[Choronzon]

"even after taking into account other factors such as smoking, high blood pressure, diabetes and age" But not IQ and social status,bilingual people are more likely to score higher on both and this could be an aspect of healthier cognitive functions rather than how many languages you know.

[madaxe_again]

Came here to say the same. Correlation is not indicative of causation. Bilingual people are more likely to be more upwardly mobile, and therefore likely have access to better care. Neurology probably has nothing to do with it.