Reading and conducting instrumental variable studies: guide, glossary, and checklist.

Competing Interests: Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/disclosure-of-interest/ and declare: support from the UK Medical Research Council, Norwegian Research Council, NIH/NHLBI, Measey Foundation, and Doris Duke Foundation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work; TF has received funding from Pfizer, Takeda, Acadia, and iHeed for unrelated consulting work, and receives funds from The BMJ for editorial work; NMD receives funds from The BMJ for editorial work; SMD receives research support from RenalytixAI and Novo Nordisk, outside the scope of the current research.