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Published on: February 2, 2017
Which factors could explain the low birth weight paradox?
Antônio Augusto Moura da Silva1, Heloisa Bettiol, Marco Antonio Barbieri
1Departamento de Saúde Pública, Universidade Federal do Maranhão, São Luís, MA, Brasil. aasilva@elo.com.br
Revista De Saude Publica
|October 26, 2006
Summary
Maternal smoking significantly explains the higher low birth weight rate in a developed Brazilian city compared to a less developed one. This factor was key in understanding the unexpected birth weight disparity.
Area of Science:
- Public Health
- Epidemiology
- Perinatal Health
Background:
- Low birth weight (LBW) is typically less common in affluent populations.
- Brazil presents a paradox: a more developed city shows a higher LBW rate than a less developed one.
- This discrepancy necessitates an investigation into the underlying causes.
Purpose of the Study:
- To investigate the reasons behind the higher low birth weight rate in Ribeirão Preto compared to São Luís.
- To identify specific risk factors contributing to this unexpected epidemiological pattern.
Main Methods:
- Comparative analysis of two birth cohorts: Ribeirão Preto (10.7% LBW) and São Luís (7.6% LBW).
- Inclusion of 2,839 newborns from Ribeirão Preto (1994) and 2,439 from São Luís (1997-1998).
- Application of multiple logistic regression analysis, adjusted for potential confounders.
Main Results:
- Maternal smoking, primiparity, and young maternal age (<18) were LBW risk factors in São Luís.
- In Ribeirão Preto, LBW risk factors included lower-middle family income, young (<18) and advanced maternal age (≥35), maternal smoking, and cesarean section.
- Ribeirão Preto exhibited a 45% higher LBW risk than São Luís, significantly reduced (49%) after adjusting for maternal smoking, indicating its crucial role.
Conclusions:
- Maternal smoking emerged as the primary factor explaining the observed difference in low birth weight rates between the two Brazilian cities.
- While other factors like cesarean section rates played a role, their contribution to the disparity was less significant compared to maternal smoking.
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