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Population Study Reveals Weak Association Between Habitual Coffee Drinking and Sleep Disruption in Middle-Aged Adults

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Coffee Consumption and Sleep: A New Perspective for Middle-Aged Adults

A recent population-level study published in PLOS ONE suggests that regular coffee consumption may not significantly disrupt sleep in middle-aged adults. Analyzing a large Swedish cohort, researchers found minimal association between habitual caffeine intake, sleep quality, and daytime sleepiness.

The study challenges the common belief that regular coffee consumption significantly disrupts sleep, suggesting possible long-term biological adaptation to caffeine in older adults.

Study Design

The cross-sectional study included 25,381 adults aged 50–64 years from the Swedish Cardiopulmonary Bioimage Study (SCAPIS).

Researchers assessed coffee intake frequency using food frequency questionnaires, categorizing participants into none, low, moderate, and high intake groups. Sleep habits were evaluated using a modified Basic Nordic Sleep Questionnaire, and daytime sleepiness was measured with the Epworth Sleepiness Scale (ESS).

Indicators of sleep quality included:

  • Trouble falling asleep
  • Sleep duration
  • Nocturnal awakenings
  • Early waking
  • Reflux after bedtime
  • Loud snoring
  • Overall sleep quality (analyzed individually and as a composite score)

Genetic analysis (GWAS) was conducted to identify established genetic variants linked to coffee intake, validating self-reported consumption. Regression models and quasi-Poisson generalized linear models were used, adjusted for confounders such as age, sex, BMI, physical activity, stress, smoking, tea intake, and sleep medication use.

Key Findings

  • Most participants (88%) reported drinking coffee daily.
  • Coffee intake showed very weak associations with sleep quality and daytime sleepiness.
  • Statistically significant associations had minimal practical impact on sleep.
  • Compared to non-drinkers, low coffee intake was associated with slightly poorer sleep quality and more difficulty falling asleep/nocturnal awakenings (odds ratios 1.16-1.17).
  • High coffee intake was linked to improved sleep quality, less trouble falling asleep, fewer early awakenings, and less reflux after bedtime (odds ratios 0.78-0.86).
  • All intake levels were associated with louder snoring (odds ratios 1.15-1.25).
  • Participants with higher coffee intake generally reported slightly less daytime sleepiness.
  • Genetic analyses confirmed known markers near AHR and CYP1A1/CYP1A2 and identified additional signals near CABIN1 and SUSD2, supporting the reliability of self-reported data.

Implications

The findings challenge the common belief that regular coffee consumption significantly disrupts sleep, suggesting possible long-term biological adaptation to caffeine. The authors hypothesize that sustained caffeine exposure may recalibrate brain adenosine signaling, particularly in older adults.

The study notes that BMI may modify these effects, indicating some individuals could be more susceptible to caffeine-related sleep disruption. Further research with objective measures and longitudinal designs is recommended to explore these nuances.