Background
Methods
Results
Characteristic | N (%) |
---|---|
Sex | |
Male | 3504 (51.1) |
Female | 3357 (48.9) |
Country | |
US-Colorado | 1110 (16.2) |
US-Georgia/Florida | 653 (9.5) |
US-Washington | 1001 (14.6) |
US-satellite sites | 7 (0.1) |
Germany | 436 (6.4) |
Finland | 1557 (22.7) |
Sweden | 2097 (30.6) |
Maternal Education | |
Basic Primary | 1252 (18.7) |
High School | 1648 (24.6) |
Beyond High School | 3800 (56.7) |
missing | 161 |
Age of Mother at Birth | |
< 25 years | 763 (11.1) |
25–29 years | 1997 (29.1) |
30–34 years | 2470 (36.0) |
> 35 years | 1631 (23.8) |
Number of room in house residence | |
≤ 3 rooms | 780 (11.7) |
3–6 rooms | 3641 (54.4) |
> 6 rooms | 2269 (33.9) |
missing | 171 |
Maternal Working Status at 9 months | |
Working | 2385 (35.7) |
Not Working | 4289 (64.3) |
missing | 187 |
Maternal Smoking Status at 9 months | |
Smoker | 618 (9.2) |
Non-smoker | 6092 (90.8) |
missing | 151 |
Age Child Started Daycare or joined social group | |
< 3 months | 2065 (30.7) |
3–6 months | 1647 (24.5) |
6–12 months | 1266 (18.8) |
12–18 months | 920 (13.7) |
≥ 18 months or no | 839 (12.5) |
missing | 124 |
Child Birthweight | |
SGA (< 2500 g) | 221 (3.3) |
AGA (2500–4000 g) | 5369 (90.2) |
LGA (> 4000 g) | 1102 (16.5) |
missing | 169 |
First Degree Relative with Type 1 Diabetes | |
Yes | 798 (11.6) |
No | 6063 (88.4) |
Single child in house at 9 months of age | |
Yes | 2806 (41.9) |
No | 3896 (58.1) |
missing | 159 |
Breastfeeding Duration | |
< 3 months | 1724 (25.2) |
3–6 months | 834 (12.2) |
6–9 months | 1420 (20.8) |
9–12 months | 1299 (19.0) |
12–15 months | 726 (10.6) |
15–18 months | 335 (4.9) |
> 18 months | 495 (7.3) |
missing | 28 |
Exclusive Breastfeeding Duration | |
< 3 months | 5201 (75.8) |
3–6 months | 1371 (20.0) |
6–9 months | 287 (4.2) |
9–12 months | 2 (0.0) |
Are exclusive and non-exclusive breastfeeding associated with presence of infection between age 3 and 6 months?
Is breastfeeding associated with presence of infection between 6 and 18 months of age?
Infection/symptoms | Age period 3 to 6 months | Age period > 6 to 18 months | ||
---|---|---|---|---|
Breastfed Yes vs. No a-OR (95% CI) | Breastfed Yes vs. No a-OR (95% CI) | p-value | ||
Respiratory | 1.04 (0.91–1.19) | 0.61 |
1.17 (1.09–1.26)
|
< 0.0001
|
With fever |
0.82 (0.70–0.95)
|
0.008
|
1.08 (1.01–1.15)
|
0.04
|
Common cold | 1.10 (0.97–1.26) | 0.15 |
1.25 (1.17–1.34)
|
< 0.0001
|
Laryngitis and tracheitis | 0.88 (0.52–1.49) | 0.64 |
0.79 (0.63–0.97)
|
0.03
|
Influenza | – | 0.85 (0.63–1.15) | 0.29 | |
Enterovirus | – | 0.97 (0.71–1.33) | 0.87 | |
Tonsillitis or Streptococcal pharyngitis | – | 1.02 (0.76–1.37) | 0.91 | |
Infection of the middle ear |
0.76 (0.62–0.94)
|
0.01
|
0.89 (0.82–0.97)
|
0.008
|
Bronchitis and lower resp. infection | 0.87 (0.71–1.06) | 0.17 | 1.00 (0.91–1.10) | 0.93 |
Conjunctivitis | 1.17 (0.87–1.57) | 0.29 |
0.86 (0.74–1.00)
|
0.04
|
Gastrointestinal |
0.66 (0.53–0.83)
|
0.0003
| 0.96 (0.88–1.05) | 0.96 |
With fever |
0.58 (0.41–0.82)
|
0.0002
| 0.91 (0.79–1.03) | 0.14 |
Infective gastroenteritis |
0.55 (0.46–0.70)
|
< 0.0001
|
0.89 (0.81–0.98)
|
0.01
|
Gastroenteritis symptoms |
0.69 (0.51–0.93)
|
0.02
| 1.05 (0.94–1.16) | 0.40 |
Does length of exclusive breastfeeding alter the change in odds of an infection after breastfeeding has stopped?
