Gender Difference in Response to Caffeine in Children and Adolescents
Condition: Healthy
Study type: Interventional

Summary: 
      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: 
      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.
    

Intervention name(s): Placebo Administration first; Low Caffeine Administration first (1mg/kg body weight); High Caffeine Administration first (2mg/kg body weight)
Intervention type(s): Drug; Drug; Drug
Intervention description(s): 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; 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; 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
Intervention MeSH terms: Caffeine
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Triple (Participant, Care Provider, Investigator)
Primary purpose: Basic Science
Keywords: Cardiovascular influences; caffeine; healthy children