Assessing causality in the association between child adiposity and physical activity levels: a Mendelian randomization analysis.

<h4>Background</h4>Cross-sectional studies have shown that objectively measured physical activity is associated with childhood adiposity, and a strong inverse dose-response association with body mass index (BMI) has been found. However, few studies have explored the extent to which this...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Rebecca C Richmond, George Davey Smith, Andy R Ness, Marcel den Hoed, George McMahon, Nicholas J Timpson
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2014
Materias:	Medicine R
Acceso en línea:	https://doaj.org/article/6c6613df2b4846abaa9028418a21100e
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:6c6613df2b4846abaa9028418a21100e
record_format	dspace
spelling	oai:doaj.org-article:6c6613df2b4846abaa9028418a21100e2021-11-18T05:42:56ZAssessing causality in the association between child adiposity and physical activity levels: a Mendelian randomization analysis.1549-12771549-167610.1371/journal.pmed.1001618https://doaj.org/article/6c6613df2b4846abaa9028418a21100e2014-03-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/24642734/pdf/?tool=EBIhttps://doaj.org/toc/1549-1277https://doaj.org/toc/1549-1676<h4>Background</h4>Cross-sectional studies have shown that objectively measured physical activity is associated with childhood adiposity, and a strong inverse dose-response association with body mass index (BMI) has been found. However, few studies have explored the extent to which this association reflects reverse causation. We aimed to determine whether childhood adiposity causally influences levels of physical activity using genetic variants reliably associated with adiposity to estimate causal effects.<h4>Methods and findings</h4>The Avon Longitudinal Study of Parents and Children collected data on objectively assessed activity levels of 4,296 children at age 11 y with recorded BMI and genotypic data. We used 32 established genetic correlates of BMI combined in a weighted allelic score as an instrumental variable for adiposity to estimate the causal effect of adiposity on activity. In observational analysis, a 3.3 kg/m² (one standard deviation) higher BMI was associated with 22.3 (95% CI, 17.0, 27.6) movement counts/min less total physical activity (p = 1.6×10⁻¹⁶), 2.6 (2.1, 3.1) min/d less moderate-to-vigorous-intensity activity (p = 3.7×10⁻²⁹), and 3.5 (1.5, 5.5) min/d more sedentary time (p = 5.0×10⁻⁴). In Mendelian randomization analyses, the same difference in BMI was associated with 32.4 (0.9, 63.9) movement counts/min less total physical activity (p = 0.04) (∼5.3% of the mean counts/minute), 2.8 (0.1, 5.5) min/d less moderate-to-vigorous-intensity activity (p = 0.04), and 13.2 (1.3, 25.2) min/d more sedentary time (p = 0.03). There was no strong evidence for a difference between variable estimates from observational estimates. Similar results were obtained using fat mass index. Low power and poor instrumentation of activity limited causal analysis of the influence of physical activity on BMI.<h4>Conclusions</h4>Our results suggest that increased adiposity causes a reduction in physical activity in children and support research into the targeting of BMI in efforts to increase childhood activity levels. Importantly, this does not exclude lower physical activity also leading to increased adiposity, i.e., bidirectional causation.Rebecca C RichmondGeorge Davey SmithAndy R NessMarcel den HoedGeorge McMahonNicholas J TimpsonPublic Library of Science (PLoS)articleMedicineRENPLoS Medicine, Vol 11, Iss 3, p e1001618 (2014)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R
spellingShingle	Medicine R Rebecca C Richmond George Davey Smith Andy R Ness Marcel den Hoed George McMahon Nicholas J Timpson Assessing causality in the association between child adiposity and physical activity levels: a Mendelian randomization analysis.
