Breathing, lung problems more common in low-income household

While air quality has improved and smoking has gone down overall in the United States in the last several decades, researchers say the level of breathing problems in lower-income households remains vastly higher than in higher-income households. Photo by Free-Photos/Pixabay

May 28 (UPI) -- People with lower household incomes in the United States have more breathing problems and lung-related illnesses like asthma than wealthier individuals, an analysis published Friday by JAMA Internal Medicine found.

Nearly half of those with annual household incomes in the lowest percentiles nationally experience shortness of breath or difficulty breathing, compared with just under 30% in the highest percentiles of household income, the data showed.

In addition, low-income people are three times more likely to report a "problem cough" than their wealthier peers.

Children and adults in low-income households are also at higher risk for asthma and chronic obstructive pulmonary disease than those living in wealthier homes, according to the researchers.

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These trends have generally remained the same, if not worsened, over the past 60 years, despite declines in smoking and improvements in air quality in the United States during the same period.

"From the 1960s to today, socioeconomic inequalities in lung health have persisted, and in some instances even worsened," study co-author Dr. Adam Gaffney told UPI in an email.

"This occurred despite improvements in air quality, overall smoking rates, healthcare access and workplace safety, suggesting that the benefits of these advances have not been equitably enjoyed, [so] our lungs reflect the inequalities of our society," said Gaffney, a pulmonary specialist and assistant professor of medicine at Harvard Medical School in Cambridge, Mass.

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The findings are based on an analysis of lung health data for more than 215,000 people across the United States, for whom information on household income was available, from 1959 through 2018.

From 1971 through 2018, the percentage of people with the highest household incomes who were current or former smokers fell to 34% from 62%, the data showed.

Among those with the lowest household incomes, the percentage of current or former smokers rose to 58% from 56% over the same period, the researchers said.

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By 2018, 48% of those with the lowest household incomes nationally reported experiencing shortness of breath, up from 45% in 1971 and higher than the rate of 28% for wealthier individuals.

Just under 17% of people in the lowest-income households across the country suffered from a "problem cough" in 2018, compared with 6% of those in wealthier homes, up from 14% in 1988.

In 2017-18, the prevalence of asthma, or chronic shortness of breath, among children was 15% in the poorest households and 7% in the wealthiest ones.

Similarly, by 2018, 16% of adults in low-income households had been diagnosed with COPD, compared with just over 4% in wealthier residences.

A study published earlier this week also showed that people living in lower-income households, as analyzed by ZIP code, had more exposure to air pollution and high levels of heat.

"We all need safe air, safe workplaces and high-quality healthcare [so] we need to advocate for the policies that can make a difference," Gaffney said.

"We should move to improve air quality standards, workplace safety and achieve universal, comprehensive healthcare," he said.

Socioeconomic Inequality in Respiratory Health in the US From 1959 to 2018

Adam W. Gaffney, MD, MPH^1,2; David U. Himmelstein, MD^1,2,3; David C. Christiani, MD, MS, MPH^2,4; et alSteffie Woolhandler, MD, MPH^1,2,3

Author Affiliations Article Information

JAMA Intern Med. Published online May 28, 2021. doi:10.1001/jamainternmed.2021.2441

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Key Points

Question  Have socioeconomic disparities in respiratory health improved in the past 6 decades in the US?

Findings  In this repeated cross-sectional analysis of national health examination surveys conducted from 1959 to 2018 and including 215 399 participants, socioeconomic disparities in respiratory symptoms, lung disease prevalence, and pulmonary function mostly persisted, and in some instances appeared to widen.

Meaning  Income- and education-based disparities in respiratory health have persisted, and potentially worsened, despite secular improvements in air quality and tobacco use, suggesting that the benefits of these improvements have not been equitably enjoyed; social class may function as an independent determinant of lung health.

Abstract

Importance  Air quality has improved and smoking rates have declined over the past half-century in the US. It is unknown whether such secular improvements, and other policies, have helped close socioeconomic gaps in respiratory health.

Objective  To describe long-term trends in socioeconomic disparities in respiratory disease prevalence, pulmonary symptoms, and pulmonary function.

Design, Setting, and Participants  This repeated cross-sectional analysis of the nationally representative National Health and Nutrition Examination Surveys (NHANES) and predecessor surveys, conducted from 1959 to 2018. included 215 399 participants aged 6 to 74 years.

