Background
Methods
Geographic and demographic characteristics
The NFPHEP project in Yunnan
Definition and Assessment of variables
Statistical analysis
Results
Dai | Han | Hani | Miao | Yi | Total | P Value | |
---|---|---|---|---|---|---|---|
Number | 8,733 | 123,600 | 5,292 | 5,639 | 34,256 | 177,520 | |
Sociodemographic characteristics, No. (%) | |||||||
Education level | < 0.001 | ||||||
N-Miss | 20 | 1,591 | 64 | 30 | 246 | 1,951 | |
Low | 2,767 (31.8) | 1,7696 (14.5) | 1,733 (33.1) | 2,990 (53.3) | 9,255 (27.2) | 34,441 (19.6) | |
Middle | 4,636 (53.2) | 6,9643 (57.1) | 2,514 (48.1) | 2,203 (39.3) | 18,391 (54.1) | 97,387 (55.5) | |
High | 1,310 (15.0) | 3,4670 (28.4) | 981 (18.8) | 416 (7.4) | 6,364 (18.7) | 43,741 (24.9) | |
Parity | < 0.001 | ||||||
N-Miss | 17 | 375 | 21 | 11 | 90 | 514 | |
0 | 2,553 (29.3) | 51,873 (42.1) | 1,495 (28.4) | 1,990 (35.4) | 11,751 (34.4) | 69,662 (39.4) | |
1 | 3,752 (43.0) | 48,116 (39.0) | 1,896 (36.0) | 2,297 (40.8) | 13,417 (39.3) | 69,478 (39.3) | |
>1 | 2,411 (27.7) | 23,236 (18.9) | 1,880 (35.7) | 1,341 (23.8) | 8,998 (26.3) | 37,866 (21.4) | |
Age | < 0.001 | ||||||
N-Miss | 26 | 146 | 11 | 32 | 25 | 240 | |
<20 | 334 (3.8) | 3,236 (2.6) | 231 (4.4) | 880 (15.7) | 1,134 (3.3) | 5,815 (3.3) | |
20-35 | 7,979 (91.6) | 112,455 (91.1) | 4,663 (88.3) | 4,393 (78.3) | 31,259 (91.3) | 160,749 (90.7) | |
≥35 | 394 (4.5) | 7,763 (6.3) | 387 (7.3) | 334 (6.0) | 1,838 (5.4) | 10,716 (6.0) | |
Birth order | < 0.001 | ||||||
N-miss | 17 | 375 | 21 | 11 | 90 | 514 | |
1 | 3,681 (42.2) | 62,506 (50.7) | 2,176 (41.3) | 2,307 (41.0) | 15,509 (45.4) | 86,179 (48.7) | |
2 | 4,901 (56.2) | 59,077 (47.9) | 2,897 (55.0) | 3,074 (54.6) | 18,080 (52.9) | 88,029 (49.7) | |
>3 | 134 (1.5) | 1,642 (1.3) | 198 (3.8) | 247 (4.4) | 577 (1.7) | 2,798 (1.6) | |
Work | < 0.001 | ||||||
N-Miss | 37 | 1,226 | 58 | 63 | 227 | 1,611 | |
Farmer | 8,390 (96.5) | 111,618 (91.2) | 4,965 (94.9) | 5,459 (97.9) | 32,605 (95.8) | 163,037 (92.7) | |
Non-farmer | 306 (3.5) | 10,756 (8.8) | 269 (5.1) | 117 (2.1) | 1,424 (4.2) | 12,872 (7.3) | |
BMI (kg/m2) | < 0.001 | ||||||
N-Miss | 3 | 232 | 6 | 4 | 38 | 283 | |
Underweight | 1,553 (17.8) | 16,969 (13.8) | 632 (12.0) | 429 (7.6) | 4,174 (12.2) | 23,757 (13.4) | |
Normal weight | 6,145 (70.4) | 93,793 (76.0) | 3,946 (74.7) | 4,678 (83.0) | 26,382 (77.1) | 134,944 (76.1) | |
Overweight | 877 (10.0) | 11,179 (9.1) | 597 (11.3) | 471 (8.4) | 3,176 (9.3) | 16,300 (9.2) | |
Obese | 155(1.8) | 1,427 (1.2) | 111 (2.1) | 57 (1.0) | 486 (1.4) | 2,236 (1.3) | |
Height (cm) | |||||||
N-miss | 3 | 232 | 6 | 4 | 38 | 283 | |
