Grip Strength Is Associated with Longitudinal Health Maintenance and Improvement in Adolescents.

Objective: To assess the effects of muscle strength, as determined by grip strength, on changes in health status in adolescents.

Study Design: Risk variables included excess body fat, elevated fasting glucose, high blood pressure, elevated serum triglycerides, and low high-density lipoprotein cholesterol. Multinomial logistic regression was used to quantify the odds of experiencing health maintenance (no risk factors identified at either time point) or health improvement (presence of ≥1 baseline risk factor and fewer or no risk factors at follow-up) over a 2-year period. The primary exposure variable was grip strength normalized by body mass (normalized grip strength [NGS]), and previous cut-offs were used to determine whether adolescents were weak or strong.

Results: Adolescents who had low NGSs had a significantly greater prevalence of health decline or poor health persistence as compared with those who were strong (boys: 60.2% vs 15.3%; girls: 51% vs 21.9%; all P < .001). Moreover, adolescents who were strong had an increased adjusted odds for health maintenance (OR 3.54; 95% CI 1.80-6.97) and health improvement (OR 1.30; 95% CI 1.05-1.60), even after we adjusted for baseline fat-free mass index, cardiorespiratory fitness, and objectively measured physical activity.

Conclusions: Greater NGS is associated with longitudinal health maintenance and health improvements in adolescents. Low NGS could be used as a prognostic indicator of cardiometabolic risk and to identify adolescents who would benefit most from lifestyle interventions to improve muscular fitness.