Amanda M. Ziegler

Cardiovascular Responses to Caffeine by Gender and Pubertal Stage

BACKGROUND: Caffeine use is on the rise among children and adolescents. Previous studies from our laboratory reported gender differences in the effects of caffeine in adolescents. The purpose of this study was to test the hypotheses that gender differences in cardiovascular responses to caffeine emerge after puberty and that cardiovascular responses to caffeine differ across the phases of the menstrual cycle. METHODS: To test these hypotheses, we examined heart rate and blood pressure before and after administration of placebo and 2 doses of caffeine (1 and 2 mg/kg) in prepubertal (8- to 9-year-olds; n = 52) and postpubertal (15- to 17-year-olds; n = 49) boys (n = 54) and girls (n = 47) by using a double-blind, placebo-controlled, dose-response design. RESULTS: There was an interaction between gender and caffeine dose, with boys having a greater response to caffeine than girls. In addition, we found interactions between pubertal phase, gender, and caffeine dose, with gender differences present in postpubertal, but not in prepubertal, participants. Finally, we found differences in responses to caffeine across the menstrual cycle in post-pubertal girls, with decreases in heart rate greater in the midluteal phase and blood pressure increases greater in the midfollicular phase of the menstrual cycle. CONCLUSIONS: These data suggest that gender differences in response to caffeine emerge after puberty. Future research will determine the extent to which these gender differences are mediated by physiological factors, such as steroid hormones, or psychosocial factors, such as more autonomy and control over beverage purchases.

Effects of acute and chronic caffeine on risk-taking behavior in children and adolescents.

Consumption of caffeinated beverages is associated with increased risk-taking behavior. The purpose of this study was to determine if acute caffeine administration influences risk-taking behavior in a dose-dependent manner. Participants were pre- (ages 8–9) and post-pubertal (ages 15–17) children who visited the laboratory three times and consumed a beverage containing 0, 1, or 2 mg/kg of caffeine. Thirty minutes later, participants completed the balloon analogue risk task (BART), the Iowa gambling task (IGT), and a delay discounting task. The number of balloons exploded on the BART task was significantly increased after 2 mg/kg of caffeine in moderate caffeine consumers, but was decreased after 2 mg/kg of caffeine in high caffeine consumers. There were no main effects of caffeine dose on the delay discounting task or on the IGT. Post-pubertal participants showed reduced delay discounting compared with pre-pubertal participants. Finally, average daily caffeine use was significantly, positively correlated with scores on a risk-taking questionnaire. These data suggest that caffeine dose-dependently influences decision making and risk taking. More research is needed to determine the mechanism of this difference as well as the extent to which sex and pubertal phase influence these relationships.

Daily exposure to either a high- or low-energy-dense snack food reduces its reinforcing value in adolescents

To examine the impact of daily exposure to a low‐energy‐dense (LED) or a high‐energy‐dense (HED) snack food on its reinforcing value (RRV) in adolescents with healthy weight, overweight, or obesity.

Soda Consumption is Associated with Risk-Taking Behaviors in Adolescents.

OBJECTIVES Soda consumption is on the rise among children and adolescents. The purpose of this study was to test the hypothesis that increased soda consumption predicts risk-taking behavior among high school students. METHODS To test this hypothesis, we used data from the 2011 Youth Risk Behavior Surveillance System to compare the odds of engaging in a series of risk-taking behaviors among students who reported no soda consumption, occasional soda consumption (1 - 6 times per week), and daily soda consumption (≥ 7 times per week). RESULTS Daily soda consumption was associated with increased odds of engaging in 90% of the risk behaviors analyzed. In addition, there were sex differences in the magnitude of the relationships for many of these behaviors. CONCLUSIONS These data suggest that in addition to increased risk of obesity, dental caries, and reduced sleep quality, soda consumption is associated with increased risk-taking behavior.