County-Level Trends in Suicide Rates in the U.S., 2005-2015

Abstract

Introduction: Understanding the geographic patterns of suicide can help inform targeted prevention efforts. Although state-level variation in age-adjusted suicide rates has been well documented, trends at the county-level have been largely unexplored. This study uses small area estimation to produce stable county-level estimates of suicide rates to examine geographic, temporal, and urban-rural patterns in suicide from 2005 to 2015.

Methods: Using National Vital Statistics Underlying Cause of Death Files (2005-2015), hierarchical Bayesian models were used to estimate suicide rates for 3,140 counties. Model-based suicide rate estimates were mapped to explore geographic and temporal patterns and examine urban-rural differences. Analyses were conducted in 2016-2017.

Results: Posterior predicted mean county-level suicide rates increased by >10% from 2005 to 2015 for 99% of counties in the U.S., with 87% of counties showing increases of >20%. Counties with the highest model-based suicide rates were consistently located across the western and northwestern U.S., with the exception of southern California and parts of Washington. Compared with more urban counties, more rural counties had the highest estimated suicide rates from 2005 to 2015, and also the largest increases over time.

Conclusions: Mapping county-level suicide rates provides greater granularity in describing geographic patterns of suicide and contributes to a better understanding of changes in suicide rates over time. Findings may inform more targeted prevention efforts as well as future research on community-level risk and protective factors related to suicide mortality.

Figure 1

Comparison of model-based versus direct estimates aggregated over larger geographies, or over 2005–2015. Note: Top left figure shows the county-level suicide rates in 2015 based on direct estimates (not model-based), with white indicating that the rates are suppressed where fewer than 20 deaths were reported. Top right figure shows county-level suicide rates based on direct estimates, aggregated over 2005–2015. Bottom left figure shows county-level suicide rates aggregated to 696 larger geographic units, based on the requirement of having 20 or more deaths in the numerator. The bottom right map shows model-based county-level estimates for 2015.

Figure 2

Model-based county-level suicide rates in the U.S., 2005 (top), 2010 (middle), and 2015 (bottom).

Figure 3

Increases in suicide rates from 2005–2015 in the U.S., by urban-rural classification. Model-based and direct estimates. Note: Urbanization level was determined using the NCHS Urban-Rural Classification Scheme for Counties from 2006 (applied to data years 2005–2012) and 2013 (applied to data years 2013–2015). Dashed lines represent direct estimates, solid lines are model-based estimates. NCHS, National Center for Health Statistics.

Figure 4

Distributions of model-based suicide rates by urban-rural classification, 2005 and 2015. Median model-based suicide rates (top) and coefficients of variation (bottom), by urban-rural classification. Note: Boxes represent interquartile ranges, points represent outliers.