Studies Reveal Surprising Benefits of Smoking Cessation and ‘Greenness’

Two new studies presented during the virtual European Society of Cardiology (ESC) Congress 2021 may provide some additional ammunition for cardiologists trying to deliver effective preventive health messages to their patients.

In the first report, smoking cessation was associated with mental health benefits in patients recovering from ACS. Depressed patients who quit after their event were less depressed a year later than those who continued to smoke, said Kristina Krasieva (University of Lausanne, Switzerland), a medical student who led the study for her master's thesis. She said her group hopes the data motivate more patients to kick the habit.

“It's encouraging that you don't get more depressed when you are asked to stop smoking. I think that’s maybe what somebody would think, and that's really important,” added Steen Dalby Kristensen, MD (Aarhus University Hospital, Denmark), who moderated a press conference where the results were presented prior to their inclusion in an ESC e-poster session.

In addition, William Aitken, MD (University of Miami, FL), reported on a study of more than 240,000 Medicare beneficiaries that found an inverse association between living in neighborhoods with more trees, plants, and green areas—“greenness”—and incidence of CVD.

Greenness, Aitken said, is a proxy for vegetative presence that is measured by satellite photos. The concept can be incorporated into existing patient education about heart-healthy food and getting regular, cardiovascular exercise—“ideally in nature, if possible,” Aitken told TCTMD.

“If they don't have access in their neighborhood to nature or any sort of breathing space, [they should] write to their local representatives to see what they can do to actually make sure that people have equitable access to that sort of environment,” he added.

Smoking and Depression

The study by Krasieva and colleagues used questionnaires and carbon monoxide breath analysis at 1 year to assess changes in depression and smoking status among ACS patients from the SPUM-ACS cohort. The 411 patients categorized as depressed at baseline hospitalization were classified into three further groups: continuous smokers (n = 115), smokers who quit (n = 88), and continuous nonsmokers (n = 208).

After adjustment, smokers who quit were more than twice as likely as those who continued to smoke at 1 year to have improvements in depressive symptoms and no longer be classified as depressed (P = 0.03).

According to Krasieva, their results are in line with other data from the general population showing that quitting smoking improves, rather than worsens, mood and mental health. She said the message to clinicians is to communicate the importance of quitting smoking on both CV and mental health in patients who have had an ACS and are depressed.

“An improvement in depression could even lead to other healthy behaviors, because patients will feel more motivated,” she added.

Benefits of ‘Greenness’

Aitken’s study found that compared with individuals living in the lowest quartile of greenness throughout the 5 years of the study, those living in the highest tertile had a 16% lower odds of developing new MI, atrial fibrillation, heart failure, ischemic heart disease, hypertension, or stroke/TIA (P < 0.001). Of those who did develop CVD during follow-up, living in high-greenness areas appeared to be protective, with fewer total new cardiovascular conditions in that group compared with those living in low-greenness areas (OR 0.96; 95% CI 0.92-0.99).

During the study period, a tree-planting and greening program was being conducted in the Miami area. This made it a possibility that people who lived in areas classified as low greenness in 2011, when the study started, could be living in a high greenness block by its end in 2016. In fact, Aitken and colleagues found that when greenness increased, there was a 15% decrease in new CV conditions compared with when vegetation levels stayed the same (P < 0.001). Among participants who developed a cardiovascular condition during follow-up, those living in neighborhoods that became greener over the study period had 9% fewer new CV conditions than those in continually less-green neighborhoods (P < 0.05).

“It ticks a number of boxes, because we know planting trees is good for the climate as we go through global warming,” noted co-moderator Christi Deaton RN, PhD (University of Cambridge, United Kingdom). “It sounds like something that would be fairly simple to persuade city planners and counties and things: to plant more greenness, plant more vegetation.”

Aitken said the way in which greenness directly impacts CV disease development, however, is unclear. Although the analysis did try to account for income and socioeconomic factors, their contributions to disease cannot be ruled out.

“In many circumstances, people living in greener areas may do more outdoor exercise and may feel less stress due to being surrounded by nature,” he noted. “But in reality, the mechanism that accounts for these health benefits really is an area for further exploration.”