Serum 25-hydroxyvitamin D concentration and its determinants in the very old: the Newcastle 85+ Study

• Published in: Osteoporosis international Vol. 27; no. 3; pp. 1199 - 1208
• Main Authors: Hill, T. R., Granic, A., Davies, K., Collerton, J., Martin-Ruiz, C., Siervo, M., Mathers, J. C., Adamson, A. J., Francis, R. M., Pearce, S. H., Razvi, S., Kirkwood, T. B. L., Jagger, C.
• Format: Journal Article
• Language: English
• Published: London Springer London 01-03-2016; Springer Nature B.V
• Subjects: Aged, 80 and over; Blood Specimen Collection - methods; Calcium, Dietary - administration & dosage; Diet - statistics & numerical data; Dietary Supplements; Endocrinology; England - epidemiology; Exercise - physiology; Female; Humans; Longitudinal Studies; Male; Medicine; Medicine & Public Health; Oldest old people; Original Article; Orthopedics; Prevalence; Residence Characteristics; Rheumatology; Risk Factors; Seasons; Studies; Vitamin D; Vitamin D - administration & dosage; Vitamin D - analogs & derivatives; Vitamin D - blood; Vitamin D Deficiency - blood; Vitamin D Deficiency - epidemiology; Vitamin D Deficiency - etiology; Aged 80 and over; Determinants; Newcastle 85+ cohort study; Serum 25-hydroxyvitamin D
• ISSN: 0937-941X; 1433-2965
• DOI: 10.1007/s00198-015-3366-9

Summary
Data on vitamin D status in very old adults are lacking. The aim of this study was to assess 25-hydroxyvitamin D [25(OH)D] concentrations and its predictors in 775 adults aged 85 years old living in North-East England. Low 25(OH)D was alarmingly high during winter/spring months, but its biological significance is unknown.
Introduction
Despite recent concerns about the high prevalence of vitamin D deficiency in much of the British adult and paediatric population, there is a dearth of data on vitamin D status and its predictors in very old adults. The objective of the present study was to describe vitamin D status and its associated factors in a broadly representative sample of very old men and women aged 85 years living in the North East of England (55° N).
Methods
Serum concentrations of 25-hydroxyvitamin D [25(OH)D] were analysed in 775 participants in the baseline phase of the Newcastle 85+ cohort study. Season of blood sampling, dietary, health, lifestyle and anthropometric data were collected and included as potential predictors of vitamin D status in ordinal regression models.
Results
Median serum 25(OH)D concentrations were 27, 45, 43 and 33 nmol/L during spring, summer, autumn and winter, respectively. The prevalence of vitamin D deficiency according to North American Institute of Medicine guidelines [serum 25(OH)D <30 nmol/L] varied significantly with season with the highest prevalence observed in spring (51 %) and the lowest prevalence observed in autumn (23 %;
P
 < 0.001). Reported median (inter-quartile range) dietary intakes of vitamin D were very low at 2.9 (1.2–3.3) μg/day. In multivariate ordinal regression models, non-users of either prescribed or non-prescribed vitamin D preparations and winter and spring blood sampling were associated with lower 25(OH)D concentrations. Dietary vitamin D intake, disability score and disease count were not independently associated with vitamin D status in the cohort.
Conclusion
There is an alarming high prevalence of vitamin D deficiency (<30 nmol/L) in 85-year-olds living in North East England at all times of the year but particularly during winter and spring. Use of vitamin D containing preparations (both supplements and medications) appeared to be the strongest predictor of 25(OH)D concentrations in these very old adults.