Sleep and Stigma: Novel Moderators in the Relationship Between Weight Status and Cognitive Function
Condition: Obesity, Childhood; Overweight, Childhood
MeSH terms: Overweight; Pediatric Obesity
Study type: Interventional

Summary: 
      The investigators aim to assess the relationship between overweight/obesity and decreased
      cognitive function in adolescents. While this relationship has been seen in past literature,
      the causal mechanisms are still unclear. Thus, the present study will assess sleep and stigma
      as possible moderators. As sleep is related to both weight and cognitive abilities it may be
      an important factor in the relationship between these two variables. Further, people with
      overweight/obesity have higher risk for stigma experiences which may increase inflammation
      through chronic stress and elevated cortisol. Because inflammation is theorized to play a
      role in the relationship between elevated BMI and decreased cognitive function, stigma may be
      an important moderator. 60 adolescent participants will complete two sleep conditions
      (adequate and restricted) in a randomized order, each followed by a lab visit during which
      participants will complete a short cognitive battery. At these visits, participants will also
      be given a self serve breakfast with a variety of whole and processed food options to further
      evaluate the relationship between overweight/obesity, sleep, nutritional intake, and
      cognitive function.
    

Detailed description: 
      Obesity represents one of our nation's leading public health issues. In 2017, over 30% of
      U.S. high school students had either overweight (15.6%) or obesity (14.8%), and the average
      U.S. BMI continues to rise. Overall, this increasing trend is associated with earlier
      mortality and lower quality of life. In 2005 it was projected that if current U.S. weight
      trends continued, the average lifespan would decrease by about 9 months. Documented declines
      exceed this calculation, with rises in BMI relating to an estimated 11-month decrease in life
      expectancy in 2011. In adolescents specifically, this epidemic shares associations with many
      negative health outcomes including poorer sleep quality, impaired academic performance, and
      lower cognitive function. Thus, it is imperative that researchers work to understand the
      complex nature of this preventable disease and recognize its significant longitudinal health
      implications.

      One factor significantly related to overweight/obesity (OWOB) is decreased cognitive
      function. However, the causal nature of this relationship is unclear. It has been
      hypothesized that impaired cognitive function and poor inhibition could predict increased
      food consumption, thus contributing to the association between cognitive deficits and OWOB.
      Alternatively, it has been suggested that biological factors stemming from obesity (i.e. low
      grade inflammation, insulin resistance, low blood flow, and increased levels of cytokines and
      leptin) work to exacerbate preexisting cognitive impairments, or are perhaps fully
      responsible for the cognitive deficits seen in individuals with OWOB. Thus, further research
      is needed to clarify these relationships.

      Research regarding OWOB and cognitive function has left a critical gap in the literature by
      failing to consider the role of sleep within this relationship. Current evidence shows that
      more than 2/3 of adolescents fail to attain the recommended minimum of 8 hours of sleep
      during the week. However, a meta-analysis found that every added hour of sleep that
      adolescents do secure relates to a 9.0% decrease in obesity risk. In line with this finding,
      sleep restriction is associated with increased appetite, hunger, and poorer nutritional food
      choices. Sleep restriction has also been tied to impairments in cognitive function including
      decreased working memory and attention. Thus, it is possible that the relationship between
      OWOB and cognitive function in adolescents is influenced by sleep behaviors.

      Another important factor to consider in the relationship between OWOB and cognitive function
      is stigma. Weight stigma is a pervasive problem with multiple implications for physical
      health. For example, chronic low-grade inflammation represents a known correlate of chronic
      stress and stigmatization. This is significant as elevated inflammation also relates to OWOB
      and decreased cognitive function. Thus, the experience of weight related stigma may
      exacerbate existing inflammation in individuals with OWOB, further impairing cognitive
      function.

      The present study seeks to expand our knowledge of these complex relationships, exploring the
      associations between weight status, eating behavior, cognitive function, sleep, and stigma.
      To do this, the study will utilize data from 2 groups: adolescents with normal weight and
      adolescents with OWOB. Adolescents in each group will complete two sleep conditions in a
      randomized order: adequate and restricted. Each sleep condition will be followed by a
      self-serve breakfast and completion of a cognitive battery. Prior to completing the sleep
      conditions, adolescents will participate in a baseline appointment during which they will
      complete a questionnaire regarding weight related stigma experiences.

      The investigators propose that cognitive function and sleep restriction may relate to
      adolescent weight status through the following mechanisms: 1) elevated adiposity will predict
      greater impairments in cognitive functioning, poorer nutritional intake, and greater food
      consumption, 2) sleep restriction will result in impaired cognitive functioning, poorer
      nutritional intake, and increased food consumption in all adolescents, 3) sleep restriction
      in adolescents with elevated adiposity will result in the greatest cognitive impairments,
      poorest nutritional intake, and greatest food consumption, and 4) decreased cognitive
      function will be associated with poorer nutritional intake and greater food consumption in
      all adolescents. The investigators also propose that stigma experiences relate to adolescent
      weight status through the following mechanisms: 1) heightened stigma experiences will predict
      impairments in cognitive functioning in all adolescents and 2) elevated adiposity will relate
      to greater stigma experiences and subsequently higher cognitive impairments, resulting in the
      worst outcomes for assessments of cognitive function .
    

Intervention name(s): Restricted Sleep; Adequate Sleep
Intervention type(s): Behavioral; Behavioral
Intervention description(s): During the restricted sleep condition adolescents will sleep 4 hours ±1 hour (0100-0500). This condition will last 1 night.; During the adequate sleep condition adolescents will sleep 9 hours ±1 hour (2100- 0800). This condition will last 1 night.
Allocation: Non-Randomized
Intervention model: Crossover Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Basic Science
Keywords: sleep; stigma; cognitive function; nutrition