The fifty percent male excess of infant respiratory mortality.
OBJECTIVE
To test whether infant mortality from clearly respiratory causes has a consistent male excess that is different from the male excess in most cardiac conditions.


METHODS
Analysis of male excess in infant mortality data from the United States and from north European countries. Data are analyzed for the period 1979-2002 in autopsied and unautopsied cohorts.


RESULTS
Several modes of respiratory death in infancy are characterized by an approximate 50% male excess. This common excess is demonstrated in vital statistics for infant respiratory distress syndrome, sudden infant death syndrome, inhalation of food and other objects causing obstruction of respiratory tract or suffocation, congenital pneumonia, viral pneumonia, bronchiolitis and bronchitis, and accidental drowning. Results are presented for these and other respiratory causes of mortality in all United States infant deaths from 1979-1998 and for sudden infant death syndrome from the United Kingdom and Scandinavia. In sudden infant death syndrome, the common male excess appears to exist only for the autopsied post-neonatal cases. Comparisons are made to the male excess mortality from congenital cardiac anomalies showing a similarly large male excess for those conditions resulting in severe hypoxic and ischemic hypoxia.


CONCLUSIONS
Because these respiratory disease conditions are quite different, it is proposed that their common approximately 50% male excess implies a common terminal hypoxic condition and mechanism of death reached via the different pathways. We hypothesize that an unknown X-linkage may be responsible for this consistent male excess in infant mortality.
Mage
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DT
Institute for Survey Research, Temple University, Philadelphia, PA 19122-6099, USA. david.mage@temple.edu
Donner
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D005060:Europe / Q000453:epidemiology; D005260:Female; D020022:Genetic Predisposition to Disease; D006330:Heart Defects, Congenital / Q000235:genetics / Q000401:mortality; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012120:Respiration Disorders / Q000235:genetics / Q000401:mortality*; D012307:Risk Factors; D017678:Sex Distribution; D012737:Sex Factors; D014481:United States / Q000453:epidemiology