Published Online
on March 31, 2009

A more recent version of this article appeared on June 1, 2009

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Original Article

A Common Variant of the FTO Gene Is Associated Not Only With Increased Adiposity But Also Elevated Blood Pressure in French-Canadians

Zdenka Pausova^1,10; Catriona A. Syme²; Michal Abarahamowicz³; Yongling Xiao³; Gabriel T. Leonard³; Michel Perron⁴; Louis Richer⁵; Suzanne Veillette⁴; George Davey Smith⁶; Ondrej Seda⁷; Johanne Tremblay⁷; Pavel Hamet⁷; Daniel Gaudet⁸ and Tomas Paus⁹

¹ Univ. of Nottingham, Nottingham, United Kingdom & CHUM, Montréal, Canada;
² University of Nottingham, Nottingham, United Kingdom;
³ McGill University, Montréal, Canada;
⁴ Groupe ECOBEs, Jonquière, Canada;
⁵ Université du Québec à Chicoutimi, Canada;
⁶ University of Bristol, Bristol, United Kingdom;
⁷ CHUM, Montréal, Canada;
⁸ Université de Montréal, Chicoutimi Hospital, Canada;
⁹ Univ. of Nottingham, Nottingham, United Kingdom & McGill Univ., Montréal, Canada

¹⁰ E-mail: zdenka.pausova{at}nottingham.ac.uk

Background—FTO is the first gene established as contributing to common forms of obesity. The gene is highly expressed in the hypothalamus and is thought to mediate this effect through its influence on energy homeostasis. The hypothalamus, however, also regulates blood pressure (BP). Therefore, here we investigated whether the FTO-risk variant is associated not only with increased adiposity but also with elevated BP, and whether the latter may be mediated, in part, by increased sympathetic modulation of vasomotor tone.

Methods and Results—The primary study was carried out in 485 adolescents recruited from a French-Canadian founder population who underwent detailed body-composition and cardiovascular phenotyping. Body fat was examined with magnetic resonance imaging, bioimpedance and anthropometry. BP was recorded beat-to-beat at rest and during physical and mental challenges. Sympathetic modulation of vasomotor tone was assessed with power spectral analysis of BP. We found that individuals with the FTO-risk genotype compared with those without it demonstrate greater adiposity, including the amount of intra-abdominal fat (by 38%). They also showed higher systolic BP throughout the entire protocol, with a maximum difference during a mental stress (6.4 [1.5 to 11.3] mm Hg). The difference in BP was accompanied by elevated index of sympathetic modulation of vasomotor tone. A replication in an independent sample of adults from the same founder population confirmed the association between FTO and BP.

Conclusions—These results suggest that, in a French-Canadian founder population, FTO may increase not only risk for obesity, as demonstrated in other populations, but also for hypertension. The latter may be related, at least in part, to the regulation of sympathetic vasomotor tone.

Key Words: genetics • hypertension • obesity • sympathetic nervous system • vasomotor tone • genetic association