title: Association between smoking and total energy expenditure in a multi-country study.
abstract: BACKGROUND
  The association between smoking and total energy expenditure (TEE) is still controversial. We examined this association in a multi-country study where TEE was measured in a subset of participants by the doubly labeled water (DLW) method, the gold standard for this measurement.
  
  
  METHODS
  This study includes 236 participants from five different African origin populations who underwent DLW measurements and had complete data on the main covariates of interest. Self-reported smoking status was categorized as either light (<7 cig/day) or high (≥7 cig/day). Lean body mass was assessed by deuterium dilution and physical activity (PA) by accelerometry.
  
  
  RESULTS
  The prevalence of smoking was 55% in men and 16% in women with a median of 6.5 cigarettes/day. There was a trend toward lower BMI in smokers than non-smokers (not statistically significant). TEE was strongly correlated with fat-free mass (men: 0.70; women: 0.79) and with body weight (0.59 in both sexes). Using linear regression and adjusting for body weight, study site, age, PA, alcohol intake and occupation, TEE was larger in high smokers than in never smokers among men (difference of 298 kcal/day, p = 0.045) but not among women (162 kcal/day, p = 0.170). The association became slightly weaker in men (254 kcal/day, p = 0.058) and disappeared in women (-76 kcal/day, p = 0.380) when adjusting for fat-free mass instead of body weight.
  
  
  CONCLUSIONS
  There was an association between smoking and TEE among men. However, the lack of an association among women, which may be partly related to the small number of smoking women, also suggests a role of unaccounted confounding factors.
authors.affiliation: Department of Epidemiology and Biostatistics, University of California, San Francisco, CA 94158 USA ; Institute of Social and Preventive Medicine, Lausanne University Hospital, Lausanne, Switzerland.
authors.forename: Semira
authors.initials: S
authors.lastname: Gonseth
authors.affiliation: Department of Public Health Sciences, Stritch School of Medicine, Loyola University Chicago, Maywood, IL USA.
authors.forename: Lara
authors.initials: L
authors.lastname: Dugas
authors.affiliation: NCD Section, Ministry of Health, Victoria, Republic of Seychelles.
authors.forename: Barathi
authors.initials: B
authors.lastname: Viswanathan
authors.affiliation: Tropical Medicine Research Institute, University of the West Indies, Kingston, Jamaica.
authors.forename: Terrence
authors.initials: T
authors.lastname: Forrester
authors.affiliation: Research Unit for Exercise Science and Sports Medicine, University of Cape Town, Cape Town, South Africa.
authors.forename: Vicki
authors.initials: V
authors.lastname: Lambert
authors.affiliation: Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
authors.forename: Jacob
authors.initials: J
authors.lastname: Plange-Rhule
authors.affiliation: Department of Public Health Sciences, Stritch School of Medicine, Loyola University Chicago, Maywood, IL USA.
authors.forename: Ramon
authors.initials: R
authors.lastname: Durazo-Arvizu
authors.affiliation: Department of Public Health Sciences, Stritch School of Medicine, Loyola University Chicago, Maywood, IL USA.
authors.forename: Amy
authors.initials: A
authors.lastname: Luke
authors.affiliation: Department of Nutritional Sciences, University of Wisconsin, Madison, WI USA.
authors.forename: Dale A
authors.initials: DA
authors.lastname: Schoeller
authors.affiliation: Institute of Social and Preventive Medicine, Lausanne University Hospital, Lausanne, Switzerland ; NCD Section, Ministry of Health, Victoria, Republic of Seychelles.
authors.forename: Pascal
authors.initials: P
authors.lastname: Bovet
keywords: Accelerometer; Body mass index; Body weight; Doubly labeled water; Physical activity; Smoking; Total energy expenditure