J Clin Endocrinol Metab. 2015 Apr 9:jc20151353. [Epub ahead of print]
Sohl E1, de Jongh RT, Heymans MW, van Schoor NM, Lips P.
1Department of Epidemiology and Biostatistics, EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands
Vitamin D is essential for bone health. In addition, vitamin D has recently been proposed to play a role in the pathophysiology of many chronic diseases. Despite the large amount of studies published on vitamin D, the threshold for a sufficient serum 25(OH)D concentration is still debated and may differ according to outcomes and subgroups.
To estimate thresholds for serum 25(OH)D concentration with respect to different outcomes and for different subgroups.
DESIGN, SETTING AND PARTICIPANTS:
Observational data from the Longitudinal Aging Study Amsterdam were used, an ongoing population-based Dutch cohort study (N=1164, mean (SD) age 75.2 (6.5) years).
MAIN OUTCOME MEASURES:
falling, fractures, hypertension, cardiovascular disease, blood pressure, parathyroid hormone (PTH), grip strength, physical performance, functional limitations, body mass index (BMI) and mortality. To determine thresholds, spline curves were used. Visual inspection and the statistical best fit of the spline regression models were used together to estimate the best estimate of the thresholds.
Thresholds for serum 25(OH)D concentrations in the whole sample ranged from 46 nmol/l (PTH) to 68 nmol/l (hypertension). On average, women, the oldest old (≥75 years) and individuals with high BMI (>25kg/m2), had lower thresholds compared to men, the youngest old (65-75 years) and individuals with low-to-normal BMI (<25kg/m2).
The results indicate that thresholds for serum 25(OH)D may vary according to different outcomes and subgroups. This study does not support the high thresholds (>75 nmol/l) as advised by some experts, and the higher requirements in women, older persons and those with high BMI.
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