State infant mortality: an ecologic study to determine modifiable risks and adjusted infant mortality rates

Area of Science:

• Public Health
• Epidemiology
• Biostatistics

Background:

• Infant mortality rates (IMR) vary significantly across US states.
• Understanding the contributing factors to state-level IMR is crucial for public health interventions.

Purpose of the Study:

• To identify key factors associated with state infant mortality rates (IMR) in the US for 2001-2002.
• To develop a risk-adjusted IMR model to better compare state-level outcomes.

Main Methods:

• Ecologic study utilizing linked birth and death certificate data from the National Center for Health Statistics.
• Multivariable linear regression analysis incorporating demographic, socioeconomic, and health-related factors.
• Risk adjustment of IMR using standardized rates and 95% confidence intervals.

Main Results:

• African-American race, teen birth rate, and smoking during pregnancy were independently associated with higher IMR.
• Risk-adjusted IMR revealed that some states' initial rates were confounded by factors like race and ethnicity.
• Certain states maintained consistently high or low IMR, while others shifted within expected ranges after adjustment.

Conclusions:

• Non-modifiable demographic variables, particularly race and ethnicity, are significant drivers of state IMR variation.
• Potentially modifiable factors like smoking during pregnancy and teen birth rates substantially impact IMR.
• Risk-adjusted IMR models highlight that factors beyond race/ethnicity influence infant mortality, necessitating targeted public health strategies.