TABLE 1.

Mediation effect of body mass index on carpal tunnel syndrome via type 2 diabetes and type 2 diabetes on carpal tunnel syndrome via body mass index.

Exposure	Mediator	Total effecta	Effect Xb	Effect Mc	Mediation effectd		Mediated proportion
		Effect size (95% CI)	Effect size (95% CI)	Effect size (95% CI)	Effect size (95% CI)	p-values	(%) (95% CI)
BMI	T2D	0.505 (0.330, 0.679)	1.087 (1.034, 1.139)	0.160 (0.064, 0.256)	0.174 (0.069, 0.279)	1.18 × 10–4	34.4% (20.9, 41.0)
T2D	BMI	0.160 (0.064, 0.256)	−0.018 (−0.029, −0.006)	0.505 (0.330, 0.679)	−0.009 (−0.016, −0.003)	0.017	−5.4% (−25.6, −1.2)

^aTotal effect: the effect of exposures on carpal tunnel syndrome.

^bEffect X: the effect of exposures on mediators.

^cEffect M: the effect of mediators on carpal tunnel syndrome.

^dMediation effect: the effect of exposures on carpal tunnel syndrome via mediators.