From @wikipedia:
Half of Wikipedia's top medical editors are health care professionals, 85% have a university education http://www.jmir.org/2015/3/e62/
FB/G+: Wikipedia is probably "the most viewed medical resource globally", according to this new study. Wikipedia's medical content is supported by more than 950,000 references and was viewed more than 4.88 billion times in 2013. Half of Wikipedia's top medical editors are health care professionals, 85% have a university education http://www.jmir.org/2015/3/e62/
(NB: this is a very similar result as https://twitter.com/Wikipedia/status/540932219955449856 , but a different study.)