Table 5.

Educational years in former smokers as compared to current smokers within discordant twin pairs by measurement year, zygosity and sex.

Measurement years	MZ twins			Same-sex DZ twins			p-value of zygosity interaction
	β	95% confidence intervals		β	95% confidence intervals
		LL	UL		LL	UL
Men
1960–1969	0.07	− 0.17	0.30	0.39	0.09	0.70	0.095
1970–1979	0.07	− 0.15	0.30	0.38	0.17	0.58	0.088
1980–1989	0.16	0.01	0.31	0.39	0.22	0.55	0.063
1990–1999	0.01	− 0.29	0.31	0.39	0.09	0.68	0.104
2000–2012	0.04	− 0.15	0.24	0.40	0.16	0.63	0.028
Women
1970–1979	− 0.04	− 0.31	0.23	0.04	− 0.21	0.30	0.712
1980–1989	0.02	− 0.11	0.15	0.30	0.13	0.47	0.015
1990–1999	0.31	0.05	0.57	0.43	0.16	0.71	0.542
2000–2012	0.19	− 0.01	0.39	0.37	0.14	0.60	0.261