Beware individual issues of journals

A journal is an ever flowing stream and to appreciate it you must immerse yourself. You may be deceived if you look at just one issue of a journal. This issue contains a confluence of streams that have been flowing through the BMJ for years. The result is not calm water but turbulence.

Since 1992 the BMJ has been publishing studies on the question of whether giving vitamin K to newborn infants increases their risk of developing childhood cancer. The first study suggested that it did. But subsequent studies mostly found no association. …