Dr Naveed Sattar and colleagues at the University of Glasgow investigated 13 statin trials in a meta-analysis published in The Lancet.
The study covered 91,140 people. In total, 4,278 developed diabetes over an average of four years. Statin therapy was associated with a 9 per cent increased risk of developing diabetes between statin and control groups.
The authors said the data suggest that statin therapy slightly increases the risk of diabetes, but the risk is low and outweighed by the benefits from reduced coronary events.
How important are these results?
Although researchers found statins slightly increase the risk of diabetes, the absolute risk is very low.
Just 174 extra cases of diabetes resulted from statin treatment over the control groups in assessed trials - equating to one additional case of diabetes per 255 for patients taking statins over four years.
This association was stronger in trials with older participants, but was not affected by baseline BMI and cholesterol levels, said the authors.
They also noted no difference in diabetes risk between types of statins, nor any increased risk in patients aged 60 or under.
Researchers also studied the benefits of the treatment. Statin therapy resulted in 5.4 fewer major coronary events per 255 patients treated over four years, compared with control therapy for cholesterol reduction.
The researchers said they expected this benefit to be even greater if the study had accounted for the effect on strokes and the need for revascularisation.
Should guidance change?
Diabetes UK was unequivocal that advice to patients should not change.
'This small increased risk is heavily outweighed by the benefits of statins in those at high risk of heart problems,' said Dr Iain Frame, director of research at Diabetes UK.
'This research, therefore, should on no account be taken as a reason for those over 60 at high risk of heart disease to stop taking statins,' he said.
The charity stressed that those on statin therapy should continue to be assessed for suitability on an individual basis.
The paper's authors also concluded that the small absolute risk of diabetes was outweighed by cardiovascular benefits in the short and medium term.
'We therefore suggest that clinical practice for statin therapy does not need to change for patients with moderate or high cardiovascular risk or existing cardiovascular disease,' they said.
However, they noted that the raised diabetes risk should be taken into account for patients at low cardiovascular risk or patient groups in which cardiovascular benefit has not been proven.
Are additional checks needed?
Researchers say further checks on older people taking statins may be necessary, saying: 'Our data suggest that surveillance for dysglycaemia might be useful for older people receiving statin therapy.'
Diabetes UK agreed and said more tests for glucose should be performed as standard.
'In the case of statins, monitoring of LFTs should be undertaken anyway, therefore a glucose test could also be incorporated as part of this review,' said Caroline Butler, care adviser at the charity.