| Literature DB >> 26075400 |
Katherine A Thurber1, Timothy Dobbins1, Martyn Kirk1, Phyll Dance2, Cathy Banwell1.
Abstract
Aboriginal and Torres Strait Islander Australians are more likely than non-Indigenous Australians to be obese and experience chronic disease in adulthood--conditions linked to being overweight in childhood. Birthweight and prenatal exposures are associated with increased Body Mass Index (BMI) in other populations, but the relationship is unclear for Indigenous children. The Longitudinal Study of Indigenous Children is an ongoing cohort study of up to 1,759 children across Australia. We used a multilevel model to examine the association between children's birthweight and BMI z-score in 2011, at age 3-9 years, adjusted for sociodemographic and maternal factors. Complete data were available for 682 of the 1,264 children participating in the 2011 survey; we repeated the analyses in the full sample with BMI recorded (n=1,152) after multilevel multiple imputation. One in ten children were born large for gestational age, and 17% were born small for gestational age. Increasing birthweight predicted increasing BMI; a 1-unit increase in birthweight z-score was associated with a 0.22-unit (95% CI:0.13, 0.31) increase in childhood BMI z-score. Maternal smoking during pregnancy was associated with a significant increase (0.25; 95% CI:0.05, 0.45) in BMI z-score. The multiple imputation analysis indicated that our findings were not distorted by biases in the missing data. High birthweight may be a risk indicator for overweight and obesity among Indigenous children. National targets to reduce the incidence of low birthweight which measure progress by an increase in the population's average birthweight may be ignoring a significant health risk; both ends of the spectrum must be considered. Interventions to improve maternal health during pregnancy are the first step to decreasing the prevalence of high BMI among the next generation of Indigenous children.Entities:
Mesh:
Year: 2015 PMID: 26075400 PMCID: PMC4468174 DOI: 10.1371/journal.pone.0130039
Source DB: PubMed Journal: PLoS One ISSN: 1932-6203 Impact factor: 3.240
Fig 1Flow chart of the LSIC study population.
* These numbers refer to interviews with the primary carer.
Distribution of Body Mass Index in LSIC Wave 4 (2011), across potential demographic and physiological confounders.
| n | Mean BMI z-score | 95% CI | % Underweight | % Normal weight | % Overweight / obese | |
|---|---|---|---|---|---|---|
|
| 1,152 | 0.28 | [0.19, 0.36] | 4.3 | 79.3 | 16.4 |
|
| ||||||
| Male | 582 | 0.28 | [0.16, 0.39] | 4.5 | 78.7 | 16.8 |
| Female | 570 | 0.27 | [0.16, 0.39] | 4.2 | 79.8 | 16.0 |
|
| ||||||
| 3–4 years | 237 | 0.36 | [0.19, 0.54] | 3.4 | 86.1 | 10.6 |
| 4–5 years | 401 | 0.28 | [0.14, 0.41] | 4.2 | 87.0 | 8.7 |
| 5–7 years | 245 | 0.20 | [0.02, 0.37] | 4.5 | 73.5 | 22.0 |
| 7–9 years | 269 | 0.26 | [0.08, 0.45] | 5.2 | 66.9 | 27.9 |
|
| ||||||
| Aboriginal | 1,027 | 0.27 | [0.18, 0.35] | 4.4 | 79.7 | 16.0 |
| Torres Strait Islander | 71 | 0.43 | [0.08, 0.77] | 5.6 | 73.2 | 21.1 |
| Both | 54 | 0.25 | [-0.13, 0.62] | 1.9 | 79.6 | 18.5 |
|
| ||||||
| SGA | 142 | -0.04 | [-0.27, 0.18] | 5.6 | 81.0 | 13.4 |
| AGA | 628 | 0.45 | [0.34, 0.55] | 2.6 | 79.1 | 18.3 |
| LGA | 91 | 0.66 | [0.36, 0.97] | 4.4 | 73.6 | 22.0 |
| Missing | 291 | -0.06 | [-0.23, 0.11] | 7.6 | 80.4 | 12.0 |
|
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| No diabetes | 987 | 0.29 | [0.21, 0.38] | 4.0 | 80.5 | 15.6 |
| Diabetes | 71 | 0.64 | [0.27, 1.02] | 1.4 | 71.8 | 26.8 |
| Missing | 94 | -0.16 | [-0.51, 0.18] | 10.6 | 72.3 | 17.0 |
|
| ||||||
| No | 513 | 0.26 | [0.14, 0.38] | 3.5 | 79.9 | 16.6 |
| Yes | 507 | 0.31 | [0.19, 0.44] | 4.5 | 79.5 | 16.0 |
| Missing | 132 | 0.18 | [-0.10, 0.45] | 6.8 | 75.8 | 17.4 |
|
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| Okay or not enough | 767 | 0.25 | [0.15, 0.35] | 4.8 | 79.4 | 15.8 |
| Too much | 107 | 0.77 | [0.48, 1.05] | 0.0 | 71.0 | 29.0 |
| Missing | 278 | 0.16 | [-0.02, 0.33] | 4.7 | 82.0 | 13.3 |
|
| ||||||
| Most advantaged | 215 | 0.43 | [0.23, 0.62] | 3.7 | 78.6 | 17.7 |
| Mid-advantaged | 699 | 0.41 | [0.31, 0.51] | 3.0 | 78.4 | 18.6 |
| Most disadvantaged | 238 | -0.27 | [-0.45, -0.08] | 8.8 | 82.4 | 8.8 |
a Includes only the sample with no missing data on BMI z-score. BMI categories were defined based on WHO standard cut-offs, which are more conservative for children ≤5 years compared to >5 years of age [16, 19]. Size for gestational age categories were defined using cut-off points of z = -1.28 and z = +1.28 were used, in alignment with standard percentile cut-offs.
Fig 2The association between BMI z-score, birthweight z-score, demographic factors, and physiological factors.
*The final model was adjusted for: age group; Indigenous identification; maternal diabetes, smoking, and weight gain during pregnancy; and area-level socioeconomic status. See S1 Table for the results of the preliminary models.