[gmane]

Here you go: https://pubmed.ncbi.nlm.nih.gov/34079693/

Edit: You can also click on his name in the original post (or the link above) and see all the papers in pubmed authored by him.

Edit 2: These two papers:

Veugelers PJ, Ekwaru JP. A statistical error in the estimation of the recommended dietary allowance for vitamin D. Nutrients. 2014;6(10):4472–4475. - PMC - PubMed Veugelers PJ, Ekwaru JP. A statistical error in the estimation of the recommended dietary allowance for vitamin D. Nutrients. 2014;6(10):4472–4475. - PMC - PubMed

and

Heaney R, Garland C, Baggerly C, French C, Gorham E. Letter to Veugelers, P.J. and Ekwaru, J.P., A statistical error in the estimation of the recommended dietary allowance for vitamin D. Nutrients 2014, 6, 4472-4475; doi:10.3390/nu6104472. Nutrients. 2015;7(3):1688–1690. - PMC - PubMed

[its-summertime]

From what I can tell, the "ecological integrative approach" is referring to the approach used in the research of that paper, not on how Vitamin D acts in relation to COVID

> Following an ecological integrative approach, we examined the associations between published representative and standardized European population vitamin D data and the Worldometer COVID-19 data at two completely different time points of the first wave of this pandemic.

and

> Thus, a major limitation of our ecological approach is that we had to rely on published - but perhaps not always completely representative - data on the vitamin D status of the populations in Europe.

[gmane]

Right, I was criticizing the approach. Edit: specifically the fact that the paper has no discussion of how the meta-analysis data was prepared, processed, or how they made sure it was complete.

[its-summertime]

Of the papers, The second one is a response to the first one. Citing both parts of a discussion seems really normal.

[gmane]

I would agree with you if this paper was citing... more papers. Since there are so few and one of the citations is a concurrence with the paper with actual data work, then it harms this paper.

Either the author didn't do a literature review before publishing, isn't well versed in the field, or chose not to cite works which may not agree with their results. Neither of which reflects well on the author.