TABLE 1.

Number of Twin Individuals and Means, Standard Deviations (SD), and the Regression Coefficients (β) With 95% Confidence Intervals (CI) of Individual Education By Sex, Zygosity and Birth Cohort

Birth cohort	MZ twins			DZ twins			Regression coefficient1
	N	Mean	SD	N	mean	D	B	95% CI
Men
1890–1899	27	5.8	3.94	41	6.6	3.81	0.32	−2.24, 2.89
1900–1909	216	9.5	4.88	353	7.8	4.41	−0.52	−1.09, 0.05
1910–1919	1,585	11.7	4.16	2,286	10.7	4.28	−0.41	−0.67, −0.15
1920–1929	6,294	12.8	3.79	8,988	11.7	4.15	−0.25	−0.39, −0.12
1930–1939	3,139	11.4	4.35	7,417	10.5	4.46	−0.12	−0.30, 0.07
1940–1949	6,087	12.7	4.21	14,297	11.5	4.40	−0.46	−0.59, −0.33
1950–1959	7,496	13.2	3.64	14,077	12.7	3.76	−0.26	−0.37, −0.16
1960–1969	3,567	13.9	2.92	5,077	13.9	2.87	−0.01	−0.15, 0.12
1970–1979	4,900	14.0	2.71	5,683	13.9	2.58	−0.18	−0.30, −0.06
1980–1989	3,948	12.9	2.54	5,117	12.7	2.47	−0.13	−0.25, −0.02
1990–1999	593	12.3	1.96	665	12.3	2.21	−0.15	−0.43, 0.12
Women
1890–1899	57	7.5	4.15	75	5.8	2.88	−0.05	−1.39, 1.30
1900–1909	403	9.2	4.62	622	8.2	4.36	−0.17	−0.62, 0.27
1910–1919	1,528	10.6	4.03	2,378	9.5	4.09	0.01	−0.23, 0.24
1920–1929	3,159	11.1	3.96	5,428	9.9	4.02	−0.21	−0.38, −0.04
1930–1939	3,988	11.3	3.95	7,640	10.4	4.16	−0.24	−0.40, −0.07
1940–1949	7,669	12.4	3.84	15,727	11.6	4.12	−0.20	−0.31, −0.09
1950–1959	10,294	13.3	3.45	15,476	13.0	3.62	−0.14	−0.23, −0.05
1960–1969	6,615	14.1	2.87	6,948	13.9	2.85	−0.13	−0.24, −0.03
1970–1979	7,124	14.5	2.88	6,875	14.4	2.71	−0.13	−0.24, −0.03
1980–1989	6,485	13.4	2.52	6,271	13.1	2.39	−0.14	−0.24, −0.05
1990–1999	988	12.8	2.22	759	12.9	2.02	0.23	0.00, 0.47

Note:

¹Adjusted for twin cohort; MZ twins used as the reference category.