In a population-based cohort study, investigators found total physical activity decreases between 12 and 16 years of age.
Aaron Kandola, MSc
A physically active lifestyle reduces the chances teenagers will develop depression, according to a new study.
A team, led by Aaron Kandola Aaron Kandola, MSc, Division of Psychiatry at the University College London, examined the associations between depressive symptoms and objectively measured physical activity and sedentary behavior in adolescents.
Identifying modifiable risk factors is needed to reduce the prevalence of adolescent depression, while self-reported data suggests physical activity and sedentary behavior might be linked to depressive symptoms in this patient population.
In the population-based cohort study, the investigators examined 4257 adolescents whose mothers were invited to participate in the 14,901 participant Avon Longitudinal Study of Parents and Children (ALSPAC) trial, with at least 1 accelerometer recording and a Clinical Interview Schedule-Revised (CIS-R) depression score at 18 years old.
The investigators measured the amount of time spent in sedentary behavior and physical activity using accelerometers at around 12, 15, and 16 years of age. They also recorded total physical activity as county per minute (CPM), with raw accelerometer counts averaged over 60 second epochs.
The team then analyzed the associations between the physical activity and sedentary behavior variables and depression scores at age 18 with regression and group-based trajectory modelling.
The longitudinal analysis included 2486 at age 12, 1938 at age 14, and 1220 at age 16 with a total follow-up time of 6 years.
Overall, the total physical activity decreased between 12 years and 16 years of age. This is likely driven by an increase in durations of light activity (mean 325.66 min/day [SD 58.09] at 12 years; 244.94 min/day [55.08] at 16 years) and an increase in sedentary behavior (430.99 min/day [65.80]; 523.02 min/day [65.25]).
Higher depression scores at 18 years old were associated with a 60 minute per day increase in sedentary behavior at 12 years (incidence rate ratio [IRR], 1.111; 95% CI, 1.051—1.176), 14 years (IRR, 1.080; 95% CI, 1.012–1.152), and 16 years of age (IRR, 1.107; 95% CI, 1.015–1.208).
However, depression scores at 18 years old were lower for every additional 60 minute per day of light activity at 12 years (IRR, 0.904; 95% CI, 0.850—0.961]), 14 years (IRR, 0.922; 95% CI, 0.857–0.992), and 16 years of age (IRR, 0.889; 95% CI, 0.809–0.974).
Group-based trajectory modeling across 12-16 years of age identified 3 latent subgroups of sedentary behavior and activity levels, where depression scores were higher in those with persistently high (IRR, 1.282; 95% CI, 1.061—1.548) and persistently average (IRR, 1.249; 95% CI, 1.078–1.446]) sedentary behavior compared with those with persistently low sedentary behavior.
On the other hand, scores were lower in those with persistently high levels of light activity (IRR, 0.804; 95% CI, 0.652—0.990) compared with those with persistently low levels of light activity.
Each 15 minute per day increase in moderate-to-vigorous physical activity at age 12 (IRR, 0.910; 95% CI, 0.857—0.966) and total physical activity per 100 CPM increase at ages 12 years (IRR, 0.941; 95% CI, 0.910–0.972) and 14 years (IRR, 0.965; 95% CI, 0.932–0.999), were negatively associated with depressive symptoms.
“Sedentary behavior displaces light activity throughout adolescence, and is associated with a greater risk of depressive symptoms at 18 years of age,” the authors wrote. “Increasing light activity and decreasing sedentary behavior during adolescence could be an important target for public health interventions aimed at reducing the prevalence of depression.”
The study, “Depressive symptoms and objectively measured physical activity and sedentary behavior throughout adolescence: a prospective cohort study,” was published online in The Lancet Psychiatry.