Introduction
Methods
Data sources
Study design and population
Exposure variables
Follow-up and outcome measurement
Statistical analysis
Results
Overview
Exposure variable |
n
| % |
---|---|---|
Birthweight (g) | ||
<2500 | 203,846 | 5.3 |
2500–2999 | 642,599 | 16.8 |
3000–3499 | 1,411,152 | 36.8 |
3500–3999 | 1,138,447 | 29.7 |
4000–5499 | 438,361 | 11.4 |
Total | 3,834,405 | 100 |
Missing | 0 | |
Gestational age at birth (weeks) | ||
<37 | 213,799 | 5.6 |
37–38 | 738,451 | 19.3 |
39–40 | 1,952,998 | 50.9 |
41 | 761,960 | 19.9 |
42–43 | 167,197 | 4.4 |
Total | 3,834,405 | 100 |
Missing | 0 | |
Maternal age at delivery (years) | ||
<25 | 995,238 | 26.0 |
25–29 | 1,040,349 | 27.1 |
30–34 | 1,083,414 | 28.3 |
35–39 | 582,444 | 15.2 |
>40 | 131,798 | 3.4 |
Total | 3,833,243 | 100 |
Missing | 1162 | |
Maternal gestational diabetesa
| ||
No | 3,788,299 | 98.8 |
Yes | 46,106 | 1.2 |
Total | 3,834,405 | 100 |
Missing | 0 | |
Maternal type 1 diabetesa
| ||
No | 3,758,249 | 98.0 |
Yes | 76,156 | 2.0 |
Total | 3,834,405 | 100 |
Missing | 0 | |
Maternal obesitya
| ||
No | 3,740,398 | 97.5 |
Yes | 94,007 | 2.5 |
Total | 3,834,405 | 100 |
Missing | 0 | |
Infant sex | ||
Male | 1,961,175 | 51.2 |
Female | 1,867,440 | 48.8 |
Total | 3,828,615 | 100 |
Missing | 5790 | |
Maternal IMD rank quintile | ||
1 (most deprived) | 763,373 | 20.0 |
2 | 762,752 | 20.0 |
3 | 762,863 | 20.0 |
4 | 763,393 | 20.0 |
5 (least deprived) | 763,832 | 20.0 |
Total | 3,816,213 | 100 |
Missing | 18,192 | |
Caesarean section | ||
No | 2,966,896 | 77.4 |
Yes | 867,509 | 22.6 |
Total | 3,834,405 | 100 |
Missing | 0 |
Crude rates analysis
Potential risk factor | Type 1 diabetes (n) | Rate | Rate ratio (95% CI) | LRT |
p value |
---|---|---|---|---|---|
Birthweight (g) | 5.9 (4) | 0.2058 | |||
<2500 | 156 | 12.0 | 1.01 (0.86, 1.20) | ||
2500–2999 | 483 | 11.9 | 1.00 (0.90, 1.12) | ||
3000–3499 | 1051 | 11.9 | Reference | ||
3500–3999 | 916 | 12.9 | 1.09 (0.99, 1.19) | ||
4000–5499 | 363 | 13.2 | 1.12 (0.99, 1.26) | ||
Gestational age (weeks) | 56.4 (4) | <0.0001 | |||
<37 | 204 | 14.9 | 1.31 (1.13, 1.51) | ||
37–38 | 726 | 15.3 | 1.34 (1.23, 1.47) | ||
39–40 | 1382 | 11.4 | Reference | ||
41 | 520 | 10.8 | 0.95 (0.86, 1.05) | ||
42–43 | 137 | 13.0 | 1.14 (0.96, 1.36) | ||
BFGA quintile | 31.4 (1) | <0.0001, trend | |||
1 (lightest) | 510 | 10.4 | Reference | ||
2 | 549 | 11.3 | 1.08 (0.96, 1.22) | ||
3 | 599 | 12.5 | 1.20 (1.07, 1.35) | ||
4 | 659 | 13.8 | 1.32 (1.18, 1.48) | ||
5 (heaviest) | 651 | 13.7 | 1.31 (1.17, 1.47) | ||
BFGA decile | 33.2 (1) | <0.0001, trend | |||
1 (lightest) | 239 | 9.7 | Reference | ||
2 | 271 | 11.2 | 1.16 (0.97, 1.38) | ||
3 | 283 | 11.5 | 1.19 (1.00, 1.41) | ||