<150 | 1,397 (16.0) | 10,827 (8.8) | 917 (17.3) | 1,998 (35.5) | 4,181 (12.2) | 19,320 (10.9) | |
≥150 | 7,333 (84.0) | 112,541 (91.2) | 4,369 (82.7) | 3,637 (64.5) | 30,037 (87.8) | 157,917 (89.1) | |
Maternal disease a | < 0.001 | ||||||
N-Miss | 71 | 981 | 64 | 31 | 286 | 1,433 | |
Yes | 261 (3.0) | 1,579 (1.3) | 101 (1.9) | 42 (0.7) | 388 (1.1) | 2,371 (1.3) | |
Economic stress | < 0.001 | ||||||
N-Miss | 51 | 700 | 39 | 31 | 187 | 1,008 | |
Never | 6,705 (77.2) | 91,354 (74.3) | 3,249 (61.9) | 4,546 (81.1) | 24,572 (72.1) | 130,426 (73.9) | |
Slightly | 1,157 (13.3) | 18,704 (15.2) | 1,023 (19.5) | 606 (10.8) | 5,317 (15.6) | 26,807 (15.2) | |
Considerable | 820 (9.4) | 12,842 (10.4) | 981 (18.7) | 456 (8.1) | 4,180 (12.3) | 19,279 (10.9) | |
Past obstetric history, No. (%) | |||||||
Induced abortion | < 0.001 | ||||||
Yes | 2,845 (32.6) | 26,052 (21.1) | 1,998 (37.8) | 1,239 (22.0) | 10,137 (29.6) | 42,271 (23.8) | |
Missing | 2,537 (29.1) | 45,518 (36.8) | 1,433 (27.1) | 1,971 (35.0) | 10,998 (32.1) | 62,457 (35.2) | |
Natural abortion | < 0.001 | ||||||
Yes | 356 (4.1) | 4,139 (3.3) | 302 (5.7) | 195 (3.5) | 1,298 (3.8) | 6,290 (3.5) | |
Missing | 2,537 (29.1) | 45,520 (36.8) | 1,433 (27.1) | 1,971 (35.0) | 10,998 (32.1) | 62,459 (35.2) | |
Stillbirth | < 0.001 | ||||||
Yes | 68 (0.8) | 1,024 (0.8) | 60 (1.1) | 43 (0.8) | 309 (0.9) | 1,504 (0.8) | |
Missing | 2,537 (29.1) | 45,520 (36.8) | 1,433 (27.1) | 1,971 (35.0) | 10,998 (32.1) | 62,459 (35.2) | |
Maternal substance use, No. (%) | |||||||
Folate use | < 0.001 | ||||||
N-Miss | 14 | 784 | 31 | 51 | 192 | 1,072 | |
Unused | 420 (4.8) | 5,092 (4.1) | 464 (8.8) | 351 (6.3) | 1591 (4.7) | 7,918 (4.5) | |
Irregular Used | 475 (5.5) | 7,831 (6.4) | 411 (7.8) | 355 (6.4) | 3,092 (9.1) | 12,164 (6.9) | |
Regular Used | 7,824 (89.7) | 109,893 (89.5) | 4,386 (83.4) | 4,882 (87.3) | 29,381 (86.3) | 156,366 (88.6) | |
Smoking status | < 0.001 | ||||||
N-Miss | 69 | 953 | 48 | 39 | 247 | 1,356 | |
Smoke free | 7,509 (86.7) | 103,543 (84.4) | 4,359 (83.1) | 5,119 (91.4) | 29,364 (86.3) | 149,894 (85.1) | |
Passive smoking (only) | 1,130 (13.0) | 18,635 (15.2) | 856 (16.3) | 473 (8.4) | 4,570 (13.4) | 25,664 (14.6) | |
Smoker | 25 (0.3) | 469 (0.4) | 29 (0.6) | 8 (0.1) | 75 (0.2) | 606 (0.3) | |
IUD use | < 0.001 | ||||||
N-Miss | 38 | 822 | 31 | 34 | 185 | 1,110 | |
Ever | 2,450 (28.2) | 26,417 (21.5) | 1,164 (22.1) | 1,010 (18.0) | 8,161 (24.0) | 39,202 (22.2) | |
Current pregnancy outcomes, No. (%) | |||||||
Fetus sex | 0.007 | ||||||
N-miss | 23 | 259 | 7 | 9 | 87 | 385 | |
Female | 4,216 (48.4) | 58,905 (47.8) | 2,464 (46.6) | 2,596 (46.1) | 16,469 (48.2) | 84,650 (47.8) | |