description	<h4>Background</h4>Cross-sectional studies have shown that objectively measured physical activity is associated with childhood adiposity, and a strong inverse dose-response association with body mass index (BMI) has been found. However, few studies have explored the extent to which this association reflects reverse causation. We aimed to determine whether childhood adiposity causally influences levels of physical activity using genetic variants reliably associated with adiposity to estimate causal effects.<h4>Methods and findings</h4>The Avon Longitudinal Study of Parents and Children collected data on objectively assessed activity levels of 4,296 children at age 11 y with recorded BMI and genotypic data. We used 32 established genetic correlates of BMI combined in a weighted allelic score as an instrumental variable for adiposity to estimate the causal effect of adiposity on activity. In observational analysis, a 3.3 kg/m² (one standard deviation) higher BMI was associated with 22.3 (95% CI, 17.0, 27.6) movement counts/min less total physical activity (p = 1.6×10⁻¹⁶), 2.6 (2.1, 3.1) min/d less moderate-to-vigorous-intensity activity (p = 3.7×10⁻²⁹), and 3.5 (1.5, 5.5) min/d more sedentary time (p = 5.0×10⁻⁴). In Mendelian randomization analyses, the same difference in BMI was associated with 32.4 (0.9, 63.9) movement counts/min less total physical activity (p = 0.04) (∼5.3% of the mean counts/minute), 2.8 (0.1, 5.5) min/d less moderate-to-vigorous-intensity activity (p = 0.04), and 13.2 (1.3, 25.2) min/d more sedentary time (p = 0.03). There was no strong evidence for a difference between variable estimates from observational estimates. Similar results were obtained using fat mass index. Low power and poor instrumentation of activity limited causal analysis of the influence of physical activity on BMI.<h4>Conclusions</h4>Our results suggest that increased adiposity causes a reduction in physical activity in children and support research into the targeting of BMI in efforts to increase childhood activity levels. Importantly, this does not exclude lower physical activity also leading to increased adiposity, i.e., bidirectional causation.
format	article
author	Rebecca C Richmond George Davey Smith Andy R Ness Marcel den Hoed George McMahon Nicholas J Timpson
author_facet	Rebecca C Richmond George Davey Smith Andy R Ness Marcel den Hoed George McMahon Nicholas J Timpson
author_sort	Rebecca C Richmond
title	Assessing causality in the association between child adiposity and physical activity levels: a Mendelian randomization analysis.
title_short	Assessing causality in the association between child adiposity and physical activity levels: a Mendelian randomization analysis.
title_full	Assessing causality in the association between child adiposity and physical activity levels: a Mendelian randomization analysis.
title_fullStr	Assessing causality in the association between child adiposity and physical activity levels: a Mendelian randomization analysis.
title_full_unstemmed	Assessing causality in the association between child adiposity and physical activity levels: a Mendelian randomization analysis.
title_sort	assessing causality in the association between child adiposity and physical activity levels: a mendelian randomization analysis.
publisher	Public Library of Science (PLoS)
publishDate	2014
url	https://doaj.org/article/6c6613df2b4846abaa9028418a21100e
work_keys_str_mv	AT rebeccacrichmond assessingcausalityintheassociationbetweenchildadiposityandphysicalactivitylevelsamendelianrandomizationanalysis AT georgedaveysmith assessingcausalityintheassociationbetweenchildadiposityandphysicalactivitylevelsamendelianrandomizationanalysis AT andyrness assessingcausalityintheassociationbetweenchildadiposityandphysicalactivitylevelsamendelianrandomizationanalysis AT marceldenhoed assessingcausalityintheassociationbetweenchildadiposityandphysicalactivitylevelsamendelianrandomizationanalysis AT georgemcmahon assessingcausalityintheassociationbetweenchildadiposityandphysicalactivitylevelsamendelianrandomizationanalysis AT nicholasjtimpson assessingcausalityintheassociationbetweenchildadiposityandphysicalactivitylevelsamendelianrandomizationanalysis
_version_	1718424791340285952

Assessing causality in the association between child adiposity and physical activity levels: a Mendelian randomization analysis.

Ejemplares similares