Obesity is the key determinant of cardiovascular risk factors in the Hong Kong Chinese population: cross-sectional clinic-based study

OBJECTIVES: To examine the interrelationships between obesity and various cardiovascular risk factors, and to investigate the relative importance of insulin and obesity in their associations with various pathophysiologies.

DESIGN: Cross-sectional clinic-based study.

SETTING: Medical clinics at a university teaching hospital, Shatin, Hong Kong.

PARTICIPANTS: A heterogeneous cohort of 767 Hong Kong Chinese subjects with a mean age of 43 (standard deviation, 14) years.

MAIN OUTCOME MEASURES: Body mass index, waist circumference, plasma insulin, insulin resistance index, fasting plasma glucose and lipid levels, blood pressure, and 24-hour urinary albumin excretion.

RESULTS: Pathophysiological abnormalities and risk factors are frequently clustered to varying degrees. Compared with the control subjects, patients with at least one component of the metabolic syndrome were more obese, hyperinsulinaemic, insulin resistant, hyperglycaemic, hypertensive, dyslipidaemic, and albuminuric (all variables, P<0.001). Increasing degrees of body mass index, waist circumference, plasma insulin level, and insulin resistance index were associated with an increasing number of risk factors after adjusting for age and sex (all variables, P<0.02). Multiple regression analysis showed that obesity, as reflected by either the body mass index or waist circumference, had a closer association than plasma insulin with the fasting plasma glucose concentration, blood pressure, and high-density lipoprotein-cholesterol and triglyceride concentrations. Using 19.0-20.9 kg/m(2) as the reference body mass index interval, the lowest cardiovascular risk was associated with a body mass index of <23.0 kg/m(2). There was an increased risk of 3.1 and 5 times when the body mass index was 23. 0-24.9 kg/m(2) and > or =25 kg/m(2), respectively.

CONCLUSIONS: Obesity, hyperinsulinaemia, and insulin resistance are characteristic features of Hong Kong Chinese patients who have various components of the metabolic syndrome. Obesity has a greater effect than plasma insulin on various pathophysiologies.