Faculty Opinions recommendation of Does physical activity attenuate, or even eliminate, the detrimental association of sitting time with mortality? A harmonised meta-analysis of data from more than 1 million men and women.

ObjectiveTo examine whether the associations between sedentary behaviours (ie, daily sitting/TV-viewing time) and mortality from cardiovascular disease (CVD) and cancer differ by different levels of physical activity (PA).DesignHarmonised meta-analysis of prospective cohort studies. Data on exposure variables were harmonised according to a predefined protocol and categorised into four groups for sedentary behaviours and into quartiles of PA (MET-hour/week).Data sourcesPubMed, PsycINFO, Embase, Web of Science, Sport Discus and Scopus.Eligibility criteria for selecting studiesIndividual level data on both sedentary behaviours and PA and reported effect estimates for CVD or cancer mortality.ResultsNine studies (n=850 060; deaths=25 730) and eight studies (n=777 696; deaths=30 851) provided data on sitting time and CVD and cancer mortality, respectively. Five studies had data on TV-viewing time and CVD (n=458 127; deaths=13 230) and cancer (n=458 091; deaths=16 430) mortality. A dose–response association between sitting time (9%–32% higher risk; p for trend <0.001) and TV time (3%–59% higher risk; p for trend <0.001) with CVD mortality was observed in the ‘inactive’, lowest quartile of PA. Associations were less consistent in the second and third quartiles of PA, and there was no increased risk for CVD mortality with increasing sedentary behaviours in the most active quartile. Associations between sedentary behaviours and cancer mortality were generally weaker; 6%–21% higher risk with longer sitting time observed only in the lowest quartile of PA.ConclusionPA modifies the associations between sedentary behaviours and CVD and cancer mortality. These findings emphasise the importance of higher volumes of moderate and vigorous activity to reduce, or even eliminate these risks, especially for those who sit a lot in their daily lives.

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Leisure Time Physical Activity Reduces the Risk for Stroke in Adults: A Reanalysis of a Meta-Analysis Using the Inverse-Heterogeneity Model

Stroke Research and Treatment ◽

10.1155/2019/8264502 ◽

2019 ◽

Vol 2019 ◽

pp. 1-6

Author(s):

George A. Kelley ◽

Kristi S. Kelley

Keyword(s):

Physical Activity ◽

Leisure Time ◽

Leisure Time Physical Activity ◽

Meta Analysis ◽

Small Study ◽

Significant Heterogeneity ◽

Men And Women ◽

Relative Risks ◽

Heterogeneity Model ◽

Q Statistic

Objective. Apply more robust and additional analyses to a previous meta-analysis that reported statistically significant associations between leisure time physical activity (LTPA) and stroke. Methods. A reanalysis of a previous meta-analysis that included nine prospective cohort studies representing 269,594 men and women 25-84 years of age and in which the association between LTPA and incident stroke was examined. Follow-up periods ranged from 7.7 to 32.0 years. Relative risks (RR) from each study were pooled using the inverse-heterogeneity model. Heterogeneity was examined using the Q statistic, inconsistency using I2, and small-study effects using Doi plots and the LFK index. Influence and cumulative meta-analysis were also conducted. Results. Using low LTPA as the reference, moderate LTPA was associated with a statistically significant reduction in the risk for stroke in men (RR = 0.79, 95% CI = 0.65 to 0.95) and a trend in women (RR = 0.88, 95% CI = 0.78 to 1.0). High LTPA was associated with a statistically significant reduction in the risk for stroke in both men (RR = 0.72, 95% CI = 0.60 to 0.86) and women (RR = 0.78, 95% CI = 0.66 to 0.92). No statistically significant heterogeneity was observed and inconsistency was low. However, potential small-study effects were observed. With each study deleted once, results remained statistically significant. Cumulative meta-analysis demonstrated stability in results since at least 2005. Conclusions. Leisure time physical activity is associated with a reduced risk of stroke in both men and women. However, the small-study effects observed suggest the possibility that results may be exaggerated.

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Physical activity, sitting time, and the risk of ovarian cancer: A brief research report employing a meta-analysis of existing

Health Care For Women International ◽

10.1080/07399332.2018.1505892 ◽

2018 ◽

Vol 40 (4) ◽

pp. 433-458 ◽

Cited By ~ 2

Author(s):

Junga Lee

Keyword(s):

Physical Activity ◽

Ovarian Cancer ◽

Meta Analysis ◽

Sitting Time ◽

Research Report

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Effects of Interrupting Prolonged Sitting with Physical Activity Breaks on Blood Glucose, Insulin and Triacylglycerol Measures: A Systematic Review and Meta-analysis

Sports Medicine ◽

10.1007/s40279-019-01183-w ◽

2019 ◽

Vol 50 (2) ◽

pp. 295-330 ◽

Cited By ~ 19

Author(s):

Roland Loh ◽

Emmanuel Stamatakis ◽

Dirk Folkerts ◽

Judith E. Allgrove ◽

Hannah J. Moir

Keyword(s):

