the retraction notice behind a pay wall was inadvertent and would be fixed.)