Table 3.
Associations between infant weight gain from birth to 2 years of age and bone mineral content, bone mineral density and bone area at 4 years of age
| Base model | Multivariable model* | Multivariable model including concurrent HAZ† | Multivariable model including concurrent HAZ & WAZ‡ | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Difference in bone outcome§ | 95 % CI | P | Difference in bone outcome§ | 95 % CI | P | Difference in bone outcome§ | 95 % CI | P | Difference in bone outcome§ | 95 % CI | P | |
| TBLH BMC (g) | ||||||||||||
| cWAZ (6 months) | 12·1 | 6·3, 17·9 | <0·001 | 13·2 | 8·1, 18·3 | <0·001 | 6·7 | 3·8, 9·5 | <0·001 | 0·4 | –2·5, 3·3 | 0·80 |
| cWAZ (12 months) | 8·9 | 0·4, 17·3 | 0·04 | 11·6 | 4·2, 19·0 | 0·002 | 5·1 | 1·1, 9·1 | 0·01 | –1·8 | –5·8, 2·2 | 0·38 |
| cWAZ (24 months) | 28·3 | 19·7, 36·9 | <0·001 | 29·3 | 21·8, 36·9 | <0·001 | 18·2 | 14·0, 22·3 | <0·001 | 7·6 | 3·2, 12·0 | 0·001 |
| HAZ at 4 years | – | – | – | – | 43·1 | 40·8, 45·5 | <0·001 | 27·2 | 23·3, 31·0 | <0·001 | ||
| WAZ at 4 years | – | – | – | – | – | – | 19·8 | 15·8, 23·8 | <0·001 | |||
| TBLH aBMD (g/cm2) | ||||||||||||
| cWAZ (6 months) | 0·010 | 0·006, 0·015 | <0·001 | 0·010 | 0·006, 0·015 | <0·001 | 0·007 | 0·003, 0·010 | <0·001 | 0·001 | –0·002, 0·005 | 0·46 |
| cWAZ (12 months) | 0·008 | 0·002, 0·015 | 0·02 | 0·009 | 0·002, 0·015 | 0·006 | 0·005 | –0·0002, 0·010 | 0·06 | –0·001 | –0·006, 0·004 | 0·76 |
| cWAZ (24 months) | 0·024 | 0·017, 0·031 | <0·001 | 0·024 | 0·017, 0·030 | <0·001 | 0·017 | 0·012, 0·022 | <0·001 | 0·008 | 0·003, 0·014 | 0·004 |
| HAZ at 4 years | – | – | – | – | 0·026 | 0·023, 0·029 | <0·001 | 0·013 | 0·008, 0·018 | <0·001 | ||
| WAZ at 4 years | – | – | – | – | – | – | 0·016 | 0·011, 0·021 | <0·001 | |||
| TBLH bone area (cm2) | ||||||||||||
| cWAZ (6 months) | 12·8 | 5·0, 20·6 | 0·001 | 15·0 | 8·3, 21·6 | <0·001 | 5·9 | 2·7, 9·2 | <0·001 | –0·2 | –3·7, 3·2 | 0·89 |
| cWAZ (12 months) | 7·2 | –4·3, 18·6 | 0·22 | 12·3 | 2·4, 22·2 | 0·02 | 3·3 | –1·4, 8·0 | 0·17 | –3·5 | –8·2, 1·3 | 0·15 |
| cWAZ (24 months) | 26·9 | 15·2, 38·5 | <0·001 | 29·1 | 19·1, 39·1 | <0·001 | 13·6 | 8·6, 18·6 | <0·001 | 3·2 | –2·2, 8·6 | 0·24 |
| HAZ at 4 years | – | – | – | – | 59·7 | 57·0, 62·5 | <0·001 | 44·1 | 39·4, 48·8 | <0·001 | ||
| WAZ at 4 years | – | – | – | – | – | – | 19·4 | 14·6, 24·2 | <0·001 | |||
n 599 for all models. aBMD, areal bone mineral density; BMC, bone mineral content; cWAZ, conditional weight-for-age z-score; HAZ, height-for-age z-score; TBLH, total body less head; WAZ, weight-for-age z-score.
Models adjusted for asset index quintile, presence of hand soap at handwashing station, household smoking, LAZ within 45 d of birth, WAZ within 45 d of birth, maternal age (years), maternal height (cm), mid-gestation maternal Hb concentrations (g/l), gestational age at birth (weeks), maternal education category, vitamin D intervention group assigned at enrolment to the MDIG trial, treatment of drinking water, child sex, exclusive breast-feeding duration (weeks) and presence of diarrheal episodes in the first 6 months of life.
Models adjusted for covariates in multivariable model and HAZ at 4 years of age.
Models adjusted for covariates in multivariable model and HAZ at 4 years of age and WAZ at 4 years of age.
Effect estimate represents the difference in bone outcome per 1 unit increase in cWAZ, HAZ or WAZ.