Division of Liberal Arts and Sciences, Aichi Gakuin University, Nisshin, Japan.
Geriatr Gerontol Int. 2014 Apr;14(2):354-61. doi: 10.1111/ggi.12109. Epub 2013 Jul 1.
Little is known about longitudinal changes of body composition measured by dual-energy X-ray absorptiometry (DXA) in middle-aged and elderly individuals. We evaluated longitudinal changes of body composition, and age and sex differences in appendicular skeletal muscle mass.
Participants were 1454 community-dwelling Japanese men and women aged 40-79 years. Body composition at baseline and 6-year follow up was measured by DXA.
Fat increased significantly in men of all ages, and in women aged in their 40s and 50s. Among men, arm lean tissue mass (LTM) changed by 0.9%, -0.5%, -1.4% and -3.7%, respectively, for the 40s to the 70s, and decreased significantly in the 60s and 70s. Leg LTM in men changed by -0.4%, -1.3%, -1.7% and -3.9%, respectively, and decreased significantly from the 50s to the 70s. Compared with the preceding age groups, significant differences were observed between the 60s and 70s in arm and leg LTM change in men. Among women, arm LTM changed by 0.7%, 0.2%, 1.6% and -1.5%, respectively, which was significant in the 60s and 70s. Leg LTM decreased significantly in all age groups of women by -2.0%, -2.8%, -2.4% and -3.9%, respectively. With respect to sex differences, leg LTM loss rates were significantly higher in women than men at the 40s and 50s.
Longitudinal data suggest that arm and leg LTM decreased markedly in men in their 70s, and leg LTM had already decreased in women in their 40s.
双能 X 射线吸收法（DXA）测量的人体成分的纵向变化在中年和老年人中鲜为人知。我们评估了身体成分的纵向变化以及四肢骨骼肌质量的年龄和性别差异。
参与者为 1454 名年龄在 40-79 岁的社区居住的日本男性和女性。基线和 6 年随访时使用 DXA 测量身体成分。
所有年龄段的男性脂肪均显著增加，40 多岁和 50 多岁的女性也如此。在男性中，手臂瘦组织量（LTM）分别变化 0.9%、-0.5%、-1.4%和-3.7%，年龄在 40 多岁到 70 多岁之间，60 多岁和 70 多岁时显著下降。男性腿部 LTM 分别变化-0.4%、-1.3%、-1.7%和-3.9%，从 50 多岁到 70 多岁时显著下降。与前几个年龄组相比，60 多岁和 70 多岁男性的手臂和腿部 LTM 变化有显著差异。在女性中，手臂 LTM 分别变化 0.7%、0.2%、1.6%和-1.5%，60 多岁和 70 多岁时显著。所有年龄段的女性腿部 LTM 均显著下降，分别为-2.0%、-2.8%、-2.4%和-3.9%。关于性别差异，40 多岁和 50 多岁时，女性腿部 LTM 流失率明显高于男性。
纵向数据表明，男性 70 多岁时手臂和腿部 LTM 明显下降，女性 40 多岁时腿部 LTM 已经下降。
