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An R-Based Landscape Validation of a Competing Risk Model
Published on: September 16, 2022
MODELLING THE RISK FACTORS FOR BIRTH WEIGHT IN TWIN GESTATIONS: A QUANTILE REGRESSION APPROACH
A John Michael1, Belavendra Antonisamy1, S Mahasampath Gowri1
1Department of Biostatistics,Christian Medical College,Vellore,India.
Insights
Maternal education significantly impacts low birth weight in twins, particularly at lower birth weight quantiles. Quantile regression reveals differential risk factor effects, outperforming ordinary least squares (OLS) estimates.
Area of Science:
- Obstetrics and Gynecology
- Perinatology
- Biostatistics
Background:
- Birth weight is a key indicator of newborn health, with low birth weight (LBW) associated with adverse short- and long-term child growth outcomes.
- LBW is more prevalent in twin gestations, necessitating specialized risk factor analysis.
- Traditional statistical methods may not fully capture the complex interplay of factors influencing birth weight distribution.
Purpose of the Study:
- To investigate the influence of maternal and socio-demographic factors on various quantiles of birth weight in twin gestations.
- To compare the efficacy of quantile regression against ordinary least squares (OLS) for identifying risk factors in twin pregnancies.
- To understand how different risk factors affect the entire spectrum of birth weight, not just the average.
Main Methods:
- Retrospective analysis of 1304 twin pregnancy records from 1991-2005 at Christian Medical College, Vellore, India.
- Application of quantile regression to assess risk factor effects across different birth weight percentiles.
- Comparison of quantile regression results with OLS estimates.
Main Results:
- Gestational age, chroniocity, gravida, and child's sex demonstrated significant effects across all birth weight quantiles.
- Maternal age showed no significant association with birth weight at any quantile.
- Maternal and paternal education exhibited substantial impact on lower birth weight quantiles (10th and 25th), effects underestimated by OLS.
Conclusions:
- Quantile regression is a valuable tool for analyzing risk factors in twin gestations, providing a more nuanced understanding than OLS.
- Socio-demographic factors, especially parental education, play a critical role in determining birth weight at the lower end of the distribution.
- The study highlights the importance of considering the entire birth weight distribution when assessing risk factors in twin pregnancies.
Abstract:
Birth weight is used as a proxy for the general health condition of newborns. Low birth weight leads to adverse events and its effects on child growth are both short- and long-term. Low birth weight babies are more common in twin gestations. The aim of this study was to assess the effects of maternal and socio-demographic risk factors at various quantiles of the birth weight distribution for twin gestations using quantile regression, a robust semi-parametric technique. Birth records of multiple pregnancies from between 1991 and 2005 were identified retrospectively from the birth registry of the Christian Medical College and hospitals in Vellore, India. A total of 1304 twin pregnancies were included in the analysis. Demographic and clinical characteristics of the mothers were analysed. The mean gestational age of the twins was 36 weeks with 51% having preterm labour. As expected, the examined risk factors showed different effects at different parts of the birth weight distribution. Gestational age, chroniocity, gravida and child's sex had significant effects in all quantiles. Interestingly, mother's age had no significant effect at any part of the birth weight distribution, but both maternal and paternal education had huge impacts in the lower quantiles (10th and 25th), which were underestimated by the ordinary least squares (OLS) estimates. The study shows that quantile regression is a useful method for risk factor analysis and the exploration of the differential effects of covariates on an outcome, and exposes how OLS estimates underestimate and overestimate the effects of risk factors at different parts of the birth weight distribution.
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