Beta estimate for total cognitive score (95% CIs) | ||||
Between-family analysis* | Within-family analysis† | Within-family analysis in DZ twins‡ | Within-family analysis in MZ twins§ | |
All with baseline age <60 years | 0.78 (0.73 to 0.83) | 0.60 (0.37 to 0.85) | 0.69 (0.39 to 0.99) | 0.32 (−0.03 to 0.68) |
Participants for whom also CAIDE available | 0.76 (0.69 to 0.83) | 0.63 (0.22 to 1.04) | 0.78 (0.25 to 1.31) | 0.12 (−0.44 to 0.68) |
Participants for whom also CAIDE available adjusted for CAIDE score without education | 0.74 (0.67 to 0.81) | 0.63 (0.22 to 1.04) | 0.78 (0.26 to 1.31) | 0.11 (−0.46 to 0.68) |
Participants for whom also CAIDE available adjusted for depressive symptoms | 0.57 (0.49 to 0.65) | 0.22 (−0.21 to 0.65) | 0.31 (−0.22 to 0.85) | −0.08 (−0.86 to 0.71) |
Participants for whom also CAIDE available adjusted for CAIDE score without education and depressive symptoms | 0.56 (0.48 to 0.64) | 0.22 (−0.21 to 0.65) | 0.31 (−0.22 to 0.85) | −0.10 (−0.91 to 0.71) |
*N=3982 all twin individuals, 2335 twin individuals for participants with also CAIDE, 2335 twin individuals in the analyses adjusted for CAIDE score without education, 1101 twin individuals in the analyses adjusted for depressive symptoms and 1101 twin individuals in the analyses adjusted for CAIDE without education and depressive symptoms.
†N=1243 all twin pairs, 570 twin pairs for participants with also CAIDE, 570 twin individuals in the analyses adjusted for CAIDE score without education, 267 twin pairs in the analyses adjusted for depressive symptoms and 267 twin pairs in the analyses adjusted for CAIDE without education and depressive symptoms.
‡N=769 all twin pairs and 343 twin pairs for participants with also CAIDE, 343 twin individuals in the analyses adjusted for CAIDE score without education, 151 twin pairs in the analyses adjusted for depressive symptoms and 151 twin pairs in the analyses adjusted for CAIDE without education and depressive symptoms.
§N=470 all twin pairs and 226 twin pairs for participants with also CAIDE, 226 twin individuals in the analyses adjusted for CAIDE score without education, 115 twin pairs in the analyses adjusted for depressive symptoms and 115 twin pairs in the analyses adjusted for CAIDE without education and depressive symptoms.
¶All the results have been adjusted for the length of follow-up. The statistically significant results are typed in bold. Higher educational-occupational score is associated with better cognition.
DZ, dizygotic; MZ, monozygotic.