Thromb Haemost 2017; 117(01): 158-163
DOI: 10.1160/TH16-07-0551
Stroke, Systemic or Venous Thromboembolism
Schattauer GmbH

Serum 25-hydroxyvitamin D and the risk of stroke in Hong Kong Chinese

Raymond Y. H. Leung*
1   Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
2   Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
,
Yi Han*
1   Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
,
Chor-Wing Sing
1   Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
,
Bernard M. Y. Cheung
2   Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
3   The State Key Laboratory of Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
,
Ian C. K. Wong
1   Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
5   Research Department of Practice and Policy, UCL School of Pharmacy, London, United Kingdom
,
Kathryn C. B. Tan
2   Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
,
Annie W. C. Kung
2   Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
,
Ching-Lung Cheung
1   Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
3   The State Key Laboratory of Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
4   Centre for Genomic Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
› Author Affiliations

Financial support: This project was funded by HMRF (HKU-12132451), HKSAR, China.
Further Information

Publication History

Received: 21 July 2016

Accepted after major revision: 30 September 2016

Publication Date:
01 December 2017 (online)

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Summary

Low vitamin D levels have been associated with various cardiovascular diseases; however, whether it is associated with stroke remains inconclusive. We aimed to evaluate the association between serum 25-hydroxyvitamin D and risk of stroke. We conducted a cohort study consisting of 3,458 participants from the Hong Kong Osteoporosis Study aged ≥45 at baseline, examined between 1995 and 2010 and followed up using electronic medical records. Ischaemic and haemorrhagic stroke were defined using the ICD-9 code. In multivariable Cox-proportional hazard regression, quintiles 1 and 4 were significantly associated with increased risk of stroke when compared to the highest quintile (Quintile 1: HR, 1.78; 95 % CI, 1.16–2.74 and quintile 4: HR, 1.61; 95 % CI, 1.07–2.43). A similar association was observed in both men and women. In subgroup analysis, the association was specifically observed for ischaemic stroke, but not haemorrhagic stroke. Using a penalized regression spline, the association between vitamin D and risk of stroke was in a reverse J-shape, with the lowest risk of stroke being observed at 25(OH)D levels between 70 and 80 nmol/l. In conclusion, a low vitamin D level is associated with increased risk of ischaemic stroke; however, whether high vitamin D level is also associated with increased risk of stroke requires further study.

Supplementary Material to this article is available at www.thrombosis-online.com.

* These authors contributed equally.