Talk:Green tea

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Mortality risk[edit]

Is this section ok from the WP:MEDRS perspective? If so, I´ll consider buying some. The sources are [1] and [2]. Gråbergs Gråa Sång (talk) 09:06, 17 March 2017 (UTC)

Mortality risk

Daily consumption of green tea is significantly associated with a lower risk of death from any cause; an increase of one cup of green tea per day is linked with a 4% lower risk of death from any cause.(ref name="Tang2015"/) A separate analysis found an increase of three cups of green tea per day was associated with a lower risk of death from any cause.(ref name="Zhang2015"/)

The citations are both high-quality MEDLINE-indexed secondary sources (in this case systematic reviews/meta-analyses, granted of observational studies but at least they're prospective) and both of them are from journals with respectable impact factors. One reason to take the information with a grain of salt is that both studies came out of China and there have been concerns with study data being falsified there but otherwise these references are certainly MEDRS-compliant. TylerDurden8823 (talk) 13:27, 17 March 2017 (UTC)
The content should be tweaked to note that these are correlations only. There are boatloads of potential confounders (like other lifestyle choices) with studies like this. Will make those tweaks. Jytdog (talk) 09:33, 18 March 2017 (UTC)
True, the RRs had high heterogeneity so the confidence in these estimates is still shaky but stating that would be our interpretation of the cited SRs and thus WP:OR. We need secondary sources to interpret it and reflect what they say. I agree there are significant limitations to the available data used in these studies. These limitations come with the nature of observational evidence (though they're marginally better for using prospective cohorts out of observational evidence). Of course, SRs/MAs of RCTs would be preferable but there aren't any that address this specific aspect of green tea consumption yet. I check PubMed SRs/MAs now and again to see if anything new has popped up but not yet. TylerDurden8823 (talk) 02:18, 19 March 2017 (UTC)

The abstract for the second ref (Zhang 2015) does not say green tea, only "tea". Does anyone have access to the complete PDF? If the article is about tea it cannot be used as a reference for this entry. Green tea and tea have major differences in polyphenol types and total content. David notMD (talk) 00:50, 25 March 2017 (UTC)

Yes, you're right that the abstract does not explicitly specify green tea but it does within the article. I have access to the whole PDF (you can email me if you would like a copy) but here is the pertinent quote from the article verbatim: "Similarly, we found that a 3 cups per day increase in the consumption of tea was associated with a reduced risk of cardiac death if the participants were women, Asian, European, or consumption of green tea; an increase of 3 cups of tea per day was associated with a reduced risk of stroke if the participants were men, Asian, or consumption of green tea; an increment in tea con- sumption by 3 cups per day was associated with a reduced risk of total mortality if the participants were women, Asian, or consumption of green tea. (my bold)"
Thanks for sharing this, TylerDurden8823. So this is our source for "A separate analysis found an increase of three cups of green tea per day was associated with a lower risk of death from any cause." It seems to say that "total mortality" concerns people who are asian (and? or?) women, so perhaps we should be more specific too. Also, tea/green tea seems to have the same effect here, so we should change the text to "three cups of tea or green tea", otherwise we imply that green tea has this effect but tea doesn´t. Gråbergs Gråa Sång (talk) 09:46, 29 March 2017 (UTC)
We should specify green tea. Many studies have found that green tea and other teas (e.g., black tea) do not have the same effect when looking at certain outcomes and do have similar effects when looking at others (so it depends on what is being discussed). In this case, I think we should be specific. I have no objection to specifying that the separate analysis found this association in Asian people and women. TylerDurden8823 (talk) 13:59, 29 March 2017 (UTC)
Not in that sentence with that source we shouldn´t. The source (at least the part quoted) treats green tea as more of an afterthought. Gråbergs Gråa Sång (talk) 19:07, 29 March 2017 (UTC)
I don't know that I agree with that assessment. That's mere speculation on your part. We don't know that the authors were thinking that so it's merely interpretation which falls afoul of WP:OR. Also, "from any cause" refers to all-cause mortality (please note this is a very frequently used term in the medical literature). TylerDurden8823 (talk) 00:26, 30 March 2017 (UTC)
"Afterthought" might be a sloppy choice of words, how about "not more prominent than" (in this context). If "from any cause" is the usual term that´s ok, of course. My thinking was that to a lay-person such as myself it can (but probably won´t) be read as including things like murder and lightningstrikes, this article is not medical literature. Gråbergs Gråa Sång (talk) 06:47, 30 March 2017 (UTC)
The article in its entirety is not but the section in question is about its health-related properties. All-cause mortality is a very common and well-accepted synonym for total mortality. I think your rephrasing/revised word choice here on the talk page is more consistent with how I would read it. Of course, further study will be required before firm conclusions about green tea consumption and total/all-cause mortality can be reached. TylerDurden8823 (talk) 06:44, 1 April 2017 (UTC)