Modeling the Age-Associated Decrease in Mortality Rate for Congenital Anomalies of the Central Nervous System Using...

Area of Science:

• Pediatrics
• Epidemiology
• Genetics

Background:

• Human mortality rates significantly decline after birth, with causes of death evolving through childhood.
• Congenital anomalies of the central nervous system (CACNS) and overall mortality patterns with age require explanation.
• Investigating the age-specific mortality trajectory for diseases of the nervous system (DNS) is crucial.

Purpose of the Study:

• To elucidate age-associated decreases in mortality for CACNS and total mortality.
• To analyze the age trajectory of mortality within the broader category of DNS.
• To explore potential explanations for observed mortality trends using the theory of congenital individual risk (TCIR).

Main Methods:

• Utilized WHO mortality data from nine European countries (Denmark, Finland, Norway, Sweden, Austria, Czech Republic, Hungary, Poland, Slovakia).
• Applied the Halley method to calculate mortality rates across all calendar years and combined countries.
• Focused analysis on age intervals [0, 10) years for total mortality and [0, 90) years for CACNS mortality.

Main Results:

• Total mortality and CACNS mortality from birth to age 10 and 90, respectively, follow an inverse proportional relationship (R²=0.996 and R²=0.990).
• DNS mortality shows a slow decrease in the first two years, then follows an inverse proportion up to age 10.
• The theory of congenital individual risk (TCIR) explains these patterns through the elimination of individuals with severe impairments (adjusted R²=0.966).

Conclusions:

• The similar age trajectories of all-cause and CACNS mortality suggest that severe congenital impairments contribute significantly to early mortality.
• The observed decrease in mortality with age may reflect the natural selection against individuals with more severe congenital conditions.
• Latent congenital impairments manifesting later in childhood could account for non-CACNS related deaths.