Table 2. Results of regression analyses of social capital according to total sibling number among Japanese parents.

			Model 1	Model 2
		Mean (SD)	coefficient (95% CI)	coefficient (95% CI)
Social cohesion (0–12)
Total number of siblings	0 (only child)	7.12 (2.55)	referent	referent
	1	7.10 (2.30)	−0.07 (−0.2 to 0.14)	−0.09 (−0.30 to 0.12)
	2	7.17 (2.38)	0.06 (−0.15 to 0.27)	0.02 (−0.18 to 0.23)
	3	7.10 (2.48)	0.02 (−0.25 to 0.29)	−0.01 (−0.28 to 0.26)
	≥4	6.82 (2.65)	−0.29 (−0.63 to 0.06)	−0.32 (−0.66 to 0.03)
Social support (0–8)
Total number of siblings	0 (only child)	2.83 (1.89)	referent	referent
	1	3.05 (1.94)	0.23 (0.06–0.40)	0.22 (0.05–0.40)
	2	3.29 (2.04)	0.46 (0.29–0.64)	0.46 (0.28–0.63)
	3	2.99 (1.86)	0.16 (−0.06 to 0.39)	0.17 (−0.05 to 0.40)
	≥4	2.86 (1.89)	0.05 (−0.24 to 0.34)	0.08 (−0.21 to 0.36)
Group affiliation (0–7)
Total number of siblings	0 (only child)	0.39 (0.64)	referent	Referent
	1	0.46 (0.76)	0.05 (−0.01 to 0.12)	0.04 (−0.02 to 0.11)
	2	0.48 (0.77)	0.09 (0.03–0.16)	0.07 (0.008–0.14)
	3	0.47 (0.75)	0.09 (0.01–0.18)	0.07 (−0.01 to 0.16)
	≥4	0.41 (0.73)	0.02 (−0.09 to 0.13)	−0.01 (−0.12 to 0.10)

CI, confidence interval; SD, standard deviation.

Model 1: Adjusted for age and sex.

Model 2: Model 1 + adjusted for number of children.