Sedentary Behavior and Health Outcomes: An Overview of Systematic Reviews

<div><p>Objective</p><p>1) To synthesize the current observational evidence for the association between sedentary behavior and health outcomes using information from systematic reviews. 2) To assess the methodological quality of the systematic reviews found.</p><p>Methodology/Principal Findings</p><p>Medline; <i>Excerpta Medica</i> (Embase); PsycINFO; and Web of Science were searched for reviews published up to September 2013. Additional publications were provided by Sedentary Behaviour Research Network members. The methodological quality of the systematic reviews was evaluated using recommended standard criteria from AMSTAR. For each review, improper use of causal language in the description of their main results/conclusion was evaluated. Altogether, 1,044 review titles were identified, 144 were read in their entirety, and 27 were included. Based on the systematic reviews with the best methodological quality, we found in children and adolescents, strong evidence of a relationship between time spent in sedentary behavior and obesity. Moreover, moderate evidence was observed for blood pressure and total cholesterol, self-esteem, social behavior problems, physical fitness and academic achievement. In adults, we found strong evidence of a relationship between sedentary behavior and all-cause mortality, fatal and non-fatal cardiovascular disease, type 2 diabetes and metabolic syndrome. In addition, there is moderate evidence for incidence rates of ovarian, colon and endometrial cancers.</p><p>Conclusions</p><p>This overview based on the best available systematics reviews, shows that sedentary behavior may be an important determinant of health, independently of physical activity. However, the relationship is complex because it depends on the type of sedentary behavior and the age group studied. The relationship between sedentary behavior and many health outcomes remains uncertain; thus, further studies are warranted.</p></div

Preferred Reporting Items for Systematic Reviews flow diagram of the studies included in our overview.

<p>Preferred Reporting Items for Systematic Reviews flow diagram of the studies included in our overview.</p

Clinical and pathological characteristics of patients in groups I and II.

<p>Clinical and pathological characteristics of patients in groups I and II.</p

Mycological and serological tests for histoplasmosis.

<p><b>A</b>, Mycological tests suggestive of histoplasmosis in a sample from a histoplasmotic patient with HIV. a, Pleural fluid stained by Giemsa, 1,500×; b, intracellular yeast in alveolar macrophages with cytoplasmic retraction by direct exams, 1,500×; c and d, blood smear stained with Giemsa, showing basophil nuclei and intracellular yeasts with cytoplasmic retraction. <b>B</b>, Immunoblotting for circulating <i>H</i>. <i>capsulatum</i> antibodies in sera from histoplasmotic patients with (GI) and without HIV (GII), and from patients with HIV or other infections only (GIV). C+, polyclonal <i>H</i>. <i>capsulatum</i> antibody (positive control); 1–10, sera from patients with suspected histoplasmosis. Fractions H (108–120 kDa) and M (70 and 94 kDa) are indicated.</p

Comparison of methods to detect <i>H</i>. <i>capsulatum</i> among groups.

<p>Comparison of methods to detect <i>H</i>. <i>capsulatum</i> among groups.</p

Individual and school-level characteristics in adolescents.

<p>* 8 missing schools (0,2%).</p><p>** n and % refer to number and proportion of schools, respectively.</p><p>Brazil, 2012.</p

Association between school level variables with physical activity level in adolescents—multilevel analysis.

<p>*Adjusted by age (in years), sex, mother’s education level, region, municipality, and type of school.</p><p>** Adjusted by age (in years), sex, mother’s education level, region, municipality, type of school, and number of enrolled students in the school.</p><p>Association between school level variables with physical activity level in adolescents—multilevel analysis.</p

Association between number of PA facilities with physical education classes, leisure-time physical activity and physical activity level in adolescents—multilevel analysis.

<p>*adjusted by age (in years), sex, mother’s education level, region, municipality, type of school, and number of enrolled students in the school (for number of PA facilities only).</p><p>** Number of PA facilities and extracurricular sports activities models were run separately.</p><p>Association between number of PA facilities with physical education classes, leisure-time physical activity and physical activity level in adolescents—multilevel analysis.</p

Association between school level variables with leisure-time physical activity in adolescents—multilevel analysis.

<p>*Adjusted by age (in years), sex, mother’s education level, region, municipality, and type of school.</p><p>** Adjusted by age (in years), sex, mother’s education level, region, municipality, type of school, and number of enrolled students in the school.</p><p>Association between school level variables with leisure-time physical activity in adolescents—multilevel analysis.</p

IL28B Gene Polymorphism SNP rs8099917 Genotype GG Is Associated with HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP) in HTLV-1 Carriers

<div><p>Background</p><p>The polymorphisms of IL28B have been described as important in the pathogenesis of infections caused by some viruses. The aim of this research was to evaluate whether IL28B gene polymorphisms (SNP rs8099917 and SNP rs12979860) are associated with HAM/TSP.</p><p>Methods</p><p>The study included 229 subjects, classified according to their neurological status in two groups: Group I (136 asymptomatic HTLV-1 carriers) and Group II (93 HAM/TSP patients). The proviral loads were quantified, and the rs8099917 and rs12979860 SNPs in the region of IL28B-gene were analyzed by StepOnePlus Real-time PCR System.</p><p>Results</p><p>A multivariate model analysis, including gender, age, and HTLV-1 DNA proviral load, showed that IL28B polymorphisms were independently associated with HAM/TSP outcome in rs12979860 genotype CT (OR = 2.03; IC95% = 0.96–4.27) and in rs8099917 genotype GG (OR = 7.61; IC95% = 1.82–31.72).</p><p>Conclusion</p><p>Subjects with SNP rs8099917 genotype GG and rs12979618 genotype CT may present a distinct immune response against HTLV-1 infection. So, it seems reasonable to suggest that a search for IL28B polymorphisms should be performed for all HTLV-1-infected subjects in order to monitor their risk for disease development; however, since this is the first description of such finding in the literature, we should first replicate this study with more HTLV-1-infected persons to strengthen the evidence already provided by our results.</p></div