Is interpersonal variation in anxiety levels mostly caused by dietary iron?
I stumbled across this paper yesterday. I haven’t looked at it very closely yet, but the high-level pitch is that they look at genetic predictors of iron deficiency and then cross that with anxiety data. It’s interesting mainly because it sounds pretty legit (i.e. the language sounds like direct presentation of results without any bullshitting, the p-values are satisfyingly small, there’s no branching paths), and the effect sizes are BIG IIUC:
The odd ratios (OR) of anxiety disorders per 1 standard deviation (SD) unit increment in iron status biomarkers were 0.922 (95% confidence interval (CI) 0.862–0.986; p = 0.018) for serum iron level, 0.873 (95% CI 0.790–0.964; p = 0.008) for log-transformed ferritin and 0.917 (95% CI 0.867–0.969; p = 0.002) for transferrin saturation. But no statical significance was found in the association of 1 SD unit increased total iron-binding capacity (TIBC) with anxiety disorders (OR 1.080; 95% CI 0.988–1.180; p = 0.091). The analyses were supported by pleiotropy test which suggested no pleiotropic bias.
Odds ratio of anxiety disorders changes by roughly 0.9 per standard deviation in iron level, across four different measures of iron level. (Note that TIBC, the last of the four iron level measures, didn’t hit statistical significance but did have a similar effect size to the other three.)
Just eyeballing those effect sizes… man, it kinda sounds like iron levels are maybe the main game for most anxiety? Am I interpreting that right? Am I missing something here?
EDIT: I read more, and it turns out the wording of the part I quoted was misleading. The number 0.922, for instance, was the odds ratio AT +1 standard deviation serum iron level, not PER +1 standard deviation serum iron level. That would be −0.078 PER standard deviation serum iron level, so it’s definitely not the “main game for most anxiety”.
Have you tested this hypothesis on your friends? Ask them for their iron level from last blood test, and ask them to self-report anxiety level (you also make a separate estimate of their anxiety level).
Is interpersonal variation in anxiety levels mostly caused by dietary iron?I stumbled acrossthis paperyesterday. I haven’t looked at it very closely yet, but the high-level pitch is that they look at genetic predictors of iron deficiency and then cross that with anxiety data. It’s interesting mainly because it sounds pretty legit (i.e. the language sounds like direct presentation of results without any bullshitting, the p-values are satisfyingly small, there’s no branching paths), and the effect sizes are BIG IIUC:Odds ratio of anxiety disorders changes by roughly 0.9 per standard deviation in iron level, across four different measures of iron level. (Note that TIBC, the last of the four iron level measures, didn’t hit statistical significance but did have a similar effect size to the other three.)Just eyeballing those effect sizes… man, it kinda sounds like iron levels are maybethemain game for most anxiety? Am I interpreting that right? Am I missing something here?EDIT: I read more, and it turns out the wording of the part I quoted was misleading. The number 0.922, for instance, was the odds ratio AT +1 standard deviation serum iron level, not PER +1 standard deviation serum iron level. That would be −0.078 PER standard deviation serum iron level, so it’s definitely not the “main game for most anxiety”.
Have you tested this hypothesis on your friends? Ask them for their iron level from last blood test, and ask them to self-report anxiety level (you also make a separate estimate of their anxiety level).