Novel association between the reverse-dipper pattern of ambulatory blood pressure monitoring and metabolic syndrome in men but not in women

The aim of this study was to investigate the relationships between nocturnal variations in blood pressure (BP) and metabolic syndrome (MetS) in different gender. This cross-sectional study involved 509 hypertensive patients (254 males and 255 females, 45 to 75 years old) from September 2013 to March 2014. BP values were acquired from ambulatory BP monitoring (ABPM). The dipper pattern of BP was defined as 10% to 20% reduction of the mean systolic BP (SBP) values at night compared with the daytime values. The diagnosis of MetS was made according to NCEP ATP-III definition. Multivariate logistic regression analyses were used to explore the relationships between ABPM results and MetS. In our study, MetS were observed in 29.1% of male and 18.4% of female participants. The prevalence of MetS was higher in the patients with reverse-dipper pattern than in others. After multivariate logistic regression analysis, the reverse-dipper pattern of BP (odds ratio 2.298; P=0.006) and 24-SBP (odds ratio 1.063; P=0.021) were independently correlated with MetS in males. However, there was no association between MetS and BP reverse dipping in females. Our cross-sectional study showed that the reverse-dipper pattern of BP is associated with MetS in male, while the underlying mechanism deserves further investigation.