Table 1 Characteristics of participants, girls aged 10 to 18Â years in KNHANES II to V
From: Age at menarche in Korean adolescents: trends and influencing factors
|  | Total 2001–2011 | II 2001 | III 2005 | IV 2007–2009 | V 2010/2011 | p-value |
|---|---|---|---|---|---|---|
N, total respondents | 3409 | 680 | 576 | 1299 | 854 | .0297 |
n, experienced menarche | 2402 | 460 | 389 | 926 | 627 | |
n, before menarche | 1007 | 220 | 187 | 373 | 227 | |
Age (y) | 13.6 ± 2.5 | 13.7 ± 2.6 | 13.5 ± 2.5 | 13.5 ± 2.5 | 13.7 ± 2.5 | .3322 |
Weight (kg) | 48.9 ± 10.8 | 49.0 ± 10.3 | 48.8 ± 10.5 | 48.3 ± 10.9 | 49.6 ± 11.2 | .1024 |
Height (cm) | 155.7 ± 8.5 | 155.1 ± 8.6 | 155.8 ± 8.3 | 155.5 ± 8.7 | 156.5 ± 8.3 | .0204 |
BMI (kg/m2) | 20.0 ± 3.3 | 20.2 ± 3.2 | 20.0 ± 3.2 | 19.8 ± 3.3 | 20.1 ± 3.5 | .0193 |
BMI percentile (%) | ||||||
 Underweight | 154 (5.1) | 22 (3.9) | 22 (5.5) | 72 (6.0) | 38 (4.5) | .0411 |
 Normal | 2422 (80.1) | 448 (78.7) | 331 (83.0) | 965 (80.2) | 678 (79.4) | |
 Overweight | 298 (9.9) | 69 (12.1) | 26 (6.5) | 118 (9.8) | 85 (10.0) | |
 Obese | 151 (5.0) | 30 (5.3) | 20 (5.0) | 48 (4.0) | 53 (6.2) | |
Household income percentile (%) | ||||||
 High | 980 (29.7) | 211 (33.7) | 146 (25.9) | 387 (30.5) | 236 (28.1) | .0030 |
 Upper middle | 1014 (30.7) | 163 (26.0) | 175 (31.0) | 411 (32.4) | 265 (31.6) | |
 Lower middle | 853 (25.8) | 152 (24.2) | 149 (26.4) | 327 (25.8) | 225 (26.8) | |
 Low | 454 (13.8) | 101 (16.1) | 94 (16.7) | 145 (11.4) | 114 (13.6) | |
Place of residence percentile (%) | ||||||
 Urban | 2327 (68.3) | 466 (68.5) | 394 (68.4) | 865 (66.6) | 602 (70.5) | .3001 |
 Rural | 1082 (31.7) | 214 (31.5) | 182 (31.6) | 434 (33.4) | 252 (29.5) | |
Maternal age at menarche percentile (%) | ||||||
 Younger (<13.0 y) | 177 (9.1) | 19 (3.2) | 26 (5.5) | 30 (11.7) | 102 (16.2) | <.0001 |
 Normal (13.0–15.9 y) | 1282 (66.2) | 324 (56.5) | 345 (72.5) | 194 (75.5) | 419 (66.6) | |
 Older (≥16.0 y) | 479 (24.7) | 233 (40.5) | 105 (22.1) | 33 (12.8) | 108 (17.2) | |