BackgroundEpidemiology of myocarditis in childhood is largely unknown. Men are known to have a higher incidence of myocarditis than women in adults aged <50 years, but whether this is true by sex in pediatric age groups is unknown. We set out to study the occurrence and potential sex differences of myocarditis in a general pediatric population.Methods and ResultsData of all hospital admissions with myocarditis in Finland occurring in patients aged ≤15 years from 2004 to 2014 were collected from a mandatory nationwide registry. All patients with myocarditis as a primary, secondary, or tertiary cause of admission were included. Total and age‐ and sexspecific incidence rates were calculated using corresponding population data. There were 213 admissions with myocarditis in pediatric patients. Myocarditis was the primary cause of admission in 86%. The overall incidence rate of myocarditis was 1.95/100 000 person‐years. Of all patients, 77% were boys, but sex differences in incidence rates were age‐dependent. In children aged 0 to 5 years, there was no sex difference in the occurrence of myocarditis. Boys aged 6 to 10 years had a higher incidence rate compared with girls (72% boys; incidence rate ratio: 2.46; 95% confidence interval, 1.03–5.89; P=0.04). Sex difference further increased in children aged 11 to 15 years (80% boys; incidence rate ratio: 3.5; 95% confidence interval, 2.68–5.67; P<0.0001).ConclusionsMyocarditis leading to hospital admission is relatively uncommon in children, but occurrence of myocarditis increases with age. There is no sex difference in the risk of myocarditis during the first 6 years of life, but boys have a significantly higher risk at ages 6 to 15 years.

No abstract

The objective of this study was to assess differences in the effects of competitive gymnastics and running on bone mineral content (BMC) of the lumbar spine and femoral neck when compared with their non-competing age-matched controls. Caucasian healthy peri-pubertal girls (52 competing gymnasts, 46 competing runners, 44 non-athletic controls) were included. Weight, height, and type and amount of exercise (MET h/week) as well as BMC of the lumbar spine and femoral neck were measured repeatedly. Statistical comparisons between groups were made using ANOVA. Repeated measures were analyzed using generalized linear mixed models. The median MET value of gymnasts was significantly higher when compared with runners and controls at baseline, P=0.001. The weekly median MET hours decreased during the follow-up. The mean (adjusted for height, weight, and years from menarche in the 7-year follow-up) BMC of the lumbar spine and femoral neck was significantly higher among gymnasts when compared with the other two groups. Group-by-time interaction was significant only at the femoral neck (P=0.048). The type of physical activity was a significant factor in BMC of the adolescent women. Gymnasts had greater BMC at lumbar spine and femoral neck during the total 7-year follow-up period when compared with runners and controls.