Effects of birth weight on body composition, physical fitness, and sarcopenia assessments in young Japanese women.

This study examined the effects of birth weight on body composition, physical fitness, and sarcopenia in adulthood among young Japanese women. Seventy young adult women (birth weight <2500 g classified as low-birth-weight group [L-BW, n = 13] and ≥2500 g classified as not low-birth-weight group [NL-BW, n = 57]) were evaluated for body composition, physical fitness, and sarcopenia. Skeletal muscle mass was significantly greater (p<0.05) in the NL-BW group than in the L-BW group for all body sites. Effect sizes for the differences in skeletal muscle mass between the two groups were all larger in the NL-BW group than in the L-BW group (0.86-1.44). Knee extension muscle strength was higher in the NL-BW group than in the L-BW group (p = 0.04), but there were no differences between groups with respect to other physical fitness indicators (p>0.05). Except for SMI (p<0.05), other sarcopenia diagnostic evaluations did not differ between the two groups (p>0.05). In conclusion, L-BW female infants were shorter in standing height and smaller in skeletal muscle mass in terms of morphology at the time of young adulthood compared to NL-BW female infants. In addition, in terms of physical fitness, those with L-BW also had a lower-limb power score and a higher proportion of low skeletal muscle mass. Thus, it was suggested that low birth weight infants may be at risk of needing nursing care in old age (i.e., a high predicted incidence of sarcopenia) as well as thinness problems in the fertile generation.