HPA Axis, Discrimination and Adolescents

• Examines the relationships between the frequency and type of everyday discrimination with diurnal cortisol levels in adolescents, as well as whether these relationships depend on ethnicity and gender.
• Considers how adolescents' attributions of discrimination relate to HPA activity.

Methods

• Participants included 292 adolescents with an average age of 16.39 years, of whom 58% were female.
• They reported the experienced frequency of everyday discrimination and whether they attributed it to race, gender, age, or height and weight.
• Five saliva samples were gathered per day across 3 days to assay cortisol levels.

Results

• Higher frequency of everyday discrimination was associated with:
  • Greater total daily cortisol output (AUC)
  • Lower wake and bedtime levels of cortisol
  • Less decline in cortisol across the day
• These associations generally did not depend on ethnicity or gender.
• Attributions for the discrimination were not as consequential as the frequency of unfair treatment.
• Everyday discrimination might contribute to heightened HPA activity among adolescents of different ethnic backgrounds and genders.
• Adolescence involves sensitivity to social evaluation, with differential treatment based on social categories like race and gender.
• Discrimination perceptions correlate with negative psychological and physical well-being during the teenage years.
• The hypothalamic-pituitary-adrenal (HPA) axis is a biological system to understand the effects; cortisol measures HPA activity.
• HPA activity is reactive during adolescence and sensitive to discrimination.
• Dysregulated HPA activity predicts chronic psychological and physical problems later in adulthood, like depression and cardiovascular disease.
• Evaluates total cortisol output and daily patterns, giving insight on dysregulation during adolescence.
• A typical cortisol pattern involves high morning wake levels, a peak 30 minutes after waking (Cortisol Awakening Response, CAR), a steep decline across the day, and lower bedtime levels
• Area Under the Curve (AUC) measures total daily cortisol output, reflecting past stress exposure; AUC is associated with SES, immigrant status, and daily stressors.
• Increased CAR suggests anticipation of negative events.
• A flatter decline is associated with worse psychological/physical adjustment, like depressive symptoms, lower feelings of control, and risk for cardiovascular disease.
• Recent work suggests racial discrimination during adolescence predicts cortisol levels during adulthood.
• Three recent studies have examined the association between discrimination and dysregulated HPA activity during adolescence.
• Past research has established a link between discrimination and HPA activity and explores if the type of discrimination matters.

Additional Considerations

• Adult and adolescent populations focus on gender or racial discrimination, where "unfair treatment" can stem from factors like age and physical stature.
• Teenagers may feel mistreated because of stereotypes or social value on thinness and height; concealable stigmas had stronger effects on psychological well-being.
• Research on discrimination have typically examined attributions at a scale level and analyzing if unfair treatment is attributed to different reasons determines the differential effects on HPA activity.
• Aims to examine ethnic and gender groups within the same study, as the impact of discrimination is unclear among them.
• Participants were recruited from public high schools in the Los Angeles area with large populations of Asian, European, or Latin American backgrounds in 10th and 11th grade classrooms.
• Adolescents from Latin American (42%), European (29%), Asian (23%), and other ethnic backgrounds (6%) were analyzed.
• Families had a range of household incomes (M= $71,374, median= $51,500).
• Participants completed a computer-assisted questionnaire and height and weight measurements during a home visit and provided saliva collection kits with labeled Salivettes, a kitchen timer, an electronic date/time stamper, and a morning checklist.
• Participants collected saliva began on the following day for three consecutive days.
• Interviewers sent text message reminders, picked up the kits and adolescents received $50 and two movie tickets upon completion; 98% provided at least one saliva sample and 96.2% provided all 5 saliva samples for at least one day.
• Participants responded to 10 items on how often certain things have happened in their day-to-day life over the last 12 months on a four-point scale.
• Participants indicated whether they attributed the discrimination to gender, race, age, or height or weight. Attribute scores could range between 0-10.
• Adolescents provided five saliva samples for three days.
• Saliva samples were frozen until shipped on dry ice to be assayed by Biochemishes Labor.
• Adolescents provided three days of cortisol samples on different days of the week, and only weekday samples were included in the analyses.
• Assessed cortisol awakening response (CAR), linear decline from wake, and total daily cortisol output (AUC); cortisol parameters were log transformed and averaged across the three days.
• Participants reported when they awoke in the morning controlled for sleep-wake cycles.
• Research staff assessed participants' height and weight; Body Mass Index (BMI) calculated.
• Everyday discrimination was infrequent, attributing discrimination to their age and race than to their gender or height/weight
• Discrimination frequency correlated with lower waking levels of cortisol, less of a daily decline, and greater bedtime levels.
• Gender attributions were associated with greater AUC and cortisol bedtime levels.
• Females attributed discrimination to gender than males, and adolescents from Latin American and Asian backgrounds attributed discrimination to race than those with European backgrounds. Adolescents from European and Asian backgrounds attributed discrimination to age than their Latin American peers.
• Higher discrimination frequency correlated with greater AUC, lower waking cortisol, greater bedtime and flatter daily decline, with higher AUC, waking, and bedtime levels of cortisol in girls.
• Attributing ethnicity to discrimination correlated with lower bedtime cortisol.
• Associations between discrimination and wake and decline significantly differed between Latino and European youth.
• Simple slope analyses indicated that greater discrimination was associated with lower waking cortisol and flatter decline in European backgrounds, but this was not present in Latino youth.
• Discrimination frequency and decline were significantly different for males (flatter decline), who reported seldomly, compared to females, but a trend.
• Ethnic attributions were associated with lower AUC, who differed from other ethnic teens and Asian teens.

Discussion

• Adolescents who perceived higher rates of unfair treatment showed elevated cortisol levels across the day consistent with previous studies.
• This convergence indicates that discrimination during adulthood may begin as early as adolescence.
• Heightened cortisol output was due less decline in cortisol across the day, linked to psychological stress and maladjustment.
• Findings suggest unfair treatment, even with varying reasons, can be consequential to adolescent health.
• Cortisol responses are stronger due to negative judgment from others.
• Unfair treatment is more salient to race than to social identities among Asian American college students
• Latino youth are less affected by discrimination, but affected by ethnic attributions, while discriminatory and atypical cortisol patterns were the same for minorities and females.
• Even ethnic discrimination could be consequential for members of the majority group that feel they are not being treated fairly because of race.
• Ethnic minority young adults may differentially attribute unfair treatment to race
• Suggests that ethnic differences may be present, but may not be obvious.
• Any unfair treatment can trigger the HPA axis and has similarly consequential results on different backgrounds
• This may be impacted over time with frequent discrimination.
• Future studies should see if clear patterns on parameters of different ethnic groups can emerge with effects on stress biology and health.

Limitations

• Daily reports would show support for the discrimination-cortisol association.
• Attributions can consist of multiple social categories.
• Results may be unique to Southern California due to location of participants, and should be noted.
• The study suggests that unfair treatment is potentially elevated and can elevate cortisol levels among adolescents.