Comparative effects of overweight on cardiovascular risk in younger versus older men. The relation of age and body mass index (BMI) to atherosclerosis risk factors was examined in 357 men. Older (greater than or equal to 45 years) men had higher (p less than 0.01) systolic and diastolic blood pressures, fasting cholesterol and glucose, and 1-hour glucose and insulin levels. Fasting insulin and triglyceride levels were not significantly different between the 2 age groups. Although older men (n = 170) had greater values for several risk factors, overweight (BMI greater than 25.5 kg/m2) increased risk factors more in men younger than 45 years (n = 187). In younger men, those with higher BMIs had a greater prevalence, respectively, of blood pressure greater than 140/90 mm Hg (35.2 vs 11.2%, p less than 0.0001), cholesterol greater than 200 mg/dl (53.5 vs 29.3%, p less than 0.001), fasting triglycerides greater than 150 mg/dl (38.0 vs 10.3%, p less than 0.0001), 1-hour glucose greater than 160 mg/dl (15.5 vs 5.2%, p less than 0.05), fasting insulin greater than 11 microU/ml (28.2 vs 5.2%, p less than 0.0001), and 1-hour insulin greater than 110 microU/ml (28.2 vs 9.5%, p less than 0.001). In contrast, among older men, the prevalence of elevated blood pressure, cholesterol, triglycerides and glucose values was not significantly greater in the subgroup with high BMI. However, elevations of fasting (19.6 vs 6.4%, p less than 0.05) and 1-hour insulin (29.3 vs 11.5%, p less than 0.01) values were more common among older men with higher BMIs. 