title: Increased health risk in subjects with high self-reported seasonality.
abstract: BACKGROUND
  Seasonal variations in mood and behaviour, termed seasonality, are commonly reported in the general population. As a part of a large cross-sectional health survey in Hordaland, Norway, we investigated the relationship between seasonality, objective health measurements and health behaviours.
  
  
  RESULTS
  A total of 11,545 subjects between 40-44 years old participated, completing the Global Seasonality Score, measuring seasonality. Waist/hip circumference, BMI and blood pressure were measured, and blood samples were analyzed for total cholesterol, HDL cholesterol, triglycerides and glucose. Subjects also completed a questionnaire on miscellaneous health behaviours (exercise, smoking, alcohol consumption). Hierarchical linear regression analyses were used to investigate associations between seasonality and objective health measurements, while binary logistic regression was used for analysing associations between seasonality and health behaviours. Analyses were adjusted for sociodemographic factors, month of questionnaire completion and sleep duration. Seasonality was positively associated with high waist-hip-ratio, BMI, triglyceride levels, and in men high total cholesterol. Seasonality was negatively associated with HDL cholesterol. In women seasonality was negatively associated with prevalence of exercise and positively associated with daily cigarette smoking.
  
  
  CONCLUSIONS
  High seasonality was associated with objective health risk factors and in women also with health behaviours associated with an increased risk for cardiovascular disease.
authors.affiliation: Department of Public Health and Primary Health Care, University of Bergen, Bergen, Norway. Nicolas.Oyane@isf.uib.no
authors.forename: Nicolas M
authors.initials: NM
authors.lastname: Øyane
authors.forename: Reidun
authors.initials: R
authors.lastname: Ursin
authors.forename: Ståle
authors.initials: S
authors.lastname: Pallesen
authors.forename: Fred
authors.initials: F
authors.lastname: Holsten
authors.forename: Bjørn
authors.initials: B
authors.lastname: Bjorvatn
mesh_terms: D000328:Adult; D000339:Affect; D002784:Cholesterol / Q000378:metabolism; D015444:Exercise; D005260:Female; D015438:Health Behavior; D006304:Health Status; D006801:Humans; D008297:Male; D009664:Norway; D012306:Risk; D012621:Seasons; D012737:Sex Factors; D012907:Smoking; D011795:Surveys and Questionnaires; D014280:Triglycerides / Q000378:metabolism
chemical_list: D014280:Triglycerides; D002784:Cholesterol