High insulin-like growth factor-binding protein-1 (IGFBP-1) is associated with low relative muscle mass in older women.

OBJECTIVE: Skeletal muscles serve several important roles in maintaining good health. Insulin-like growth factor-1 (IGF-1) is a promoter of protein synthesis in skeletal muscle. Its binding protein, Insulin-like growth factor-binding protein-1 (IGFBP-1) can be one determinant of IGF-1 activity. In the present study we investigate the association between serum IGFBP-1 and muscle mass.

DESIGN: Cross-sectional analysis of 4908 women, between 55 and 85years old, participating in the Swedish Mammography Cohort-Clinical.

METHODS: We defined low relative muscle mass (LRMM) as an appendicular lean mass divided by height squared of less than 5.45 (kg/m2 ), assessed by dual energy x-ray absorptiometry. IGFBP-1 was measured by radioimmunoassay. Logistic regression was used to calculate odds-ratios of LRMM across quartiles of IGFBP-1.

RESULTS: The odds of LRMM increased across quartiles of IGFBP-1. In the age-adjusted model the odds-ratio (OR) of LRMM was 3.41 (95% CI: 2.55-4.56), comparing the highest to the lowest quartile. This estimate was attenuated in multivariate models (OR: 1.84, 95% CI: 1.34-2.53), mainly due to inclusion of fat mass index.

CONCLUSION: Women with higher IGFBP-1 were more likely to have a low relative muscle mass. High IGFBP-1 may be a marker of a catabolic state.