Bone Mineral Density, Body Composition, Physical Activity Level, Muscle Strength and Smoking Status in Adults Men After Spinal Cord Injuries

Abstract

Background In this cross-sectional study we aimed to investigate the association of physical activity level, muscle strength, body composition and smoking status with bone mineral density in adults men after spinal cord injuries. Methods The study covered 50 men after spinal cord injuries aged 35.6 ± 4.9 years (25 wheelchair rugby players and 25 without sports training). Bone mineral density was measured by densitometry. Body Mass Index and body fat percentage was calculated. Fat mass and fat-free mass were estimated from somatic. An interview method using the Global Adult Tobacco Survey. Muscle strength- maximal hand grip strength was measured using a Jamar dynamometer. Results The active men after SCI were significantly higher bone parameters BMD prox, BMC dis and prox, and T-score prox (large effect). Of all the variables analysed, the strongest relationships with bone parameters were consistently found for PA, FM, and age. The strength of bone status relationships with PA is mostly higher than that of the relationships with FM except BMD dis (F = 4.4 v. 12.4). The BMC parameter proved to be the most reliable (for both dis and prox) and the highest values of R^2 corr were found, ranging at 7–8% of the analysed set of traits exhausting the variance of this parameter. HGS and AS in years proved to be relevant only for BMD dis. Age when injury occurred (years) proved to be relevant only for T-score prox. Nonsmoking activity men after SCI had the most advantageous values of means BMD in forearm. Conclusion Despite its high injury rates, rugby can be considered a sport that has a beneficial effect on BMD. Physical activity level in the form of 5 and more years wheelchair rugby training has been shown to be the strongest factor affecting bone health. Active smoking especially in rugby players influenced lower averaged BMD values.