The role of smoking in the relationship between intimate partner violence and age at natural menopause: a mediation analysis

Table 4 Natural direct and indirect effects of intimate partner violence on the age at natural menopause and the proportion mediated through smoking (n = 6138)^a

	OR^NDE (95% CI)	OR^NIE (95% CI)	OR^TE (95% CI)	Proportion mediated by smoking (%)
Early menopause (ANM <45 vs. ≥45 years)
Mediator: smoking
Smoking status (5 categories)	1.31 (1.02–1.68)	1.14 (1.09–1.18)	1.49 (1.16–1.90)	36.7
Current vs. non-current smoking (2 categories)	1.34 (1.04–1.72)	1.13 (1.08–1.18)	1.51 (1.18–1.93)	33.7
	β^NDE (95% CI)	β^NIE (95% CI)	β^TE (95% CI)	Proportion mediated by smoking (%)
Continuous ANM
Mediator: smoking
Smoking status (5 categories)	−0.38 (−0.68 to −0.08)	−0.22 (−0.28 to −0.16)	−0.60 (−0.89 to −0.30)	37.0
Current vs. non-current smoking (2 categories)	−0.41 (−0.71 to −0.11)	−0.18 (−0.23 to −0.12)	−0.59 (−0.94 to −0.24)	29.8

ANM age at natural menopause, NDE natural direct effect, NIR natural indirect effect, TE total effect
^aAll estimates were adjusted for education level, income difficulties, and age at menarche. The mediation analysis was performed by fitting a logistic regression model for the binary outcome (ANM <45 vs. ≥45 years) and a linear regression model for the continuous ANM and fitting a linear or logistic regression model for the ordinal or binary mediator. The proportion mediated was calculated as [(OR^NDE (OR^NIE – 1)] / [OR^NDE × OR^NIE –1] × 100% for the binary outcome or (β^NIE/β^TE) × 100% for the continuous outcome

ISSN: 2054-2690