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Effect of smoking on physical and cognitive capability in later life: a multicohort study using observational and genetic approaches

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Effect of smoking on physical and cognitive capability in later life: a multicohort study using observational and genetic approaches. / North, Teri-Louise; Palmer, Tom M.; Lewis, Sarah J. et al.
In: BMJ Open, Vol. 5, No. 12, e008393, 15.12.2015.

Research output: Contribution to Journal/Magazine › Journal article › peer-review

Harvard

North, T-L, Palmer, TM, Lewis, SJ, Cooper, R, Power, C, Pattie, A, Starr, JM, Deary, IJ, Martin, RM, Aihie Sayer, A, Kumari, M, Cooper, C, Kivimaki, M, Kuh, D, Ben-Shlomo, Y & Day, INM 2015, 'Effect of smoking on physical and cognitive capability in later life: a multicohort study using observational and genetic approaches', BMJ Open, vol. 5, no. 12, e008393. https://doi.org/10.1136/bmjopen-2015-008393

APA

North, T.-L., Palmer, T. M., Lewis, S. J., Cooper, R., Power, C., Pattie, A., Starr, J. M., Deary, I. J., Martin, R. M., Aihie Sayer, A., Kumari, M., Cooper, C., Kivimaki, M., Kuh, D., Ben-Shlomo, Y., & Day, I. N. M. (2015). Effect of smoking on physical and cognitive capability in later life: a multicohort study using observational and genetic approaches. BMJ Open, 5(12), Article e008393. https://doi.org/10.1136/bmjopen-2015-008393

Vancouver

North TL, Palmer TM, Lewis SJ, Cooper R, Power C, Pattie A et al. Effect of smoking on physical and cognitive capability in later life: a multicohort study using observational and genetic approaches. BMJ Open. 2015 Dec 15;5(12):e008393. doi: 10.1136/bmjopen-2015-008393

Author

North, Teri-Louise ; Palmer, Tom M. ; Lewis, Sarah J. et al. / Effect of smoking on physical and cognitive capability in later life : a multicohort study using observational and genetic approaches. In: BMJ Open. 2015 ; Vol. 5, No. 12.

Bibtex

@article{5b4fcd35aad240b4b6ee0aab50d50978,
title = "Effect of smoking on physical and cognitive capability in later life: a multicohort study using observational and genetic approaches",
abstract = "Objectives The observed associations between smoking and functional measures at older ages are vulnerable to bias and confounding. Mendelian randomisation (MR) uses genotype as an instrumental variable to estimate unconfounded causal associations. We conducted a meta-analysis of the observational associations and implemented an MR approach using the smoking-related single nucleotide polymorphism rs16969968 to explore their causal nature.Setting 9 British cohorts belonging to the HALCyon collaboration.Participants Individual participant data on N=26 692 individuals of European ancestry (N from earliest phase analysed per study) of mean ages 50–79 years were available for inclusion in observational meta-analyses of the primary outcomes.Primary outcomes Physical capability, cognitive capability and cognitive decline. The smoking exposures were cigarettes per day, current versus ex-smoker, current versus never smoker and ever versus never smoker.Results In observational analyses current and ever smoking were generally associated with poorer physical and cognitive capability. For example, current smokers had a general fluid cognition score which was 0.17 z-score units (95% CI −0.221 to −0.124) lower than ex-smokers in cross-sectional analyses. Current smokers had a walk speed which was 0.25 z-score units lower than never smokers (95% CI −0.338 to −0.170). An MR instrumental variable approach for current versus ex-smoker and number of cigarettes smoked per day produced CIs which neither confirmed nor refuted the observational estimates. The number of genetic associations stratified by smoking status were consistent with type I error.Conclusions Our observational analysis supports the hypothesis that smoking is detrimental to physical and cognitive capability. Further studies are needed for a suitably powered MR approach.",
author = "Teri-Louise North and Palmer, {Tom M.} and Lewis, {Sarah J.} and Rachel Cooper and Chris Power and Alison Pattie and Starr, {John M.} and Deary, {Ian J.} and Martin, {Richard M.} and {Aihie Sayer}, Avan and Meena Kumari and Cyrus Cooper and Mika Kivimaki and Diana Kuh and Yoav Ben-Shlomo and Day, {Ian N. M.}",
year = "2015",
month = dec,
day = "15",
doi = "10.1136/bmjopen-2015-008393",
language = "English",
volume = "5",
journal = "BMJ Open",
issn = "2044-6055",
publisher = "BMJ Publishing Group Ltd",
number = "12",

}

RIS

TY - JOUR

T1 - Effect of smoking on physical and cognitive capability in later life

T2 - a multicohort study using observational and genetic approaches

AU - North, Teri-Louise

AU - Palmer, Tom M.

