PT  - JOURNAL ARTICLE
AU  - Taylor, Amy E
AU  - Fluharty, Meg E
AU  - Bjørngaard, Johan H
AU  - Gabrielsen, Maiken Elvestad
AU  - Skorpen, Frank
AU  - Marioni, Riccardo E
AU  - Campbell, Archie
AU  - Engmann, Jorgen
AU  - Mirza, Saira Saeed
AU  - Loukola, Anu
AU  - Laatikainen, Tiina
AU  - Partonen, Timo
AU  - Kaakinen, Marika
AU  - Ducci, Francesca
AU  - Cavadino, Alana
AU  - Husemoen, Lise Lotte N
AU  - Ahluwalia, Tarunveer Singh
AU  - Jacobsen, Rikke Kart
AU  - Skaaby, Tea
AU  - Ebstrup, Jeanette Frost
AU  - Mortensen, Erik Lykke
AU  - Minica, Camelia C
AU  - Vink, Jacqueline M
AU  - Willemsen, Gonneke
AU  - Marques-Vidal, Pedro
AU  - Dale, Caroline E
AU  - Amuzu, Antoinette
AU  - Lennon, Lucy T
AU  - Lahti, Jari
AU  - Palotie, Aarno
AU  - Räikkönen, Katri
AU  - Wong, Andrew
AU  - Paternoster, Lavinia
AU  - Wong, Angelita Pui-Yee
AU  - Horwood, L John
AU  - Murphy, Michael
AU  - Johnstone, Elaine C
AU  - Kennedy, Martin A
AU  - Pausova, Zdenka
AU  - Paus, Tomáš
AU  - Ben-Shlomo, Yoav
AU  - Nohr, Ellen A
AU  - Kuh, Diana
AU  - Kivimaki, Mika
AU  - Eriksson, Johan G
AU  - Morris, Richard W
AU  - Casas, Juan P
AU  - Preisig, Martin
AU  - Boomsma, Dorret I
AU  - Linneberg, Allan
AU  - Power, Chris
AU  - Hyppönen, Elina
AU  - Veijola, Juha
AU  - Jarvelin, Marjo-Riitta
AU  - Korhonen, Tellervo
AU  - Tiemeier, Henning
AU  - Kumari, Meena
AU  - Porteous, David J
AU  - Hayward, Caroline
AU  - Romundstad, Pål R
AU  - Smith, George Davey
AU  - Munafò, Marcus R
TI  - Investigating the possible causal association of smoking with depression and anxiety using Mendelian randomisation meta-analysis: the CARTA consortium
AID  - 10.1136/bmjopen-2014-006141
DP  - 2014 Oct 01
TA  - BMJ Open
PG  - e006141
VI  - 4
IP  - 10
4099  - http://bmjopen.bmj.com/content/4/10/e006141.short
4100  - http://bmjopen.bmj.com/content/4/10/e006141.full
SO  - BMJ Open2014 Oct 01; 4
AB  - Objectives To investigate whether associations of smoking with depression and anxiety are likely to be causal, using a Mendelian randomisation approach. Design Mendelian randomisation meta-analyses using a genetic variant (rs16969968/rs1051730) as a proxy for smoking heaviness, and observational meta-analyses of the associations of smoking status and smoking heaviness with depression, anxiety and psychological distress. Participants Current, former and never smokers of European ancestry aged ≥16 years from 25 studies in the Consortium for Causal Analysis Research in Tobacco and Alcohol (CARTA). Primary outcome measures Binary definitions of depression, anxiety and psychological distress assessed by clinical interview, symptom scales or self-reported recall of clinician diagnosis. Results The analytic sample included up to 58 176 never smokers, 37 428 former smokers and 32 028 current smokers (total N=127 632). In observational analyses, current smokers had 1.85 times greater odds of depression (95% CI 1.65 to 2.07), 1.71 times greater odds of anxiety (95% CI 1.54 to 1.90) and 1.69 times greater odds of psychological distress (95% CI 1.56 to 1.83) than never smokers. Former smokers also had greater odds of depression, anxiety and psychological distress than never smokers. There was evidence for positive associations of smoking heaviness with depression, anxiety and psychological distress (ORs per cigarette per day: 1.03 (95% CI 1.02 to 1.04), 1.03 (95% CI 1.02 to 1.04) and 1.02 (95% CI 1.02 to 1.03) respectively). In Mendelian randomisation analyses, there was no strong evidence that the minor allele of rs16969968/rs1051730 was associated with depression (OR=1.00, 95% CI 0.95 to 1.05), anxiety (OR=1.02, 95% CI 0.97 to 1.07) or psychological distress (OR=1.02, 95% CI 0.98 to 1.06) in current smokers. Results were similar for former smokers. Conclusions Findings from Mendelian randomisation analyses do not support a causal role of smoking heaviness in the development of depression and anxiety.