The ICMJE guidelines state that a conflict of interest exists when professional judgment concerning a primary interest (such as patients' welfare or the validity of research) may be influenced by a secondary interest (such as financial gain). Anything that could be perceived as a conflict of interest should be declared. Some examples are: financial relationships (such as employment, consultancies, stock ownership or options, honoraria, patents, and paid expert testimony), personal relationships or rivalries, academic competition, and intellectual beliefs. 

All manuscripts should include a mandatory conflict of interest statement as mentioned under author guidelines.  If there are no conflicts of interest then the author should enter “The authors declare no potential conflicts of interest with respect to research, authorship and/or publication of this article".