Could vitamin D reduce obesity-associated inflammation? Observational and Mendelian randomization study
Year: 2020
Type: article
Study design: Observational Study
Abstract: BACKGROUND: Obesity is associated with inflammation but the role of vitamin D in this process is not clear. OBJECTIVES: We aimed to assess the associations between serum 25-hydroxyvitamin D [25(OH)D], BMI, and 16 inflammatory biomarkers, and to assess the role of vitamin D as a potential mediator in the association between higher BMI and inflammation. METHODS: Northern Finland Birth Cohort 1966 (NFBC1966) 31-y data on 3586 individuals were analyzed to examine the observational associations between BMI, 25(OH)D, and 16 inflammatory biomarkers. Multivariable regression analyses and 2-sample regression-based Mendelian randomization (MR) mediation analysis were performed to assess any role of vitamin D in mediating a causal effect of BMI on inflammatory biomarkers [soluble intercellular adhesion molecule 1 (sICAM-1), high sensitivity C-reactive protein (hs-CRP), and α1-acid glycoprotein (AGP)] for which observational associations were detected. For MR, genome-wide association study summary results ranging from 5163 to 806,834 individuals were used for biomarkers, 25(OH)D, and BMI. Findings were triangulated with a literature review of vitamin D supplementation trials. RESULTS: In NFBC1966, mean BMI (kg/m2) was 24.8 (95% CI: 24.7, 25.0) and mean 25(OH)D was 50.3 nmol/L (95% CI: 49.8, 50.7 nmol/L). Inflammatory biomarkers correlated as 4 independent clusters: interleukins, adhesion molecules, acute-phase proteins, and chemokines. BMI was positively associated with 9 inflammatory biomarkers and inversely with 25(OH)D (false discovery rate < 0.05). 25(OH)D was inversely associated with sICAM-1, hs-CRP, and AGP, which were positively associated with BMI. The MR analyses showed causal association of BMI on these 3 inflammatory biomarkers. There was no observational or MR evidence that circulating 25(OH)D concentrations mediated the association between BMI and these 3 inflammatory markers. Review of randomized controlled trials (RCTs) supported our findings showing no impact of vitamin D supplementation on inflammatory biomarkers. CONCLUSIONS: The findings from our observational study and causal MR analyses, together with data from RCTs, do not support a beneficial role of vitamin D supplementation on obesity-related inflammation.
DOI: 10.1093/ajcn/nqaa056
Authors: Saranya Palaniswamy, Dipender Gill, N Maneka De Silva, Estelle Lowry, Jari Jokelainen, Toni Karhu, Shivaprakash J Mutt, Abbas Dehghan, Eeva Sliz, Daniel I Chasman, Markku Timonen, Heimo Viinamäki, Sirkka Keinänen-Kiukaanniemi, Elina Hyppönen, Karl-Heinz Herzig, Sylvain Sebert, Marjo-Riitta Järvelin
Institutions: MRC Centre for Environment and Health, Imperial College London, University of Oulu, Oulu University Hospital, Brigham and Women's Hospital, Harvard University, University of Eastern Finland, Kuopio University Hospital, University of South Australia, South Australian Health and Medical Research Institute, Poznan University of Medical Sciences, Brunel University of London
Language: English
Topic: Vitamin D Research Studies
Subfield: Pathology and Forensic Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $5,200
Funders: Yrjö Jahnssonin Säätiö, Joint Programming Initiative A healthy diet for a healthy life, Imperial College London, European Commission, Academy of Finland, Suomen Kulttuurirahasto, Juho Vainion Säätiö, Päivikki ja Sakari Sohlbergin Säätiö, Emil Aaltosen Säätiö, Orionin Tutkimussäätiö, Directorate for Biological Sciences, Horizon 2020 Framework Programme, Medical Research Council, National Health and Medical Research Council, Biocenter, University of Oulu
Awards: G1938092250, Understanding the dynamic determinants of glucose homeostasis and social capability to promote Healthy and active aging, G2772632885, G3105035837, G3257889090, G3414747767, Early-life stressors and LifeCycle health, G3511822935, G3705522972, G4129240715, G434337789, G4586264007, G490277885, G4937468798, G5374962834, G609373764, The dark side of vitamin D supplementation, Family-based intervention to improve healthy lifestyle and prevent Type 2 Diabetes amongst South Asians with central obesity and prediabetes, G7881413137
OpenAlex ID: W3013984341