Table 4.
Menstrual Cycle Characteristics and Age-Adjusted GM AMH Levels Among Participants in the Nested Case-Control Study (n = 820) of Early Natural Menopause, Selected From Women in NHS2
| Case Subjects (n = 328) | Control Subjects (n = 492) | All Subjects (n = 819a) | Control Subjects Only (n = 492a) | |||||
|---|---|---|---|---|---|---|---|---|
| AMH GM (95% CI) | P b | P trend c | AMH GM (95% CI) | P b | P trend c | |||
| Age at menarche, y | 0.007 | 0.85 | <0.001 | 0.04 | ||||
| ≤9 | 6 | 9 | 4.7 (2.2 to 9.8) | 5.6 (2.6 to 12.0) | ||||
| 10 | 13 | 22 | 5.2 (3.2 to 8.4) | 10.6 (6.5 to 17.3) | ||||
| 11 | 58 | 93 | 3.9 (3.1 to 4.9) | 6.6 (5.2 to 8.4) | ||||
| 12 | 98 | 158 | 4.2 (3.5 to 5.0) | 8.3 (6.9 to 9.9) | ||||
| 13 | 102 | 127 | 4.7 (3.9 to 5.7) | 12.1 (9.8 to 14.8) | ||||
| 14 | 34 | 40 | 2.5 (1.8 to 3.4) | 5.0 (3.5 to 7.2) | ||||
| 15 | 10 | 27 | 7.0 (4.4 to 11.2) | 11.1 (7.1 to 17.3) | ||||
| 16 | 4 | 13 | 7.7 (3.9 to 15.5) | 16.3 (8.6 to 30.8) | ||||
| ≥17 | 3 | 3 | 2.1 (6.5 to 6.7) | 9.9 (2.7 to 37.2) | ||||
| Y to regularity | <0.001 | <0.001 | 0.002 | <0.001 | ||||
| ≤1 | 182 | 231 | 3.5 (3.1 to 4.1) | 7.6 (6.6 to 8.9) | ||||
| 1–2 | 81 | 124 | 4.1 (3.4 to 5.0) | 8.3 (6.8 10.2) | ||||
| 3–4 | 20 | 39 | 4.9 (3.4 to 7.1) | 7.9 (5.5 to 11.5) | ||||
| ≥5 | 29 | 55 | 6.1 (4.5 to 8.3) | 11.4 (8.4 to 15.6) | ||||
| Never | 16 | 43 | 8.9 (6.1 to 12.9) | 15.9 (11.2 to 22.6) | ||||
| Cycle regularity in HS | 0.002 | <0.001 | 0.004 | 0.001 | ||||
| Very regular | 121 | 162 | 3.7 (3.1 to 4.4) | 7.8 (6.5 to 9.3) | ||||
| Regular | 118 | 163 | 4.1 (3.4 to 4.8) | 8.5 (7.1 to 10.2) | ||||
| Usually irregular | 33 | 63 | 6.6 (4.9 to 8.9) | 11.9 (8.9 to 16.0) | ||||
| Always irregular/no periods | 23 | 48 | 6.1 (4.4 to 8.6) | 13.2 (9.4 to 18.4) | ||||
| Cycle regularity at 18–22 y | <0.001 | <0.001 | 0.013 | 0.004 | ||||
| Very regular | 82 | 100 | 3.6 (2.9 to 4.5) | 7.4 (5.9 to 9.3) | ||||
| Regular | 64 | 83 | 4.8 (3.8 to 6.1) | 11.1 (8.6 to 14.4) | ||||
| Usually irregular | 18 | 28 | 6.5 (4.3 to 9.9) | 11.0 (7.1 to 17.1) | ||||
| Always irregular/no periods | 7 | 22 | 10.6 (6.3 to 18.1) | 15.2 (9.3 to 24.9) | ||||
| Cycle length at 18–22 y, d | 0.006 | <0.001 | 0.006 | 0.003 | ||||
| <25 | 19 | 23 | 3.8 (2.4 to 5.9) | 8.5 (5.2 to 13.7) | ||||
| 26–31 | 123 | 153 | 4.0 (3.4 to 4.8) | 8.1 (6.7 to 9.8) | ||||
| 32–39 | 24 | 40 | 6.7 (4.6 to 9.5) | 15.1 (10.4 to 21.7) | ||||
| ≥40 | 9 | 19 | 8.8 (5.1 to 15.2) | 15.3 (9.0 to 26.0) | ||||
Women reporting OC use in high school or at age 18 y were dropped from models of cycle length and regularity.
Abbreviations: GM, geometric mean; HS, high school.
a
AMH levels were unavailable for one case subject.
b
P values for F tests restricted to those with information on the main menstrual characteristic for each model.
c
P for trend from models with each variable as ordinal categorical with risk.