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

Dear Editor, It was very interesting to read the manuscript “Prehypertension is a comorbid state with autonomic and metabolic dysfunction.” written byJung MH. et al on a topic of prehypertension and its link to metabolic dysfunction.1 As claimed in paper published in Your Journal, little is known about the pathophysiology of prehypertension (especially in the healthy, normal weight subjects) so we decided to share our own experiences. Our aim was to determine a possible relation between blood pressure values and body composition in patient without elements of metabolic syndrome. Fourteen participants of normal weight (6 males, 8 females; median age 33 years, median body mass index 22.84 kg/m2) were included in the small study. Participants were healthy as determined by fasting routine blood parameters also including aldosterone, plasma renin activity, antidiuretic hormone, N-terminal pro-brain natriuretic peptide, oral glucose tolerance test, 24-hour urine protein excretion. Evaluation included bioelectrical impedance analysis (total body water, fat percentage, fat mass, muscle mass, and visceral fat rating). Blood pressure was estimated by 24-hour monitoring; median diastolic blood pressure was 71 mm Hg (range 42-80), and median systolic blood pressure was 115 mm Hg, range (103-137). Participants were divided into two groups according to the systolic blood pressure; cutoff value was the median systolic blood pressure of all the participants. In the first group (three males, four females) had an average systolic blood pressure (estimated by 24-hour monitoring) higher than 115 mm Hg and the second one (three males, four females) lower than mentioned value. The systolic blood pressure values of the first group were approximately in the range of high/normal blood pressure (115-137 mm Hg), which could be defined as prehypertension. Data were analyzed using two-sample t test. Characteristics that were significantly different between the groups were body mass index (24.4 ± 2.7 vs 21.5 ± 1.9 kg/m2 P = 0.02) and visceral fat rating (5.3 ± 2 vs 2.2 ± 1.6 P = 0.009). Adipose tissue is metabolically active; it is as an endocrine organ capable of synthesizing many compounds that influence metabolism.2 Oversecretion of potentially harmful adipocytokines, and hyposecretion of potentially beneficial adipocytokines, may be one of the major mechanisms involved in the development of hypertension.3 A recent cross-sectional study among adult participants showed that those with high body fat had two times greater odds of being hypertensive, and those with high visceral fat had three times greater odds of being hypertensive.4 The bioelectrical impedance analysis is a widely used method for estimating body composition, by measuring electric resistance of total body fat. Visceral fat rate is estimated by the fact that intra-abdominal fat has greater voltage than fat-free mass.5 Our findings support that body composition estimated by bioelectrical impedance analysis, even in normal weight individuals, influences the level of systolic blood pressure within normal ranges. It confirms the observation by. Deshpande-Joshi SS. and Rao S. that lean participants are at risk of hypertension, probably due to visceral fat deposition.1 In short, people with normal weight approaching the overweight limit and/or having higher visceral fat rate estimated by bioelectrical impedance analysis have higher risk for development of prehypertension. Body composition elements should be identified as risk factors for hypertension even in lean participants, while planning further studies evaluating prehypertension body composition analysis should be taken into consideration. The authors report no specific funding in relation to this research and no conflicts of interest to disclose. Maja Baretić was responsible for the study design and data collection; Ana Reschner for data analysis and data interpretation; Ivo Planinc for literature search. All authors were involved in writing the paper and had final approval of the submitted and published versions.