Fig. 2

Directed acyclic graph (DAG) of the association between lipid-related obesity indicators with severe headache or migraine. Note: The variable in green and with the “►” symbol inside the rectangle was the exposure variable; the in blue and with the letter “I” inside the rectangle was the outcome variables; variables in blue are the antecedents of the outcome variable; and those in red are antecedents of the outcome and exposure variable