Table 2.
Participants’ socio-demographic characteristics (n = 10,598) .
| 20–34 years (n = 1,889) | p value | 35–49 years (n = 8,709) | p value | |||||
|---|---|---|---|---|---|---|---|---|
| All | Anemia | Without anemia | All | Anemia | Without anemia | |||
| n = 263 | n = 1,626 | n = 1,548 | n = 7,161 | |||||
| 13.9% | 86.1% | 17.8% | 82.2% | |||||
| Median (IQRa) or N (%) or Mean ± SD | Median (IQRa) or N (%) or Mean ± SD | |||||||
| Age (years) | 30.0 (26.0–32.0) | 30.0 (26.0–32.0) | 30.0 (26.0–32.0) | 0.729b | 44.0 (40.0–47.0) | 44.0 (41.0–47.0) | 44.0 (40.0–47.0) | 0.008b |
| Body mass index (kg/m2) | 0.445c | 0.051c | ||||||
| less than 18.5 | 402 (21.3) | 48 (18.3) | 354 (21.7) | 1,503 (17.3) | 262 (16.9) | 1,241 (17.3) | ||
| 18.5–24.9 | 1,375 (72.8) | 201 (76.4) | 1,174 (72.2) | 6,308 (72.4) | 1,154 (74.5) | 5,154 (72.0) | ||
| 25.0–29.9 | 96 (5.1) | 13 (4.9) | 83 (5.1) | 720 (8.3) | 102 (6.6) | 618 (8.6) | ||
| 30.0 or more | 16 (0.8) | 1 (0.4) | 15 (0.9) | 177 (2.0) | 30 (1.9) | 147 (2.1) | ||
| Weight change over the past year | 0.067c | 0.021c | ||||||
| No change | 1,384 (73.3) | 208 (79.1) | 1,176 (72.3) | 6,532 (75.0) | 1,203 (77.7) | 5,329 (74.4) | ||
| 3 kg or more increase | 343 (18.2) | 39 (14.8) | 304 (18.6) | 1,750 (20.1) | 273 (17.6) | 1,477 (20.6) | ||
| 3 kg or more decrease | 161 (8.5) | 16 (6.0) | 145 (8.4) | 427 (4.9) | 72 (4.7) | 355 (5.0) | ||
| Current medical history | ||||||||
| Adenomyosis | 8 (0.4) | 0 (0.0) | 8 (0.5) | 0.301d | 127 (1.5) | 30 (1.9) | 97 (1.4) | 0.082c |
| Endometriosis enterna (e.g. chocolate cyst, endometriosis cyst) | 30 (1.6) | 2 (0.8) | 28 (1.7) | 0.190d | 241 (2.8) | 40 (2.6) | 201 (2.8) | 0.628c |
| Uterine myoma | 20 (1.1) | 4 (1.5) | 16 (1.0) | 0.300d | 827 (3.5) | 202 (13.0) | 625 (8.7) | <0.001c |
| Cervical cancer | 2 (0.1) | 1 (0.4) | 1 (0.1) | 0.259d | 48 (0.6) | 7 (0.5) | 41 (0.6) | 0.562c |
| Endometrial cancer | 1 (0.1) | 0 (0.0) | 1 (0.1) | 0.861d | 13 (0.1) | 1 (0.1) | 12 (0.2) | 0.299d |
| Ovarian tumor (malignant/benign) | 10 (0.5) | 2 (0.8) | 8 (0.5) | 0.416d | 122 (1.4) | 20 (1.3) | 102 (1.4) | 0.688c |
| Abnormality of uterine cytology | 35 (1.9) | 5 (1.9) | 30 (1.8) | 0.550d | 315 (3.6) | 47 (3.0) | 268 (3.7) | 0.177c |
| Breast cancer/mastopathy | 9 (0.5) | 1 (0.4) | 8 (0.5) | 0.637d | 374 (4.3) | 66 (4.3) | 308 (4.3) | 0.947c |
| Gastric ulcer | 0 | 0 | 0 | 5 (0.1) | 2 (0.1) | 3 (0.0) | 0.218d | |
| Duodenal ulcer | 0 | 0 | 0 | 5 (0.1) | 3 (0.2) | 2 (0.0) | 0.042d | |
| Ulcerative colitis | 3 (0.2) | 1 (0.4) | 2 (0.1) | 0.362d | 25 (0.3) | 7 (0.5) | 18 (0.3) | 0.141d |
