TY - JOUR
T1 - Heavier smoking increases coffee consumption
T2 - Findings from a Mendelian randomization analysis
AU - Bjørngaard, Johan H.
AU - Nordestgaard, Ask Tybjærg
AU - Taylor, Amy E.
AU - Treur, Jorien L.
AU - Gabrielsen, Maiken E.
AU - Munafó, Marcus R.
AU - Nordestgaard, Børge Grønne
AU - Åsvold, Bjørn Olav
AU - Romundstad, Pål
AU - Smith, George Davey
N1 - Funding Information: CGPS: this work was supported by Herlev and Gentofte Hospital, Copenhagen University hospital. The funding organization had no role in the design and conduct of the study, the collection, analysis, and interpretation of the data, or in the writing of the paper. UK Biobank: this research has been conducted using the UK Biobank Resource (application 9142). A.E.T. and M.R.M. are members of the UK Centre for Tobacco and Alcohol Studies, a UKCRC Public Health Research: Centre of Excellence. Funding from British Heart Foundation, Cancer Research UK, Economic and Social Research Council, Medical Research Council and the National Institute for Health Research, under the auspices of the UK Clinical Research Collaboration, is gratefully acknowledged. This work was supported by the Medical Research Council (grant number: MC_UU_12013/1, MC_UU_12013/6). The Nord-Trøndelag Health Study (the HUNT Study) is collaboration between HUNT Research Centre (Faculty of Medicine, NTNU, Norwegian University of Science and Technology), Nord-Trøndelag County Council and the Norwegian Institute of Public Health. Publisher Copyright: © The Author 2017.
PY - 2017/12/1
Y1 - 2017/12/1
N2 - Background: There is evidence for a positive relationship between cigarette and coffee consumption in smokers. Cigarette smoke increases metabolism of caffeine, so this may represent a causal effect of smoking on caffeine intake. Methods: We performed Mendelian randomization analyses in the UK Biobank (N=114 029), the Norwegian HUNT study (N=56 664) and the Copenhagen General Population Study (CGPS) (N=78 650). We used the rs16969968 genetic variant as a proxy for smoking heaviness in all studies and rs4410790 and rs2472297 as proxies for coffee consumption in UK Biobank and CGPS. Analyses were conducted using linear regression and meta-analysed across studies. Results: Each additional cigarette per day consumed by current smokers was associated with higher coffee consumption (0.10 cups per day, 95% CI: 0.03, 0.17). There was weak evidence for an increase in tea consumption per additional cigarette smoked per day (0.04 cups per day, 95% CI: -0.002, 0.07). There was strong evidence that each additional copy of the minor allele of rs16969968 (which increases daily cigarette consumption) in current smokers was associated with higher coffee consumption (0.16 cups per day, 95% CI: 0.11, 0.20), but only weak evidence for an association with tea consumption (0.04 cups per day, 95% CI: -0.01, 0.09). There was no clear evidence that rs16969968 was associated with coffee or tea consumption in never or former smokers or that the coffeerelated variants were associated with cigarette consumption. Conclusions: Higher cigarette consumption causally increases coffee intake. This is consistent with faster metabolism of caffeine by smokers, but could also reflect a behavioural effect of smoking on coffee drinking.
AB - Background: There is evidence for a positive relationship between cigarette and coffee consumption in smokers. Cigarette smoke increases metabolism of caffeine, so this may represent a causal effect of smoking on caffeine intake. Methods: We performed Mendelian randomization analyses in the UK Biobank (N=114 029), the Norwegian HUNT study (N=56 664) and the Copenhagen General Population Study (CGPS) (N=78 650). We used the rs16969968 genetic variant as a proxy for smoking heaviness in all studies and rs4410790 and rs2472297 as proxies for coffee consumption in UK Biobank and CGPS. Analyses were conducted using linear regression and meta-analysed across studies. Results: Each additional cigarette per day consumed by current smokers was associated with higher coffee consumption (0.10 cups per day, 95% CI: 0.03, 0.17). There was weak evidence for an increase in tea consumption per additional cigarette smoked per day (0.04 cups per day, 95% CI: -0.002, 0.07). There was strong evidence that each additional copy of the minor allele of rs16969968 (which increases daily cigarette consumption) in current smokers was associated with higher coffee consumption (0.16 cups per day, 95% CI: 0.11, 0.20), but only weak evidence for an association with tea consumption (0.04 cups per day, 95% CI: -0.01, 0.09). There was no clear evidence that rs16969968 was associated with coffee or tea consumption in never or former smokers or that the coffeerelated variants were associated with cigarette consumption. Conclusions: Higher cigarette consumption causally increases coffee intake. This is consistent with faster metabolism of caffeine by smokers, but could also reflect a behavioural effect of smoking on coffee drinking.
KW - Coffee
KW - Mendelian randomization
KW - Smoking
KW - Tea
UR - http://www.scopus.com/inward/record.url?scp=85039554082&partnerID=8YFLogxK
U2 - https://doi.org/10.1093/ije/dyx147
DO - https://doi.org/10.1093/ije/dyx147
M3 - Article
C2 - 29025033
SN - 0300-5771
VL - 46
SP - 1958
EP - 1967
JO - International journal of epidemiology
JF - International journal of epidemiology
IS - 6
ER -