Physical Activity ◽

Meta Analysis ◽

Arterial Disease ◽

Sitting Time ◽

Chronic Obstructive ◽

Eligibility Criteria ◽

Metabolic Markers ◽

Obstructive Pulmonary Disease ◽

Continuous Exercise ◽

Prolonged Sitting

Abstract Background Physical activity (PA) breaks in sitting time might attenuate metabolic markers relevant to the prevention of type 2 diabetes. Objectives The primary aim of this paper was to systematically review and meta-analyse trials that compared the effects of breaking up prolonged sitting with bouts of PA throughout the day (INT) versus continuous sitting (SIT) on glucose, insulin and triacylglycerol (TAG) measures. A second aim was to compare the effects of INT versus continuous exercise (EX) on glucose, insulin and TAG measures. Methods The review followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) recommendations. Eligibility criteria consisted of trials comparing INT vs. SIT or INT vs. one bout of EX before or after sitting, in participants aged 18 or above, who were classified as either metabolically healthy or impaired, but not with other major health conditions such as chronic obstructive pulmonary disease or peripheral arterial disease. Results A total of 42 studies were included in the overall review, whereas a total of 37 studies were included in the meta-analysis. There was a standardised mean difference (SMD) of − 0.54 (95% CI − 0.70, − 0.37, p = 0.00001) in favour of INT compared to SIT for glucose. With respect to insulin, there was an SMD of − 0.56 (95% CI − 0.74, − 0.38, p = 0.00001) in favour of INT. For TAG, there was an SMD of − 0.26 (95% CI − 0.44, − 0.09, p = 0.002) in favour of INT. Body mass index (BMI) was associated with glucose responses (β = − 0.05, 95% CI − 0.09, − 0.01, p = 0.01), and insulin (β = − 0.05, 95% CI − 0.10, − 0.006, p = 0.03), but not TAG (β = 0.02, 95% CI − 0.02, 0.06, p = 0.37). When energy expenditure was matched, there was an SMD of − 0.26 (95% CI − 0.50, − 0.02, p = 0.03) in favour of INT for glucose, but no statistically significant SMDs for insulin, i.e. 0.35 (95% CI − 0.37, 1.07, p = 0.35), or TAG i.e. 0.08 (95% CI − 0.22, 0.37, p = 0.62). It is worth noting that there was possible publication bias for TAG outcomes when PA breaks were compared with sitting. Conclusion The use of PA breaks during sitting moderately attenuated post-prandial glucose, insulin, and TAG, with greater glycaemic attenuation in people with higher BMI. There was a statistically significant small advantage for PA breaks over continuous exercise for attenuating glucose measures when exercise protocols were energy matched, but no statistically significant differences for insulin and TAG. PROSPERO Registration: CRD42017080982. PROSPERO Registration CRD42017080982.

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Abstract 49: A Genome-wide Meta-analysis of the Combined Influence of Physical Activity and Genetic Variants on Body Fat Distribution in 94,779 Individuals of European Descent

Circulation ◽

10.1161/circ.129.suppl_1.49 ◽

2014 ◽

Vol 129 (suppl_1) ◽

Author(s):

Mariaelisa Graff ◽

L Xue ◽

Tuomas O Kilpeläinen ◽

Anne Justice ◽

Thomas Winkler ◽

...

Keyword(s):

Physical Activity ◽

Body Fat ◽

Genetic Variants ◽

Meta Analysis ◽

Interaction Effects ◽

Central Adiposity ◽

Men And Women ◽

Genome Wide ◽

Main Effect ◽

Genome Wide Significance

Central adiposity, assessed by waist-to-hip ratio (WHR), has been associated with increased risk for cardiovascular disease. Both genetic and lifestyle factors, including physical inactivity, have been independently associated with WHR adjusted for BMI (WHRadjBMI). Physical activity (PA) is an important component of interventions for reducing or preventing central adiposity and has been shown to attenuate genetic influences on adiposity. However, the influence of PA on loci associated with central fat, independent of total body fat, is unknown. Our objective was to identify genetic variants whose effects on WHRadjBMI are modified by PA. To this end, we performed a meta-analysis of 36 genome-wide association studies, including 94,779 individuals of European ancestry. PA was standardized within each study (physically active and inactive) with the lowest quintile being defined as inactive. WHR was adjusted for BMI, age, and age 2 in men and women separately. Each study tested the SNP x PA interaction alone, and also tested the joint effects of both the interaction and SNP main effect using a two degree of freedom (2df) test. We pooled the results from individual studies using fixed-effects inverse variance weighted meta-analysis in men and women combined and separately. The 2df joint test reached genome-wide significance (p<5e -8 ) for 23 loci, which included 11 novel loci for WHRadjBMI. Of these 11 loci, 7 were identified in women only, and one in men only. For each of the 23 loci, the association of the joint test was primarily driven by the SNP main effect on WHRadjBMI, rather than its interaction with PA. When we examined the interaction effects of the 23 loci, separately from main effect, the interaction reached nominal significance for 11 loci (5 of these were novel): e.g. established loci in/near LYPLAL1 (p=1.0e -7 ), VEGFA (p=3.8e -4 ), TBX15 (p=2.1e -5 in women), and RSPO3 (p=5.5e -3 ), and novel (in women only), in/near TMEM131 (p =3.2e -4 ), FAM186A (p=4.1e -4 ), and FLJ45974 (p=1.9e -3 ). In each case, the effect of the WHRadjBMI-increasing allele was smaller in the active group than in the inactive group; e.g. for the SNP near LYPLAL1 , in the active versus inactive: β[SE] = 0.024(0.036) vs 0.215(0.084), respectively. For the interaction term alone, no loci reached genome-wide significance, but a search at P<1e -6 revealed 3 additional novel loci; 2 in men and women combined (in/near MYO18B and COX11P ) and 1 in men only (in SNW1 ). Our findings suggest that joint tests of main and interaction effects help elucidate the genetic basis of abdominal obesity and that genetic effects are larger in physically inactive compared to active individuals. To follow-up our initial findings, we are currently collecting data from 25 additional studies with genome-wide or Metabochip data.

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