Caffeine intake has no effect on sleep quality in community dwellers living in a rural Ecuadorian village (The Atahualpa Project)

Abstract

More information is needed to better understand the effect of caffeine on sleep quality at the community level. In a population-based, cross-sectional study design, we aimed to assess the effect of caffeine intake on sleep quality by the use of a multivariate exposure-effect model, adjusted for relevant confounders. All Atahualpa residents aged ≥40 years were identified during a door-to-door survey and interviewed with the Pittsburgh Sleep Quality Index (PSQI) and a structured instrument designed to estimate the daily amount of caffeine intake. An exposure-effect model was built using augmented inverse probability weighting taking into account variables that were associated with exposure (using a probit model) and variables that were associated with outcome (in a linear model). Out of 779 eligible individuals, 716 (92%) were included. Consumption of <100 mg/day of caffeine was recorded in 320 (45%) participants, from 100 to 200 mg/day in 299 (42%), and >200 mg/day in 97 (13%). Mean score in the PSQI was 4.5±2.2 points, with 203 (28%) individuals classified as poor sleepers (≥6 points). The exposure-effect model, adjusted for variables associated with the exposure (symptoms of depression, total cholesterol blood levels and smoking) and the outcome (age, symptoms of depression, physical activity and fasting glucose levels), revealed no effect of caffeine intake in sleep quality (average exposure effect: 0.027, 95% C.I.: −0.284 to 0.338, p=0.866). This population-based study shows that caffeine intake has no effect on sleep quality in community-dwelling adults living in a rural village of Ecuador.

Low dose of caffeine enhances the efficacy of antidepressants in major depressive disorder and the underlying neural substrates

“…Therefore, we assessed the TST, SWS, and REM for five nights during the baseline and the 4‐wk experimental procedure of caffeine intake. These results indicate that daily caffeine consumption at the dose of 60 and 120 mg did not affect sleep quality as measured by PSG recording consistent with recent population‐based study, which showed that caffeine intake has no effect on Pittsburgh Sleep Quality Index score in community‐dwelling adults .…”

Effects of caffeine on sleep quality and daytime functioning

“…Caffeine’s reputation, of course, means that the substance carries significant expectancy effects, with Sun et al38 finding that an initial dose of caffeine followed by a placebo 4 h later helped extend the cognitive performance of the initial caffeine dose beyond the period when elevated blood pressure and heart rate subsided. However, the Atahualpa Project, using data collected in an Ecuadoran village with no fast food outlets, almost no shift work, and little light or noise pollution during the evening and night hours—and almost certainly a very different cultural orientation toward caffeine—found no impact of caffeine consumption on sleep patterns when controlling for other physiological variables 39. The researchers note that the absence of caffeine impact on night sleep quality may be associated with the absence of other secondary triggers to wakefulness, such as noise or artificial light.…”

“…For example, it is often ingested by those who are already fatigued, as well as being implicated in causing the fatigue in the first place. Research by del Brutto et al39 noted secondary triggers to wakefulness, such as noise and artificial light, as well as interactions with other factors such as diet which may interfere with sleep.…”

Nutritional Elements in Sleep

“…However, one study found that morning caffeine use affected sleep efficiency and total sleep time negatively [ 107 ]. On the contrary, another study of an Ecuadorian village found no significant effect of daytime caffeine use on nighttime sleep [ 108 ]. Another study found that 400 mg of caffeine - equivalent to four cups of coffee (a high dose considering the average caffeine consumption) - taken 0, 3, or even 6 hours before bedtime significantly disrupted sleep.…”