The Disabled States of America: regional disparities in healthy life expectancy

m6228a1f3The CDC recently released their latest data on healthy life expectancy across the US. The data reveal stark inequalities not only in overall death rates, but moreover in how extremely disabled various parts of the country are as compared to healthier areas.

 

The concept of “healthy life expectancy” (HLE) refers to the idea that life expectancy itself doesn’t capture common states of chronic disability; in theory, medicine and public health are not just striving to achieve longer lives, but happier, less painful ones. HLE measures both mortality (death rates) and morbidity (health status, or quality of life measures). In addition to helping predict where health services might be needed the most, HLE measures over time also give a sense of how well public health and healthcare systems might be functioning, and how heavily the “social determinants of health” (e.g., pollution, stress-related disease, injury from neighborhood violence, work-related injury) may be falling disproportionately on some populations over others.

To determine state-level HLE estimates, the CDC used data from the National Vital Statistics Systems (NVSS), along with data from the US Census and the Behavioral Risk Factor Surveillance System (BRFSS) to calculate HLEs for persons aged 65 years, by sex and race, for each of the 50 states and the District of Columbia. [For those interesting learning how to analyze these datasets, we’ve shared (free, open-source) statistical code for such an analysis on our Stanford laboratory website.]

The HLE calculations indicate that, during 2007–2009, as per usual, women had a greater HLE than men at age 65 years across the country. Those results in themselves may not be new, but what’s of particular interest is the size and trend over time in regional disparities in HLE. Among both men and women, HLE was less in the South than elsewhere in the United States by as much as six years. Furthermore, HLE among particularly older women appears to be falling in some groups rather than improving.

HLE was also greater for Whites than for Blacks in all states from which sufficient data were available, but with some notable exceptions (see the map below for HLE at age 65, by state). A few southwestern states actually did not have this disparity: Nevada and New Mexico in particular. But this doesn’t appear to be cause for celebration; rather than “catching up” with Whites, it appears that Blacks may have relatively stable HLE in these states while poorer Whites (particularly women) may actually have declining HLE. The largest difference in HLE between whites and blacks was 7.8 years in Iowa.

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Some recent analyses have tried to understand the underlying determinants beneath these regional disparities in HLE, which do not appear to be related to poverty and its correlates alone. While a famous paper published in 2006 claimed that longevity in America was divided into eight regions with different mortality levels that couldn’t be explained by conventional hypotheses (poverty, race, healthcare access, etc.), a recent analysis found a common set of other “social determinants of health” could in fact explain much of the racial disparities between Whites and Blacks in terms of survival (S70: survival from birth to age 70) across the US.

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Further extensive studies have found that rather than shrinking over time (as would be expected if such regional inequalities were just a historical vestige of racism being repaired slowly with more-equal generations), there has actually been a steady increase in mortality inequality across US regions, even though the disparities between racial groups has narrowed. Female mortality appears to have increased in a large number of areas, much of it not explained by conventional correlates of disease like income, education or race. Further work into this problem suggests that the disparity may start very early in life and manifest even among middle-aged adults, not just among older persons. This may be due to factors like drug overdose. The early manifestation of disparities in death rates also appears to explain a lot of the gap between the US and European countries, where life expectancy is significantly better despite not much of the death rate being explained by differences in healthcare systems.

What appears to be a common theme in extensive reviews of these data is that the health of individuals is driven in part by the health of neighborhoods–and early causes of death (violence, drug overdose) as well as later causes (chronic diseases related to poor nutrition and tobacco use) cluster in ways that aren’t simply about income or education or historical racism alone, but were previously well-correlated to those factors and have now evolved into the ‘structural landscape’ of unhealthy neighborhoods where social norms influence disease risks cyclically (smoking, drug overdose, food availability/quality, violence, pollution), and the inability to improve neighborhoods (chronically low tax bases and poor representation) are all wrapped up together to manifest in ill health over time among both sexes, many race/ethnicities, and both low- and some middle-income populations that can’t escape the neighborhood. The frustrating aspect of such explanations related to the “social determinants of health”, however, is their vagueness; isolating those states and counties that have improved HLE recently may provide the suitable “natural experiments” to identify sources of success or failure in understanding these neighborhood influences on health and identifying effective programs to mitigate the negative trends. Some databases have started to gather the information necessary to conduct such analyses; we look forward to seeing some results from the study of that data in the near future…

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