title: Longitudinal study of diet quality and change in asthma symptoms in adults, according to smoking status.
abstract: It has been hypothesised that increased asthma prevalence in westernised countries is associated with changes in lifestyle factors, including a poorer diet. However, little is known regarding the association between diet quality and asthma. In the diet-asthma association, the role of BMI as a potential mediator needs clarification; moreover, potential effect modification by non-diet sources of oxidants, such as smoking, merits investigation. We investigated the association between diet quality and change in asthma symptoms, as well as assessed effect modification by smoking, while accounting for BMI as a potential mediator. Using data from the French prospective Epidemiological study on the Genetics and Environment of Asthma study, we assessed diet quality using the Alternate Healthy Eating Index 2010 (AHEI-2010) at baseline and change in asthma symptoms (stable (reference), worsening, improved; mean follow-up time: 7 years). Mediation analysis was used to disentangle total and direct effects and the indirect effect mediated by BMI. The analyses included 969 adults (mean age 43 years; 49 % men; 42 % ever asthma). We observed a significant interaction between smoking and AHEI-2010 on change in asthma symptoms (P for interaction=0·04). Among never smokers (n 499), we observed a positive total effect (multivariable OR 1·39; 95 % CI 1·07, 1·80) and a positive direct effect (OR 1·41; 95 % CI 1·09, 1·80) of the AHEI-2010 (per ten-point increment) on improved symptoms. No indirect effect mediated through BMI was observed (OR 0·99; 95 % CI 0·91, 1·07). Among former and current smokers, all effects were statistically non-significant. Better diet quality was associated with improved asthma symptoms over time in never smokers, independently of BMI.
authors.affiliation: 1Inserm, U1168, VIMA: Aging and Chronic Diseases,Epidemiological and Public Health Approaches,Villejuif F-94807,France.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Li
authors.affiliation: 4Université Paris 13, Equipe de Recherche en Epidémiologie Nutritionnelle (EREN),Centre de recherche en Epidémiologie et Statistiques Sorbonne Paris Cité, Inserm (U1153),Inra (U1125),Cnam, COMUE Sorbonne Paris Cité,Bobigny F-93000,France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Kesse-Guyot
authors.affiliation: 1Inserm, U1168, VIMA: Aging and Chronic Diseases,Epidemiological and Public Health Approaches,Villejuif F-94807,France.
authors.forename: Orianne
authors.initials: O
authors.lastname: Dumas
authors.affiliation: 5ISGlobal, Centre for Research in Environmental Epidemiology (CREAL),Barcelona E-08003,Spain.
authors.forename: Judith
authors.initials: J
authors.lastname: Garcia-Aymerich
authors.affiliation: 8Inserm, U1152,Physiopathologie et épidémiologie des maladies respiratoires, équipe Epidémiologie,Paris F-75018,France.
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Leynaert
authors.affiliation: 10Clinique Universitaire de Pneumologie, Pôle Thorax et Vaisseaux,Centre Hospitalier Universitaire (CHU) de Grenoble,Grenoble F-38043,France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Pison
authors.affiliation: 1Inserm, U1168, VIMA: Aging and Chronic Diseases,Epidemiological and Public Health Approaches,Villejuif F-94807,France.
authors.forename: Nicole
authors.initials: N
authors.lastname: Le Moual
authors.affiliation: 13Instituto Nacional De Salud Publica,Cuernavac 62508, Mexico; currently at International Agency for Research on Cancer,Lyon F-69008,France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Romieu
authors.affiliation: 14Inserm, Institut Albert Bonniot (IAB),Team of Environmental Epidemiology Applied to Reproduction and Respiratory Health, Grenoble F-38042,France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Siroux
authors.affiliation: 17Department of Emergency Medicine,Massachusetts General Hospital, Harvard Medical School,Boston,MA 02114,USA.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Camargo
authors.affiliation: 1Inserm, U1168, VIMA: Aging and Chronic Diseases,Epidemiological and Public Health Approaches,Villejuif F-94807,France.
authors.forename: Rachel
authors.initials: R
authors.lastname: Nadif
authors.affiliation: 1Inserm, U1168, VIMA: Aging and Chronic Diseases,Epidemiological and Public Health Approaches,Villejuif F-94807,France.
authors.forename: Raphaëlle
authors.initials: R
authors.lastname: Varraso
mesh_terms: D000328:Adult; D001249:Asthma / Q000150:complications* / Q000178:diet therapy; D015992:Body Mass Index; D004032:Diet / Q000592:standards; D005247:Feeding Behavior; D005260:Female; D005602:France; D015438:Health Behavior; D006801:Humans; D008019:Life Style; D008137:Longitudinal Studies; D008297:Male; D016017:Odds Ratio; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking
keywords:  AHEI-2010 Alternate Healthy Eating Index 2010;  EGEA Epidemiological study on the Genetics and Environment of Asthma;  SU.VI.MAX SUpplémentation en VItamines et Minéraux AntioXydants; Asthma; BMI; Diet scores; Mediation analysis; Smoking