Background: A number of studies have shown strong graded positive relationships between size at birth, grip strength, and estimates of muscle mass in older people. However no studies to date have included direct measures of muscle size.
Methods: We studied 313 men and 318 women born in Hertfordshire, United Kingdom between 1931 and 1939 who were still resident there and had historical records of growth in early life. Information on lifestyle was collected, and participants underwent peripheral quantitative computed tomography to directly measure forearm and calf muscle size.
Results: Birth weight was positively related to forearm muscle area in the men (r = 0.24, p <.0001) and women (r = 0.17, p =.003). There were similar but weaker associations between birth weight and calf muscle area in the men (r = 0.13, p =.03) and in the women (r = 0.17, p =.004). These relationships were all attenuated by adjustment for adult size.
Conclusion: We present first evidence that directly measured muscle size in older men and women is associated with size at birth. This may reflect tracking of muscle size and is important because it suggests that benefit may be gained from taking a life course approach both to understanding the etiology of sarcopenia and to developing effective interventions.