Low socio-economic status is a newly identified independent risk factor for poor vitamin D status in severely obese adults

J Hum Nutr Diet. 2017 Apr;30(2):203-215. doi: 10.1111/jhn.12405. Epub 2016 Aug 15.

Abstract

Background: 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.

Methods: 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.

Results: 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).

Conclusions: 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.

Keywords: deprivation; obesity; vitamin D deficiency.

MeSH terms

  • Adiposity
  • Adult
  • Blood Glucose / metabolism
  • Body Mass Index
  • C-Reactive Protein / metabolism
  • Diet
  • Female
  • Humans
  • Insulin Resistance
  • Male
  • Metabolic Syndrome / blood
  • Metabolic Syndrome / epidemiology*
  • Middle Aged
  • Nutritional Status*
  • Obesity / blood*
  • Prevalence
  • Retrospective Studies
  • Risk Factors
  • Socioeconomic Factors*
  • Vitamin D / blood*
  • Vitamin D Deficiency / blood
  • Vitamin D Deficiency / epidemiology*
  • Waist Circumference

Substances

  • Blood Glucose
  • Vitamin D
  • C-Reactive Protein