Table 1

Number of twin pairs of the Finnish Twin Cohort study where at least one twin had migrated to Sweden. By sex and age at baseline in 1975

	One twin migrated			Both twins migrated
Age 1975	Men	Women	All	Men	Women	All	Total
<30 y	256	278	534	155	159	314	848
30–39 y	196	142	388	56	33	89	427
40–49 y	72	60	132	21	18	39	171
≥50 y	36	50	86	4	6	10	96

Total	560	530	1090	236	216	452	1542