Comparison of US population and live birth rates with poison exposures reported to the National Poison Data System (NPDS): children ages 0-5 years from 2000 to 2012.

BACKGROUND: Monitoring of poison control center data has provided an important public health surveillance tool. Previous work has identified the population with the greatest risk of poisoning as children of < 6 years. It follows that the size of the population at highest risk should be an important driver/factor of poison center volume. Therefore, one would expect population changes to be reflected in corresponding National Poison Data system (NPDS) call volume changes. We examined this relationship.

METHOD: This was a retrospective comparison of young children's poison exposures reported to NPDS with changes in US population as reported by the US Census Bureau and by live birth counts in the United States. We examined the relation of population and live birth counts to NPDS exposures in children of 0-5 years and for the total (children of 0-5 years).

RESULTS: There was a statistically significant relation between exposures and population for the three of the seven age groups (1-3 years old) and between exposures and live birth counts for the five of the seven age groups (1-4 years old and total (0-5)). The highest correlation was seen with the age groups of 2-year olds (r = 0.815; slope, 4.7373; 95% CI, 2.36-7.11) and 1-year olds (r = 0.785; slope, 4.878; 95% CI, 2.163-7.592). Live birth count was more closely related than population for all but the 1-year-old age groups.

DISCUSSION: Our study reports a number of interesting findings including 1) live birth counts and population are closely associated with each other, 2) poison exposures in NPDS were more strongly associated with live birth counts than with population, 3) the population at greatest risk is the 1- and 2-year-old age groups and the strongest associations between exposures and population and exposures and live birth counts occurred in these two age groups, and 4) changes occurring in the live birth counts, both positive and negative, were reflected in annual changes reported in NPDS human exposures in children < 6 years. These results mean that population changes underlie 37%-66% of the changes in poison exposures and suggests that the population at risk should be considered in monitoring poisoning injuries in the future.

CONCLUSION: These results provide a quantitative assessment of the age-based risk rates and changes over time for NPDS exposure in children who are 0-5 years old. With the decrease in live births noted over the last 4 years (2008, 2009, 2010, and estimated 2011), US poison centers may expect a similar decline in human exposures in children of 0-5 years. Our analysis adds additional support to the validity of this data set as a public health surveillance tool.