Association between childhood friendship and cognitive ageing trajectory in later life: evidence from the China Health and Retirement Longitudinal Study (CHARLS)

Xie, Jinzhao; Fan, Xiaoyan; Yin, Ping; Gu, Jing; Yang, Chengwu

doi:10.1186/s12877-022-03181-6

Table 2 Association between childhood friendship status and cognitive ageing trajectory in middle-aged and older adults

From: Association between childhood friendship and cognitive ageing trajectory in later life: evidence from the China Health and Retirement Longitudinal Study (CHARLS)

Fixed effect	β (95% CI)	Model 2^b	Model 3^c	Model 4^d
Fixed effect	Model 1^a	Model 2^b	Model 3^c	Model 4^d
Total cognitive function
Constant	15.37 (14.86, 15.88)^***	15.54 (15.01, 16.07)^***	12.00 (11.33, 12.67)^***	12.20 (11.49, 12.90)^***
Time	-0.21 (-0.23, -0.19)^***	-0.36 (-0.44, -0.28)^***	-0.36 (-0.44, -0.28)^***	-0.35 (-0.43, -0.27)^***
Childhood friendship (Ref: poor)
Fair	0.71 (0.51, 0.91)^***	0.54 (0.32, 0.76)^***	0.26 (0.04, 0.48)^*	0.25 (0.03, 0.46)^*
Good	1.23 (1.05, 1.41)^***	1.00 (0.78, 1.22)^***	0.40 (0.18, 0.62)^***	0.37 (0.16, 0.58)^***
Childhood friendship (Ref: poor) × Time
Childhood friendship (fair) × Time	–	0.15 (0.05, 0.25)^**	0.13 (0.03, 0.23)^**	0.12 (0.03, 0.22)^*
Childhood friendship (good) × Time	–	0.21 (0.13, 0.29)^***	0.19 (0.09, 0.29)^***	0.19 (0.10, 0.28)^***
p value for trend	–	< 0.001	< 0.001	< 0.001
Mental intactness
Constant	9.48 (9.15, 9.81)^***	9.55 (9.22, 9.88)^***	7.20 (6.75, 7.65)^***	7.27 (6.80, 7.74)^***
Time	-0.24 (-0.26, -0.22)^***	-0.29 (-0.35, -0.23)^***	-0.29 (-0.35, -0.23)^***	-0.29 (-0.34, -0.23)^***
Childhood friendship (Ref: poor)
Fair	0.39 (0.27, 0.51)^***	0.33 (0.19, 0.47)^***	0.17 (0.03, 0.31)^*	0.16 (0.02, 0.31)^*
Good	0.67 (0.55, 0.79)^***	0.59 (0.45, 0.73)^***	0.24 (0.10, 0.38)^***	0.23 (0.09, 0.37)^**
Childhood friendship (Ref: poor) × Time
Childhood friendship (fair) × Time	–	0.05 (-0.01, 0.11)^†	0.05 (-0.01, 0.11)	0.04 (-0.02, 0.10)
Childhood friendship (good) × Time	–	0.07 (0.01, 0.13)^*	0.07 (0.01, 0.13)^*	0.06 (0.00, 0.12)^*
p value for trend	–	0.024	0.038	0.044
Episodic memory
Constant	6.00 (5.73, 6.27)^***	6.12 (5.85, 6.39)^***	4.85 (4.48, 5.22)^***	4.97 (4.58, 5.37)^***
Time	0.03 (0.01, 0.05)^**	-0.07 (-0.11, -0.03)^**	-0.07 (-0.13, -0.01)^**	-0.07 (-0.12, -0.02)^*
Childhood friendship (Ref: poor)
Fair	0.33 (0.23, 0.43)^***	0.21 (0.09, 0.33)^***	0.08 (-0.06, 0.22)	0.08 (-0.05, 0.21)
Good	0.57 (0.47, 0.67)^***	0.40 (0.28, 0.52)^***	0.15 (0.03, 0.27)^*	0.13 (0.01, 0.26)^*
Childhood friendship (Ref: poor) × Time
Childhood friendship (fair) × Time	–	0.10 (0.04, 0.16)^***	0.09 (0.03, 0.15)^**	0.08 (0.02, 0.14)^**
Childhood friendship (good) × Time	–	0.14 (0.08, 0.20)^***	0.13 (0.07, 0.19)^***	0.13 (0.07, 0.19)^***
p value for trend	–	< 0.001	< 0.001	< 0.001

^†0.05 ≤ p < 0.1; ^*p < 0.05; ^**p < 0.01; ^***p < 0.001
–: Not included in model
^aModel 1 was adjusted for age and sex
^bModel 2 was adjusted as per Model 1 plus with the interaction term of time and childhood friendship
^cModel 3 was adjusted as per Model 2 plus with sociodemographic factors (residence, marital status, educational level, and household expenditure per capita)
^dModel 4 was adjusted as per Model 3 plus with childhood conditions (childhood family financial situation, childhood first hukou, childhood health, and adverse childhood experiences)

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ISSN: 1471-2318

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