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Comment by mettamage | Hacker News Reader

Mice study, should be in title?

Although mice are mentioned in the abstract, it seems like they tested mice and humans, and put both sets of results in one paper:

"In both mice and human males, increased appetite is correlated with elevated levels of circulating ghrelin."

Oh, whoops, read too fast, my bad.

No, they also have human participants:

> To further explore the difference between the response of men and women to solar exposure, we asked volunteers (n = 5 men and n = 5 women; age 18–55 years) to expose, for about 25 min, to the sun on a bright sunny midday (2,000 mJ/cm2 UVB). [...] Our data demonstrate that, while both sexes increase their response to environmental cues and decrease their extracellular vesicle pathways, in terms of the immune system and metabolism, men and women react in the distinct manner

Hmm; n=5? Is that enough? Was this study so difficult to perform with higher n? (Didn’t read beyond the abstract)

That was only the experimental part of the study, which they did to explore what had been suggested by observational results[0] on a much larger group:

> A meta-analysis of several research studies has found differing results for the influence of seasonality on food intake[23]. We, therefore, analyzed data from a 3-year national nutrition survey of approximately 3,000 people. Using a generalized linear model adjusted for age, we found a significant interaction (P <0.001) between sex and season, revealing that men are markedly affected by solar radiation and its seasonal fluctuation compared to women (Fig. [1a]). Additionally, we averaged the monthly direct solar radiation data (KJ/m2) (Fig. [1a]) and found that men significantly increase energy consumption during the summer (March to September) as compared to winter (October to February) (2,188 Kcal versus 1,875 Kcal, respectively; p <0.001), while energy consumption in women remains the same (1,475 Kcal versus 1,507 Kcal, respectively; p = 0.79) (Fig. [1b] and Extended Data Fig. [1a]). Notably, since we found a significant increase in nutrients including: carbohydrates, proteins, fat, sodium, omega-3, zinc and iron in men during the summer (Extended Data Fig. [1a]), it is possible that the increase in men’s energy intake is due to an increase in appetite-stimulating nutrients such as sodium.

[0] https://www.nature.com/articles/s42255-022-00587-9#Sec2

[23] https://www.nature.com/articles/s42255-022-00587-9#ref-CR23

[1a, 1b] https://www.nature.com/articles/s42255-022-00587-9#Fig1

The conclusions drawn from that 3-year longitudinal nutrition survey are questionable. There does not appear to be any attempt to correct for seasonal energy expenditure changes. Ideally, you'd like to see some questions regarding activity level by season as well as energy intake. It's a perfectly reasonable alternative hypothesis that men are eating more in the sunnier seasons because they're doing more outdoor work. It's also possible the people answering these surveys are not accurately weighing and logging their meals, as those numbers in all cases are suspiciously low, but that wouldn't necessarily affect the relative changes as long as they're equally wrong in all seasons.

If they can see a significant effect is a small number of participants, that is good - it means they didn't need to search for the effect of UV light, it was obvious. The reason to have a big sample is usually to control for side-effects in drug testing. Often, the big sample size will mean that even very, very small effects are statistically significant.

Spent the minute it takes to parse the abstract and learn it is not just about mice.

It says right there in the paper

“ In both mice and human males”

It’s become a meme to point out studies are done on just mice (to contextualize how sensationalist science media can be), but it’s had the effect of making commenting contests where the first one to point it out gets many upvotes.

So people seek it out without reading the full paper

They missed a chance to say "in males both Of Mice and Men"

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