title: Low socio-economic status is a newly identified independent risk factor for poor vitamin D status in severely obese adults.
abstract: Hypovitaminosis D is very prevalent, especially in the obese population. However, the degree of severity and the parameters involved in vitamin D deficiency in this population are still unclear. The present study aimed to identify, from among the factors known to influence vitamin D status in a healthy population, those impacting the same parameter in obese population.
  
  
  
  Serum 25-OH-D concentration was measured in 564 patients with class III obesity [i.e. severe and morbid obesity; mean (SD) body mass index (BMI) 42.04 (6.92) kg m-2] and their demographic, clinical, biological, anthropometric, dietary and socio-economic data were collected.
  
  
  
  We observed that 96% of the obese patients had serum 25-OH-D lower than 30 ng mL-1. Severe vitamin D deficiency (serum 25-OH-D concentration <10 ng mL-1) affected 35% of this population. We found an inverse relationship between 25-OH-D levels and BMI (P = 0.012), fat mass (P = 0.041), metabolic syndrome (P < 0.0001), fasting blood glucose (P = 0.023), homeostasis model assessment for insulin resistance (P = 0.008), waist circumference (P = 0.001), and fasting blood triglycerides (P = 0.002) and C-reactive protein (P = 0.005). Low socio-economic status independently increased the risk of severe vitamin D deficiency [odds ratio (OR) = 1.98; 95% confidence interval (CI) 1.25-3.13], especially in the autumn-winter season (OR = 2.94; 95% CI 1.98-4.36), morbid obesity (OR = 3.19; 95% CI 1.49-6.82), metabolic syndrome (OR = 1.6; 95% CI 1.06-2.42) and inflammation (OR = 1.03; 95% CI 1.01-1.06).
  
  
  
  Vitamin D deficiency is extremely common among obese patients, and the prevalence of severe deficiency is high. The association of adiposity, high body mass index, metabolic syndrome and inflammation with vitamin D status is marked, whereas low socio-economic status appears to be a major risk factor for severe vitamin D deficiency, suggesting that vitamin D deficiency may at least in part be responsible for the greater health vulnerability of populations with low socio-economic status.
authors.affiliation: CHU Clermont-Ferrand, Service Nutrition Clinique, Clermont-Ferrand, France.
authors.forename: J
authors.initials: J
authors.lastname: Léger-Guist'hau
authors.affiliation: INRA, UMR 1019, UNH, CRNH Auvergne, Clermont-Ferrand, France.|Unité de Nutrition Humaine, Clermont Université, Université d'Auvergne, Clermont-Ferrand, France.
authors.forename: C
authors.initials: C
authors.lastname: Domingues-Faria
authors.affiliation: CHU Clermont-Ferrand, Service Nutrition Clinique, Clermont-Ferrand, France.
authors.forename: M
authors.initials: M
authors.lastname: Miolanne
authors.affiliation: CHU Clermont-Ferrand, Santé Publique, Clermont-Ferrand, France.|Clermont Université, Université d'Auvergne Clermont, Clermont-Ferrand, France.
authors.forename: F
authors.initials: F
authors.lastname: Peyrol
authors.affiliation: CHU Clermont-Ferrand, Santé Publique, Clermont-Ferrand, France.|Clermont Université, Université d'Auvergne Clermont, Clermont-Ferrand, France.
authors.forename: L
authors.initials: L
authors.lastname: Gerbaud
authors.affiliation: CHU Clermont-Ferrand, Santé Publique, Clermont-Ferrand, France.|Clermont Université, Université d'Auvergne Clermont, Clermont-Ferrand, France.
authors.forename: B
authors.initials: B
authors.lastname: Perreira
authors.affiliation: CHU Clermont-Ferrand, Service de Biochimie, Clermont-Ferrand, France.
authors.forename: R
authors.initials: R
authors.lastname: Minet-Quinard
authors.affiliation: CHU Clermont-Ferrand, Service de Biochimie, Clermont-Ferrand, France.
authors.forename: V
authors.initials: V
authors.lastname: Sapin
authors.affiliation: INRA, UMR 1019, UNH, CRNH Auvergne, Clermont-Ferrand, France.|Unité de Nutrition Humaine, Clermont Université, Université d'Auvergne, Clermont-Ferrand, France.
authors.forename: S
authors.initials: S
authors.lastname: Walrand
authors.affiliation: CHU Clermont-Ferrand, Service Nutrition Clinique, Clermont-Ferrand, France.|INRA, UMR 1019, UNH, CRNH Auvergne, Clermont-Ferrand, France.|Unité de Nutrition Humaine, Clermont Université, Université d'Auvergne, Clermont-Ferrand, France.
authors.forename: Y
authors.initials: Y
authors.lastname: Boirie
mesh_terms: D050154:Adiposity; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000378:metabolism; D004032:Diet; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000453:epidemiology*; D008875:Middle Aged; D009752:Nutritional Status; D009765:Obesity / Q000097:blood*; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D012959:Socioeconomic Factors; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*; D055105:Waist Circumference
chemical_list: D001786:Blood Glucose; D014807:Vitamin D; D002097:C-Reactive Protein
keywords: deprivation; obesity; vitamin D deficiency