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diagnose depression and anxiety disorders.
Initial analyses of the actigraphy data
demonstrate that prior day sleep has
a strong impact on next-day positive
and negative mood, net of the effect of
prior-day mood, which implies that sleep
timing and quality helps to determine
daily emotional experience. At age 16,
higher stress levels and cortisol predicted
depression 18 months later. This suggests
that measurements of psychosocial
and biological stress in high school are
important predictors of later depression as
adolescents transition to adulthood.
Adam and her colleagues are also examining
how sleep can affect metabolism and
thus children’s development and health.
Adam, IPR graduate research assistant
Emily Snell, and economist Greg Duncan
studied data on 1,400 kids ages 3 to 12
from two waves of the Panel Study of
Income Dynamics (PSID). They found
that fewer hours of sleep predicted an
increase in body mass index (BMI) five
years later. This is the first study to show
convincing links between sleep and BMI
in children and adolescents, a population
for whom concern regarding obesity is
high, due to its associations with serious
future health problems such as diabetes
and cardiovascular disease. The findings
also show that many children are not
getting their recommended hours of sleep.
A second study using the PSID data,
conducted with human development
and social policy graduate students Snell
and Patricia Pendry, addresses the social
determinants of total sleep hours and
timing. How do demographic variables,
structural constraints such as school
start times, children’s activity choices,
and aspects of their family functioning
relate to the sleep behaviors of America’s
children? Among the many findings of
this study: African American children
and adolescents sleep approximately 30
minutes less than white children on both
weekends and weekdays, placing them
at a cognitive and health disadvantage.
Some of this sleep deprivation relates to
black children having to wake up earlier
because of longer school commute times.
Adam was also lead author of a study in
the Proceedings of the National Academy of
Sciences showing that when older adults
go to bed lonely, sad, or overwhelmed,
they have elevated levels of the stress
hormone cortisol shortly after waking
the next morning. This rise could help
give them a needed boost of energy to
meet the demands of their day, providing
evidence that cortisol influences—and is
influenced by—the daily experiences of
older adults. The study takes a rare look
at the physiological, social, and emotional
dynamics of day-to-day experiences in
real-life settings. The results were reported
by Scientific American and ABCNews.com,
among others.
Developmental Health Disparities
from Conception Through Adulthood
In the area of developmental
health disparities from conception
through adulthood, research
focuses in particular on prenatal
and perinatal environments and
how they interact with social,
genetic, and other biological
influences. Social and biological
risks to health across the life span
are also addressed.
Working with U.S. and Filipino
collaborators, anthropologist
Christopher Kuzawa studies the
influence of fetal and infant
nutrition and growth on adult health
and function in the Philippines. The
Cebu Longitudinal Health and Nutrition
Survey has followed more than 3,000
mothers who were pregnant in 1983,
and their children, who are now young
adults and having children of their own.
He and his colleagues have recently
Adam and her
colleagues are also
examining how sleep
can affect metabolism
and thus children’s
development and
health.
B. Kelley
www.northwestern.edu/ipr 39