Gender Difference in Response to Caffeine in Children and Adolescents

Study Overview
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Brief Summary
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Caffeine use is on the rise in America, and one of the most popular sources is soda. Among youth ages 8-16, caffeine consumption has increased by over 70% in the past 30 years. Few studies have examined the role of hormones in caffeine consumption within this age group. The purpose of the current experiment was to determine the effect of caffeine on children 8 and 9 compared to those 15 and 16 years of age. The investigators were looking at the effect of puberty on the consumption of caffeine as well as the effect that the caffeine has on the body (for example: heart rate, blood pressure) and cognitive function.

Detailed Description
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Our previous studies have demonstrated sex differences in both the reinforcing properties of (Temple JL, Briatico LN, Clark EN, Dewey AM, 2009) and physiological responses to (Temple JL, Dewey AM, Briatico LN, 2010) caffeine. This is consistent with the literature on other types of drugs showing that men and women often differ in both drug self administration (Lynch WJ,2008 ) and drug sensitivity (Temple, JL, et al, 2008). These differences have been attributed, at least in part, to differences in gonadal hormones (Lynch WJ, 2008) ,Dreher JC et al, 2007). Our laboratory conducted a study investigating subjective effects of caffeine in post-pubertal adolescents and found that boys reported greater drug effects and liking of drug effects than did females (Temple JL, Dewey AM, Briatico LN, 2010, Temple JL, Ziegler AM,2011). In addition, the differences in feeling of the drug effects were related to salivary estradiol levels in females, but not in males, suggesting that steroid hormones can mediate the subjective effects of caffeine. When taken together, these data suggest that there are gender differences in acute and chronic effects of caffeine and that these differences may be mediated by differences in circulating steroid hormones. Previous studies have shown that subjective responses to caffeine vary across the menstrual cycle (Terner JM, de Wit H, 2006), with the greatest subjective effects occurring during the follicular phase, when estradiol levels begin to rise and peak just prior to the ovulatory LH surge. To date, no well-controlled studies have been conducted in humans examining the relationship between steroid hormones and caffeine effects on cognition, which the investigators will address in this study.

Official Title
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Sex and Pubertal Stage Differences in Cardiovascular Responses to Caffeine in Children

Conditions
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Healthy

Intervention / Treatment
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* Drug: Placebo Administration first
* Drug: Low Caffeine Administration first (1mg/kg body weight)
* Drug: High Caffeine Administration first (2mg/kg body weight)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: males and females from 8-9 yoa or 15-17 yoa (post pubertal) those 8-9 much have Tanner Staging below 3 those 15-17 much have Tanner Staging above 3. willing to come into the lab 6 times for 1.5-2 hours each those willing to abstain from consuming caffeine for 24 hours before each appointment those willing to withdraw from consuming anything other than water for 2 hours before each appointment. 15-17 year old females much have begun menarche Exclusion Criteria: those on ADHD medication or other's impacting caffeine metabolism those reporting being on birth control or other hormones those that are pregnant or breastfeeding those outside the given age range or pubertal classification those reporting having an adverse effect of caffeine in the past

Ages Eligible for Study
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Minimum Age: 8 Years
Maximum Age: 17 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 1mg/kg Caffeine<br>Order of Caffeine Administration for Visits 1-6: 1mg, 2mg, 0mg, 1mg, 2mg, 0mg | Drug: Low Caffeine Administration first (1mg/kg body weight)<br>* On two of the 6 visits, participants received a placebo (flattened sprite) added to their beverage. Order of Caffeine Administration for Visits 1-6: 1mg, 2mg, 0mg, 1mg, 2mg, 0mg<br>|
| Experimental: 2mg/kg caffeine<br>Order of Caffeine Administration for Visits 1-6: 2mg, 0mg, 1mg, 2mg, 0mg, 1mg | Drug: High Caffeine Administration first (2mg/kg body weight)<br>* On two of the 6 visits, participants received a placebo (flattened sprite) added to their beverage. Order of Caffeine Administration for Visits 1-6: 2mg, 0mg, 1mg, 2mg, 0mg, 1mg<br>|
| Experimental: Placebo<br>Order of Administration for Visits 1-6: 0mg, 1mg, 2mg, 0mg, 1mg, 2mg | Drug: Placebo Administration first<br>* All participants received each dose on two days and the order of administration was counterbalanced. Order of Administration for Visits 1-6: 0mg, 1mg, 2mg, 0mg, 1mg, 2mg<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Peak Heart Rate After 2 mg/kg of Caffeine | Heart rate measurements were taken every 10 minutes, following 1 minute of rest with an automated Welch Allen Blood Pressure Cuff. We have reported the data as the peak heart rate after 2 mg/kg. | Heart rate was collected every 10 minutes for 60 minutes after the dose of caffeine. | 
| Peak Systolic Blood Pressure | Blood pressure measurements were taken every 10 minutes, following 1 minute of rest with an automated Welch Allen Blood Pressure Cuff. We have reported the peak heart rate after the 2 mg/kg dose of caffeine. | Blood pressure was assessed every 10 minutes for 60 minutes after caffeine was administered. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Cardiovascular influences, caffeine, healthy children