Hourly and daily intake patterns among U.S. caffeinated beverage consumers based on the National Health and Nutrition Examination Survey (NHANES, 2013-2016).

Characterization of 'hour-of-day' or 'day-of-week' caffeine intake for the National Health and Nutrition Examination Survey (NHANES) population is limited. No study has focused on patterns from an individual perspective. The NHANES 2013-2016 survey respondents' dietary recalls were analyzed to gain a better understanding of caffeine intake patterns for different caffeinated beverage consumer types - defined by beverage type consumed and daily caffeine intake levels. Dominant caffeinated beverage consumers (≥143 mg) were identified by a reported daily caffeine intake level greater than or equal to the 50th percentile among those 1-80 y. Dominant caffeinated beverage consumers - irrespective of age groups investigated - typically reported the greatest caffeine intake early in the day from coffee. Analyses by consumer type, relevant age brackets and 'hour-of-day' or 'day-of-week' indicated that caffeinated beverage consumers generally do not cluster multiple caffeine intake events over short periods of time (i.e., less than fours). Dominant caffeinated beverage consumers appear to maintain a relatively stable daily caffeine intake by substitution of secondary sources of caffeine. Only a small fraction (4.1%) of individuals within 13-29 y respondents consumed caffeine at levels in excess of 400 mg/day, compared to 14% within the 30-80 y old survey respondent group.