Aspects of Non-Dipping Blood Pressure Variations in Juvenile, Middle-Aged, And Adult Kazakhs

Juvenile, middle-aged, and elderly Kazakhs have been found to exhibit non-dipping blood pressure variations (BPV). Such variations are seen more often in middle-aged and elderly Kazakhs than in juvenile Kazakhs. The purpose of this study was to determine whether non-dipping BPV become more common in Kazakhs with advancing age and to compare the characteristics of non-dipper and dippers in order to clarify the effects of ageing on non-dipping type BPV. We performed ambulatory blood pressure monitoring. Juvenile, middle-aged, and elderly Kazakhs were enrolled. Each age group was further divided into those with dipping and non-dipping type BPV. We analyzed systolic blood pressure (SBP) variations with the maximum entropy method (MEM). Dippers and non-dippers accounted for 81% and 19% of the juvenile Kazakhs, 48% and 52% of the middle-aged Kazakhs, and 28% and 72% of the elderly Kazakhs, respectively. MEM analysis revealed that among the middle-aged and elderly Kazakhs the SBP variations of the non-dippers exhibited a 24-hour periodicity with a weak power spectral density as well as an ultradian periodicity. These features may have contributed to the generation of a decreased circadian rhythm in SBP, and thus, ultimately led to the non-dipping SBP variations observed in the middle-aged and elderly non-dipping Kazakhs. The non-dipping type BPV may have resulted from an effect of aging in Kazakhs since non-dipping BPV variations were more common in middle-aged and elderly Kazakhs than in juvenile Kazakhs.