Objective: To determine the prevalence of low back pain in children and its relationship with gender, age, exercise practice and sedentary activities (time on TV and on computer and/or video game). Methods: We conducted a cross-sectional study with a sample of 1,461 students, being 754 males and 707 females enrolled in the 5th to 8th grades of all five local elementary schools of urban Ourinhos, SP, Brasil, aged 10-14 years old, from whom sociodemographic data, time spent on sedentary activities such as TV and computer and/or video game were collected. We conducted a descriptive, bivariate and multivariate binary logistic regression. Results: The results showed that the prevalence of low back pain in the sample was 18.5%, being 15.5% in boys and 21.6% in girls. Low back pain was associated to the female gender, age range between 12-14 years and the habit of watching TV more than three times a week and over 3 hours per day. Conclusion: The students analyzed showed high prevalence of low back pain related to gender, age and habit of watching TV. Appropriate interventions should be implemented to reduce the occurrences of back pain in schoolchildren. Level of Evidence III, Cross Sectioning.

INTRODUÇÃO: A dor cervical é uma condição musculoesquelética com alta prevalência que pode afetar os aspectos físicos, sociais e psicológicos dos indivíduos, contribuindo para o aumento de custos na sociedade e nos negócios. OBJETIVOS: Determinar a prevalência de dor cervical e analisar a associação com variáveis sociodemográficas e dispositivos eletrônicos. MÉTODOS: Foi realizado um estudo observacional transversal com uma amostra de 1143 universitários, que responderam ao questionário sobre aspectos sociodemográficos, uso de dispositivos eletrônicos e o questionário nórdico. Foram realizadas análises descritivas, bivariadas e de regressão de Poisson. RESULTADOS: A prevalência de dor cervical foi de 66,7% (IC 63,8 a 69,3), sendo que, 57,6% (IC 52,9 a 62,1) em homens e 72,3% (IC 68,8 a 79,4) em mulheres. Na análise ajustada, o sexo feminino (RP = 1,92, 1,49-2,47), tempo de uso da TV acima de 3 horas por dia (RP = 1,35; 1,05 - 1,79), tempo de uso do computador acima de 3 horas por dia (RP = 1,41; 1,08 - 1,85), tempo de uso de videogame acima de 3 horas por dia (RP = 1,42; 1,02 - 1,97), uso do tablet à distância do olho na tela acima de 20 cm (RP = 1,08, 1,01 - 1,17), postura deitada no uso do celular (RP = 1,67, 1,04 - 1,72), postura semi-deitada no uso do celular (RP = 1,28; 1,02 - 1,65), postura sentada no uso do tablet (RP = 1,54; 1,03 - 2,38), postura deitada no uso do tablet (RP = 1,83; 05 - 3,18) e usar o tablet por duas ou mais horas por dia (RP = 2,28, 1,15 - 4,49) permaneceu associado à dor cervical. CONCLUSÃO: Existe alta prevalência de dor cervical em estudantes universitários e associação marcante com o sexo feminino e com o uso de dispositivos eletrônicos.

Purpose: To determine the prevalence of thoracic spine pain (TSP) in adolescents and to analyze its association with sociodemographic characteristics, use of electronic devices, habitual practice of physical activity and mental health problems. Methods: Cross-sectional study with 1628 students of public schools from the city of Bauru/SP. Data collection: 1. Characterization of the participants, use of electronic devices (TV, computer, tablet and phone), psychosocial factors and lifestyle; 2. Strengths and difficulties questionnaire (SDQ); 3. Baecke Questionnaire; 4. Nordic questionnaire. Descriptive analyzes, bivariate and multivariate logistic regression were used. Results: The overall prevalence of TSP was 51.5% (CI 49.1 to 53.9). Women showed a prevalence of 59.6% (CI 56.2 to 62.9) and men of 43.1% (CI 39.7 to 46.5), with significant difference. The variables associated with TSP were: female gender (PR= 1.96), use of computer for more than 3 hours per day (PR= 1.29), use of computer for more than 3 times per week (PR= 1.35), distance from eye to the computer screen (PR= 1.29), use of cell phone in semi-lying position (PR= 1.37), time of use of cell phone for more than 3 hours per day (PR= 1.44), use of tablet in sitting position (PR= 1.47) and presence of mental health problems (PR= 2.62) Conclusion: There is a high prevalence of TSP in adolescents and a marked association with female sex, the use of electronic devices, the presence of mental health problems. The level of physical activity was a protective factor.