TABLE 3.

Impact of pulmonary function impairment on functional limitation (lower extremity functioning, exercise performance, and balance), California, 2005-2007

Functional limitation	Test	Odds ratio or mean change in score*	95% confidence interval	p value	Odds ratio or mean change in score†	95% confidence interval	p value
Lower extremity  function‡	Short Physical Performance  Battery total score  (lowest quartile)	1.6§	1.3, 2.0	<0.0001	1.5§	1.2, 1.9	0.0003
Submaximal exercise  performance¶	6-Minute Walk Test (feet#)	-172	-141, -204	<0.0001	-160	-128, -191	<0.0001
Standing balance¶	Functional Reach Test (cm)	-0.61	1.32, -0.10	0.09	-0.50	1.21, -0.22	0.17

^*Per 1-liter decrease in forced expiratory volume in 1 second (FEV₁) controlling for age, sex, and height.

^†Per 1-liter decrease in FEV₁ controlling for age, sex, height, race, educational attainment, and smoking.

^‡Because the requirement for linear regression was not met for the Short Physical Performance Battery (SPPB) score, we dichotomized it into the lowest quartile (“poor SPPB score”) as the dependent variable. We used logistic analysis, and the odds ratio is the risk of poor SPPB score for each 1-liter decrement in FEV₁.

^§Odds ratio.

^¶Results from linear regression are the mean change in the dependent variable for each 1-liter decrement in FEV₁. There were 18 subjects who could not perform the 6-Minute Walk Test and 35 who could not perform the Functional Reach Test. The chair stand and gait speed subscores were statistically related to FEV₁ (p<0.05), whereas the tandem stand balance subscore was not (p = 0.78).

^#One foot = 0.3048 m.