Exposures  Family income quintile defined using year-specific thresholds; educational attainment.

Main Outcomes and Measures  Trends in socioeconomic disparities in prevalence of current/former smoking among adults aged 25 to 74 years; 3 respiratory symptoms (dyspnea on exertion, cough, and wheezing) among adults aged 40 to 74 years; asthma stratified by age (6-11, 12-17, and 18-74 years); chronic obstructive pulmonary disease ([COPD] adults aged 40-74 years); and 3 measures of pulmonary function (forced expiratory volume in 1 second [FEV₁], forced vital capacity [FVC], and FEV₁/FVC<0.70) among adults aged 24 to 74 years.

Results  Our sample included 215 399 individuals surveyed between 1959 and 2018: 27 948 children aged 6 to 11 years; 26 956 children aged 12 to 17 years; and 105 591 adults aged 18 to 74 years. Income- and education-based disparities in smoking prevalence widened from 1971 to 2018. Socioeconomic disparities in respiratory symptoms persisted or worsened from 1959 to 2018. For instance, from 1971 to 1975, 44.5% of those in the lowest income quintile reported dyspnea on exertion vs 26.4% of those in the highest quintile, whereas from 2017 to 2018 the corresponding proportions were 48.3% and 27.9%. Disparities in cough and wheezing rose over time. Asthma prevalence rose for all children after 1980, but more sharply among poorer children. Income-based disparities in diagnosed COPD also widened over time, from 4.5 percentage points (age- and sex-adjusted) in 1971 to 11.3 percentage points from 2013 to 2018. Socioeconomic disparities in FEV₁ and FVC also increased. For instance, from 1971 to 1975, the age- and height-adjusted FEV1 of men in the lowest income quintile was 203.6 mL lower than men in the highest quintile, a difference that widened to 248.5 mL from 2007 to 2012 (95% CI, −328.0 to −169.0). However, disparities in rates of FEV₁/FVC lower than 0.70 changed little.

Conclusions and Relevance  Socioeconomic disparities in pulmonary health persisted and potentially worsened over the past 6 decades, suggesting that the benefits of improved air quality and smoking reductions have not been equally distributed. Socioeconomic position may function as an independent determinant of pulmonary health.

Introduction

Over the past half century, air quality has improved in the US: regulations have reduced emissions of sulfur dioxide, nitrogen oxide, and ozone concentrations, and haze has cleared.¹ Adult smoking rates, meanwhile, have fallen from 42.6% to 13.7%.² In addition, although many people still face workplace hazards, safety regulations and economic change have reduced exposure to occupational pollutants such as silica and coal dust, causing deaths from pneumoconiosis to plummet.³

However, among both children and adults, socioeconomic disparities in respiratory symptoms, disease,^4,5 and function^6,7 remain, probably owing to persistent disparities in exposure to unclean air, tobacco smoke, dusts and gases in the workplace, nutrition, access to health care,⁸ or other factors.^6,9 Disparities in chronic obstructive lung disease (COPD) may have worsened in recent decades consequent to the growing socioeconomic divide in tobacco use.¹⁰ For instance, county-level geographic differences in COPD mortality widened from 1980 to 2014,¹¹ and inequalities in asthma morbidity and mortality may have persisted,^9,12-16 or even worsened in the twenty-first century.^4,5

Yet few studies of socioeconomic disparities in lung health have spanned the period that saw landmark policy changes affecting smoking (the 1964 Surgeon General’s Report), air quality (the 1970 Clean Air Act), occupational exposures (the establishment of OSHA in 1971), and health care access (Medicare, Medicaid, and the Affordable Care Act). Moreover, because reduced lung function is associated with elevated all-cause mortality (through mechanisms not fully understood),^17,18 increased socioeconomic disparities in lung function may contribute to the widening gap in life expectancy between poorer and wealthier Americans in the twenty-first century.^19,20

Using national health examination surveys conducted over 6 decades, we evaluated changes in socioeconomic inequality in respiratory health in the US.

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Socioeconomic Inequality in Respiratory Health in the US From 1959 to 2018 | Asthma | JAMA Internal Medicine | JAMA Network