Left handedness and risk of thoracic hyperkyphosis in prepubertal schoolchildren.

BACKGROUND: Hand dominance and spinal posture were studied for their prediction of the development of thoracic hyperkyphosis during the pubertal growth spurt.

METHODS: The cohort consisted of all the fourth-grade school children of the Western School District of Helsinki, Finland, in the spring of 1986. They were examined annually from the mean age of 10.8 to 13.8 years. Handedness was determined at the baseline examination by observing the hand with which the child was writing. Anthropometric measurements, posture and growth were followed-up annually. A lateral standing radiograph was undertaken in those children who had pronounced thoracic kyphosis in spinal pantography. Kyphotic angles > or = 45 degrees were considered hyperkyphotic.

RESULTS: In both girls and boys, left handedness was found to be a powerful determinant of hyperkyphosis. In left handed children the odds ratio (OR), adjusted for baseline spinal measurements, was 4.11 (95% confidence interval [CI]: 1.39-12.13). Hump size measured by the forward bending test also predicted significantly the development of thoracic hyperkyphosis (OR = 1.48; 95% CI: 1.23-1.76, per one degree).

CONCLUSIONS: Left handedness may be a risk factor for thoracic hyperkyphosis during the pubertal growth spurt.