Data collection
LC and LDM extracted Odds Ratios (ORs) with 95% Confidence Intervals
(CIs) and other usable data using a data extraction sheet on Excel,
Microsoft Office 365 (Redmond, WA, USA). If other usable data were
reported (e.g. count data), they were converted to ORs. When more than
one study reported data from the same cohort, we used the most complete
results. We extracted missing data from less complete results where
suitable.