Caffeine intake in children in the United States and 10-y trends: 2001–20101–4

Namanjeet Ahluwalia, Kirsten Herrick, Alanna Moshfegh, and Michael Rybak

ABSTRACT Background: Because of the increasing concern of the potential adverse effects of caffeine intake in children, recent estimates of caffeine consumption in a representative sample of children are needed. Objectives: We provide estimates of caffeine intake in children in absolute amounts (mg) and in relation to body weight (mg/kg) to examine the association of caffeine consumption with sociodemo- graphic factors and describe trends in caffeine intake in children in the United States. Design: We analyzed caffeine intake in 3280 children aged 2–19 y who participated in a 24-h dietary recall as part of the NHANES, which is a nationally representative survey of the US population with a cross-sectional design, in 2009–2010. Trends over time be- tween 2001 and 2010 were examined in 2–19-y-old children (n = 18,530). Analyses were conducted for all children and repeated for caffeine consumers. Results: In 2009–2010, 71% of US children consumed caffeine on a given day. Median caffeine intakes for 2–5-, 6–11-, and 12–19-y olds were 1.3, 4.5, and 13.6 mg, respectively, and 4.7, 9.1, and 40.6 mg, respectively, in caffeine consumers. Non-Hispanic black chil- dren had lower caffeine intake than that of non-Hispanic white counterparts. Caffeine intake correlated positively with age; this association was independent of body weight. On a given day, 10% of 12–19-y-olds exceeded the suggested maximum caffeine intake of 2.5 mg/kg by Health Canada. A significant linear trend of decline in caffeine intake (in mg or mg/kg) was noted overall for children aged 2–19 y during 2001–2010. Specifically, caffeine in- take declined by 3.0 and 4.6 mg in 2–5- and 6–11-y-old caffeine consumers, respectively; no change was noted in 12–19-y-olds. Conclusion: A majority of US children including preschoolers con- sumed caffeine. Caffeine intake was highest in 12–19-y-olds and remained stable over the 10-y study period in this age group. Am J Clin Nutr 2014;100:1124–32.

INTRODUCTION

Caffeine is a commonly consumed stimulant present naturally in or added to foods and beverages. Caffeine consumption in children has received considerable interest because of the con- cern of adverse health effects. Caffeine intake of 100–400 mg has been associated with nervousness, jitteriness, and fidgetiness (1, 2). Because of the continued brain development involving myelination and pruning processes, children may be particularly sensitive to caffeine (3, 4). There has been some evidence that has linked caffeine intake in children to sleep dysfunction, el-

evated blood pressure, impairments in mineral absorption and bone health, and increased alcohol use or dependence (1, 5–7). In addition, the routine use of caffeinated sugar-sweetened beverages may contribute to weight gain and dental cavities (8). Caffeine toxicity in children has also been described involving tachycardia, central nervous system agitation, gastrointestinal disturbance, and diuresis (6, 9, 10). Health Canada has put forth maximal daily caffeine intake guidelines for children and ado- lescents (6, 11). Although no such recommendations have been set in the United States, the American Academy of Pediatrics has underscored that “caffeine and other stimulant substances contained in energy drinks have no place in the diet of children” (12).

Caffeine consumption has also been associated with certain health benefits such as increased endurance, attention, and vig- ilance and a reduced reaction time in some studies (9, 13, 14). Perceived positive effects on mood and cognition as well as physical performance may encourage preteens and adolescents to consume caffeinated products (2, 15, 16).

The literature on caffeine consumption in a representative sample of US children has been primarily based on older data, namely the US Department of Agriculture Continuing Survey of Food Intakes by Individuals (CSFII)5 1994–1996 and 1998 (16, 17). In addition, caffeine intake from beverages from the 1999 US Share of Intake Panel (SIP) survey in caffeine consumers has also been published (18). A 2010 US Food and Drug Admin- istration report also presented findings from the analysis of older data from NHANES 2005–2006 (19). Because of the current

1 From the Division of Health and Nutrition Examination Surveys, Na-

tional Center for Health Statistics, CDC, Hyattsville, MD (NA and KH);

the National Center for Environmental Health, CDC, Atlanta, GA (MR);

and the Food Surveys Research Group, Beltsville Human Nutrition Research

Center–Agricultural Research Service, USDA, Beltsville, MD (AM). 2 Findings and conclusions in this report are those of the authors and do

not necessarily represent the official position of the National Center for

Health Statistics, CDC. 3 Thiswork was not supported by any external grant. 4 Address correspondence to N Ahluwalia, Division of Health and Nutri-

tion Examination Surveys, National Center for Health Statistics, CDC, 3311

Toledo Road, Room 4110, Hyattsville, MD 20782. E-mail: naman.ahluwalia@

cdc.gov. 5 Abbreviations used: CSFII, Continuing Survey of Food Intakes by In-

dividuals; MEC, mobile examination center; PIR, poverty income ratio; SIP,

Share of Intake Panel.

