Cross-sectional relations of whole-blood miRNA expression levels and hand grip strength in a community sample

MicroRNAs (miRNAs) regulate gene expression with emerging data suggesting miRNAs play a role in skeletal muscle biology. We sought to examine the association of miRNAs with grip strength in a community-based sample. Framingham Heart Study Offspring and Generation 3 participants (n = 5668 54% women, mean age 55 years, range 24, 90 years) underwent grip strength measurement and miRNA profiling using whole blood from fasting morning samples. Linear mixed-effects regression modeling of grip strength (kg) versus continuous miRNA 'Cq' values and versus binary miRNA expression was performed. We conducted an integrative miRNA mRNA coexpression analysis and examined the enrichment of biologic pathways for the top miRNAs associated with grip strength. Grip strength was lower in women than in men and declined with age with a mean 447 (10.0) kg in men and 26.5 (63) kg in women. Among 299 miRNAs interrogated for association with grip strength, 93 (31%) had FOR q value < 005, 54(18%) had an FOR q value < 0.01, and 15 (5%) had FOR q value < 0.001. For almost all miRNA-grip strength associations, increasing miRNA concentration is associated with increasing grip strength. miR-20a-5p (FOR q 1.8 x 10) had the most significant association and several among the top 15 miRNAs had links to skeletal muscle including miR-126-3p, miR-30a-5p, and rniR-30d-5p. The top associated biologic pathways included metabolism, chemokine signaling, and ubiquitin-mediated proteolysis. Our comprehensive assessment in a corrimunity-based sample of miRNAs in blood associated with grip strength provides a framework to further our understanding of the biology of muscle strength.