| Body fat percentage | 24.8 ± 5.6 | 24.1 ± 5.2 | 25.0 ± 5.6 | 0.026e | 25.8 ± 6.33 | 24.8 ± 5.8 | 26.0 ± 6.4 | <0.001 f |
| Smoking habits | 0.245c | <0.001c | ||||||
| Non-smoker | 1,689 (89.5) | 243 (92.3) | 1,446 (88.9) | 7,110 (81.6) | 1,340 (86.6) | 5,770 (80.6) | ||
| Current smoker | 47 (2.5) | 5 (1.9) | 42 (2.6) | 422 (4.8) | 58 (3.7) | 364 (5.1) | ||
| Smoked in the past | 152 (8.1) | 15 (5.7) | 137 (8.4) | 1,177 (13.5) | 150 (9.7) | 1,027 (14.3) | ||
| Number of tobacco per day | 8.0 (5.0–12.0) | 8.0 (5.0–10.0) | 8.0 (4.0–12.0) | 0.825b | 10.0 (5.0–15.0) | 10.0 (5.0–10.0) | 10.0 (5.0–15.0) | 0.119b |
| Drinking habits | 0.015c | <0.001c | ||||||
| Non-drinker | 1,058 (56.0) | 169 (64.3) | 889 (54.7) | 4,195 (48.2) | 813 (52.5) | 3,382 (47.2) | ||
| Occasional drinker | 306 (16.2) | 36 (13.6) | 270 (16.6) | 1,464 (16.8) | 289 (18.7) | 1,175 (16.4) | ||
| Habitual drinker | 524 (27.8) | 58 (22.1) | 466 (28.7) | 3,050 (35.0) | 446 (28.8) | 2,604 (36.4) | ||
| Number of days per week with alcohol consumption | 2.0 (1.0–4.0) | 2.0 (1.0–3.25) | 2.0 (1.0–4.0) | 0.149b | 3.0 (1.0–5.0) | 2.0 (1.0–5.0) | 3.0 (1.0–5.0) | 0.001b |
| Sleeping habits | 0.152c | 0.072c | ||||||
| 7 hours or more | 299 (29.3) | 36 (13.6) | 263 (16.2) | 1,273 (24.5) | 205 (22.2) | 1,068 (25.0) | ||
| 6 hours or below | 722 (70.7) | 112 (42.5) | 610 (37.5) | 3,913 (75.5) | 717 (77.8) | 3,196 (75.0) | ||
| Exercise habits (light exercise, including walking for more than 20 minutes) | 0.892c | 0.284c | ||||||
| No exercise | 837 (44.3) | 113 (42.9) | 724 (44.5) | 3,509 (40.3) | 655 (42.3) | 2,854 (39.9) | ||
| Exercising 1–2 days per week | 677 (35.9) | 97 (36.8) | 580 (35.7) | 3,250 (37.3) | 557 (36.0) | 2,693 (37.6) | ||
| Exercising 3–5 days per week | 240 (12.7) | 36 (13.6) | 204 (12.5) | 1,370 (15.7) | 242 (15.6) | 1,128 (15.8) | ||
| Exercising almost every day | 134 (7.1) | 17 (6.4) | 117 (7.2) | 580 (6.7) | 94 (6.1) | 486 (6.8) | ||
a: IQR = interquartile range (25th – 75th percentile), b: Mann-Whitney U test, c: Chi-square test, d: Fisher’s exact test, e: Student’s t-test, f: Welch’s t-test.
Anemia: Hb < 12.0 g/dL
Without anemia: Hb ≥ 12.0 g/dL
20–34 years: n = 1,888 for Weight change over the past year, Smoking habits, Drinking habits, Exercise habits. n = 1,886 for Body fat percentage. n = 199 for Number of tobacco per day. n = 830 for Number of days per week with alcohol consumption. n = 1,021 for Sleeping habits.
35–49 years: n = 8,708 for Body Mass Index. n = 8,706 for Body fat percentage. n = 1,599 for Number of tobacco per day. n = 4,514 for Number of days per week with alcohol consumption. n = 5,186 for Sleeping habits.