Table 2.
Types of products and average duration of use and age of users at first recorded purchase classified by those who initiated the estrogen use (either alone or as a combination product) before the follow-up period and during the follow-up period
| AD n of users = 6352 |
No AD n of users = 6280 |
|
|---|---|---|
| Use before the follow-up period | ||
| Estrogen only | ||
| Mean (95% CI) age at first purchase (years) | 67.4 (67.1–67.7) | 67.5 (67.2–67.8) |
| Oral, n (%) | 3160 (49.7) | 3085 (49.1) |
| Mean (95% CI) duration of use (years) | 5.2 (5.0–5.4) | 5.7 (5.5–5.9) |
| Transdermal, n (%) | 1192 (18.8) | 1247 (19.8) |
| Mean (95% CI) duration of use (years) | 5.5 (5.2–5.7) | 6.1 (5.8–6.4) |
| Oral and transdermal, n (%) | 701 (11.1) | 670 (10.7) |
| Mean (95% CI) duration of use (years) | 7.7 (7.5–8.2) | 8.2 (7.8–8.6) |
| Combination products | ||
| Mean (95% CI) age at first purchase (years) | 63.0 (61.7–64.4) | 62.3 (60.1–63.6) |
| Oral, n (%) | 69 (1.1) | 74 (1.2) |
| Mean (95% CI) duration of use (years) | 2.5 (2.0–3.0) | 3.2 (2.4–3.9) |
| Oral and transdermal, n (%) | 141 (2.2) | 107 (1.7) |
| Mean (95% CI) duration of use (years) | 2.4 (2.0–2.8) | 2.4 (2.0–2.9) |
| Both estrogen and combination, n (%) | 930 (14.6) | 935 (14.9) |
| Mean (95% CI) age at first purchase (years) | 64.0 (63.6–64.5) | 64.4 (63.9–64.9) |
| Mean (95% CI) duration of use (years) | 5.7 (5.6–5.9) | 6.2 (6.0–6.4) |
| Initiated during the follow-up period | ||
| Estrogen only | ||
| Mean (95% CI) age at first purchase (years) | 81.8 (78.1–85.5) | 80.5 (75.5–85.5) |
| Oral, n (%) | 133 (2.1) | 133 (2.1) |
| Mean (95% CI) duration of use (years) | 1.3 (1.1–1.4) | 1.6 (1.4–1.8) |
| Transdermal, n (%) | 19 (0.3) | 19 (0.3) |
| Mean (95% CI) duration of use (years) | 1.2 (0.9–1.5) | 1.4 (1.2–1.6) |
| Oral and transdermal, n (%) | 1 (< 0.1) | 4 (0.5) |
| Mean (95% CI) duration of use (years) | 2.0 | 2.5 (1.7–3.2) |
| Combination products | ||
| Mean (95% CI) age (years) | 49.5 (47.3–51.7) | No data available |
| Oral, n (%) | 0 | 0 |
| Mean (95% CI) duration of use (years) | No data available | No data available |
| Oral and transdermal, n (%) | 2 (< 0.1) | 0 |
| Mean (95% CI) duration of use (years) | 1.7 (0.7–2.6) | No data available |
| Both estrogen and combination, n (%) | 4 (0.1) | 6 (0.1) |
| Mean (95% CI) age at first purchase (years) | 86.5 (82.4–90.6) | 86.0 (82.7–89.3) |
| Mean (95% CI) duration of use (years) | 1.7 (1.1–2.4) | 2.3 (1.8–2.8) |
AD Alzheimer’s disease, CI confidence interval