TABLE 1.
Demographic information for the female and male dizygotic twin samples and the subsamples tested in the study
| Number of individual twins | Birth year mean and range | Proportion of sample with dementia | Average age at onset and SD | Average censored age and SD | |
|---|---|---|---|---|---|
| Female SS twins | |||||
| Entire sample | 13,348 | 1933 (1906, 1957) | 14.5% | 77.56 (6.81) | 75.08 (9.37) |
| Sample with APOE ε4 data | 2,827 | 1935 (1906, 1956) | 16.3% | 78.75 (6.79) | 76.45 (9.09) |
| Female OS twins | |||||
| Entire sample | 9,274 | 1938 (1906, 1956) | 11.5% | 76.37 (6.69) | 73.77 (8.89) |
| Sample with APOE ε4 data | 2,278 | 1938 (1908, 1956) | 11.5% | 76.64 (6.75) | 75.52 (8.56) |
| Male SS twins | |||||
| Entire sample | 11,710 | 1934 (1906, 1956) | 8.9% | 75.80 (6.84) | 73.21 (8.34) |
| Sample with APOE ε4 data | 2,142 | 1936 (1906, 1956) | 12.7% | 77.03 (7.16) | 76.27 (8.17) |
| Male OS twins | |||||
| Entire sample | 8,922 | 1938 (1906, 1957) | 9.3% | 75.39 (6.40) | 73.36 (8.40) |
| Sample with APOE ε4 data | 2,230 | 1937 (1907, 1956) | 11.4% | 76.79 (6.07) | 75.82 (7.88) |
Abbreviations: APOE, apolipoprotein E; OS = opposite‐sex; SD, standard deviation; SS = same‐sex.