Table 1.
Basic characteristics of the study population by age at menarche
| Age at menarche | ||||||
|---|---|---|---|---|---|---|
| Variables | Total (n = 60,135) | ≤12 | 13 | 14 | 15 | ≥16 |
| (n = 9347) | (n = 13,476) | (n = 23,184) | (n = 9017) | (n = 5108) | ||
| Age at enrolment, mean (SD) | 29 (4) | 30 (4) | 30 (40) | 29 (4) | 29 (4) | 30 (4) |
| BMI (kg/m2), mean (SD) | 23 (4) | 23 (4) | 23 (4) | 22 (4) | 22 (4) | 22 (4) |
| Overweight (BMI 24–28), n (%) | 11,613 (19) | 2060 (18) | 2652 (23) | 4319 (37) | 1621 (14) | 961 (8) |
| Obese (BMI ≥ 28), n (%) | 4244 (7) | 894 (21) | 973 (23) | 1474 (35) | 580 (14) | 323 (8) |
| SBP (mmHg), n (%) | 112 (10) | 112 (11) | 112 (10) | 112 (10) | 112 (10) | 112 (10) |
| DBP (mmHg), n (%) | 72 (8) | 72 (9) | 72 (8) | 72 (8) | 72 (8) | 72 (8) |
| Alcohol drinker, n (%) | 4237 (7) | 1388 (33) | 1022 (24) | 988 (23) | 450 (11) | 389 (9) |
| Active smoker, n (%) | 774 (1) | 241 (31) | 182 (24) | 167 (22) | 101 (13) | 83 (11) |
| Passive smoking, n (%) | 14,892 (25) | 4103 (28) | 3622 (24) | 3683 (25) | 1926 (13) | 1558 (10) |
| Imbalanced diet, n (%) | 1350 (2) | 274 (20) | 327 (24) | 359 (27) | 181 (13) | 209 (15) |
| Education (years) | ||||||
| ≤ 9, n (%) | 22,537 (37) | 1466 (7) | 4698 (21) | 10,159 (45) | 4122 (18) | 2092 (9) |
| 10~ 15, n (%) | 11,372 (19) | 1507 (13) | 2518 (22) | 4540 (40) | 1696 (15) | 1111 (10) |
| ≥ 16, n (%) | 26,181 (44) | 6362 (24) | 6250 (24) | 8473 (32) | 3194 (12) | 1902 (7) |
| Occupation | ||||||
| Manual work, n (%) | 43,286 (73) | 4454 (10) | 9250 (21) | 18,632 (43) | 7149 (17) | 3801 (9) |
| Non-manual work, n (%) | 15,178 (26) | 4294 (28) | 3841 (25) | 4170 (27) | 1709 (11) | 1164 (8) |
| Unemployed, n (%) | 883 (2) | 298 (34) | 200 (23) | 213 (24) | 94 (11) | 78 (9) |
| Region | ||||||
| Rural, n (%) | 39,233 (65) | 3242 (8) | 8409 (21) | 17,356 (44) | 6662 (17) | 3564 (9) |
| Urban, n (%) | 20,911 (35) | 6105 (29) | 5076 (24) | 5830 (28) | 2356 (11) | 1544 (7) |
| Psychological stress, n (%) | 14,306 (24) | 4306 (30) | 3560 (25) | 3505 (25) | 1726 (12) | 1209 (8) |
| Parity | ||||||
| None, n (%) | 28,325 (47) | 5920 (21) | 6600 (23) | 10,210 (36) | 3664 (13) | 1931 (7) |
| ≥ 1, n (%) | 31,810 (53) | 3427 (11) | 6876 (22) | 12,976 (41) | 5354 (17) | 3177 (10) |
| Oral contraceptive use, n (%) | 417 (1) | 115 (28) | 113 (27) | 102 (24) | 44 (11) | 43 (10) |
| Family history of hypertension, n (%) | 95 (0) | 28 (29) | 23 (24) | 28 (29) | 10 (11) | 6 (6) |
| Diabetes, n (%) | 809 (1) | 157 (19) | 187 (23) | 274 (34) | 115 (14) | 76 (9) |
| Hypertension, n (%) | 1798 (3) | 412 (23) | 414 (23) | 541 (30) | 241 (13) | 190 (11) |
BMI body mass index, SBP systolic blood pressure, DBP diastolic blood pressure, oral contraceptive use was defined as current or ever use