The association between masked hypertension and waist circumference as an obesity-related anthropometric index for metabolic syndrome: the Ohasama study

Masked hypertension has been proven to be associated with an increased risk for cardiovascular diseases. The purpose of this study was to examine the direct associations of obesity-related anthropometric indices, including waist circumference, with masked hypertension. Participants in this population-based survey included 395 residents (> or = 35 years) of Ohasama, a rural Japanese community. They measured blood pressure at home (HBP) and underwent an oral glucose-tolerance test. Participants were classified into four groups on the basis of their HBP and casual-screening blood pressure (CBP) values: sustained normotension, white-coat hypertension, masked hypertension or sustained hypertension. The relationships between the obesity-related anthropometric indices and the four blood pressure groups were examined using multivariate analysis adjusted for confounding factors. The mean waist circumference in men was significantly higher in individuals with masked hypertension (87.3 cm) than in those with sustained normotension (81.0 cm) and white-coat hypertension (79.3 cm), whereas the mean waist circumference in women was significantly higher in individuals with sustained hypertension (79.5 cm) than in those with sustained normotension (75.0 cm). In the multivariate analysis, waist circumference, body mass index (BMI) and waist-to-hip ratio were significantly associated with masked hypertension, particularly in individuals with normal CBP. Our results suggest that HBP measurements might be particularly important in abdominally obese people for the early detection of masked hypertension.