title: Sex differences in the contributions of visceral and total body fat to blood pressure in adolescence.
abstract: Excess body fat deposited viscerally rather than elsewhere in the body is associated with higher risk for hypertension; this relationship is stronger in men than in women. Here we investigated whether similar sex dimorphism exists already in adolescence. A population-based sample of adolescent boys (n=237) and girls (n=262), age 12 to 18 years, was studied. Total body fat (TBF) was assessed with multifrequency bioelectrical impedance, and visceral fat (VF) was quantified with MRI. Blood pressure (BP) was measured beat by beat during an hour-long protocol, including supine, standing, sitting, mental stress, and poststress sections. Multivariate mixed-model analysis was used to assess the relative contributions of TBF and VF to BP during these sections. In boys, BP was strongly positively associated with VF (P<0.0001), whereas it was less strongly and negatively associated with TBF (P=0.004); these relationships did not substantially vary during the protocol. In contrast, in girls, BP was strongly positively associated with TBF (P=0.0006), whereas it was not associated with VF (P=0.08); the relationship with TBF varied during the protocol and was most apparent during mental stress (TBF*section interaction: P=0.002). Furthermore, when waist circumference was included in multivariate models instead of VF, it was not associated with BP in either sex; this indicates that waist circumference may not be an appropriate surrogate for VF. Thus, in adolescence, adiposity-related BP elevation is driven mainly by visceral fat in males and by fat deposited elsewhere in females. This dimorphism suggests sex-specific mechanisms of obesity-induced hypertension and the need for sex-specific criteria of its prevention.
authors.affiliation: Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada. zdenka.pausova@sickkids.ca
authors.forename: Zdenka
authors.initials: Z
authors.lastname: Pausova
authors.forename: Amel
authors.initials: A
authors.lastname: Mahboubi
authors.forename: Michal
authors.initials: M
authors.lastname: Abrahamowicz
authors.forename: Gabriel T
authors.initials: GT
authors.lastname: Leonard
authors.forename: Michel
authors.initials: M
authors.lastname: Perron
authors.forename: Louis
authors.initials: L
authors.lastname: Richer
authors.forename: Suzanne
authors.initials: S
authors.lastname: Veillette
authors.forename: Daniel
authors.initials: D
authors.lastname: Gaudet
authors.forename: Tomas
authors.initials: T
authors.lastname: Paus
mesh_terms: D000293:Adolescent; D001794:Blood Pressure / Q000502:physiology*; D050218:Body Fat Distribution; D002648:Child; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D015994:Incidence; D050152:Intra-Abdominal Fat; D008297:Male; D009765:Obesity / Q000150:complications / Q000453:epidemiology* / Q000503:physiopathology; D050177:Overweight / Q000150:complications / Q000453:epidemiology* / Q000503:physiopathology; D015995:Prevalence; D011792:Quebec / Q000453:epidemiology; D012307:Risk Factors; D012737:Sex Factors; D011795:Surveys and Questionnaires