ReceivedDecember 19, 2013. Accepted for publication July 3, 2014.

First published online August 27, 2014; doi: 10.3945/ajcn.113.082172.

1124 Am J Clin Nutr 2014;100:1124–32. Printed in USA. � 2014 American Society for Nutrition

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debate on the safety of caffeine intake by children (1, 12, 18) and deliberations to evaluate maximal intake recommendations, it is important to describe caffeine intake from more recent data available on a nationally representative sample such as the NHANES.

Trends in beverage consumption have changed over time (16, 20), and several caffeinated beverages and energy drinks have been introduced in the past decade, some marketed especially to youth (12, 15, 16). Few reports have described trends in caffeine intake both in milligrams and milligrams per kilogram of body weight by age in the United States (16, 21). Thus, our objective was to provide estimates of the distribution of caffeine intake in absolute amounts and in milligrams per kilogram in a representative sample of American children (2–19 y old) by using the most recent di- etary data available from the NHANES (ie, 2009–2010) in re- lation to demographic characteristics and examine the trends in caffeine consumption between 2001 and 2010 in children.

SUBJECTS AND METHODS

Study design

TheNHANES is a series of large, complex, stratified, multistage probability surveys of the US civilian, noninstitutionalized pop- ulation conducted by the National Center for Health Statistics, CDC (22). Briefly, NHANES is conducted yearly in w5000 individuals, and data are publicly released every 2 y onw10,000 individuals. Participants in the NHANES are administered a se- ries of questionnaires in a detailed in-home interview followed by a scheduled visit at the mobile examination center (MEC). At the MEC visit, participants receive a physical examination as well as a dietary interview, which is commonly referred to as the What We Eat in America component of the NHANES. The NHANES protocol was approved by the National Center for Health Statistics’s Research Ethics Review board. Informed consent was obtained from persons aged $18 y. For participants ,18 y of age, written parental consent was obtained, and child assent was obtained for individuals from 7 to 17 y of age. The most recent available data on caffeine intake from the NHANES (from the 2009–2010 survey) were used for the current analysis to describe caffeine consumption by demographic characteris- tics; data from this single survey cycle were sufficient to provide stable national estimates. We used NHANES data from 2001 to 2010 (2001–2002, 2003–2004, 2005–2006, 2007–2008, and 2009–2010 survey cycles) to conduct the trends analysis; be- cause of changes in the dietary data collection methodology on merging of the CSFII with NHANES in 1999–2000, data from 1999 to 2000 were not included in the trends analysis. The un- weighted total examination response rate for the 5 survey cycles examined for participants 2–19 y of age ranged from 81% to 88% (23).

Dietary interview

The type and quantity of all foods and beverages consumed in a single 24-h period, specifically the 24-h period before the dietary interview (from midnight to midnight) at the MEC, were collected by trained interviewers with the use of a computer- assisted dietary interview system with standardized probes (ie, the USDA’s Automated Multiple-Pass Method). Specifically for

beverages for which caffeine may be removed such as soda, coffee, tea, and energy drinks, probes were used to ascertain if the bev- erage reported was caffeine free. The Automated Multiple-Pass Method is designed to enhance a complete and accurate data collection while reducing the respondent burden (24, 25). For children aged #5 y, interviews were obtained through proxies, generally a parent. Proxies also assisted with dietary interviews of children aged 6–11 y. Dietary intakes were self-reported for participants aged $12 y. Since 2003–2004, a second, telephone- administered 24-h recall has been collected (3–10 d after the first 24-h recall at the MEC), but only one 24-h dietary recall was included in this analysis to maximize the comparability between surveys. Furthermore, one 24-h recall is sufficient to estimate population means because the effects of random errors associ- ated with dietary recall, including the day-to-day variability, are generally assumed to cancel out if days of the week are evenly represented (26).

Caffeine intake for all…