Smoking during surgical mask use may impair vascular function

Smoking during prolonged use of surgical facemasks due to the COVID-19 pandemic may further compromise vascular function, a study has shown.

“Our study showed that smoking while wearing a surgical mask resulted in a twofold rise of exhaled carbon monoxide (CO) and concomitant impairment of arterial elasticity in [conventional and heat-no-burn (HNB) cigarette] smokers,” said the investigators. “[This effect was seen] at least partly because of increased CO re-inhalation and/or vapour rich in nicotine. These detrimental effects were not evident in non-smokers.”

A total of 120 medical personnel working in a tertiary care university hospital (mean age 45 years, 72 percent female) were evaluated for a month. Of these, 80 were cigarette smokers (conventional [n=40] and HNB [n=40]) while the rest were not. [Eur J Prev Cardiol 2022;doi:10.1093/eurjpc/zwac101]

Baseline measurements were taken early in the morning following a night’s sleep without a mask. After which, participants were randomized to a second evaluation at the end of an 8-hour morning work shift while wearing a mask, or to an evaluation at the end of an 8-hour morning period without a mask during activities outside of work. Participants were then crossed over to a third evaluation – either at the end of an 8-hour period without a mask out of hospital following their morning shift, or to an 8-hour afternoon period wearing a mask during an afternoon shift.

Participants wore their masks consistently throughout their shifts and did not use any other face shield. They were instructed to abstain from smoking at least an hour prior to measurement-taking to avoid any acute effect from smoking.

Compared with smokers who were unmasked for 8 hours, those who wore masks had a greater increase in CO from baseline (absolute difference, 9.45 vs 4.15 ppm [conventional] and 1.05 vs 0.28 ppm [HNB]; p<0.001 for both).

Vascular markers in conventional cigarette smokers also increased from baseline, more so with than without a mask for 8 hours. These markers were PWV* (0.98 vs 0.26 m/sec; p=0.001), SBP** (8.3 vs 4.2 mm Hg; p<0.001 [central] and 7.0 vs 6.7 mm Hg; p=0.004 [brachial]), and Aix75*** (9.8 percent vs 5.7 percent; p=0.01). These effects were similarly seen among HNB cigarette users (0.59 vs 0.15 m/sec; p=0.003 [PWV], 9.1 vs 3.9 mm Hg; p=0.035 [central SBP], 14.3 vs 3.4 mm Hg; p=0.012 [brachial SBP], and 11.0 percent vs 2.6 percent; p=0.001 [Aix75]).

“Aix75 is a marker of the effect of wave reflections on the aortic pulse wave … In a stiff aorta, because of increased PWV, the wave reflections return early in systole and augment central SBP. In a compliant aorta, these arrive in diastole and augment central DBP,” the researchers explained.

Hence, the early return of wave reflections in a stiff aorta raises cardiac afterload and subsequently myocardial oxygen demand, while reducing diastolic pressure and coronary perfusion leading to a reduction in myocardial oxygen delivery. “Therefore, increased arterial stiffness, as assessed by PWV and Aix, results in impaired cardiac function,” they continued.

In non-smokers, the use of masks did not alter exhaled CO and had a neutral effect on vascular markers (p>0.05 for both).

“[Our findings imply that] smokers should definitely abstain from smoking while wearing a mask,” said the researchers. “[Better yet,] quitting both conventional and HNB cigarettes is imperative for a better health in the COVID-19 pandemic.”

The researchers recommended follow-up to ascertain whether the increases in the evaluated markers during prolonged use of masks is tied to a higher incidence of cardiovascular disease. They also noted that the observed changes in the markers evaluated in the study could have been influenced by the effects of diet, sleep, work stress, or environmental pollution, as these were not excluded.