Higher caffeine consumption is associated with insufficient sleep time in Brazilian adults (CUME study)

Abstract

We aimed to evaluate the association between caffeine intake and sleep time in Brazilian adults. This cross-sectional study was conducted with 6,356 participants from the Cohort of Universities of Minas Gerais (CUME Study). Data was collected through an online self-report questionnaire. Of the total, 31.9% of the participants had insufficient sleep. Women were found to sleep less than men (64.1 vs. 35.9%; p < 0.001), as well as being more likely to consume higher doses of caffeine (55.2%, p < 0.001). Coffee (35.7%), dark chocolate (25.2%), milk chocolate (15.2%), and diet soda (11.0%) were the foods that more contributed to caffeine intake. Individuals in the highest quartile of caffeine intake (87.0 − 572.0 mg/day) had a 19% higher prevalence of insufficient sleep compared with the lowest quartile (PR: 1.19; 95%CI: 1.08 − 1.31). Future studies are needed to investigate the genetic and hormonal factors involved in the interindividual response in this population.

Keywords:

• Caffeine consumption
• coffee
• caffeinated beverages
• sleep
• cohort

Acknowledgements

The authors acknowledge all the participants of the summit project, without whom this research would not be possible.

Ethical approval

This study was approved by the Human Research Ethics Committee (n˚596.741-0/2013) and approved by ethics committees of all participating institutions and was conducted by the ethical standards of the Declaration of Helsinki. All participants provided written informed consent before participating in the study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was partially funded by the Coordenação De Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Financial code 001. J Bressan, HHM Hermsdorff, and AM Pimenta are CNPq research productivity fellows.