Table 4.

Results of a 2-Stage Forward Selection Procedure

Stopping Rule: δC ≥ 0.01
Variable	Cumulative Concordance	δC	$\widehat{\beta }\pm 2\mathrm{S}\mathrm{E}(\widehat{\beta })$
Age	0.681	0.681	0.097 (0.089, 0.105)
Self-reported overall health	0.705	0.023
Poor			0.995 (0.812, 1.179)
Fair			0.454 (0.344, 0.565)
Good			Ref.
Excellent			−0.125 (−0.253, 0.003)
Gender (male)	0.717	0.012	0.358 (0.263, 0.452)
RA	0.733	0.016	−0.351 (−0.389, −0.313)
Stopping Rule: δC ≥ 0.001
Age	0.681	0.681	0.085 (0.077, 0.094)
Self-reported overall health	0.705	0.023
Poor			0.546 (0.348, 0.744)
Fair			0.220 (0.102, 0.338)
Good			Ref.
Excellent			0.019 (−0.112, 0.150)
Gender (male)	0.717	0.012	0.412 (0.312, 0.512)
Cigarette smoking	0.724	0.007
Never			Ref.
Former			0.198 (0.100, 0.295)
Current			0.656 (0.507, 0.805)
Longstanding illness/disability	0.728	0.004	0.246 (0.142, 0.349)
Cancer	0.731	0.003	0.397 (0.267, 0.528)
BMI	0.733	0.002
Underweight			0.509 (−0.042, 1.060)
Normal			Ref.
Overweight			−0.045 (−0.155, 0.064)
Obese			0.079 (−0.047, 0.206)
Injury/illness within past 2 years	0.734	0.001	0.312 (0.182, 0.443)
Alcohol consumption	0.735	0.001
Daily or almost daily			Ref.
3 or 4 times a week			−0.163 (−0.291, −0.035)
Once or twice a week			−0.000 (−0.126, 0.125)
1–3 times a month			−0.087 (−0.258, 0.085)
Special occasions only			0.023 (−0.144, 0.189)
Never			0.155 (−0.028, 0.339)
RA	0.745	0.009	−0.264 (−0.312, −0.217)
TA	0.746	0.001	−0.378 (−0.502, −0.255)
ST, min	0.748	0.001	−0.002 (−0.003, −0.001)

Note: BMI = body mass index; RA = relative amplitude; ST = sedentary time; TA = total acceleration. The first phase uses variables that exclude physical activity predictors, while the second phase adds PA variables. Results are presented for 2 different stopping rules based on improvement in Concordance (δC). Variables are listed in order of their inclusion into the model and the 10-fold cross-validated Concordance from a model which includes all variables up to the current variable is presented in the second column. The third column presents the improvement in cross-validated Concordance from including the current variable in the model. The fourth column presents the estimated coefficient and 95% confidence intervals obtained from the final model fit. Coefficient for relative amplitude has been standardized such that interpretation is in units of SDs.