A lower T/S ratio is associated with advanced age (had to dig hard to find that one- check out page 9 of this paper: <a href="https://www.rug.nl/research/genetics/students/internships/anastassiablanter_bsc_thesis.pdf" rel="nofollow">https://www.rug.nl/research/genetics/students/internships/an...</a>). In other words, high T/S = good.<p>As far as statistical correlation, the p-value of 0.02 (lower, and further away from 0.05, is better) is pretty strong.<p>Where this article fails to convince me to start waving red meat in the faces of all the vegs I know is the limited sample size of a couple dozen people. Maybe there's some protective factor in red meat, or maybe their small sample size just overrepresented young carnivores and old vegetarians.
<i>Physical activity... was not related to telomere status.</i><p>Other studies say the opposite:<p><a href="https://www.ucsf.edu/news/2013/09/108886/lifestyle-changes-may-lengthen-telomeres-measure-cell-aging" rel="nofollow">https://www.ucsf.edu/news/2013/09/108886/lifestyle-changes-m...</a><p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2581416/" rel="nofollow">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2581416/</a><p><a href="http://www.edinformatics.com/news/exercise_and_aging.htm" rel="nofollow">http://www.edinformatics.com/news/exercise_and_aging.htm</a>
Note: as an observational study, this is not the final word on the subject. A p of 0.02 being the strongest evidence may also be the result of p-hacking. More research is needed. Causal studies should be performed to confirm.<p>Further, the sample size is exceptionally low (n=28).
I am extremely skeptical about the statistical analysis here.<p>It sounds like they tested nine food types, eight beverages and then even tried out different types of comparisons for each food/beverage. And the best p-value they observed was p=0.02:<p>"Among nine food types (cereal, fruits, vegetables, diary, red meat, poultry, fish, sweets and salty snacks) and eight beverages (juices, coffee, tea, mineral water, alcoholic- and sweetened carbonated beverages) only intake of red meat was related to T/S ratio. Individuals with increased consumption of red meat have had higher T/S ratio and the strongest significant differences were observed between consumer groups: “never” and “1–2 daily” (p = 0.02)."<p>Nowhere in their methods do they mention adjusting for multiple testing. If we do that using the standard Bonferroni approach, the p-value would have to be multiplied by a factor of at least 17 x 2 to account for the number of options that they tried. So the adjusted p-value would be 0.02 x 17 x 2 = 0.68 and thus far from statistical significance.<p>In other words, this seems to be a real-life example of this: <a href="https://xkcd.com/882/" rel="nofollow">https://xkcd.com/882/</a><p>Maybe I missed something, but if this is really the case then it's embarrassing that this made it through peer review.
Can someone rephrase the conclusion and results? I read through it multiple times but can't figure out if a higher T/S ratio is a good thing or not.
> Many factors can modify telomere length, among them are: nutrition and smoking habits, physical activities and socioeconomic status measured by education level.<p>That seems especially poorly worded.
All speculative but... I've assumed since hearing about telomeres that they were a failsafe against cancer; X cell divisions allowed, then apoptosis. If so, maybe shorter telomeres are something you can afford if you have the energy (etc) to engage in a lot of DNA maintenance.
This whole study strikes me as rather weak, I wouldn't give assign too much importance to the results.<p>As mentioned below, the number of participants was rather low (though that is not uncommon in the life sciences and medicine). Also, the statistics appear to be sloppy, or at any rate not sufficiently documented to be verifiable. Thirdly, they tried to investigate too many things at once ("diet, smoking habit, physical activity and education"). And lastly, they base their whole study on the supposed link between telomere length and human longevity - a somewhat obsolete hypothesis.
<p><pre><code> Study included 28 subjects (seven male and
21 female, age 18–65 years) completed the
questionnaire and gave blood for testing
peripheral blood mononuclear cells telomere
length.
</code></pre>
So, in other words anecdotal evidence, and an interesting sidebar, but really just some notes about one type of tissue sample across 28 people.<p>If it were any other look at any other tissue sample, what would you say about the sample size and the reliability of voluntary answers from subjects based on memory?
Funny how a shitty study about how butter is good for you funded by the meat and dairy industry is lavished with praise, but any study that says your bad habits are bad for you is met with "oh I am unconvinced. Probably p-hacked. Too small a sample size."
Honest, slightly OT question: what motivates researchers to perform and publish studies with low N? Can it have a positive or negative impact on their career?
> Study included 28 subjects<p>Well beside the other process issues, 28 is a farcically small set to draw any conclusions, even future hypotheses from.<p>Scale that to 2800 and we can talk.