Association between breastfeeding and lung function measurements in all participants, basic model and fully adjusted model*
| Lung function (unit) | Basic model† | Adjusted model‡ | ||
|---|---|---|---|---|
| estimates (CI) | p Value | estimates (CI) | p Value | |
| FVC§ (L) | ||||
| No BF (mean) | 3.31 (3.12 to 3.49) | 3.39 (3.18 to 3.61) | ||
| BF ≤3 months (% difference) | 3.07 (−4.30 to 10.44) | 0.407 | 4.20 (−3.03 to 11.43) | 0.245 |
| BF >3 months (% difference) | 4.44 (−2.65 to 11.52) | 0.210 | 4.20 (−2.40 to 10.80) | 0.203 |
| FEV1§ (L) | ||||
| No BF (mean) | 2.82 (2.66 to 2.98) | 2.93 (2.73 to 3.13) | ||
| BF ≤3 months (% difference) | 4.33 (−3.43 to 12.08) | 0.264 | 5.42 (−2.34 to 13.17) | 0.160 |
| BF >3 months (% difference) | 5.66 (−1.80 to 13.12) | 0.126 | 5.41 (−1.67 to 12.48) | 0.124 |
| FEF50§ (L/s) | ||||
| No BF (mean) | 3.20 (2.86 to 3.55) | 3.46 (2.98 to 3.95) | ||
| BF ≤3 months (% difference) | 9.16 (−6.04 to 24.35) | 0.217 | 9.71 (−7.14 to 26.56) | 0.237 |
| BF >3 months (% difference) | 9.92 (−4.54 to 24.39) | 0.159 | 9.67 (−5.62 to 24.95) | 0.194 |
| FRC§ (L) | ||||
| No BF (mean) | 1.99 (1.87 to 2.12) | 1.96 (1.79 to 2.13) | ||
| BF ≤3 months (% difference) | 3.03 (−5.57 to 11.64) | 0.483 | 4.72 (−5.12 to 14.55) | 0.336 |
| BF >3 months (% difference) | 6.58 (−1.89 to 15.06) | 0.116 | 5.76 (−3.36 to 14.87) | 0.203 |
| RV§ (L) | ||||
| No BF (mean) | 1.11 (1.01 to 1.21) | 1.08 (0.96 to 1.20) | ||
| BF ≤3 months (% difference) | −1.27 (−12.62 to 10.09) | 0.828 | −0.59 (−12.75 to 11.57) | 0.924 |
| BF >3 months (% difference) | 8.32 (−3.53 to 20.18) | 0.152 | 11.27 (−1.22 to 23.75) | 0.062 |
| TLC§ (L) | ||||
| No BF (mean) | 4.31 (4.11 to 4.51) | 4.38 (4.15 to 4.62) | ||
| BF ≤3 months (% difference) | 3.00 (−3.13 to 9.13) | 0.330 | 4.36 (−1.59 to 10.31) | 0.143 |
| BF >3 months (% difference) | 6.13 (0.12 to 12.14) | 0.039 | 6.57 (0.99 to 12.14) | 0.017 |
| ADC§ (cm2/s) | ||||
| No BF (mean) | 0.09 (0.09 to 0.10) | 0.09 (0.08 to 0.10) | ||
| BF ≤3 months (% difference) | ||||
| Absolute ADC value | 3.00 (−3.58 to 9.57) | 0.365 | 0.59 (−6.31 to 7.49) | 0.867 |
| Average alveolar size¶ | 7.38 (−8.45 to 24.71) | 1.45 (−14.51 to 19.03) | ||
| BF >3 months (% difference) | ||||
| Absolute ADC value | 0.69 (−5.43 to 6.81) | 0.824 | 1.88 (−4.56 to 8.32) | 0.563 |
| Average alveolar size¶ | 1.69 (−12.52 to 17.17) | 4.64 (−10.72 to 21.18) | ||
*The analyses were performed using the natural logarithm of the outcome variable; the estimates were back-transformed from the logarithmic scale to the original scale, therefore the means represent the geometric means, not the arithmetic ones.
†In the basic model we adjusted for age, sex and height.
‡In the adjusted model we included, additionally, preterm status, birth weight, Townsend score, smoking during pregnancy, maternal asthma, maternal ethnicity and early-onset wheeze (wheezing history with onset during the first year of life).
§All analysis were performed using the natural logarithm; the estimates were back-transformed from the logarithmic scale to the original scale, therefore the coefficients are multiplicative (they represent ratios; eg, in the basic model, participants breastfed ≤3 months had an ADC absolute value 3% higher than participants who were not breastfed).
¶Calculated with the formula ADC ratio=(volume ratio)0.415, see Narayanan et al.13
ADC, apparent diffusion coefficient; BF, breastfeeding; FEF50, forced mid-expiratory flow; FEV1, forced expiratory volume at 1 s; FRC, functional residual capacity; FVC, forced vital capacity; RV, residual volume; TLC, total lung capacity.