Background: Although 36% of US men and 42% of US women are of normal weight, the health implications of greater weight in ostensibly normal-weight individuals are seldom acknowledged.
Methods and results: Self-reported physician-diagnosed incident diabetes, high cholesterol, and hypertension were compared with adult body mass index (BMI), and body circumferences in 29,139 male and 11,985 female nonsmoking runners followed prospectively for 7.7 and 7.4 years, respectively. Included among these were 20,731 men and 11,197 women who were of normal weight at baseline (BMI < 25 kg/m2). During follow-up, 2342 men (8.53%) and 499 women (4.26%) became hypertensive, 3330 men (12.2%) and 599 women (5.14%) were diagnosed with high cholesterol, and 197 men (0.68%) and 28 women (0.23%) became diabetic. Increasing BMI and waist circumference at baseline significantly increased the log odds for normal-weight men becoming hypertensive (P<0.0001), hypercholesterolemic (P<0.0001), and diabetic (P<0.02), and for normal-weight women becoming hypertensive (P=0.05). The log odds for being diagnosed with high cholesterol also increased with baseline BMI in normal-weight women (P<0.05). Relative to men with BMI < 20 kg/m2, the odds for being diagnosed with hypertension or high cholesterol increased by 45% (P=0.05) and 64% (P=0.002), respectively, for those with 20 < or = BMI < 22.5 kg/m2, and by 121% (P<0.0001) and 135% (P<0.0001), respectively, for those with 22.5 < or = BMI < 25 kg/m2. The odds for women with 22.5 < or = BMI < 25 kg/m2 developing hypertension or high cholesterol were 33% (P=0.02) and 29% (P=0.03) higher, respectively, than for women with 20 < or = BMI < 22.5 kg/m2, and 64% (P=0.0007) and 41% (P=0.008) higher, respectively, than women with BMI < 20 kg/m2. Relative to men and women with BMI < 22.5 kg/m2, the odds for developing diabetes during follow-up increased by 119% (P=0.009) and 116% (P=0.17), respectively, for those with 22.5 < or = BMI < 25 kg/m2.
Conclusions: Greater BMI and larger waist circumference increase the risks for hypertension, high cholesterol, and diabetes even among normal-weight nonsmoking runners, although overall risks remain relatively low vis-a-vis those for the overweight or obese.