Table 5.

Lower Limits of Normal and 95% Confidence Intervals for Spirometry Parameters for Men and Women Aged 45 Years and of Average Height

	Women		Men
	LLN (95% CI)	Ratio Relative to Mexicans	LLN (95% CI)	Ratio Relative to Mexicans
FEV1, L
Central American	2.08 (2.03–2.12)	0.98	2.85 (2.78–2.93)	0.97
Cuban	2.05 (2.01–2.08)	0.97	2.86 (2.80–2.92)	0.97
Dominican	1.93 (1.87–1.99)	0.92	2.65 (2.58–2.72)	0.90
Mexican	2.11 (2.08–2.14)	—	2.94 (2.88–2.99)	—
Puerto Rican	1.95 (1.86–2.03)	0.92	2.70 (2.62–2.78)	0.92
South American	2.13 (2.07–2.18)	1.01	2.97 (2.89–3.05)	1.01
Other or mixed	2.04 (1.91–2.18)	0.97	2.89 (2.78–3.01)	0.99
FVC, L
Central American	2.56 (2.51–2.61)	0.97	3.57 (3.48–3.66)	0.96
Cuban	2.53 (2.48–2.57)	0.96	3.55 (3.48–3.62)	0.96
Dominican	2.34 (2.28–2.40)	0.89	3.24 (3.16–3.33)	0.88
Mexican	2.63 (2.59–2.66)	—	3.70 (3.64–3.76)	—
Puerto Rican	2.41 (2.31–2.51)	0.92	3.37 (3.28–3.47)	0.91
South American	2.65 (2.58–2.72)	1.01	3.75 (3.65–3.85)	1.01
Other or mixed	2.50 (2.33–2.67)	0.95	3.52 (3.37–3.68)	0.95
FEV1/FVC ratio, %
Central American	74.51 (74.00–75.02)	1.01	72.42 (71.61–73.24)	1.01
Cuban	74.42 (73.92–74.92)	1.01	72.92 (72.34–73.50)	1.01
Dominican	75.73 (75.05–76.41)	1.03	73.86 (73.00–74.72)	1.03
Mexican	73.80 (73.45–74.15)	—	71.84 (71.25–72.43)	—
Puerto Rican	74.26 (73.47–75.05)	1.01	72.61 (71.70–73.52)	1.01
South American	73.85 (73.20–74.50)	1.00	71.64 (70.69–72.59)	1.00
Other or mixed	75.13 (73.79–76.47)	1.02	74.06 (72.86–75.27)	1.03

Definition of abbreviations: CI = confidence interval; LLN = lower limit of normal; MSE = mean squared error.

LLN was constructed using age = 45, height = 170 cm for men and 156 cm for women.

$\text{LLN}=({\mathrm{\beta }}_0+{\text{β}}_1\text{Age}+{\text{β}}_2{\text{Age}}^2+{\text{β}}_3\text{Height})\hspace{0.17em}-\hspace{0.17em}\left(1.64\sqrt{\text{MSE}}\right)$. 95% CI = LLN ± $1.96\sqrt{\text{Var}\left(\text{LLN}\right)}$, where $\text{Var}\left(\text{LLN}\right)=\text{Var}\left({\text{β}}_0+{\text{β}}_1\text{Age}+{\text{β}}_2{\text{Age}}^2+{\text{β}}_3\text{Height}\right)+({1.64}^2\text{MSE}/2\text{n})$, derived from the variance/covariance matrix of the regression coefficients and the variance of model MSE.