Depressive symptoms and objectively measured physical activity and sedentary behaviour throughout adolescence, 2020, Kandola et al

[Andy]

Full title: Depressive symptoms and objectively measured physical activity and sedentary behaviour throughout adolescence: a prospective cohort study

Background
Identifying modifiable risk factors is essential to reduce the prevalence adolescent depression. Self-report data suggest that physical activity and sedentary behaviour might be associated with depressive symptoms in adolescents. We examined associations between depressive symptoms and objectively measured physical activity and sedentary behaviour in adolescents.

Methods
From a population-based cohort of adolescents whose mothers were invited to participate in the Avon Longitudinal Study of Parents and Children (ALSPAC) study, we included participants with at least one accelerometer recording and a Clinical Interview Schedule-Revised (CIS-R) depression score at age 17·8 years (reported as age 18 years hereafter). Amounts of time spent in sedentary behaviour and physical activity (light or moderate-to-vigorous) were measured with accelerometers at around 12 years, 14 years, and 16 years of age. Total physical activity was also recorded as count per minute (CPM), with raw accelerometer counts averaged over 60 s epochs. Associations between the physical activity and sedentary behaviour variables and depression (CIS-R) scores at age 18 years were analysed with regression and group-based trajectory modelling.

Findings
4257 adolescents from the 14 901 enrolled in the ALSPAC study had a CIS-R depression score at age 18 years. Longitudinal analyses included 2486 participants at age 12 years, 1938 at age 14 years, and 1220 at age 16 years. Total follow-up time was 6 years. Total physical activity decreased between 12 years and 16 years of age, driven by decreasing 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 increasing sedentary behaviour (430·99 min/day [65·80]; 523·02 min/day [65·25]). Higher depression scores at 18 years were associated with a 60 min/day increase in sedentary behaviour at 12 years (incidence rate ratio [IRR] 1·111 [95% CI 1·051–1·176]), 14 years (1·080 [1·012–1·152]), and 16 years of age (1·107 [1·015–1·208]). Depression scores at 18 years were lower for every additional 60 min/day of light activity at 12 years (0·904 [0·850–0·961]), 14 years (0·922 [0·857–0·992]), and 16 years of age (0·889 [0·809–0·974]). Group-based trajectory modelling across 12–16 years of age identified three latent subgroups of sedentary behaviour and activity levels. Depression scores were higher in those with persistently high (IRR 1·282 [95% CI 1·061–1·548]) and persistently average (1·249 [1·078–1·446]) sedentary behaviour compared with those with persistently low sedentary behaviour, and were lower in those with persistently high levels of light activity (0·804 [0·652–0·990]) compared with those with persistently low levels of light activity. Moderate-to-vigorous physical activity (per 15 min/day increase) at age 12 years (0·910 [0·857–0·966]) and total physical activity (per 100 CPM increase) at ages 12 years (0·941 [0·910–0·972]) and 14 years (0·965 [0·932–0·999]), were negatively associated with depressive symptoms.

Interpretation
Sedentary behaviour displaces light activity throughout adolescence, and is associated with a greater risk of depressive symptoms at 18 years of age. Increasing light activity and decreasing sedentary behaviour during adolescence could be an important target for public health interventions aimed at reducing the prevalence of depression.

Open access, https://www.thelancet.com/journals/lanpsy/article/PIIS2215-0366(20)30034-1/fulltext

Interpretation
Sedentary behaviour displaces light activity throughout adolescence, and is associated with a greater risk of depressive symptoms at 18 years of age. Increasing light activity and decreasing sedentary behaviour during adolescence could be an important target for public health interventions aimed at reducing the prevalence of depression.

Perhaps there are reasons for the increased sedentary behaviour, and identifying them might be useful. Or we could just go with the easy assumption and call it quits...

"Children who sit too much 'more likely to get depressed'"

Children who spend lots of time sitting still are more likely to develop depression by the age of 18, a study suggests.

Researchers at University College London looked at the activity levels of 4,257 12- to 16-year-olds.

Those who did an additional hour of light activity each day, such as walking or chores, had fewer depressive symptoms when they reached adulthood.

The study suggests people of all ages should be encouraged to move more.

https://www.bbc.co.uk/news/education-51475399

 

[Wonko]

Rich people spend more money than poor people, therefore we can cure poverty by encouraging poor people to spend more money (not actually give them any more, just tell them that it's their fault they are poor coz they don't spend enough)

 

[Amw66]

Without context for the sedentary behaviour this seems an assumption .

Teenagers generally are less mobile - there are many reasons why. Without a societal context this seems a half baked study

 

[rvallee]

Not impressed, there is no way of telling what is causative. There are many reasons why someone may be active, including liking physical activity, not a universal thing, and having the time to do so. That we have no reliable means of testing for depression means a wide error margin, this unfortunately makes interpretation difficult given too many people's convictions about exercise being itself evidence of less depression, a conviction that is likely wrong.

Sedentary behaviour displaces light activity throughout adolescence

Yes, as people get older they have more obligations, more school work, have to start working, etc. Some more than others and it's impossible to account for the reasons. Those are the same reasons adults seldom engage in physical activity, they simply don't have the time. As an observation, this is about as naive as being puzzled at why people's height changes during adolescence.

 

[MEMarge]

At least they realise they need an objective measure for activity:

"Nearly all previous studies have used self-report measures of activity, which are prone to bias, provide unreliable estimates, and do not sufficiently account for sedentary behaviour or light activity, which comprise most of daily waking activity."

 

[alktipping]

I would be impressed if somebody actually found the real cause of depression from what I have seen low grade inflammation may be key in understanding why some people are prone to lifelong clinical depression . it would also be really nice if there was some way of measuring what people call depression considering this disease effects so many people who from the outside at least do not seem to have very hard lives a possible clue to the fact that it is not caused by stress or the way people think . edited to add just look at the numbers of professional athletes who end up with depression as a diagnosis I am pretty sure they where very active as teenagers once again asking the wrong questions to justify activity as a cheap cure all damned lazy thinking.

 

[beverlyhills]

Ironically, the RBC study and this study have the same mis-attribution of causality.

RBC variance is a function of physical activity, even in healthy people.

I am not going to hold a student's thesis to a higher standard than a trial published in the Lancet though.

 

[beverlyhills]

professional athletes who end up with depression as a diagnosis I am pretty sure they where very active as teenagers once again .

Most athletes were never going to get depression in the first place, even if they were completely sedentary. They have young fit parents without depression, some of whom were professional athletes. It really screws up research.

Sam Darnold is an NFL quarterback that got sick with mono pretty late (at 22) during an NFL season and returned to play. His grandpa was Dick Hammer, a former Olympian. His dad played college ball. His mom is a PE teacher.

 

[Snow Leopard]

Also note, in the methodology:

We used group-based trajectory modelling to generate trajectories of depressive symptoms through ages 12 years, 14 years, and 16 years using MFQ scores. We then entered this as a categorical covariate into the regression models, instead of baseline depression, to adjust for varying depressive symptoms throughout adolescence.

As depressive symptoms exist on a continuum, we use continuous depression scores as our primary outcome in the main analyses. For other analyses, we defined possible cases of depression as scores of at least 10 on the MFQ and at least 7 on the CIS-R.

Also, the use of incidence rate ratio is strange, given they are not using it as the rate ratio of the incidence of reaching those thresholds on the questionnaires, but simply a point increase in scores.

 

[Sid]

Some people would argue that depression is a metabolic disturbance in the brain. Therefore, it's no wonder it is associated with physical inactivity and alterations in sleep cycle, appetite etc.