Sari Aaltonen

Effects of 32-Year Leisure Time Physical Activity Discordance in Twin Pairs on Health (TWINACTIVE Study): Aims, Design and Results for Physical Fitness

The physically active lifestyle is associated with low future morbidity and mortality, but the causality between physical activity and health is not always clear. As some inherited biological characteristics and childhood experiences may cause selection bias in observational studies, we sought to take them into account by identifying 16 twin pairs (7 MZ, 9 DZ, mean age 60 years) discordant for leisure time physical activity habits for thirty years. We conducted detailed health-related examinations among these twin pairs. Our main aims were to study the effects of physical activity and genes on fitness and body composition, with special reference to body fat compartments, metabolic syndrome components and related diseases and risk factor levels, status of arteries, structure and function of the heart, bone properties, and muscle and fat tissue-related mechanisms linked to physical activity and chronic disease development. Our physical activity assessments showed that inactive co-twins were on average 8.8 MET hours/day less active than their active co-twins through out their midlife (2.2+/-2.3 vs. 11.0+/-4.1 MET h/day, p< .001). Follow-up fitness tests showed that physically inactive co-twins were less fit than their active co-twins (estimated VO(2peak) 26.4+/-4.9 vs. 32.5+/-5.5 ml/kg/min, p< .001). Similar differences were found in both MZ and DZ pairs. On the basis of earlier epidemiological observations on nonrelated individuals, these physical activity and fitness differences are large enough to cause differences in many mechanisms and risk factors related to the development of chronic diseases and to permit future analyses.

A longitudinal study on genetic and environmental influences on leisure time physical activity in the Finnish Twin Cohort.

The purpose of this study was to examine changes in the contribution of genetic and environmental influences to leisure time physical activity among male and female twins over a 6-year follow-up. At baseline the sample comprised 4,280 monozygotic and 9,276 dizygotic twin individuals, and at follow-up 4,383 monozygotic and 9,439 dizygotic twin individuals. Participants were aged 18-54 years at baseline. Genetic modeling results showed that genetic influences on leisure time physical activity declined from baseline (44%) to follow-up (34%). Most of the genetic influences identified at baseline were present at followup (r(g) = 0.72). Specific environmental influences increased from baseline (56%) to follow-up (66%) while at follow-up new environmental time-specific influences were observed (r(e) = 0.23). The model with sex differences showed a higher estimate of genetic influences for men than women both at baseline (men 47% vs. women 42%) and at follow-up (men 38% vs. women 31%). The additive genetic correlation for this phenotype was greater for men (r(g) = 0.79) than women (r(g) = 0.64). The specific environmental influences were corresponding; at baseline men 53% and women 56% and at follow-up men 62 % and women 69%. The environmental correlations between the two time points were similar for men (r(e)= 0.21) and for women (r(e)= 0.24). In conclusion, in a sample of healthy twins most of the genetic influences on leisure time physical activity expressed at baseline were present at 6 years of follow-up. New specific environmental factors underlying follow-up leisure time physical activity were observed.

INTERVENTIONS TO PREVENT SPORTS RELATED INJURIES: A SYSTEMATIC REVIEW AND META-ANALYSIS OF RANDOMISED CONTROLLED TRIALS

Background The effects of methods to prevent injuries have been studied in several systematic reviews. However, no meta-analysis taking into account all randomised controlled intervention trials aiming at prevention of sports injuries has been published. Objective To summarise the effects of sports injury prevention interventions. Design Systematic review and meta-analysis. Setting Systematic literature search was conducted in September 2013 using following data-bases: PubMed, MEDLINE, SPORTDiscus, Cochrane Central Register of Controlled Trials, CINAHL, PEDro, Web of Science. The reference lists of retrieved articles and reviews were hand searched. Eligibility criteria for selecting studies Selected articles had to examine the effects of any preventive intervention on sports injuries, be randomised/quasi-randomised, controlled trials, published in a peer-reviewed journal. The outcome of the trial had to be injury rate or the number of injured individuals. Interventions The effectiveness of following interventions was studied: insoles, external joint supports, training programmes, stretching, protective head equipment, modified shoes, injury prevention videos. Main outcome measurements The number of injuries or injured individuals. Results The systematic review included 68 trials and the meta-analysis 60 trials. Insoles (OR 0.51, 95% CI 0.32–0.81), external joint supports (OR 0.40, 95% CI 0.30–0.53), and specific training programmes (OR 0.55, 95% CI 0.46–0.66) appeared to be effective in reducing the risk of sports injuries. Stretching (OR 0.92, 95% CI 0.80-1.06), modified shoes (OR 1.23, 95% CI 0.81–1.87), and preventive videos (OR 0.86, 95% CI 0.44–1.68) seemed not to be effective. Conclusions Certain sports specific interventions can reduce the risk of sports injuries. There were limitations regarding the quality of the trials, generalisability of the results, and heterogeneity of the study designs. In future, the mechanisms behind effective methods and the most beneficial elements of preventive training programmes need to be clarified.