The causal claim is itself a (stronger form of) correlation,
so how is that a contradiction? They claim:
1. To demonstrate a causal pathway
2. There was not a previous correlative claim that this merely strengthened
Also, given it's in an open access journal, you can trivially verify from the source rather than rely on a press release.
"we describe a pathway wherein sleep fragmentation raises inflammatory-related white blood cell counts (neutrophils and monocytes), thereby increasing atherosclerosis severity" [https://journals.plos.org/plosbiology/article?id=10.1371/jou...]
> "A first limitation is that our analyses were constrained by the use of cross-sectional data, which precludes definitive assessment of directionality of associations. For example, it could be that cardiovascular disease (or associated treatments) may also drive sleep fragmentation in addition to, or rather than, the other way around."
1. To demonstrate a causal pathway
2. There was not a previous correlative claim that this merely strengthened
Also, given it's in an open access journal, you can trivially verify from the source rather than rely on a press release. "we describe a pathway wherein sleep fragmentation raises inflammatory-related white blood cell counts (neutrophils and monocytes), thereby increasing atherosclerosis severity" [https://journals.plos.org/plosbiology/article?id=10.1371/jou...]