title: Is the Association between Vitamin D and Cardiovascular Disease Risk Confounded by Obesity? Evidence from the Andhra Pradesh Children and Parents Study (APCAPS).
abstract: BACKGROUND
  Evidence of an association between serum vitamin D and cardiovascular disease risk is inconsistent and comes predominantly from studies in high-income settings. We assessed the association between serum levels of 25-hydroxyvitamin D3 (25(OH)D) and cardiovascular disease risk factors in a population of young Indian adults.
  
  
  METHODS
  Cross-sectional analyses of data from APCAPS (Andhra Pradesh Children and Parents Study); a prospective birth cohort study in rural south India. Participants were 1038 (40.3% females) adults aged 18-24 years. Main outcome measures were blood pressures, fasting serum lipids (cholesterols and triglycerides), fasting glucose, insulin, measures of arterial stiffness (aortic augmentation index and aortic pulse wave velocity (aPWV)), carotid intima-media thickness, body mass index (BMI) and body fat (dual X-ray absorptiometry).
  
  
  RESULTS
  Vitamin D deficiency (≤20ng/ml) was observed in 41.1% of this lean (mean BMI: 19.5) and active (mean minutes of moderate or vigorous physical activity per day: 186) population. Vitamin D deficiency was associated with higher median body fat in both males (15.9% body fat in vitamin D deficient males vs. 14.6% in non-deficient males, p<0.05) and females (29.1% body fat in vitamin D deficient females vs. 27.8% in non-deficient females, p<0.05) but no associations were observed between vitamin D deficiency and mean BMI or median fat mass index (FMI). Except a weak inverse association with fasting insulin in males, there was no clear association between serum vitamin D levels and cardiovascular disease risk factors in fully adjusted models.
  
  
  CONCLUSIONS
  We did not find clear evidence for an association between serum vitamin D levels and cardiovascular disease risk factors. Our results, consistent with the limited evidence from randomised trials of vitamin D supplementation and Mendelian randomisation experiments, suggest that the postulated link between serum vitamin D and cardiovascular disease may be non-causal. Instead, it may be attributable to confounding by lifestyle factors such as obesity and physical inactivity which may provide more fruitful targets for cardiovascular disease prevention.
authors.affiliation: Department of Non-Communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Christopher Paul
authors.initials: CP
authors.lastname: Baker
authors.affiliation: National Institute of Nutrition, Hyderabad, India.
authors.forename: Bharati
authors.initials: B
authors.lastname: Kulkarni
authors.affiliation: National Institute of Nutrition, Hyderabad, India.
authors.forename: K V
authors.initials: KV
authors.lastname: Radhakrishna
authors.affiliation: National Institute of Nutrition, Hyderabad, India.
authors.forename: M S
authors.initials: MS
authors.lastname: Charyulu
authors.affiliation: Department of Non-Communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: John
authors.initials: J
authors.lastname: Gregson
authors.affiliation: Department of Non-Communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Mika
authors.initials: M
authors.lastname: Matsuzaki
authors.affiliation: School of Experimental Psychology, University of Bristol, Bristol, United Kingdom.
authors.forename: Amy E
authors.initials: AE
authors.lastname: Taylor
authors.affiliation: Centre for Chronic Disease Control, New Delhi, India.
authors.forename: Dorairaj
authors.initials: D
authors.lastname: Prabhakaran
authors.affiliation: National Institute of Nutrition, Hyderabad, India.
authors.forename: Raja Sriswan
authors.initials: RS
authors.lastname: Mamidi
authors.affiliation: Childhood Nutrition Research Centre, University College London Institute of Child Health, London, United Kingdom.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Wells
authors.affiliation: Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Ian
authors.initials: I
authors.lastname: Wilkinson
authors.affiliation: Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Carmel
authors.initials: C
authors.lastname: McEniery
authors.affiliation: Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, United Kingdom.
authors.lastname: Yasmin
authors.affiliation: School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom.
authors.forename: George
authors.initials: G
authors.lastname: Davey Smith
authors.affiliation: School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom.
authors.forename: Yoav
authors.initials: Y
authors.lastname: Ben-Shlomo
authors.affiliation: Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Hannah
authors.initials: H
authors.lastname: Kuper
authors.affiliation: Department of Non-Communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Kinra
mesh_terms: D000293:Adolescent; D002318:Cardiovascular Diseases / Q000097:blood* / Q000150:complications / Q000453:epidemiology*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000150:complications*; D012307:Risk Factors; D014807:Vitamin D / Q000097:blood*; D055815:Young Adult
chemical_list: D014807:Vitamin D