Table 3.

Linear-mixed effect models showing the effect of demographic variables on the rate of change of spirometric measures, MIPs and MEPs in community-dwelling older adults.

	Spirometry			Respiratory muscle strength
Model term	PVC	FEV	PEF	MEP	MIP
Annual rate of change	−0.069	−0.066	−0.052	−0.046	−0.043
	0.003, <0.001	0.003, <0.001	0.003, <0.001	0.003, <0.001	0.003, <0.001
Age × annual rate of change	−0.001	−0.001	−0.001	−0.001	−0.001
	0.0003, <0.001	0.0003, <0.001	0.0003, 0.005	0.0004, <0.001	0.0004. 0.018
Sex × annual rate of change	−0.021	−0.025	−0.022	−0.023	−0.020
	0.006, <0.001	0.005, <0.001	0.006, <0.001	0.007, <0.001	0.006, 0.001
Education × annual rate of change	−0.001	−0.001	−0.0003	−0.0005	0.001
	0.001, 0.189	0.001, 0.061	0.009, 0.700	0.001, 0.613	0.001, 0.195

Linear-mixed effect models were performed for each of the 3 components (vital capacity, forced expiratory volume, peak expiratory force) used to construct composite spirometry and the two components used to construct composite respiratory muscle strength (RMS; maximal expiratory pressure, MEP and maximal inspiratory pressure, MIP). Each model included a term for Time in years since the baseline which quantifies the rate of change in the spirometry or RMS measure which was being examined. To control for the effect of demographic variables, we also included terms for age, sex and education and their interaction with the annual rate of change in the respiratory measure which was examined. The cross sectional terms which were included in these models are not shown in this table. The mean annual rate of change in standardized units for spirometric measures was larger than for RMS measures [PVC: −0.07 (SD = 0.02); FEV: −0.07 (SD = 0.02); PEF: −0.06 (SD = 0.02); MEP: −0.05 (SD = 0.02); MIP: −0.05 (SD = 0.02)].