Table 3.
Multivariable linear regression of cognitive function in midlife (age ~50 years) on average annual LTL attrition (bp/year) from age ~30 years (baseline) to ~43 years (follow-up)
| Models | Global (n = 497)a | Attention (n = 497)a | Information processing speed (n = 468) | Executive (n = 496) | Visual spatial (n = 495) | Memory (n = 489)a | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Model 1 | Model 2 | Model 1 | Model 2 | Model 1 | Model 2 | Model 1 | Model 2 | Model 1 | Model 2 | Model 1 | Model 2 | |
| β [p value] | β [p value] | β [p value] | β [p value] | β [p value] | β [p value] | β [p value] | β [p value] | β [p value] | β [p value] | β [p value] | β [p value] | |
| 1. LTL attrition (per SD = 15.4 bp/year) | −.125 [.008] | −.119 [.004] | −.061 [.194] | −.064 [.144] | −.128 [.009] | −.102 [.024] | −.032 [.500] | −.038 [.404] | −.091 [.051] | −.102 [.017] | −.113 [.019] | −.093 [.045] |
| 2. LTL attrition (sex-specific tertiles) (2 df)b | ||||||||||||
| 1st tertile | 0 [.096]c [.037]d |
0 [.033]c [.012]d |
0 [.375]c [.189]d |
0 [.228]c [.107]d |
0 [.062]c [.033]d |
0 [.036]c [.031]d |
0 [.296]c [.471]d |
0 [.203]c [.375]d |
0 [.438]c [.209]d |
0 [.179]c [.064]d |
0 [.174]c [.070]d |
0 [.216]c [.097]d |
| 2nd tertile | −.030 [.558] | −.032 [.471] | −.014 [.790] | −.016 [.737] | −.014 [.793] | .003 [.944] | .042 [.420] | .042 [.391] | −.022 [.671] | −.038 [.412] | −.070 [.184] | −.068 [.179] |
| 3rd tertile | −.112 [.037] | −.118 [.012] | −.071 [.187] | −.081 [.106] | −.121 [.032] | −.111 [.031] | −.040 [.460] | −.046 [.367] | −.067 [.208] | −.090 [.065] | −.098 [.071] | −.087 [.099] |
Model 1: Adjusted for sex and LTL at baseline
Model 2: Fully-adjusted model: age at cognitive assessment, sex, education, leisure-time vigorous activity, sibship size, birth order, plasma homocysteine, anxiety, and LTL at baseline. Reference level of dummy variables: sex, females; educational level, elementary (<9 years); leisure-time vigorous activity, none. Age, anxiety, sibship size, birth order and homocysteine, all introduced as continuous/interval variables
β = standardized regression coefficient
aBox-Cox transformed cognitive z-scores (λ = −.5)
bTertile cutoffs of 18 and 31 bp/year in men and 22 and 33 bp/year in women
cF test p value for the LTL attrition tertiles introduced as dummy variables (2 df)
dTest for trend for the LTL attrition tertiles introduced as an ordinal variable (1 df)