Niccolai et al. Respond

Abstract

We appreciate the opportunity to extend discussion about poverty and health. It was not our intention to introduce a new term, “geographic poverty,” into the public health lexicon. As clearly described throughout our article, our analysis examined an area-based measure of poverty (i.e., proportion of residents living at or below the federal poverty level) at the census tract level. Given the wordiness of that phrase, we abbreviated this to “geographic poverty” selectively and for convenience. In hindsight, we agree that it may have been preferable not to use this, and we hope that readers will understand our intent and not perpetuate this term going forward. Kirby correctly understood the point we intended to make: area-based measures of poverty are associated with health disparities. A growing body of research demonstrates the importance of area-based poverty as a correlate of a variety of health outcomes including low birth weight and childhood lead poisoning, infectious diseases, late stage cancer diagnoses, utilization of health care services for infectious and chronic conditions, and premature mortality.1-7 It is becoming increasingly clear that place matters for health. We believe that a more important issue for public health than that of our chosen terminology is the question, What does area-based poverty actually mean? Is it an independent predictor of health and, if so, what are the mechanisms? Or, is it a marker for other factors difficult to know and measure but that are more direct determinants? Or is it something else? Others have written and we agree that area-based poverty is not merely a proxy for individual poverty as Krieger et al. stated: [A]rea-based socioeconomic measures capture a mix of any individual-level and area-based socioeconomic effects. Likely at issue is a complex combination of 3 factors: (1) composition… , (2) context (people in poor areas also have poor health because a concentration of poverty creates or exacerbates harmful social interactions), and (3) location of public goods.8(p317) The extent to which each of these factors (and maybe others) has an independent or synergistic role in health is challenging to determine and remains somewhat elusive. A deeper understanding of these complex relationships can lead to targeted interventions with the greatest likelihood of success in protecting and promoting the health of vulnerable populations.