Background
Methods
Study design and participants
Measures
Exposure
Outcome
Statistical analysis
Covariates
Results
Cesarean section | |||||
---|---|---|---|---|---|
No | Yes | ||||
(n = 58,530) | (n = 13,348) | ||||
n | (%) | n | (%) | p | |
Toddler | |||||
Infant sex | |||||
Male | 29,855 | (51.0) | 6,809 | (51.0) | 0.994 |
Female | 28,675 | (49.0) | 6,539 | (49.0) | |
Any major congenital anomaly | |||||
No | 57,394 | (98.1) | 12,892 | (96.6) | < 0.001 |
Yes | 1,136 | (1.9) | 456 | (3.4) | |
Gestational age, wk | |||||
≥41 | 5,786 | (9.9) | 1,012 | (7.6) | < 0.001 |
37–40 | 50,898 | (87.0) | 10,914 | (81.8) | |
34–36 | 1,654 | (2.8) | 965 | (7.2) | |
<34 | 192 | (0.3) | 457 | (3.4) | |
Started solid food at 6 months | |||||
No | 42,934 | (73.4) | 9,367 | (70.2) | < 0.001 |
Yes | 14,669 | (25.1) | 3,744 | (28.1) | |
Missing | 927 | (1.6) | 237 | (1.8) | |
Breastfeeding | |||||
Already weaned or formula-fed | 21,989 | (37.6) | 5,701 | (42.7) | < 0.001 |
Yes at least till 1 year | 25,749 | (44.0) | 5,156 | (38.6) | |
Yes at least till 2 years | 9,546 | (16.3) | 2,226 | (16.7) | |
Missing | 1,246 | (2.1) | 265 | (2.0) | |
Attendance at a childcare facility (daycare center/nursery) at 1 year | |||||
No | 42,262 | (72.2) | 9,661 | (72.4) | 0.541 |
Yes | 14,763 | (25.2) | 3,366 | (25.2) | |
Missing | 1,505 | (2.6) | 321 | (2.4) | |
Attendance at a preschool or childcare facility (daycare center/nursery) at 3 years | |||||
No | 21,218 | (36.3) | 4,658 | (34.9) | 0.012 |
Yes | 35,579 | (60.8) | 8,278 | (62.0) | |
Missing | 1,733 | (3.0) | 412 | (3.1) | |
Constipation at 1 year | |||||
No | 56,204 | (96.0) | 12,855 | (96.3) | 0.321 |
Yes | 776 | (1.3) | 164 | (1.2) | |
Missing | 1,550 | (2.7) | 329 | (2.5) | |
Mother | |||||
Age during pregnancy, y | |||||
<25 | 5,705 | (9.8) | 802 | (6.0) | < 0.001 |
25 to <30 | 17,245 | (29.5) | 2,842 | (21.3) | |
30 to <35 | 20,950 | (35.8) | 4,635 | (34.7) | |
≥35 | 14,286 | (24.4) | 4,960 | (37.2) | |
Missing | 344 | (0.6) | 109 | (0.8) | |
Pre-pregnancy body mass index, kg/m2 | |||||
<18.5 | 9,947 | (17.0) | 1,719 | (12.9) | < 0.001 |
18.5 to <25 | 43,514 | (74.3) | 9,523 | (71.3) | |
≥25 | 5,036 | (8.6) | 2,096 | (15.7) | |
Missing | 33 | (0.1) | 10 | (0.1) | |
Parity | |||||
Primipara | 25,128 | (42.9) | 5,759 | (43.2) | 0.902 |
Multipara | 31,904 | (54.5) | 7,250 | (54.3) | |
Missing | 1,498 | (2.6) | 339 | (2.5) | |
Maternal history of allergy | |||||
No | 29,208 | (49.9) | 6,663 | (49.9) | 0.993 |
Yes | 28,989 | (49.5) | 6,608 | (49.5) | |
Missing | 333 | (0.6) | 77 | (0.6) | |
Use of antibacterial drug during pregnancy | |||||
No | 52,370 | (89.5) | 11,906 | (89.2) | 0.345 |
Yes | 6,160 | (10.5) | 1,442 | (10.8) | |
Annual household income, million Japanese yen | |||||
<4 | 21,211 | (36.2) | 4,783 | (35.8) | 0.047 |
4 to <6 | 18,282 | (31.2) | 4,098 | (30.7) | |
≥6 | 14,882 | (25.4) | 3,549 | (26.6) | |
