Sexual dimorphism in spine alignment. Implications in sports medicine

Introduction: Differences in the physiological curvatures of the spine (cervical, thoracic, lumbar, and sacral regions) were evaluated by sex, considering the impact of physical exercise and other influencing variables such as sociodemographic characteristics, body composition, and the presence of diagnosed scoliosis. Materials and method: The sample comprised 301 participants of both sexes, aged >18 years (mean: 47.0 ± 20.5 years). Sex, age, and educational level (basic or higher) were recorded. Physical activity was assessed using the International Physical Activity Questionnaire (IPAQ) for adults, classified by METs as light, moderate, or vigorous. Waist circumference was measured with a tape measure, and scoliosis was evaluated with the Adams test and a Bunnell®️ scoliometer. Spinal curvatures were measured in the standing position using a Unilevel®️ inclinometer. Results and conclusions: Sex showed a significant association (P <0.001) with the sacral angle, which was greater in women (β = 2.832, 95% CI = 1.319–4.346). Although the lumbar angle showed significant differences (P <0.01), only the sacral region remained associated with sex. The relationship between adjacent curvatures (cervical-thoracic, thoracic-lumbar, and lumbar-sacral) was significant in linear regression (P <0.001). Age was associated with greater cervical curvature (β = 0.085, 95% CI = 0.040–0.129) and reduced lumbar curvature (β = -0.138, 95% CI = -0.188 - -0.087). Waist circumference correlated with cervical curvature (P <0.05; β = 0.080, 95% CI = 0.008-0.152), and scoliosis influenced sacral curvature (P <0.05; β = 1.542, 95% CI = 0.116-2.968). Participants engaging in vigorous activity had smaller thoracic angles compared to those performing light or moderate activity (P <0.05). These results underscore the influence of sex, age, body composition, and scoliosis on spinal curvatures, suggesting that exercise may affect thoracic curvature, which could be relevant in clinical postural interventions.