Prediction equations of forced oscillation technique: the insidious role of collinearity

Respiratory Research

Table 1 Comparison of published equations since 2005 of airway resistance (Rrs) at 5 or 6 or 8 Hz with the explanatory variables used in their respective regression model

Authors (reference)	Ethnic group	Equipment used	Subject number	Age range Years	Reported resistance	Variables entered in the model	Indication if collinearity was considered
Frei [12]	Canadian	IOS Jaeger	222	3–10	Rrs5	Height	No
Hall [14]	Australian	FOT, I2M	158	2–7	Rrs6	Height	No
Vu [13]	Vietnamese	FOT, Pulmosfor	175	6–11	Rrs8	Height	No
Calogero [9]	Italian	FOT, I2M	163	2–6	Rrs6	Height	No
Shackleton [11]	Mexican	FOT, I2M	584	3–5	Rrs6	Height	No
Dencker [10]	Scandinavian	IOS Jaeger	360	2–11	Rrs5	Height	No
Dencker [10]	Scandinavian	IOS Jaeger	360	2–11	Rrs5	Weight	No
Nowowiejska [16]	Polish	IOS Jaeger	626	3–18	Rrs5	Height	No
Park [17]	Korean	IOS Jaeger	119	3–6	Rrs5	Height	No
Park [17]	Korean	IOS Jaeger	119	3–6	Rrs5	Gender	No
Calogero [8]	Italian and Australian	FOT, I2M	760	2–13	Rrs6	Height	No
Calogero [8]	Italian and Australian	FOT, I2M	760	2–13	Rrs6	Gender	No
Amra [15]	Iranian	IOS Jaeger	509	5–18	Rrs5	Height	No
						Weight
						Age

Rrs resistance, IOS impulse oscillation system, FOT forced oscillation technique

ISSN: 1465-993X