Sitting still linked to increased risk of depression in adolescents
February 11, 2020
Science Daily/University College London
Too much time sitting still -- sedentary behaviour -- is linked to an increased risk of depressive symptoms in adolescents, finds a new UCL-led study.
The Lancet Psychiatry study found that an additional 60 minutes of light activity (such as walking or doing chores) daily at age 12 was associated with a 10% reduction in depressive symptoms at age 18.
"Our findings show that young people who are inactive for large proportions of the day throughout adolescence face a greater risk of depression by age 18. We found that it's not just more intense forms of activity that are good for our mental health, but any degree of physical activity that can reduce the time we spend sitting down is likely to be beneficial," said the study's lead author, PhD student Aaron Kandola (UCL Psychiatry).
"We should be encouraging people of all ages to move more, and to sit less, as it's good for both our physical and mental health."
The research team used data from 4,257 adolescents, who have been participating in longitudinal research from birth as part of the University of Bristol's Children of the 90s cohort study. The children wore accelerometers to track their movement for at least 10 hours over at least three days, at ages 12, 14 and 16.
The accelerometers reported whether the child was engaging in light activity (which could include walking or hobbies such as playing an instrument or painting), engaging in moderate-to-physical activity (such as running or cycling), or if they were sedentary. The use of accelerometers provided more reliable data than previous studies which have relied on people self-reporting their activity, which have yielded inconsistent results.
Depressive symptoms, such as low mood, loss of pleasure and poor concentration, were measured with a clinical questionnaire. The questionnaire measures depressive symptoms and their severity on a spectrum, rather than providing a clinical diagnosis.
Between the ages of 12 and 16, total physical activity declined across the cohort, which was mainly due to a decrease in light activity (from an average of five hours, 26 minutes to four hours, five minutes) and an increase in sedentary behaviour (from an average of seven hours and 10 minutes to eight hours and 43 minutes).
The researchers found that every additional 60 minutes of sedentary behaviour per day at age 12, 14 and 16 was associated with an increase in depression score of 11.1%, 8% or 10.5%, respectively, by age 18. Those with consistently high amounts of time spent sedentary at all three ages had 28.2% higher depression scores by age 18.
Every additional hour of light physical activity per day at age 12, 14 and 16 was associated with depression scores at age 18 that were 9.6%, 7.8% and 11.1% lower, respectively.
The researchers found some associations between moderate-to-vigorous activity at earlier ages and reduced depressive symptoms, although they caution that their data was weaker due to low levels of activity of such intensity in the cohort (averaging around 20 minutes per day), so the findings do not clarify whether moderate-to-vigorous activity is any less beneficial than light activity.
While the researchers cannot confirm that the activity levels caused changes to depressive symptoms, the researchers accounted for potentially confounding factors such as socioeconomic status, parental history of mental health, and length of time wearing the accelerometer, and avoided the possibility of reverse causation by adjusting their analysis to account for people with depressive symptoms at the study outset.
"Worryingly, the amount of time that young people spend inactive has been steadily rising for years, but there has been a surprising lack of high quality research into how this could affect mental health. The number of young people with depression also appears to be growing and our study suggests that these two trends may be linked," Kandola added.
The study's senior author, Dr Joseph Hayes (UCL Psychiatry and Camden and Islington NHS Foundation Trust), said: "A lot of initiatives promote exercise in young people, but our findings suggest that light activity should be given more attention as well."
"Light activity could be particularly useful because it doesn't require much effort and it's easy to fit into the daily routines of most young people. Schools could integrate light activity into their pupils' days, such as with standing or active lessons. Small changes to our environments could make it easier for all of us to be a little bit less sedentary," he added.
https://www.sciencedaily.com/releases/2020/02/200211193051.htm
Spending too much time sitting down linked to around early 50,000 deaths per year in the UK
And ill health associated with sedentary behavior costs the NHS at least £0.7 billion per year
March 25, 2019
Science Daily/BMJ
Spending large amounts of time sitting or lounging around during the day is linked to around 50,000 deaths per year in the UK and the NHS spends in excess of £0.7bn per year treating the health consequences, suggests research from Queen's University Belfast and Ulster University published online in the Journal of Epidemiology & Community Health.
A large proportion of the UK population have sedentary jobs and leisure activities, and official physical activity recommendations regarding sedentary behaviour are vague.
Previous studies have shown that spending large parts of the day sitting down increases the risk of cardiovascular disease, type 2 diabetes, cancer and death and is a burden on health services.
But no estimate of the financial impact that sedentary behaviour has on the NHS has been calculated, so the authors set out to do just that.
Figures calculated by other researchers on the impact sedentary behaviour has on the relative risks of five specific health conditions (type 2 diabetes, cardiovascular disease, colon cancer, endometrial cancer and lung cancer) and deaths from all causes were combined with figures on the percentage of adults who are sedentary on any given day of the week to estimate the overall impact sedentary behaviour has at a UK population level (population attributable fraction).
Figures on sedentary behaviour were taken from the Health Survey for England 2012, which reported that 30% of adults in England spent at least six hours/day sedentary on weekdays and that this increased to 37% of adults on weekends.
Actual overall NHS spending on each of the five conditions, uplifted for inflation, was used to estimate the financial impact sedentary behaviour had on the NHS for each of the conditions in the UK in 2016-17.
For all five conditions combined, this amounted to £0.8bn in 2016-17.
As a proportion of patients will have more than one of the five conditions, for example around 30% of people with type 2 diabetes will also have cardiovascular disease, the researchers revised their figures to adjust for double-counting caused by comorbidity. This reduced the overall cost of sedentary behaviour to the NHS for these five health conditions to £0.7bn in 2016-17.
Next they took the figure calculated for the fraction of deaths from all causes that could be attributed to a sedentary lifestyle and multiplied it with the actual numbers of deaths that occurred in the UK in 2016.
The researchers say their results suggest that 11.6% of all deaths were associated with sedentary behaviour and that 69,276 deaths might have been avoided in 2016 if sedentary behaviour was eliminated in the UK.
This is an observational study, and as such, can't establish cause, and it also relied on estimates of people's self-reported activity levels, which may not be accurate. The study was also limited by the evidence available for the link between sedentary behaviour and health outcomes.
The authors point out that these costs are probably a conservative estimate of the true burden of sedentary behaviour because sedentary behaviour is likely to be associated with several other cancers, musculoskeletal disorders, and mental health disorders, not included in their analysis.
Official physical activity recommendations regarding sedentary behaviour are vague, they say. Lead Investigator, Leonie Heron from the Centre of Public Health at Queen's University Belfast, said: "Many individuals in the UK spend their leisure time in sedentary behaviour, and the workplace represents a significant proportion of unavoidable daily sitting time for many people."
Measures should be taken to reduce sedentary behaviour with the aim of improving population health and reducing the financial burden to the health service, they conclude.
https://www.sciencedaily.com/releases/2019/03/190325184118.htm