Classical regression equations of spirometric parameters are not applicable for diagnosing spirometric abnormalities in adipotic adults

Table 3 Incidence of obese subjects (cohort B) who are judged to have impaired lung function

	Measured values < LLNs of adipotic equations	Measured values < LLNs of non-adipotic equations
FVC
M	0.40%	24.8%b
F	6.20%	24.1%b
FEV1
M	0.40%	26.1%b
F	8.40%	47.8%b
FEV1/FVC
M	3.10%	16.8%b
F	2.20%	6.6%d
PEF
M	1.30%	26.5%b
F	3.60%	19.3%b
FEF50
M	0.90%	27.9%b
F	11.70%	16.40%
FEF75
M	1.30%	11.5%b
F	5.50%	6.60%

^bP < 0.0001.

^dP < 0.02 between the two conditions (the χ² test). LLNs of respective SPs are estimated from the 5^th percentiles of the residual’s distributions applying eq. (3) to adipotic and non-adipotic regression equations. M: Male; F: Female; A: Age; FVC: Forced vital capacity (L); FEV1: Forced expiratory volume after one second (L); PEF: Peak expiratory flow rate (L/s); FEF₅₀: Forced expiratory flow rate at 50% expiration of FVC (L/s); FEF₇₅: Forced expiratory flow rate at 75% expiration of FVC (L/s).