Spatially varying predictors of teenage birth rates among counties in the United States.

Abstract BACKGROUND Limited information is available about teenage pregnancy and childbearing in rural areas, even though approximately 20 percent of the nation's youth live in rural areas. Identifying whether there are differences in the teenage birth rate (TBR) across metropolitan and nonmetropolitan areas is important because these differences may reflect modifiable ecological-level influences such as education, employment, laws, healthcare infrastructure, and policies that could potentially reduce the TBR. OBJECTIVES The goals of this study are to investigate whether there are spatially varying relationships between the TBR and the independent variables, and if so, whether these associations differ between metropolitan and nonmetropolitan counties. METHODS We explore the heterogeneity within metropolitan/nonmetropolitan county groups separately using geographically weighted regression (GWR), and investigate the difference between metropolitan/nonmetropolitan counties using spatial regime models with spatial errors. These analyses were applied to county-level data from the National Center for Health Statistics and the US Census Bureau. RESULTS GWR results suggested that non-stationarity exists in the associations between TBR and determinants within metropolitan/nonmetropolitan groups. The spatial regime analysis indicated that the effect of socioeconomic disadvantage on TBR significantly varied by the metropolitan status of counties. CONCLUSIONS While the spatially varying relationships between the TBR and independent variables were found within each metropolitan status of counties, only the magnitude of the impact of the socioeconomic disadvantage index is significantly stronger among metropolitan counties than nonmetropolitan counties. Our findings suggested that place-specific policies for the disadvantaged groups in a county could be implemented to reduce TBR in the US. 1. Introduction Limited information is available about teenage pregnancy and childbearing in rural areas (Loda et al. 1997), even though approximately 20 percent of the nation's youth live in rural areas (Economic Research Service 2005). Most of the previous research on teenage pregnancy has concentrated on teenage pregnancy prevention, with very few studies that have compared the teenage birth rate (TBR) across states (Crosby and Holtgrave 2006) and no nationally representative studies that provide pregnancy or birth rates for teenagers living in nonmetropolitan3 areas (Skatrud, Bennett and Loda 1998). Identifying whether there are differences in the TBR across metropolitan and nonmetropolitan areas is important because these differences may reflect ecological- level influences such as education, employment, laws, healthcare infrastructure, and policies that could be changed in an effort to reduce the TBR (Crosby and Holtgrave 2006). Skatrud et al. (1998) wrote the most recent and comprehensive overview of the literature on teenage pregnancy in nonmetropolitan areas. Of the 500 articles reviewed, the authors identified only six articles focused on teenage pregnancy in nonmetropolitan areas. In addition, these six published articles focused specifically on one or a few states and used samples which were not racially or ethnically diverse. One of the articles only focused on sexual activity among rural teenagers rather than teenage pregnancy or birth rates. By compiling this comprehensive literature review, Skatrud et al. (1998) identified that there is a genuine need for a thorough examination of comparative data for representative samples of rural and urban teenagers. Among their recommendations was the need for a study on teenage pregnancy and childbearing that includes both rural and urban areas of the country. Our study is motivated by Skatrud et al.'s work. Using county-level data from the National Center for Health Statistics and the U. …