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

Transport

Domestic

Work

THEN NOW

The spectrum of physical activity energy expenditure

Sleeping

[0.9 MET]

Sitting [1-1.5 MET]

Light [1.5 – 3 MET]

Moderate [3 - 6 MET]

Vigorous [6-9 MET]

Very vigorous [>9 MET] Maximal

Currently promoted ?????

*METS, Metabolic equivalent ~ amount of oxygen required for a given activity in relation to

sitting (1 MET)

Sedentary time

9.3 hrs/day (60%)

Moderate-vigorous activities

0.7 hrs/day (5%)

Light-intensity

6.5 hrs/day (35%)

Even physically active people record high

amounts of sedentary

Hamer et al. AJPM 2010.

TV viewing and mental health

Data from 2003 Scottish Health Survey, N= 3,920 adults.

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 health-

related) 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 (% semi-

skilled 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

Self-report

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

*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

Self-report

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

*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