Length of exclusive Breastfeeding on odds of infection in a 3 month period | ||
---|---|---|
/ months a-OR (95% CI) | p-value | |
Respiratory | ||
Overall | 1.009 (0.994–1.023) | 0.25 |
With fever | 1.004 (0.990–1.017) | 0.61 |
Common cold | 1.013 (0.999–1.028) | 0.07 |
Laryngitis and tracheitis | 0.985 (0.939–1.033) | 0.54 |
Influenza | 1.027 (0.983–1.073) | 0.23 |
Enterovirus | 1.002 (0.959–1.048) | 0.92 |
Tonsillitis or Streptococcal pharyngitis | 0.996 (0.956–1.035) | 0.84 |
Infection of the middle ear |
0.971 (0.952–0.991)
|
0.004
|
Bronchitis and lower resp. infection | 0.993 (0.974–1.012) | 0.48 |
Conjunctivitis | 0.988 (0.964–1.012) | 0.33 |
Gastrointestinal | ||
Overall | 1.010 (0.996–1.024) | 0.16 |
With fever | 0.998 (0.977–1.018) | 0.81 |
Infective gastroenteritis | 1.014 (0.997–1.031) | 0.11 |
Gastroenteritis symptoms | 1.010 (0.994–1.026) | 0.22 |
Are the associations between breastfeeding and reported infections modified by sex of child, place of residence or season?
Factor | N | % Reporting febrile respiratory infection by whether or not child still breastfeeding at 3 months of age | Breastfeeding on odds of Febrile respiratory infection between 3 and 6 months of age | |||
---|---|---|---|---|---|---|
No | Yes | a-OR | 95% CI | Interaction p-value | ||
Gender | ||||||
Female | N = 3276 | 24.9% | 20.4% |
0.66
|
0.54–0.83
| |
Male | N = 3418 | 23.3% | 23.9% |
0.98
|
0.80–1.21
|
0.01
|
Continent | ||||||
US | N = 2665 | 19.1% | 15.6% | 0.80 | 0.62–1.03 | |
Europe | N = 4029 | 28.9% | 26.0% | 0.82 | 0.68–0.99 | 0.51 |
Season age 3mo | ||||||
Dec – Feb | N = 1595 | 26.9 | 19.5 |
0.56
|
0.41–0.76
| |
Mar – May | N = 1275 | 29.9 | 27.0 |
0.85
|
0.64–1.12
| |
Jun – Aug | N = 1672 | 24.0 | 25.6 |
1.05
|
0.78–1.43
| |
Sept - Nov | N = 1730 | 16.5 | 16.5 |
0.83
|
0.59–1.16
|
0.02
|
Factor | N | % Reporting infection of middle ear by whether or not child still breastfeeding at 3 months of age | Breastfeeding on odds of infection of middle between 3 and 6 months of age | |||
---|---|---|---|---|---|---|
No | Yes | a-OR | 95%CI | Interaction p-value | ||
Gender | ||||||
Female | N = 3276 | 14.1% | 9.0% |
0.55
|
0.41–0.74
| |
Male | N = 3418 | 12.2% | 11.4% |
1.02
|
0.77–1.35
|
0.02
|
Continent | ||||||
US | N = 2665 | 17.4% | 13.6% | 0.76 | 0.58–0.99 | |
Europe | N = 4029 | 9.1% | 8.4% | 0.77 | 0.57–1.05 | 0.68 |
Season age 3mo | ||||||
Dec – Feb | N = 1595 | 14.2% | 7.8% |
0.45
|
0.29–0.70
| |
Mar – May | N = 1275 | 15.6% | 12.1% |
0.77
|
0.53–1.12
| |
Jun – Aug | N = 1672 | 12.8% | 13.1% |
1.00
|
0.67–1.48
| |
Sept - Nov | N = 1730 | 10.4% | 8.1% |
0.85
|
Few infections
|
0.02
|