AU - Lewis, Sarah J.

AU - Cooper, Rachel

AU - Power, Chris

AU - Pattie, Alison

AU - Starr, John M.

AU - Deary, Ian J.

AU - Martin, Richard M.

AU - Aihie Sayer, Avan

AU - Kumari, Meena

AU - Cooper, Cyrus

AU - Kivimaki, Mika

AU - Kuh, Diana

AU - Ben-Shlomo, Yoav

AU - Day, Ian N. M.

PY - 2015/12/15

Y1 - 2015/12/15

N2 - Objectives The observed associations between smoking and functional measures at older ages are vulnerable to bias and confounding. Mendelian randomisation (MR) uses genotype as an instrumental variable to estimate unconfounded causal associations. We conducted a meta-analysis of the observational associations and implemented an MR approach using the smoking-related single nucleotide polymorphism rs16969968 to explore their causal nature.Setting 9 British cohorts belonging to the HALCyon collaboration.Participants Individual participant data on N=26 692 individuals of European ancestry (N from earliest phase analysed per study) of mean ages 50–79 years were available for inclusion in observational meta-analyses of the primary outcomes.Primary outcomes Physical capability, cognitive capability and cognitive decline. The smoking exposures were cigarettes per day, current versus ex-smoker, current versus never smoker and ever versus never smoker.Results In observational analyses current and ever smoking were generally associated with poorer physical and cognitive capability. For example, current smokers had a general fluid cognition score which was 0.17 z-score units (95% CI −0.221 to −0.124) lower than ex-smokers in cross-sectional analyses. Current smokers had a walk speed which was 0.25 z-score units lower than never smokers (95% CI −0.338 to −0.170). An MR instrumental variable approach for current versus ex-smoker and number of cigarettes smoked per day produced CIs which neither confirmed nor refuted the observational estimates. The number of genetic associations stratified by smoking status were consistent with type I error.Conclusions Our observational analysis supports the hypothesis that smoking is detrimental to physical and cognitive capability. Further studies are needed for a suitably powered MR approach.

AB - Objectives The observed associations between smoking and functional measures at older ages are vulnerable to bias and confounding. Mendelian randomisation (MR) uses genotype as an instrumental variable to estimate unconfounded causal associations. We conducted a meta-analysis of the observational associations and implemented an MR approach using the smoking-related single nucleotide polymorphism rs16969968 to explore their causal nature.Setting 9 British cohorts belonging to the HALCyon collaboration.Participants Individual participant data on N=26 692 individuals of European ancestry (N from earliest phase analysed per study) of mean ages 50–79 years were available for inclusion in observational meta-analyses of the primary outcomes.Primary outcomes Physical capability, cognitive capability and cognitive decline. The smoking exposures were cigarettes per day, current versus ex-smoker, current versus never smoker and ever versus never smoker.Results In observational analyses current and ever smoking were generally associated with poorer physical and cognitive capability. For example, current smokers had a general fluid cognition score which was 0.17 z-score units (95% CI −0.221 to −0.124) lower than ex-smokers in cross-sectional analyses. Current smokers had a walk speed which was 0.25 z-score units lower than never smokers (95% CI −0.338 to −0.170). An MR instrumental variable approach for current versus ex-smoker and number of cigarettes smoked per day produced CIs which neither confirmed nor refuted the observational estimates. The number of genetic associations stratified by smoking status were consistent with type I error.Conclusions Our observational analysis supports the hypothesis that smoking is detrimental to physical and cognitive capability. Further studies are needed for a suitably powered MR approach.

U2 - 10.1136/bmjopen-2015-008393

DO - 10.1136/bmjopen-2015-008393

M3 - Journal article

VL - 5

JO - BMJ Open

JF - BMJ Open

SN - 2044-6055

IS - 12

M1 - e008393

ER -