Abstract
BACKGROUND: Smokers tend to weigh less than never smokers, while successful quitting leads to an increase in body weight. Because smokers and non-smokers may differ in genetic and environmental family background, we analysed data from twin pairs in which the co-twins differed by their smoking behaviour to evaluate if the association between smoking and body mass index (BMI) remains after controlling for family background.
METHODS AND FINDINGS: The international CODATwins database includes information on smoking and BMI measured between 1960 and 2012 from 156,593 twin individuals 18-69 years of age. Individual-based data (230,378 measurements) and data of smoking discordant twin pairs (altogether 30,014 pairwise measurements, 36% from monozygotic [MZ] pairs) were analysed with linear fixed-effects regression models by 10-year periods. In MZ pairs, the smoking co-twin had, on average, 0.57 kg/m2 lower BMI in men (95% confidence interval (CI): 0.49, 0.70) and 0.65 kg/m2 lower BMI in women (95% CI: 0.52, 0.79) than the never smoking co-twin. Former smokers had 0.70 kg/m2 higher BMI among men (95% CI: 0.63, 0.78) and 0.62 kg/m2 higher BMI among women (95% CI: 0.51, 0.73) than their currently smoking MZ co-twins. Little difference in BMI was observed when comparing former smoking co-twins with their never smoking MZ co-twins (0.13 kg/m2, 95% CI 0.04, 0.23 among men; -0.04 kg/m2, 95% CI -0.16, 0.09 among women). The associations were similar within dizygotic pairs and when analysing twins as individuals. The observed series of cross-sectional associations were independent of sex, age, and measurement decade.
CONCLUSIONS: Smoking is associated with lower BMI and smoking cessation with higher BMI. However, the net effect of smoking and subsequent cessation on weight development appears to be minimal, i.e. never more than an average of 0.7 kg/m2.
| Original language | English |
|---|---|
| Article number | e0200140 |
| Pages (from-to) | 1-17 |
| Number of pages | 17 |
| Journal | PLoS ONE |
| Volume | 13 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - 12 Jul 2018 |
Funding
This study was conducted within the CODATwins project (Academy of Finland grant #266592 to KS). Since its origin, the East Flanders Prospective Survey has been partly supported by grants from the Fund of Scientific Research, Flanders and Twins, a non-profit Association for Scientific Research in Multiple Births (Belgium). Data collection and analyses in Finnish twin cohorts have been supported by ENGAGE - European Network for Genetic and Genomic Epidemiology, FP7- HEALTH-F4-2007 (grant agreement number 201413), National Institute of Alcohol Abuse and Alcoholism (grants AA-12502, AA-00145, and AA-09203 to RJ Rose), the Academy of Finland Center of Excellence in Complex Disease Genetics (grant numbers: 213506, 129680), and the Academy of Finland (grants 100499, 205585, 118555, 141054, 265240, 263278 and 264146 to JK). JK also acknowledges support from the Sigrid Juselius Foundation. KS is supported by Osaka University’s International Joint Research Promotion Program. Anthropometric measurements of the Hungarian twins were supported by Medexpert Ltd., Budapest, Hungary. Data collection and research stemming from the Norwegian Twin Registry is supported, in part, from the European Union’s Seventh Framework Programmes ENGAGE Consortium (grant agreement HEALTH-F4- 2007-201413), and BioSHaRE EU (grant agreement HEALTH-F4-2010-261433). The Murcia Twin Registry is supported by Fundación Séneca, Regional Agency for Science and Technology, Murcia, Spain (08633/PHCS/08, 15302/PHCS/10 & 19479/PI/14) and Ministry of Science and Innovation, Spain (PSI2009-11560 & PSI2014-56680-R). The Australian Twin Registry is supported by a Centre of Research Excellence grant (ID 1079102) from the National Health and Medical Research Council administered by the University of Melbourne. The QIMR twin study acknowledges grants from the Australian National Health and Medical Research Council and the Australian Research Council. SM is supported by an Australian National Health and Medical Research Council fellowship (SRFB-1103623). The NAS-NRC Twin Registry acknowledges financial support from the National Institutes of Health grant number R21 AG039572. The Vietnam Era Twin Study of Aging was supported by National Institute of Health grants NIA R01 AG018384, R01 AG018386, R01 AG022381, and R01 AG022982, and, in part, with resources from the VA San Diego Center of Excellence for Stress and Mental Health. The Cooperative Studies Program of the Office of Research & Development of the United States Department of Veterans Affairs has provided financial support for the development and maintenance of the Vietnam Era Twin (VET) Registry. The content of this manuscript is solely the responsibility of the authors and does not necessarily represent the official views of the NIA/ NIH, or the VA. The Colorado Twin Registry is funded by NIDA-funded center grant DA011015 and Longitudinal Twin Study HD10333; BH was supported by 5T32DA017637 and 5T32AG052371. The Osaka University Aged Twin Registry is supported by grants from JSPS KAKENHI JP (23593419, 24792601, 26671010, 24590695, 26293128, 16K15385, 16K15978, 16K15989, 16H03261). The Korean Twin-Family Register was supported by the Global Research Network Program of the National Research Foundation (NRF 2011-220- E00006). SÖ and FA are supported by Kırıkkale University Research Grant: KKU, 2009/43 and TUBITAK grant 114C117. None of the funders including HealthTwiSt GmbH and Pfizer Inc played a role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript and only provided financial support in the form of authors’ salaries, excluding HealthTwiSt GmbH and Pfizer Inc, and/or research materials. The funder HealthTwiSt GmbH did not provide support in the form of salaries for authors (AB). HealthTwiSt GmbH collects data on twin samples and makes these available to academic researchers for a service fee to cover the costs (technical staff salaries and material costs). The funder (Pfizer Inc) did provide support in the form of consultation fees for authors (JK and TK) outside of the submitted work. Lindon Eaves is acknowledged for his contribution to the data collection of the Mid Atlantic Twin Registry.
| Funders | Funder number |
|---|---|
| National Institutes of Health | AG018384, AG022381, R21 AG039572, AG018386, AG022982 |
| National Institute on Alcohol Abuse and Alcoholism | AA-00145, AA-09203, AA-12502 |
| National Institute on Aging | T32AG052371 |
| Myelin Project | #266592 |
| Institute for Advanced Study | HD10333 |
| Fundación Séneca | 08633/PHCS/08, 15302/PHCS/10, 19479/PI/14 |
| National Research Foundation | 2011-220- E00006 |
| National Health and Medical Research Council | SRFB-1103623 |
| Japan Society for the Promotion of Science | 16K15978, 16K15989, 24590695, 16H03261, 16K15385, 26293128, 23593419, 26671010, 24792601 |
| Academy of Finland | 141054, 264146, 205585, 118555, 263278, 265240, 100499, 213506, 129680 |
| Osaka University | |
| Pamukkale Üniversitesi | KKU, 2009/43 |
| Türkiye Bilimsel ve Teknolojik Araştirma Kurumu | 114C117 |
| Ministerio de Ciencia e Innovación | PSI2009-11560, PSI2014-56680-R |
| Seventh Framework Programme | HEALTH-F4- 2007-201413 |
| Center for Genomic Epidemiology | 201413, FP7- HEALTH-F4-2007 |
| BHF Centre of Research Excellence, Oxford | 1079102 |
| Internationale Bodensee-Hochschule | 5T32DA017637, 5T32AG052371 |
| Erzincan Üniversitesi | HEALTH-F4-2010-261433 |
| National Institute of Development Administration | DA011015 |
Cohort Studies
- Netherlands Twin Register (NTR)
