2.4.1 UVMR and MVMR analyses
For UVMR, we used inverse variance weighted MR (IVW MR) along with the
complementary methods: simple mode, MR–Egger, weighted mode and
weighted median to assess the evidence of the causal effects of each
factor on MA, in order to detect the sensitivity of the results to
different patterns of violations of IV assumptions, as consistency of
results across methods strengthens an inference of causality[17].
For our MVMR analyses, combining EA along with HI, and risky behaviors
along with HI or EA, and reproductive factors (AFS, LNSP) along with HI
or EA, we used the multivariable inverse-variance weighted (IVW) method
as the primary method to estimate the causal associations since it
possesses the highest statistical power. The multivariable MR-Egger
method was adopted as a complementary method to strengthen the main
results.