Low wintertime pre-diagnostic vitamin D status is associated with an increased risk of internal malignancies in kidney transplant recipientsElectronic supplementary information (ESI) available. See DOI: 10.1039/c7pp00404d

• Main Authors: de Gruijl, Frank R, Wolterbeek, Ron, Pavel, Stan, de Fijter, Johan W, Hamdy, Neveen A. T, Bouwes Bavinck, Jan Nico
• Format: Journal Article
• Published: 05.12.2018
• ISSN: 1474-905X; 1474-9092
• DOI: 10.1039/c7pp00404d

Low serum 25-hydroxyvitamin D (25OHD) concentrations have been associated with increased cancer risk, but the relative importance of seasonality, i.e. high summer concentrations versus low winter concentrations, is unclear. We investigated this issue in a high risk group: kidney transplant recipients with known increased risk of cancer and low vitamin D statuses. We examined the relationship between registered concentrations of 25OHD binned by quarter and subsequent risk of internal malignancy or cutaneous squamous cell carcinoma in 1112 kidney transplant recipients. Hazard ratios for internal malignancies were significantly increased with lower pre-diagnostic 25OHD concentrations in the first quarter of the year (January-March); a 1.4 fold increase (95%CI 1.1;1.7) per 10 nmol L −1 decrease in 25OHD. Except for women in April-June (1.3 (1.01;1.7) per 10 nmol L −1 decrease) pre-diagnostic 25OHD concentrations in the other quarters were not statistically significantly associated with internal malignancies. Higher 25OHD concentrations tended to be associated with the development of cutaneous squamous cell carcinomas, independent of the time of the year. Our study indicates that low wintertime 25OHD concentrations are associated with an increased risk of internal malignancies and that transplant recipients may benefit from wintertime vitamin D supplementation. Our findings need further corroboration, but suggest that the lowest concentrations of vitamin D, which occur in winter, are important for the risk of internal malignancies. Kidney transplant recipients with the lowest wintertime vitamin D levels appear to run the highest risk of internal malignancies. The effect was strongest in women.