Missing | 4,155 | (7.1) | 918 | (6.9) | |
Highest education level, y | |||||
≤12 | 19,602 | (33.5) | 4,600 | (34.5) | < 0.001 |
>12 to <16 | 24,733 | (42.3) | 5,737 | (43.0) | |
≥16 | 13,578 | (23.2) | 2,836 | (21.3) | |
Missing | 617 | (1.1) | 175 | (1.3) | |
Employed during pregnancy | |||||
No | 26,177 | (44.7) | 5,982 | (44.8) | 0.025 |
Yes | 31,553 | (53.9) | 7,143 | (53.5) | |
Missing | 800 | (1.4) | 223 | (1.7) | |
Marital status | |||||
Married | 55,577 | (95.0) | 12,728 | (95.4) | < 0.001 |
Single | 2,004 | (3.4) | 383 | (2.9) | |
Divorced or widowed | 386 | (0.7) | 118 | (0.9) | |
Missing | 563 | (1.0) | 119 | (0.9) | |
Physical activity | |||||
No | 13,625 | (23.3) | 3,404 | (25.5) | < 0.001 |
Yes | 44,424 | (75.9) | 9,802 | (73.4) | |
Missing | 481 | (0.8) | 142 | (1.1) | |
Quintile of energy intake, cal | |||||
Q1 (≤1,228) | 11,389 | (19.5) | 2,566 | (19.2) | 0.001 |
Q2 ( 1,229–1,490) | 11,934 | (20.4) | 2,583 | (19.4) | |
Q3 ( 1,491–1,750) | 11,807 | (20.2) | 2,697 | (20.2) | |
Q4 ( 1,751–2,127) | 11,687 | (20.0) | 2,680 | (20.1) | |
Q5 (≥2,128) | 11,368 | (19.4) | 2,712 | (20.3) | |
Missing | 345 | (0.6) | 110 | (0.8) | |
Smoking status at 1 month | |||||
Never smoked | 35,428 | (60.5) | 7,755 | (58.1) | < 0.001 |
Previously smoked but quit before finding out about the current pregnancy | 12,936 | (22.1) | 3,126 | (23.4) | |
Previously smoked but quit after finding out about the current pregnancy | 7,795 | (13.3) | 1,815 | (13.6) | |
Still smokes (1–10 per day) | 1,558 | (2.7) | 394 | (3.0) | |
Still smokes (≥11 per day) | 368 | (0.6) | 95 | (0.7) | |
Missing | 445 | (0.8) | 163 | (1.2) | |
Passive smoking status at 1 month | |||||
No one smoked | 28,634 | (48.9) | 6,564 | (49.2) | < 0.001 |
Someone smoked but not in the presence of the baby | 28,212 | (48.2) | 6,308 | (47.3) | |
Someone smoked in the presence of the baby | 1,295 | (2.2) | 298 | (2.2) | |
Missing | 389 | (0.7) | 178 | (1.3) | |
Alcohol consumption at 1 month | |||||
Never drank | 53,390 | (91.2) | 12,045 | (90.2) | < 0.001 |
Drank in the past but stopped drinking | 2,535 | (4.3) | 603 | (4.5) | |
Still drinks | 2,205 | (3.8) | 538 | (4.0) | |
Missing | 400 | (0.7) | 162 | (1.2) |
“Yes” answer | ||
---|---|---|
n | (%)a | |
1. Two or fewer defecations per week | 3,315 | (4.6) |
2. At least 1 episode per week of incontinence after the acquisition of toileting skills | 4,609 | (6.4) |
3. History of excessive stool retention | 5,795 | (8.1) |
4. History of painful or hard bowel movements | 14,704 | (20.5) |
5. Presence of a large fecal mass in the rectum | 4,787 | (6.7) |
6. History of large-diameter stools that may obstruct the toilet | 2,040 | (2.8) |
Cesarean section | ||
---|---|---|
No | Yes | |
Prevalence, % | 12.1 | 13.1 |
Cases, n | 7,060 | 1,751 |
Subtotal, n | 58,530 | 13,348 |
Crude odds ratio | 1.000 (Ref.) | 1.101 [1.041, 1.164] |
Adjusted odds ratioa | 1.000 (Ref.) | 1.064 [1.004, 1.128] |