4 | 266 | 11.1 | 1.15 (0.97, 1.37) | ||
5 | 323 | 13.4 | 1.38 (1.17, 1.63) | ||
6 | 276 | 11.6 | 1.20 (1.01, 1.43) | ||
7 | 322 | 13.4 | 1.39 (1.17, 1.64) | ||
8 | 337 | 14.2 | 1.46 (1.24, 1.73) | ||
9 | 290 | 12.2 | 1.26 (1.06, 1.49) | ||
10 (heaviest) | 361 | 15.2 | 1.57 (1.33, 1.84) | ||
Mother’s age at delivery (years) | 12.7 (4) | 0.0129 | |||
<25 | 704 | 11.2 | Reference | ||
25–29 | 805 | 12.3 | 1.10 (0.99, 1.22) | ||
30–34 | 882 | 12.7 | 1.13 (1.03, 1.25) | ||
35–39 | 475 | 13.4 | 1.19 (1.06, 1.34) | ||
40–49 | 103 | 14.3 | 1.28 (1.04, 1.57) | ||
Maternal gestational diabetesa
| 3.6 (1) | 0.0594 | |||
No | 2910 | 12.3 | Reference | ||
Yes | 59 | 15.9 | 1.3 (1.00, 1.68) | ||
Maternal type 1 diabetesa
| 203.4 (1) | <0.0001 | |||
No | 2880 | 12.0 | Reference | ||
Yes | 89 | 90.6 | 7.55 (6.12, 9.33) | ||
Maternal obesitya
| 1.9 (1) | 0.1625 | |||
No | 2897 | 12.3 | Reference | ||
Yes | 72 | 14.6 | 1.19 (0.94, 1.5) | ||
Infant sex | 0.2 (1) | 0.6446 | |||
Male | 1532 | 12.4 | Reference | ||
Female | 1436 | 12.2 | 0.98 (0.92, 1.06) | ||
IMD rank quintile | 5.3 (4) | 0.256 | |||
1 (most deprived) | 549 | 11.5 | Reference | ||
2 | 567 | 12.1 | 1.05 (0.93, 1.18) | ||
3 | 590 | 12.4 | 1.08 (0.96, 1.21) | ||
4 | 628 | 13.0 | 1.13 (1.01, 1.27) | ||
5 (least deprived) | 627 | 12.7 | 1.1 (0.98, 1.24) | ||
Caesarean section | 20.2 (1) | <0.0001 | |||
No | 2209 | 11.8 | Reference | ||
Yes | 760 | 14.3 | 1.21 (1.12, 1.32) |
Multivariable analysis
Gestational age (weeks) | Type 1 diabetes (n) | Partially adjusteda HR (95% CI) | Further adjustedb HR (95% CI) | Fully adjustedc HR (95% CI) |
---|---|---|---|---|
Preterm: <37 | 204 | 1.29 (1.12, 1.50) | 1.19 (1.03, 1.38) | 1.17 (1.01, 1.36) |
Early term: 37–38 | 726 | 1.33 (1.22, 1.46) | 1.27 (1.16, 1.39) | 1.24 (1.13, 1.36) |
Full term: 39–40 | 1382 | Reference | Reference | Reference |
Late term: 41 | 520 | 0.95 (0.86, 1.05) | 0.95 (0.86, 1.05) | 0.95 (0.86, 1.06) |
Post-term: 42–43 | 137 | 1.14 (0.95, 1.35) | 1.14 (0.96, 1.36) | 1.14 (0.96, 1.36) |
Birthweight (g) | Type 1 diabetes (n) | Partially adjusteda HR (95% CI) | Gestational-age adjustedb HR (95% CI) | Further adjustedc HR (95% CI) | Fully adjustedd HR (95% CI) |
---|---|---|---|---|---|
<2500 | 156 | 1.01 (0.85, 1.19) | 0.76 (0.63, 0.92) | 0.81 (0.67, 0.98) | 0.82 (0.67, 0.99) |
2500–2999 | 483 | 1.00 (0.90, 1.11) | 0.90 (0.81, 1.01) | 0.92 (0.82, 1.03) | 0.93 (0.83, 1.04) |
3000–3499 | 1051 | Reference | Reference | Reference | Reference |
3500–3999 | 916 | 1.09 (0.99, 1.19) | 1.15 (1.05, 1.25) | 1.13 (1.03, 1.23) | 1.11 (1.02, 1.22) |
4000–5499 | 363 | 1.12 (0.99, 1.26) | 1.20 (1.07, 1.36) | 1.16 (1.02, 1.31) | 1.12 (0.99, 1.27) |