Waist circumference, body mass index and health risk factors among middle aged Thais.

Body mass index (BMI) and waist circumference (WC) are important contributors to major causes of health risk factors such as high blood cholesterol, high fasting blood sugar and high blood pressure. This analysis was designed to assess the associations between WC, BMI and each health risk factor in suitable cut-off points for WC and BMI among middle aged men and women of Thai population. Cross sectional data from the Second National Health Survey in Thailand was analysed. This set of data collected by the Ministry of Public Health from 1996 to 1997 was obtained from a total of 998 subjects (comprising 396 men and 602 women) aged 45-50. Results from the Receiver Operating Characteristic curve (ROC curve) identified those with health risk factors demonstrating cut-off points for WC between 81.5-84 centimeters for men and 76-80.5 centimeters for women and BMI between 23.3-23.9 kg/m2 for both genders, respectively. Results from the Multiple logistic regression analysis demonstrated lower risks of having high blood cholesterol, high fasting blood sugar and high blood pressure with cutoff points 84 cm for men, 80 cm for women and BMI 23 kg/m2 for both genders compared to cut-off points 102 cm for men, 88 cm for women and BMI 25 kg/m2 for both genders as specified for the population in Western countries. This study has proposed a waist circumference of 84 cm (33.6 inches) for middle aged Thai men and 80 cm (32 inches) for middle aged Thai women and BMI of 23 kg/m2 for both genders. Monitoring changes in the waist circumference over time along with BMI may be convenient and useful for middle aged Thais to prevent health risk conditions, even in the absence of a change in BMI.