Infant and Maternal Risk Factors for Diarrhea-Associated Infant Mortality in the United States, 2005-2006 Open Access

Mehal, Jason (2011)

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BACKGROUND: Diarrhea-associated illness and mortality continue to affect children in the United States, especially infants. Diarrheal mortality had fallen in the 30 years prior to 1985 and had remained consistent for several years. Despite identification of risk factors for diarrhea-associated mortality and the recent addition of a rotavirus vaccine to the national routine immunization program, morbidity has remained high in recent years while the number of deaths due to diarrhea has increased.

METHODS: The 2005 and 2006 United States Linked Birth/Infant Death datasets were used to select infant deaths records listing a diarrhea-associated International Classification of Diseases, Tenth Revision (ICD-10) code as a cause of death anywhere on the death certificate. Selected records were restricted to singleton infants with birth weight >500 and ≤8000 grams. Infant mortality rates (IMRs) were calculated overall and by sex, race, Hispanic origin, birth weight, age at death, and region. A retrospective case-control study was used to identify potential infant and maternal risk factors for diarrheal mortality.

RESULTS: The overall IMR was 6.9 deaths per 100,000 live births (95% CI: 6.1-7.8) and was higher among males than among females. Black infants, those with low birth weight (<1500g and <2500g), and non-Hispanic infants experienced the highest mortality rates. Multivariable analysis identified male sex and low 5-minute Apgar score as significant risk factors for diarrheal mortality. There were also significant interaction terms. Among infants with low birth weight, older maternal age led to a higher chance of death, and among infants with normal birth weight, younger maternal age led to higher chance of death. Diarrhea-associated deaths were more likely to black infants than were survivors, regardless of marital status.

CONCLUSIONS: The number of diarrhea-associated deaths continues to increase in recent years, despite previous identification of infant and maternal risk factors for diarrheal mortality. Social risk factors influence diarrheal death more among normal birth weight infants while biological risk factors influence death more among low birth weight infants. With the high percentage of infants dying after 6 weeks, the minimum age of vaccination, timely vaccination could help to reduce the diarrheal mortality among infants in the United States.

Table of Contents

List of Tables...1
List of Figures...2

1. Introduction...3

1.1 Prevention/Immunization...3
1.2 Biology - Signs/Symptoms...4
1.3 Diagnosis...5
1.4 Treatment...6
1.5 Epidemiology...7
1.6 Risk Factors...9

2. Methods...10

2.1. Epidemiological Methods...10
2.2 Calculating Confidence Intervals for IMRs...12
2.3 Case-Control Methods...13
2.4 Case-Control Application...16

3. Results...18

3.1 Infant Mortality Rates...18
3.2 Risk Factors Associated with Diarrhea Death...19

4. Discussion...23

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