Associations between objectively assessed
and self-reported sedentary time with mental
health in adults: HSE 2008
M Hamer, N Coombs, E Stamatakis
Dept Epidemiology & Public Health
m.hamer@ucl.ac.uk
THEN
NOW
Transport
Domestic
Work
The spectrum of physical activity energy expenditure
*METS, Metabolic equivalent ~ amount of oxygen required for a given activity in relation to
sitting (1 MET)
Sitting
[1-1.5 MET]
Sleeping
[0.9 MET]
Very vigorous
[>9 MET]
Moderate
[3 - 6 MET]
Light
[1.5 – 3 MET]
?????
Vigorous
[6-9 MET]
Currently promoted
Maximal
Even physically active people record high
amounts of sedentary
Moderate-vigorous activities
0.7 hrs/day (5%)
Light-intensity
6.5 hrs/day (35%)
Sedentary time
9.3 hrs/day (60%)
TV viewing and mental health
Data from 2003 Scottish Health Survey, N= 3,920 adults.
Hamer et al. AJPM 2010.
Sedentary behaviour and risk of depression
Zhai et al. BJSM
(in press)
Aim of study
Examine associations between objectively
assessed and self-reported sedentary time with
mental health in adults using HSE 2008.
Key measures
Exposure
 Objective 7 d sedentary time using Actigraph GT1M
 Self reported sedentary time (TV, other leisure
sitting, work based sitting)
Outcome
 Psychological distress: 12 item General Health
Questionnaire (GHQ-12)
Covariates
 age, sex, smoking, alcohol intake, BMI, social
occupational group, education, (non mental healthrelated) long standing illness, Actigraph wear time,
MVPA.
Sample characteristics
GHQ-12 <4
(N= 10172)
GHQ-12 ≥ 4
(N=1486)
Age (yrs [mean±SD] )
50.0 ± 17.6
48.3 ± 17.2
Sex (% men)
48.1
38.2
Social class (% semiskilled or lower)
21.7
26.4
Smoking (%)
20.6
29.9
Chronic illness (%)
39.8
57.3
Body mass index (kg/m2
[mean±SD] )
27.3 ± 5.0
27.8 ± 6.0
Results
Crude daily sedentary time in relation to psychological distress
Associations between sedentary time and
psychological distress (GHQ-12 >=4)
Exposure (tertile)
Age, sex adjusted
OR (95% CI)
Multivariable model*
OR (95% CI)
Objective
Low
1.00 (ref)
1.00
Medium
1.00 (0.66, 1.53)
1.09 (0.70, 1.71)
High
1.52 (0.98, 2.35)
1.74 (1.07, 2.83)
P-trend
0.072
0.037
Low
1.00
1.00
Medium
1.11 (0.95, 1.29)
0.97 (0.83, 1.13)
High
2.07 (1.79, 2.38)
1.34 (1.15, 1.56)
P-trend
<0.001
<0.001
Self-report
*Adjusted for: age, sex, smoking, alcohol, BMI, social occupational group, education, long
standing illness, Actigraph wear time (objective analysis), MVPA.
Associations between MVPA and psychological
distress
Exposure (tertile)
Age, sex adjusted
OR (95% CI)
Multivariable model*
OR (95% CI)
Objective
Low
1.00 (ref)
1.00
Medium
0.67 (0.45, 0.99)
0.90 (0.59, 1.37)
High
0.84 (0.55, 1.28)
1.27 (0.80, 2.04)
P-trend
0.13
0.28
Low
1.00
1.00
Medium
0.56 (0.49, 0.65)
0.70 (0.60, 0.81)
High
0.52 (0.45, 0.60)
0.65 (0.56, 0.76)
P-trend
<0.001
<0.001
Self-report
*Adjusted for: age, sex, smoking, alcohol, BMI, social occupational group, education, long
standing illness, Actigraph wear time (objective data only), total sitting.
Discussion points
Limitations
 Cross-sectional design (causality/ direction of
association?)
 Actigraph measures were only collected over one week
whereas self-report enquired about activity over the last 4
weeks.
Key strengths
 Large representative sample
 Adjustment for key confounders
Conclusion
Associations with mental health are similar
whether using objective and self reported
sedentary data.
Associations with MVPA and mental health only
observed with self reported data.
Full paper available: Hamer et al. BMJ Open 2014;4:e004580.
doi:10.1136/bmjopen-2013-004580