Optimal waist circumference cutoff value reflecting insulin resistance as a diagnostic criterion of metabolic syndrome in a nondiabetic Korean population aged 40 years and over: the Chungju Metabolic Disease Cohort (CMC) study

PURPOSE

We aimed at determining the cutoff value of waist circumference with respect to its ability to reflect insulin resistance in a Korean population.

MATERIALS AND METHODS

A total of 8,817 subjects aged 40 years and over were analyzed. Insulin resistant individuals were defined as those who had the highest quartile value of the homeostasis model assessment of insulin resistance (HOMA-IR) in a non-diabetic population. Receiver operating characteristic (ROC) curve analysis and multiple logistic regression analysis were applied.

RESULTS

The cutoff value of waist circumference reflecting insulin resistance from the ROC analysis was 84.4 cm for men and 80.6 cm for women. Sensitivity and specificity were 70.0% and 54.2% in men and 71.1% and 59.3% in women, respectively. After being controlled for other covariates, the odds ratio for the risk of insulin resistance using < 70 cm of waist circumference as a reference increased significantly in the category of 85.0-89.9 cm for men and 80.0-84.9 cm for women. In addition, statistically significant associations were consistently observed over the category of 85.0-89.9 cm for men and 80.0-84.9 cm for women.

CONCLUSION

The optimal cutoff value for waist circumference reflecting insulin resistance is considered to be 85 cm for men and 80 cm for women, suggesting that the Asian criterion of abdominal obesity (90 cm for men and 80 cm for women) as a component of metabolic syndrome (MetS) might not be applicable for middle-aged to older men in Korea.

Factors associated with control of blood pressure among elderly people diagnosed with hypertension in a rural area of South Korea: the Chungju Metabolic Disease Cohort Study (CMC study)

OBJECTIVE

Control of blood pressure is important in old age for prevention of hypertension-associated complications. This study aimed to investigate the factors associated with control of hypertension in elderly people (>or=60 years old) diagnosed with hypertension.

METHODS

The subjects were those who had a self-reported diagnosis of hypertension (532 men and 1078 women) from a stratified random cluster sample of 4201 people aged 60 years or older. Controlled hypertension was defined as a systolic blood pressure (SBP) <140 mmHg and diastolic blood pressure (DBP) <90 mmHg, and SBP <130 mmHg and DBP <80 mmHg for subjects with diabetes.

RESULTS

The prevalence of controlled hypertension (25.9%) was low. In older women, the prevalence of isolated uncontrolled SBP was increased. After adjusting for other covariates, uncontrolled hypertension was positively associated with body mass index (BMI>or=23 kg/m(2)), and negatively associated with balanced diet and a past history of cardiovascular disease in men, whereas in women it was positively associated with waist circumference (>or=80 cm).

CONCLUSIONS

In elderly people diagnosed with hypertension general obesity (high BMI) appears to have an important influence on uncontrolled hypertension in men, whereas abdominal obesity (high waist circumference) appears to be an important factor in women.