Table 2. Multivariate regression analysis of leukocyte telomere length.

Variable	Coefficient (SE)	t-statistic	P
Outcome: actual LTL (mean TRF)
Intercept	8.43 (0.201)	41.88	2.43E-227
Age	-0.022 (0.002)	-11.14	2.33E-27
Female	0.132 (0.036)	3.71	2.15E-4
Race: European	0.029 (0.112)	0.26	7.97E-1
smoke: Former	0.132 (0.063)	2.11	3.50E-2
smoke: Never	0.113 (0.062)	1.82	6.95E-2
BMI	-0.007 (0.003)	-2.15	3.16E-2
JHS	0.005 (0.126)	0.04	9.66E-1
WHI BA23	-0.093 (0.084)	-1.10	2.73E-1
Outcome: DNAmTL
Intercept	8.046 (0.069)	116.16	<1.0E-300
Age	-0.018 (0.001)	-27.32	5.97E-125
Female	0.099 (0.012)	8.14	1.14E-15
Race: European	-0.136 (0.039)	-3.52	4.57E-4
smoke: Former	0.08 (0.022)	3.72	2.09E-4
smoke: Never	0.096 (0.021)	4.51	7.11E-6
BMI	-0.002 (0.001)	-2.19	2.91E-2
JHS	0.069 (0.044)	1.59	1.11E-1
WHI BA23	0.049 (0.029)	1.69	9.15E-2

BMI=body mass index; SE=standard error.

In the upper panel, we present results from a multivariate linear regression model analysis of actual LTL (mean TRF, dependent variable) on different covariates (rows) in the test data set (comprised of 1078 individuals). The model was regressed on age, sex, race/ethnicity, smoking status, and study cohort. Race/ethnicity is a dichotomized variable (European versus African Ancestry). Smoking status is a three-category variable: never, former and current smokers (as a reference). Study cohort is a trivariate variable (FHS, WHI BA23 and JHS cohort).

In the lower panel, we present the analogous multivariate model but its dependent variable is DNAmTL.