Every hour that a person spends watching television on a daily basis could increase their risk of developing diabetes by more than 3%, a new study has found.

US researchers looked at over 3,200 overweight adults who had been enrolled in a diabetes prevention programme in the late 1990s. While this programme had been successful in helping people to lose weight and exercise more, little attention had been paid to the effects of a sedentary lifestyle.

This latest study looked at whether the programme reduced sedentary time and whether sedentary behaviour, such as sitting watching TV, had an effect on the development of diabetes.

The study found that prior to the programme, the participants spent an average of two hours and 20 minutes watching television every day. This time reduced by up to 37 minutes per day following participation in the programme.

The researchers decided to assess the impact of sedentary behaviour over time on the incidence of diabetes. They found that the risk of developing the disease increased by 3.4% for each hour spent watching television on a daily basis.

Therefore watching TV for three hours per day could increase a person's risk of developing diabetes by more than 10%.

"It is likely that a lifestyle intervention programme that incorporates a specific goal of decreasing sitting time would result in greater changes in sitting and likely more health improvements than are demonstrated here.

"These results should inform future intervention efforts that already focus on goals of increasing activity and reducing weight to also consider emphasising sitting less," commented the study's lead author, Dr Andrea Kriska, of the University of Pittsburgh.

Details of these findings are published in Diabetologia, the journal of the European Association for the Study of Diabetes.