To investigate factors associated with the development of type 2 diabetes mellitus (DM) during a 20-year follow-up in a homogeneous group of initially healthy middle-aged men with similar socioeconomic status.
We studied 1802 executives and businessmen, born 1919-34, without type 2 DM at baseline and with coronary heart disease (CHD) risk factor measurements in 1974-75. Diagnosis of type 2 DM during the follow-up was based on entitlement to re-imbursement for type 2 DM medication during 1975-1995, retrieved from national registers, self-report of type 2 DM or fasting blood glucose (> or = 6.7 mmol/L) in 1985-1986 (72% of the initial cohort re-evaluated). During the follow-up (up to 1995) type 2 DM was diagnosed using the above criteria in 94 men (5.2%). At baseline, men who later developed type 2 DM smoked more (p = 0.01), and had significantly higher body mass index (BMI), systolic and diastolic blood pressure, pulse pressure, serum triglycerides, and fasting and one-hour blood glucose. In a subset of high-risk men, those who developed type 2 DM also showed signs of white-coat effect on blood pressure (p = 0.008). Already at baseline, the CHD risk score was 23% higher in future type 2 DM subjects (p = 0.008). Re-evaluation in 1985-1986 showed essentially similar results for risk factors, but in addition, LDL cholesterol without lipid lowering drugs was significantly lower (p = 0.0018) in type 2 DM subjects. During the follow-up, 23.4% of the men with type 2 DM developed CHD as compared to 13.4% of those without (p = 0.008).
During a 20-year follow-up, several cardiovascular risk factors, including smoking, pulse pressure and the white-coat effect, predicted the development of type 2 DM in initially healthy middle-aged men. However, despite the higher incidence of CHD, development of type 2 DM was associated with lowered LDL cholesterol.