PLANETARY HEALTH WEEKLY

The Ubiquitous Health Impacts of Socioeconomic Gradients

June 16, 2022

much air can you blow out in one second.  You can measure it non-invasively by blowing into a spirometer, a tube that measures how much air passes though in the first second.  People with bigger lungs can blow out more air in one second so the number has to be normalized for body size.  A review study looked at many different countries and populations (Hegewald, M. J. and R. O. Crapo (2007). “Socioeconomic Status and Lung Function.” Chest 132(5): 1608-1614 ).  The SES relationship held after controlling for various environment factors including smoking.  This paper has been cited over 200 times so it is having an impact on how experts think.  It seemed intuitive, since poorer people had poorer health, that poorer people should have poorer functioning organs.  The lung is an easy organ to study since all you have to do is blow into a tube.  Other organ systems generally require more invasive measurements such as taking a blood or urine sample, or monitoring what goes through the digestive tract.  When done the same finding for other organs is seen. 

There is an ethical issue here going back to Thomas Malthus in the late 1700s who argued that there should be limits on people’s reproduction so population growth doesn’t outstrip growth in food production.  If poorer people have poorer health, and poorer functioning organs that result in more illness, then poorer folk shouldn’t have children.  Such thinking has led, historically, to forced sterilization of various categories of people.  What is presented here is that the choices made at the societal level lead to poorer people having poorer health.  Poverty is a policy choice.  It is not the fault of the individual. 

It has been well-established that poorer people have more lung disease, the commonest being chronic obstructive pulmonary disease (COPD) or emphysema. True for asthma too.   Once you establish something like that the usual response is to provide treatment for those with COPD and not focus on their poverty.  Typically one administers various drugs to treat cells in the lung to help sufferers get over a crisis.  I did that all the time as an emergency physician.  To be honest I felt I had accomplished something when they could breathe more easily.  We often see people who carry portable oxygen canisters around to make up for what their lungs can no longer do effectively.  Here we look at an organ and diseases that affect the response most often taken.  Having a disease perspective on health leads to treating diseases.  My perspective has changed to wanting to treat the population.  I no longer treat sick individuals though of course I’m glad that others do.

Once we see that poorer individuals have poorer functioning lungs, what about the neighborhoods in which they live?  Recall Rose and his sick individuals and sick populations ideas in the previous blog.  Can a neighborhood be sick?  Earlier this year a study appeared considering measures of neighborhood deprivation and lung health in people living there (Thatipelli, S., K. N. Kershaw, L. A. Colangelo, P. Gordon-Larsen, D. R. Jacobs, M. T. Dransfield, D. Meza, S. R. Rosenberg, G. R. Washko, T. M. Parekh, M. R. Carnethon and R. Kalhan (2022). “Neighborhood Socioeconomic Deprivation in Young Adulthood and Future Respiratory Health: The CARDIA Lung Study.” The American Journal of Medicine 135(2): 211-218.e211).  This builds on many studies showing that living in more deprived neighborhoods makes it more likely you will have lung disease, and more health decline as you age, among others.  In this U.S. study neighborhood deprivation was characterized at the census block by median household income, proportion below the 150% poverty level, and adults with less than a high school education.  Those living in the most deprived areas over 20 years (from age 10 to 30) had a much larger decline in their FEV₁ measure than those in the least deprived.  Also there was a greater risk of COPD as these people aged.

What should our response be?  Provide more and better treatment to those folk, or decrease deprivation?  Both of course.  The medical care community, that represents 18% of the total US economy, will do what it is trained to do.  More and better treatment.  The other ‘treatment’ would be political and include changing the economic structure of the United States so there is less deprivation.  Or eliminate deprivation.  That such studies are being done and published represents progress that would have been unthinkable a half-century ago.  What does deprivation mean?  Typically the lack of material benefits required to live in a society.  It is really about poverty, but deprivation doesn’t sound as harsh.  Poverty in a society is a political choice.  While we separate the terms policy and politics, in French politique combines them.  The USA has the most poverty and the most child poverty of all rich nations.  This country chooses to have many poor.  We will further explore poverty and being poor in a future blog. 

There was a billboard once that said:  “Your zip (or postal) code is more important for your health than your genetic code.”  Translated, this means that living in a deprived neighborhood is really not good for being healthy.  Your genes matter but not that much as we will also see in a future blog.

A study of the trends in the United States relating socioeconomic status and lung function or disease over time has shown the gradient becoming steeper (Gaffney, A. W., D. U. Himmelstein, D. C. Christiani and S. Woolhandler (2021) and “Socioeconomic inequality in respiratory health in the US From 1959 to 2018.” JAMA Internal Medicine 181(7): 968-976.).  Namely those poorer are suffering more, namely having worse functioning lungs and more illness relating to that organ.  This country is not responding the way it should because deprivation is increasing in the U.S.

Again there is nothing special about the lung regarding these relationships.  Breathing is a core function to sustain life.  I had the rule of fours in my emergency department.  You could survive for 4 minutes without air, 4 days without water and 4 weeks without food.  If your lungs aren’t working I had to act fast.

Is the SES gradient there for other conditions?  Certainly.  Other countries?  Yes.  Do we need the same response?  Yes.  Besides focusing on treating those illnesses we must decrease deprivation or poverty. Economic inequality is a fundamental cause of health problems because it increases deprivation.  We explore how inequality kills in the next blog.