Higher visceral fat rate estimated by bioelectrical impedance analysis increases risk for prehypertension in normal weight healthy adults

We read with interest the letter by Baretić and colleagues in response to our published article regarding the relationship between prehypertension and autonomic and metabolic dysfunction.1 We completely agree that little is known about the pathophysiology of prehypertension especially in nonobese, relatively healthy participants. Furthermore, it is a relevant public health issue to identify the attributing factors to prehypertension in order to prevent its progression. As discussed in our study, prehypertension is not a simple precursor state of an elevated blood pressure; rather, it is a comorbid state with autonomic and metabolic dysfunction.1 The work by Baretić et al demonstrated the pathologic role of “visceral fat” in the pathogenesis of prehypertension even if the participant has a normal weight (body mass index <25 kg/m2).2 We previously reported that patients with prehypertension had a greater increased fat mass and decreased muscle mass (kg; absolute value) compared to patients with optimal blood pressure using a bioelectrical impedance analysis device (InBody 720, BioSpace, Seoul, Korea). However, in that study, when we adjusted for the total body weight (fat % or muscle %; relative value), there was no significant difference between the two groups.3 Recent studies have revealed that “visceral fat” is more sensitive to lipolysis and secretes a higher amount of inflammatory cytokines, compared to “subcutaneous fat.” Furthermore, “visceral fat” had a close correlation with incident hypertension even after adjustment for traditional hypertension risk factors.4, 5 As the body composition analysis used in our study (InBody 720)3 did not report data regarding visceral fat, we could not further evaluate whether visceral fat differs between the optimal blood pressure and prehypertension groups. However, some body composition analyses have been reported to show the visceral fat level. It is an important issue regarding how to measure visceral fat and what kind of machines are used for that. Also, it seems that some patients were in a hypertension state considering that the highest 24-hour systolic blood pressure value was 137 mm Hg. Despite these limitations, a detailed analysis of the body composition, including visceral fat, would be helpful to identify a risk factor for incident hypertension in these normal weight prehypertensive patients. Finally, prehypertension is associated with autonomic/ metabolic disarrangement and subclinical target organ damage as well as higher visceral fat. In patients with prehypertension, early identification and active intervention of those parameters might be important to halt development of hypertension and structural and functional deterioration of the cardiovascular system. None.