Effect of Polymorphisms in the FCN1, FCN2, and FCN3 Genes on the Susceptibility to Develop Rheumatoid Arthritis: A Systematic Review

Table 2

Risk of bias assessment of included studies based on the Newcastle-Ottawa scale.

Study		Newcastle-Ottawa scale domains
		Selection				Comparability	Exposition			Total
First author	Year	Proper case definition	Representivity of the cases	Selection of controls	Definition of controls	Control of important factors	Exposure assessment	Same method for the measurement of all subjects	Nonresponse rate
Addobbati C	2015	1	1	1	1	2	1	1	1	9
Pieczarka C	2020	1	1	1	1	2	1	1	1	9
Vander Cruyssen B	2007	1	1	1	1	2	1	1	1	9

A score greater than or equal to 7 indicates low risk of bias and good methodological quality of the case-control study in the domains of selection, comparability, and exposure.