Male | 4,463 (51.2) | 63,924 (51.8) | 2,807 (53.1) | 3,002 (53.3) | 17,577 (51.4) | 91,773 (51.8) | |
Unknown b | 31 (0.4) | 512 (0.4) | 14 (0.3) | 32 (0.6) | 123 (0.4) | 712 (0.4) | |
Preterm births c | 667 (7.6) | 6,235 (5.0) | 351 (6.6) | 364 (6.5) | 1,607 (4.7) | 9,224 (5.2) | < 0.001 |
Congenital anomalies | 0.454 | ||||||
N-Miss | 23 | 261 | 7 | 9 | 87 | 387 | |
Yes | 13 (0.1) | 159 (0.1) | 7 (0.1) | 5 (0.1) | 31 (0.1) | 215 (0.1) | |
Stillbirth | 90 (1.0) | 705 (0.6) | 37 (0.7) | 31 (0.5) | 223 (0.7) | 1,086 (0.6) | < 0.001 |
Female stillbirth | 25 (0.3) | 218 (0.2) | 13 (0.2) | 12 (0.2) | 67 (0.2) | 335 (0.2) | |
Male stillbirth | 33 (0.4) | 261 (0.2) | 13 (0.2) | 9 (0.2) | 90 (0.3) | 406 (0.2) | |
Sex-unknown b stillbirth | 31 (0.4) | 224 (0.2) | 11 (0.2) | 10 (0.2) | 64 (0.2) | 340 (0.2) | |
Sex-missing stillbirth | 1 (0.0) | 2 (0.0) | 0 (0.0) | 0 (0.0) | 2 (0.0) | 5 (0.0) |
Maternal Age | RR (95% CI) | Education | RR (95% CI) | Birth Order | RR (95% CI) | ||||
---|---|---|---|---|---|---|---|---|---|
<20 | 20-35 vs <20 | >35 vs <20 | High | Middle vs High | Low vs High | 1 | 2 vs 1 | >2 vs 1 | |
Dai | 11.98 | 0.84 (0.31,2.28) | 1.27 (0.36,4.46) | 9.16 | 1.11 (0.59,2.09) | 1.18 (0.61,2.30) | 8.15 | 1.45 (0.94,2.25) | 0.92 (0.13,6.70) |
Han | 5.56 | 0.97 (0.61,1.55) | 1.76 (1.05,2.94) | 5.77 | 0.9 (0.76,1.07) | 1.28 (1.03,1.59) | 4.70 | 1.39 (1.19,1.62) | 2.85 (1.85,4.38) |
Hani | 4.33 | 1.73 (0.24,12.57) | 0.60 (0.04,9.55) | 5.10 | 1.48 (0.55,3.95) | 1.47 (0.53,4.11) | 3.22 | 3 (1.31,6.86) | 3.14 (0.66,15.01) |
Miao | 5.68 | 0.96 (0.37,2.51) | 1.05 (0.20,5.39) | 4.81 | 1.04 (0.23,4.68) | 1.25 (0.29,5.37) | 4.33 | 1.35 (0.62,2.92) | 2.8 (0.78,10.11) |
Yi | 4.41 | 1.40 (0.58,3.40) | 3.08 (1.18,8.02) | 5.50 | 1.03 (0.70,1.51) | 1.57 (1.06,2.33) | 5.67 | 1.19 (0.91,1.56) | 3.97 (2.23,7.07) |
Gestational age (weeks) | Number of deliveries (stillbirths) | Hazard/1000 ongoing pregnancies | Relative rate of stillbirth hazard to Han women (95% CI) | |||
---|---|---|---|---|---|---|
Han | Dai | Hani | Miao | Yi | ||
20-23 | 234 (182) | 0.93 | 3.20 (2.23,4.61) | 2.24 (1.33,3.77) | 0.57 (0.19,1.69) | 0.85 (0.57,1.26) |
24-27 | 357 (192) | 1.01 | 1.93 (1.22,3.05) | 1.13 (0.53,2.39) | 1.06 (0.51,2.21) | 1.10 (0.79,1.53) |
28-31 | 1,150 (243) | 1.26 | 1.10 (0.64,1.90) | 1.37 (0.76,2.45) | 1.28 (0.72,2.25) | 1.35 (1.04,1.75) |
32-36 | 7,483 (213) | 1.16 | 1.97 (1.28,3.01) | 0.68 (0.27,1.74) | 0.79 (0.35,1.79) | 1.19 (0.88,1.60) |
37-40 | 151,291 (228) | 2.41 | 1.29 (0.78,2.13) | 1.05 (0.53,2.08) | 1.17 (0.63,2.15) | 1.00 (0.74,1.35) |
41-42 | 17,005 (28) | 2.49 | 1.74 (0.41,7.50) | 0 a | 0 a | 2.87 (1.34,6.15) |