Birthweight Related Factors in Northwestern Iran: Using Quantile Regression Method
Ramazan Fallah1, Anoshirvan Kazemnejad, Farid Zayeri
1. r.fallahvalamdehi@modares.ac.ir.
Insights
Quantile regression offers a more comprehensive analysis of birthweight factors than traditional methods. This study in Zanjan province highlights its value for understanding infant health indicators.
Area of Science:
- Medical Statistics
- Perinatal Health
- Epidemiology
Background:
- Birthweight is a critical predictor of adult health and a key infant health indicator.
- Maintaining balanced birthweight is a global health system priority.
- This study focuses on assessing neonatal birthweight in Zanjan province.
Purpose of the Study:
- To evaluate neonatal birthweight in Zanjan province.
- To compare the efficacy of quantile regression versus multiple linear regression for birthweight analysis.
Main Methods:
- Analytical descriptive study utilizing pre-registered data (March 2010 - March 2012).
- Employed multiple-stage cluster sampling in Zanjan province's urban and rural health centers.
- Analyzed data using multiple linear regression and quantile regression with SAS 9.2 software.
Main Results:
- Analyzed 8456 neonates; 49% were female, with a mean maternal age of 27.1 years.
- Mean neonatal birthweight was 3104 ± 431 grams; 6.8% were low birthweight (<2500g).
- Gestational age, maternal weight, and maternal education significantly correlated with birthweight across quantiles; other factors showed no consistent significance.
Conclusions:
- Multiple linear regression and quantile regression yielded different results.
- Quantile regression is recommended for analyzing asymmetric response variables or data with outliers in birthweight studies.
Introduction:
Birthweight is one of the most important predicting indicators of the health status in adulthood. Having a balanced birthweight is one of the priorities of the health system in most of the industrial and developed countries. This indicator is used to assess the growth and health status of the infants. The aim of this study was to assess the birthweight of the neonates by using quantile regression in Zanjan province.
Methods:
This analytical descriptive study was carried out using pre-registered (March 2010 - March 2012) data of neonates in urban/rural health centers of Zanjan province using multiple-stage cluster sampling. Data were analyzed using multiple linear regressions andquantile regression method and SAS 9.2 statistical software.
Results:
From 8456 newborn baby, 4146 (49%) were female. The mean age of the mothers was 27.1±5.4 years. The mean birthweight of the neonates was 3104 ± 431 grams. Five hundred and seventy-three patients (6.8%) of the neonates were less than 2500 grams. In all quantiles, gestational age of neonates (p<0.05), weight and educational level of the mothers (p<0.05) showed a linear significant relationship with the i of the neonates. However, sex and birth rank of the neonates, mothers age, place of residence (urban/rural) and career were not significant in all quantiles (p>0.05).
Conclusion:
This study revealed the results of multiple linear regression and quantile regression were not identical. We strictly recommend the use of quantile regression when an asymmetric response variable or data with outliers is available.
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