Seasonality of vitamin D status in older people in Southern Germany: implications for assessment

• Published in: Age and ageing 2013-05, Vol.42 (3), p.404-408
• Main Authors: Klenk, Jochen, Rapp, Kilian, Denkinger, Michael Dieter, Nagel, Gabriele, Nikolaus, Thorsten, Peter, Richard, Koenig, Wolfgang, Böhm, Bernhard Otto, Rothenbacher, Dietrich
• Format: Article
• Language: English
• Subjects: Age; Age Factors; Aged; Aged, 80 and over; Alfacalcidol; Biomarkers - blood; Calcifediol; Cross-Sectional Studies; Daylight; Demographic aspects; Elderly; Female; Food and nutrition; Germany; Germany - epidemiology; Health aspects; Humans; Influence; Linear Models; Male; Older people; Photoperiod; Radiation; Seasonal variations (Diseases); Seasons; Serum; Sunlight; Time Factors; Vitamin D; Vitamin D - analogs & derivatives; Vitamin D - blood; Vitamin D Deficiency - blood; Vitamin D Deficiency - epidemiology; Vitamin deficiency
• ISSN: 0002-0729; 1468-2834
• DOI: 10.1093/ageing/aft042

from a clinical and public health perspective, it is important to understand the influence of seasonality on the serum vitamin D level to adequately assess and interpret an individual measurement. Therefore, the aim of this study was to analyse the effects of seasonal conditions on 25-hydroxyvitamin D (25(OH)D) serum levels in a population-based cohort of older people. between March 2009 and April 2010 the 25(OH)D serum level was assessed in 1,418 community-dwelling individuals living in Germany aged ≥65 years (56.7% men) with no subscribed vitamin D supplementation. Least-square means of monthly 25(OH)D serum levels with 95% confidence intervals (CI) were estimated, adjusted for gender, age and body mass index. Additionally, the proportion of vitamin deficiency (