Smokers tend to suffer from poor sleep health, reports a new study presented at the recently concluded 2019 International Conference of the American Thoracic Society (ATS 2019). Moreover, having poor sleep health may intensify existing deficits in lung health in these individuals.

Forty-one smokers of African-American descent (mean age, 56.6±5.03 years) were enrolled in the present cross-sectional study. Only those without signs of a sleep disorder or moderate-to-severe chronic obstructive pulmonary disorder were eligible. Objective measures of lung function, sleep efficiency and sleep duration, as well as self-reported smoking status, were included in the analysis.

Participants smoked a mean of 8.3±6.57 cigarette sticks per day, while the average sleep efficiency was 70.10±13.7 percent. Majority (93 percent; n=38) had objectively short sleep duration. The ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC), used as a measure of lung function, had a mean value of 0.83±0.15. [ATS 2019, A1377/P1201]

There was a negative correlation between smoking rate and FEV1/FVC (r, –0.29). The opposite was observed for the association between smoking and sleep duration (r, 0.12), though statistical significance was not achieved.

Notably, among short sleepers, those who smoked >10 cigarettes per day (heavy smokers) showed poorer lung function than their light smoking counterparts (mean, 0.87±0.20 vs 0.87±0.12; t, 1.05). The difference, however, failed to reach significance.

A similar pattern was observed after disaggregating for sleep efficiency. Among those with inefficient sleep (<85 percent), heavy smokers had nominally worse lung function than light smokers (mean, 0.79±0.21 vs 0.87±0.13; t, 1.16).

Despite an established relationship among smoking, lung disease and disturbed sleep patterns, “[n]ot known is the extent to which upstream sleep health metrics may relate to smoking rate and lung function in smokers who do not yet have lung disease,” said researchers.

Specifically, the aim of the present study was to determine “if poor sleep health accentuates the negative effects of smoking on lung function.”

“While the small sample size precluded the finding of statistically significant group differences, these data show that the majority of this high-risk population have poor sleep health, and that poor sleep health may accentuate lung health deficits in heavier smokers,” they continued.

These findings are in agreement with a previous study, which has shown that smoking disrupts sleep architecture. Current smokers, for instance, suffer from prolonged sleep latency and less overall sleep time, as well as a shift toward the lighter stages of sleep. [Am J Epidemiol 2006;164:529-537]

Smoking impairs sleep in children, too, according to a 2010 study, which reports that even exposure to secondhand smoke can elicit sleep problems in children with asthma. [Pediatrics 2010;125:e261-e268]

Despite its clear conclusions and consonance with existing literature, “[t]hese hypothesis-generating findings warrant testing in larger studies,” researchers said.