What you mention is just showing that economical distress and similar are a _bigger_ factor. But that only implies light is a very weak factor if you assume som

What you mention is just showing that economical distress and similar are a _bigger_ factor. But that only implies light is a very weak factor if you assume some trivial linear-ish relationship between factors. Through that is likely not the case. I.e. someone who is already in distress due to other factors is much more likely to not eat properly or take Vitamin D supplements or get out during the short time of the day where the sun is up or get more affected by short days making it harder to have a regular sleep rithm, especially if you are depressed enough to have problems getting out of the bad for hours etc. Non of this does mean you are wrong, but also not that you are right. It's just way more complex and interlocked with other factors then just linear adding up some negative factors.