Hacker News Reader

Comment by defrost | Hacker News Reader

>> A meta-analysis of several research studies has found differing results for the influence of seasonality on food intake23. 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 ...

It's a correlation .. is "markedly affected by solar radiation" a reach when the same correlation exists for tempreture?

Is it the UV or is it that men eat more and more active in the summer than in winter?

Hmmm.

View on HN

the mention that they controlled for age also directly says they didn't correct for anything else. e.g. if for whatever reason the male study population has a significant shift into any direction (income, physical characteristics like height, weight, etc.) bam you're entire data set is essentially useless.

and this is almost certainly going to be the case. it's nigh impossible to get similar averages for all metrics in a male between female comparison.

the data is very valuable on its own. but once again I have no idea how they think it remotely allows them to draw the specific conclusions regarding causality that they do.

It's both. The light-sensitive supraoptic part of your brain directly triggers your hypothalamums to release more or less corticotropin-releasing hormone. Which directly triggers adrenocorticotropic hormone+melanocyte [melanin cell] stimulating hormone.

There is also some mouse experimental data

Sure .. does the effect correlate with both UV AND temp or have they ANOVA'd enough to say that that anything observed is predominently due to UV alone?

They work out the mechanism of UV induced orexia, then knockout the gene in the mouse thus abolishing the phenotype. They also work out why the effect is sexually dimorphic.

Also vitamin D and testosterone production

This paper is not merely a meta-analysis.

Reply on news.ycombinator.com