Influence of age on the relation between waist circumference and cardiometabolic risk markers.

BACKGROUND AND AIMS

To determine whether the relation between waist circumference (WC) and cardiometabolic risk markers is attenuated with advancing age.

METHODS AND RESULTS

The study population consisted of 5222 adults from the 1999 to 2004 U.S. National Health and Nutrition Examination Survey, a nationally representative cross-sectional study. Study variables were assessed in a clinical exam. Subjects were grouped into low, moderate, and high sex-specific WC tertiles. The cardiometabolic risk markers examined consisted of insulin resistance (HOMA method), high C-reactive protein, hypertension, and high LDL-cholesterol. Logistic regression was used to determine and compare the association between WC categories with high-risk cardiometabolic risk marker values within young (20-39 years), middle-aged (40-59 years), and older (60+ years) adults. With few exceptions, within each of the three age categories, individuals with a moderate and high WC were significantly more likely to have elevated cardiometabolic risk markers than individuals with a low WC. There was a significant interaction between age and WC indicating that the relation between WC with insulin resistance, high CRP, and hypertension was attenuated in older adults. For example, the odds ratio for hypertension in those with a high relative to low WC was 11.07 (95% CI: 6.13-20.00) in young adults, 3.67 (2.47-5.46) in middle-aged adults, and 2.68 (2.00-3.59) in older adults. Similar observations were made for BMI to those reported for WC.

CONCLUSIONS

A high WC was associated with elevated cardiometabolic risk markers irrespective of age. However, the association between WC and cardiometabolic risk markers was greatly attenuated with advancing age.