Sleep and circadian differences between light and heavy adult alcohol drinkers

Abstract

Background Numerous studies have reported that eveningness is associated with increased alcohol consumption. However, biological markers of circadian timing, such as dim light melatonin onset (DLMO) and circadian photoreceptor responsivity (post‐illumination pupil response, PIPR), have rarely been assessed in the context of habitual alcohol consumption. This study aimed to examine sleep, circadian timing, and photoreceptor responsivity in adult alcohol drinkers. Methods Participants (21 to 45 years) included 28 light and 50 heavy drinkers. The 8‐day study consisted of a week of ad lib sleep monitored with wrist actigraphy, followed by a 9‐h laboratory session with a photoreceptor responsivity and circadian phase assessment. Results The heavy drinkers obtained on average 28 more minutes of sleep (p = 0.002) and reported more eveningness than the light drinkers (p = 0.029). There was a trend for a shorter DLMO‐midsleep interval (p = 0.059) in the heavy drinkers, reflecting a tendency for them to sleep at an earlier circadian phase. The PIPR in the heavy drinkers was significantly smaller than in the light drinkers (p = 0.032), suggesting reduced circadian photoreceptor responsivity in the heavy drinkers. A larger PIPR was significantly associated with a later DLMO in the light drinkers (r = 0.44, p = 0.019), but this relationship was absent in the heavy drinkers (r = −0.01, p = 0.94). Conclusions These results are consistent with earlier reports of more eveningness and a shorter DLMO‐midsleep interval being associated with heavier alcohol drinking. The novel finding of reduced circadian photoreceptor responsivity in heavy drinkers is consistent with prior rodent studies. Future studies should explore the impact of habitual alcohol consumption on other measures of circadian photoreceptor responsivity.

Do sleep and circadian characteristics predict alcohol use in adult drinkers?

“…Furthermore, none of the circadian-related measures were associated with future alcohol use, suggesting that the apparent cross-sectional differences in circadian function that we previously observed between light-and heavy-drinking adults (Burgess et al, 2022) do not meaningfully contribute to changes in alcohol use over time. This contrasts with findings among adolescent samples, where sleep and circadian timing have been linked to higher alcohol use both cross-sectionally and longitudinally (Hasler et al, 2017(Hasler et al, , 2023Tavernier & Willoughby, 2014;Troxel et al, 2021).…”

“…The present project examined longitudinal associations between sleep and circadian characteristics and alcohol use in a sample of adults reporting a range of alcohol use, extending prior findings from the parent study that examined cross-sectional associations between alcohol use, sleep and circadian characteristics, and circadian photoreceptor responsivity (Burgess et al, 2022). While the parent study focused on baseline group differences between light and heavy drinkers, here we combined the sample to generate a single sample of adults with a range of alcohol use.…”

“…The participants and the methods associated with the baseline data collection have been previously described (Burgess et al., 2022). Here we provide a brief description of the baseline sleep and circadian assessment of the participants, followed by details on the prospective data collection across the 12‐month follow‐up period.…”

“…The participants and the methods associated with the baseline data collection have been previously described (Burgess et al, 2022).…”

“…The shorter DLMO-midsleep intervals suggest more circadian misalignment, in which individuals with later circadian timing are attempting to maintain too-early sleep schedules. Most recently, we reported that heavy-drinking adults (relative to light-drinking adults) reported more eveningness and exhibited a statistical trend (p = 0.059) toward a shorter DLMO-midsleep interval (Burgess et al, 2022). The heavydrinking adults also exhibited reduced retinal responsivity to early evening light based on the post-illumination pupil response (PIPR), which could increase the risk for circadian disruption due to insufficient light input into the circadian pacemaker.…”