Table 4. Instrumental Variable and Observational Associations of Duration and Exclusivity of Breastfeeding (≥3 Months vs <3 Months) With Atopic Eczema, Lung Function, and Asthma Outcomes.
| Variable | Instrumental Variable Analysis, OR (95% CI) | Observational Analysis, OR (95% CI) | ||
|---|---|---|---|---|
| Cluster Adjusted | Further Adjusteda | Cluster Adjusted | Further Adjusteda | |
| Flexural eczema on skin examination | 0.34 (0.13 to 0.85) |
0.34 (0.16 to 0.72) |
0.70 (0.36 to 1.36) |
0.64 (0.33 to 1.25) |
| Flexural eczema past year | 0.55 (0.19 to 1.60) |
0.56 (0.22 to 1.38) |
0.89 (0.50 to 1.60) |
0.85 (0.47 to 1.53) |
| Persistent flexural eczema past year | 0.40 (0.14 to 1.12) |
0.39 (0.15 to 1.01) |
0.71 (0.29 to 1.75) |
0.70 (0.28 to 1.72) |
| Sleep disturbed flexural eczema past year (ever) | 0.41 (0.13 to 1.23) |
0.46 (0.17 to 1.25) |
0.96 (0.41 to 2.23) |
0.98 (0.41 to 2.30) |
| Wheezing past 12 mo | 0.86 (0.44 to 1.68) |
0.73 (0.38 to 1.40) |
1.02 (0.85 to 1.24) |
1.03 (0.85 to 1.24) |
| Ever asthma | 0.85 (0.39 to 1.85) |
0.82 (0.41 to 1.63) |
0.99 (0.70 to 1.39) |
0.98 (0.70 to 1.38) |
| Asthma attack in past 12 mo | 1.14 (0.50 to 2.59) |
1.06 (0.51 to 2.18) |
1.35 (0.75 to 2.44) |
Did not converge |
Abbreviation: OR, odds ratio.
a
Adjusted for stratum-level variables (urban vs rural and East vs West Belarus), and for child age at follow-up, sex, birthweight, and maternal and paternal education. Asthma and lung function models were also adjusted for gestational age at birth.