咀嚼筋の特性と脂肪率および一般的な筋力との関係：人口に基づく研究

Masticaticatory muscles characteristics in relation to adiposity and general muscular fitness: a population-based study.

抄録

咀嚼が肥満に与える影響については、いまだにかなりの論争がある。本研究の目的は、ドイツの一般集団において、咀嚼筋、歯、全身筋力の相互作用と、それらがどのように体脂肪率に寄与しているかを明らかにすることである。この横断的研究は、ポメラニアの人口ベースの健康調査から616人（男性300人、女性316人、年齢31-93歳）を対象としたものである。咬筋、内側翼突筋、外側翼突筋の断面積を磁気共鳴画像法（MRI）で、筋力を手指握力（HGS）で、体脂肪分布を生体電気インピーダンス分析（BIA）およびMRIで測定した。我々のコホートでは、肥満の全体的な有病率は高かった。咬筋の断面積は，年齢，性別，歯数，BMI，BMIで調整すると，歯数，BMI，HGSと正の相関を示し，BIAによる体脂肪と負の相関を示した．特に、その相関は強かった（p<0.001）。咬筋、HGS、MRIで測定した皮下脂肪の間にも同様の関係が観察された。これらの関連は咬筋で最も顕著であったが、両翼突筋でも有意であった。咀嚼筋は歯の数の影響を受けるが、歯は咬筋と脂肪率の関係に影響を及ぼさない。体力と咀嚼能力は、関連する筋肉によって制御・指示される体型と関連している。

There is still considerable controversy surrounding the impact of mastication on obesity. The aim of this study was to identify the interplay between the masticatory muscles, teeth, and general muscular fitness and how they contribute to body adiposity in a general German population. This cross-sectional study included 616 participants (300 male, 316 female, age 31-93 years) from the population-based Study of Health in Pomerania. The cross-sectional areas of the masseter, medial and lateral pterygoid muscles were measured using magnetic resonance imaging (MRI), muscular fitness assessed by hand grip strength (HGS) and body fat distribution was measured by bioelectrical impedance analysis (BIA) and MRI. The overall prevalence of obesity was high in our cohort. The cross-sectional area of the masseter muscles was positively associated with the number of teeth, body mass index (BMI) and HGS, and negatively associated with the BIA-assessed body fat when adjusted for age, sex, teeth, and BMI. Especially the correlation was strong (p < 0.001). Analogous relationships were observed between the masseter, HGS and MRI-assessed subcutaneous fat. These associations were most pronounced with masseter, but also significant with both pterygoid muscles. Though the masticatory muscles were affected by the number of teeth, teeth had no impact on the relations between masseter muscle and adiposity. Physical fitness and masticatory performance are associated with body shape, controlled and directed by the relevant muscles.