Screen time link to heart disease and cancer

● Study finds risk in watching too much TV for those with poor fitness

Too long spent watching television or l ooking at a computer s creen during l ei s ure time is linked to a higher risk o f d e a t h a nd he a r t d i s e a s e , according to new research.

The study, led by the University of Glasgow and published to day in BMC Medicine, has revealed a strong association between discretionary screen time and adverse health outcomes, par ticularly in those wi t h l ow f i t n e s s , l ow mus cle strength or poor physical activity levels.

Discretionary screen time is an impor tant contributor to overall sedentar y behaviour, which is associated with higher risk of mortality and cardiovascular disease. This is the largest single study to fo cus on this area.

The r esearchers l o oked at 3 9 0,0 8 9 p a r t i c i p a n t s f r o m the UK Biobank and analysed

0 Watching TV or staring at a screen during leisure time is linked to a higher risk of heart disease their amount of discretionary screen time.

The team found the association bet ween a high level of time spent staring at a screen and adverse health outcomes was almost twice as strong in those with low fitness levels or low grip strength, but were much s maller i n t hose who had the highest l evels of f i tness and grip strength.

Prof Ja s on Gil l , one of t he lead authors, said: “Our study shows that the risks associated with sedentary behaviour may not be the same for everyone, with the association between l ei sure t i me screen use and a d v e r s e h e a l t h o u t c o m e s being strongest in those with low levels of physical activity, fitness or strength.

“This has potential implications for public health guida n c e a s , i f t h e f i n d i n g s a r e causal, these data suggest that s p e c i f i c a l l y t a rg e t i ng t hos e with low fitness and strength t o r e d u c e t h e i r s e d e n t a r y behaviour may be an effective approach.”

The researchers also found t hat hi gher l e ve l s of s c r e e n time were associated with a greater risk of allcause mortality, as well as a higher risk of both heart disease and cancer.

The findings were independent of physical activit y, grip strength, BMI, smoking, diet and other major confounding factors, including socio eco nomic status.

Dr Carlos Celis, first author of the study, said: “If the discretionary screen time health associations we found in this study are causal, i t suggests people with the lowest levels of strength, fitness and physical activit y could potentially gain the greatest benefit from health promotion i nter ventions aimed at reducing sedentary behaviours.

“While fitness testing can be difficult to measure in healthcare and community settings, grip strength is a quick, simple and cheap to measure so could easily be implemented as a screening tool.”