The identified clusters provide unique information on LBP and its impact during the transition from adolescence to young adulthood. Consideration of these trajectories could be important in the design of early prevention and management strategies.

Musculoskeletal pain in multiple sites is common already in adolescence, and may lead to subsequent musculoskeletal complaints in adulthood. We examined predictive factors for the persistence of multiple musculoskeletal pains in adolescence over a 2-year time span. A postal questionnaire was administered to a subsample of the Northern Finland Birth Cohort 1986 (n=1773) when subjects were aged 16 and 18. The adjusted odds ratios (OR) and 95% confidence intervals (CI) for the possible risk factors of new-onset of multiple pains at 18 years and 2-year persistence of multiple pains were obtained using multinomial logistic regression. Multiple musculoskeletal pains were common; 43% of boys and 63% of girls at 16, and 61% of boys and 81% of girls at 18 reported pain in more than one site during the last 6 months. Moreover, multiple pains had a high persistence rate, as 75% of boys and 88% of girls with multiple pains at 16 reported multiple pains also at 18. In the multivariate analysis, emotional and behavioral problems (internalizing problems, OR 2.3; externalizing problems, OR 2.2), and high sitting time (OR 1.6) among boys, and internalizing problems (OR 3.7), high physical activity level (OR 1.6), short sleeping time (OR 1.7), and smoking (OR 1.9) among girls were predictive factors for the persistence of multiple pains. No statistically significant associations between the baseline variables and new-onset multiple pains were found. Multiple musculoskeletal pains appear to have a high tendency to persist in adolescence; both psychosocial factors and lifestyle factors contribute to this vulnerability.

Vertebral fractures are a common burden amongst elderly and late middle aged people. Vertebral cross-sectional area (CSA) is a major determinant of vertebral strength and thus associated with vertebral fracture risk. Previous studies suggest that physical activity affects vertebral CSA. We aimed to investigate the relationship between leisure-time physical activity (LTPA) from adolescence to middle age and vertebral dimensions in adulthood. We utilized the Northern Finland Birth Cohort 1966, of which 1188 subjects had records of LTPA at 14, 31 and 46 years, and had undergone lumbar magnetic resonance imaging (MRI) at the mean age of 47 years. Using MRI data, we measured eight dimensions of the L4 vertebra. Socioeconomic status, smoking habits, height and weight were also recorded at 14, 31 and 46 years. We obtained lifetime LTPA (14–46 years of age) trajectories using latent class analysis, which resulted in three categories (active, moderately active, inactive) in both genders. Linear regression analysis was used to analyze the association between LTPA and vertebral CSA with adjustments for vertebral height, BMI, socioeconomic status and smoking. High lifetime LTPA was associated with larger vertebral CSA in women but not men. Further research is needed to investigate the factors behind the observed gender-related differences.