Key points from article :
May be detectable 20 years before the disease is diagnosed.
Elevated fasting blood sugar levels and insulin resistance are signs.
Interventions to stop the disease should begin far earlier in life.
27,000 non-diabetics aged between 30 and 50 (mostly men) studied.
Participants followed until diagnosed type-2 diabetes or end of trial.
1 million people in UK may have type-2 diabetes and not yet know it.
The study was published in The Journal of Endocrine Society.
