title: Vitamin D levels in asymptomatic adults--a population survey in Karachi, Pakistan.
abstract: BACKGROUND
  It is well established that low levels of 25(OH) Vitamin D (<30 ng/dL) are a common finding world over, affecting over a billion of the global population. Our primary objective was to determine the prevalence of vitamin D deficiency and insufficiency in the asymptomatic adult population of Karachi, Pakistan and the demographic, nutritional and co-morbidity characteristics associated with serum vitamin D levels.
  
  
  METHODS
  A cross-sectional population survey was conducted at two spaced out densely populated areas of the city. Serum levels of 25OH vitamin D were measured and GFR as renal function was assessed by using 4 variable MDRD formula.
  
  
  RESULTS
  Our sample of 300 had a median age of 48(interquartile range 38-55) years. The median level of serum vitamin D was 18.8 (IQ range 12.65-24.62) ng/dL. A total of 253 (84.3%) respondents had low levels (<30 ng/dL) of 25OH vitamin D. Serum PTH and vitamin D were negatively correlated (r = -0.176, p = 0.001). The median PTH in the vitamin D sufficiency group was 38.4 (IQ range28.0-48.8)pg/mL compared with 44.4 (IQ range 34.3-56.8) pg/mL in the deficiency group (p = 0.011).The median serum calcium level in the sample was 9.46(IQ range 9.18-9.68) ng/dL. Low serum levels of vitamin D were not associated with hypertension (p = 0.771) or with an elevated spot blood pressure (p = 0.164).In our sample 75(26%) respondents had an eGFR corresponding to stage 2 and stage 3 CKD. There was no significant correlation between levels of vitamin D and eGFR (r = -0.127, p-value = 0.277). Respondents using daily vitamin D supplements had higher 25 OH vitamin D levels (p-value = 0.021).
  
  
  CONCLUSIONS
  We observed a high proportion of the asymptomatic adult population having low levels of vitamin D and subclinical deterioration of eGFR. The specific cause(s) for this observed high prevalence of low 25OH vitamin D levels are not clear and need to be investigated further upon.
authors.affiliation: Medical College, Aga Khan University Hospital, Karachi, Pakistan.
authors.forename: Adil
authors.initials: A
authors.lastname: Sheikh
authors.forename: Zeb
authors.initials: Z
authors.lastname: Saeed
authors.forename: Syed Ali Danial
authors.initials: SA
authors.lastname: Jafri
authors.forename: Iffat
authors.initials: I
authors.lastname: Yazdani
authors.forename: Syed Ather
authors.initials: SA
authors.lastname: Hussain
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D010154:Pakistan / Q000453:epidemiology; D010281:Parathyroid Hormone / Q000097:blood; D011159:Population Surveillance; D018401:Sample Size; D014807:Vitamin D / Q000097:blood*
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D