Sleep Quality and Attention May Correlate With Hand Grip Strength: FARM Study

OBJECTIVE: To determine the socio-demographic, psychologic, hematologic, or other relevant factors associated with hand grip strength in Korean farmers. METHODS: A total of 528 healthy Korean farmers were enrolled. Hand grip strength was measured in both hands using a hydraulic dynamometer. Socio-demographic characteristics were assessed and anthropometric measurements were obtained. Psycho-cognitive measurements such as sleep quality (Pittsburgh Sleep Quality Index) and Go/No-Go test response time were conducted. In addition to physical measurements, serologic parameters including insulin-like growth factor 1 were measured. The factors associated with hand grip strength were analyzed using multiple linear regression analysis after adjusting for age, height, and weight. RESULTS: The mean hand grip strength was associated with the Pittsburgh Sleep Quality Index total score (β=-0.12, p=0.01), the Go/No-Go test response time (β=-0.18, p=0.001), vitamin D (β=0.12, p=0.02), and insulin-like growth factor 1 levels (β=0.1, p=0.045). In female farmers, hand grip strength was only associated with the Pittsburgh Sleep Quality Index total score (β=-0.32, p<0.001). CONCLUSION: The results of this study demonstrate that hand grip strength was associated with sleep quality and attention in Korean farmers.