Poverty Affects Response to Ozone Exposure in COPD Patients

Ingrid Hein

August 14, 2020

Current and former smokers with chronic obstructive pulmonary disease (COPD) who live in high-poverty neighborhoods are more likely to be affected by ozone pollution than those who live in low-poverty neighborhoods.

Even when pollution levels are the same, a 60-year-old white male smoker in a poor neighborhood will be more likely than a person with the same profile in an affluent neighborhood to have shortness of breath, to need antibiotics or steroids for COPD, and to need hospitalization, said Daniel Belz, MD, from the Johns Hopkins School of Medicine in Baltimore.

"The neighborhood where you live has a direct effect on your respiratory health," he told Medscape Medical News. "This needs to be taken into account when assessing individual risk for respiratory outcomes and morbidity in a patient with COPD."

The multicenter SPIROMICS project recently demonstrated that long-term ambient ozone exposure is associated with respiratory morbidity in smokers with COPD. In fact, an increase in ozone concentration of just 5 parts per billion over 10 years was shown to lead to higher rates of emphysema (β = 0.94; 95% CI, 0.25 - 1.64; P = .007) and air trapping (β = 1.60; 95% CI, 0.16 - 3.04; P = .03) in 1874 current or former smokers with COPD and at least 20 pack-years of smoking. Elevated ozone levels also increased exacerbations (odds ratio [OR], 1.37; 95% CI, 1.12 - 1.66; P = .002) and the severity of exacerbations (OR, 1.37; 95% CI, 1.07 - 1.76; P = .01).

For their study, Belz and his colleagues examined the link between ozone levels and poverty as part of SPIROMICS AIR, which is looking at individual-level exposure to air pollution in the SPIROMICS cohort.

The results — the first to show an interaction between ozone levels and poverty in current and former smokers with COPD — were presented at the virtual American Thoracic Society 2020 International Conference.

The neighborhood where you live has a direct effect on your respiratory health.

Belz's team collected data on poverty levels in seven cities — Ann Arbor, Michigan; Baltimore; Los Angeles; New York City; Salt Lake City; San Francisco; and Winston-Salem, North Carolina — using 2010 Census data.

"We looked at neighborhoods below the poverty line," which was "about $10,000 per year for an individual or $22,000 for a family of four," Belz reported.

The researchers compared outcomes in neighborhoods with poverty rates above and below the mean national rate of 11.8%, after adjustment for age, sex, race, smoking status, pack-years, education, individual income, body mass index, and occupational exposure.

The effect of ozone exposure on respiratory outcomes was significantly stronger in neighborhoods with high levels of poverty than in neighborhoods with low levels, as indicated by COPD Assessment Test score, modified Medical Research Council dyspnea score, St. George's Respiratory Questionnaire score, 6-minute walk distance, percent air trapping, risk for COPD exacerbation, and risk for severe exacerbation (P < .05 for all).

For neighborhoods with poverty rates in the 90th percentile, an increase in ambient ozone concentration of 5 parts per billion led to an 81% rise in COPD exacerbations (OR, 1.81; P < .0001). In contrast, for neighborhoods with poverty rates in the 10th percentile, there was no significant association between the ozone increase and COPD exacerbation (OR, 1.09; P = .44).

"Poverty was an association that really stood out," said Belz, but more data need to be gathered to better understand the effect of poverty on health. "How much does it have to do with access to care? Or specialty care?"

Or are people more likely to stay inside, smoke inside, and therefore not get fresh air, if they are worried about the safety of their neighborhoods? "We don't know," he said. But "what we need to take away from this is an understanding that poor neighborhoods are at higher risk than higher-income neighborhoods."

Poverty and Smoking

"If you are smoking tobacco sitting in a mansion, you have the same risk of cancer and cardiovascular disease as someone who smokes in a poor neighborhood," said Smita Pakhale, MD, from the Ottawa Hospital Research Institute in Canada, who presented findings from a participatory study that is exploring poverty and tobacco inequity at the virtual meeting.

However, "there are a lot of layers intertwined with poverty," she told Medscape Medical News. "It gets you a double whammy; you suffer both the side effects of tobacco and of other exposures, such as lack of housing security, mental disorders, poor access to help for ongoing trauma, racism, carding, police brutality, and even unwarranted time in prison."

"At the end of the day, a person living in poverty smoking will always have worse outcomes than the person in the mansion smoking," she said.

Belz and Pakhale have disclosed no relevant financial relationships.

American Thoracic Society International Conference (ATS) 2020: Session D15. Presented August 5, 2020.

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